CHAPTER- 1

INTRODUCTION OF LIFT

1.1. Introduction:

The elevator (or lift in the Commonwealth excluding Canada) is a type of vertical transport equipment that efficiently moves people or goods between floors (levels, decks) of a building, vessel or other structures. Elevators are generally powered by electric motors that either drive traction cables or counterweight systems like a hoist, or pump hydraulic fluid to raise a cylindrical piston like a jack.

In agriculture and manufacturing, an elevator is any type of conveyor device used to lift materials in a continuous stream into bins or silos. Several types exist, such as the chain and bucket elevator, grain auger screw conveyor using the principle of Archimedes' screw, or the chain and paddles/forks of hay elevators.

Lift is most commonly associated with the wing of a fixed-wing aircraft, although lift is also generatedby propellers, kites, helicopterrotors, rudders, seals and keels on sailboats, hydrofoils, wings on auto racing cars, wind turbines and other streamlined objects. While the common meaning of the word "lift" assumes that lift opposes gravity, lift in its technical sense can be in any direction since it is defined with respect to the direction of flow rather than to the direction of gravity.

When an aircraft is flying straight and level (cruise) most of the lift opposes gravity. However, when an aircraft is climbing, descending, or banking in a turn the lift is tilted with respect to the vertical. Lift may also be entirely downwards in some aerobatic manoeuvres, or on the wing on a racing car. In this last case, the term down force is often used. Lift may also be horizontal, for instance on a sail on a sail boat.

An airfoil is a streamlined shape that is capable of generating significantly more lift than drag. Non-streamlined objects such as bluff bodies and flat plates may also generate lift when moving relative to the fluid, but will have a higher drag coefficient dominated by pressure drag.

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1.2. Principle of Lift:

The concept of an elevator is incredibly simple -- it's just a compartment attached to a lifting system. Tie a piece of rope to a box, and you've got a basic elevator.

Of course, modern passenger and freight elevators are a lot more elaborate than this. They need advanced mechanical systems to handle the substantial weight of the elevator car and its cargo. Additionally, they need control mechanisms so passengers can operate the elevator, and they need safety devices to keep everything running smoothly.

There are two major elevator designs in common use today:

Hydraulic elevators  Roped elevators.

Hydraulic elevator systems lift a car using a hydraulic ram, a fluid-driven piston mounted inside a cylinder. 

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CHAPTER- 2

ELEVATORS

2.1. Introduction of Elevators:

2.1.1. Origin:

The first reference to an elevator is in the works of the Roman architect  Vitruvius, who reported that Archimedes (c. 287 BC – c. 212 BC) built his first elevator probably in 236 BC. In some literary sources of later historical periods, elevators were mentioned as cabs on a hemp rope and powered by hand or by animals. It is supposed that elevators of this type were installed in the Sinai monastery of Egypt.

Ancient and medieval elevators used drive systems based on hoists or winders. The invention of a system based on the screw drive was perhaps the most important step in elevator technology since ancient times, leading to the creation of modern passenger elevators. The first screw drive elevator was built by Ivan Kulibin and installed in Winter Palace in 1793. Several years later another of Kulibin's elevators was installed in Arkhangelskoye near Moscow. In 1823, an "ascending room" made its debut in London.

Starting in the coal mines, by the mid-19th century elevators were operated with steam power and were used for moving goods in bulk in mines and factories In 1823 in London, an "ascending room" was built and operated by two architects, Burton and Hormer. It was designed as a tourist attraction to elevate paying customers to a panoramic view of the city. The "Teagle" - a belt-driven elevator with a counterweight was developed in 1835 by Frost and Stutt in England.

The hydraulic crane was invented by Sir William Armstrong in 1846 for use primarily at the docks of London for loading cargo. These quickly supplanted the earlier steam driven lifts as they were able to leverage Pascal's law for a much greater force. They used a plunger below the car to raise or lower the elevator. A pump applied water pressure to a steel column inside a vertical cylinder. Increasing the pressure caused the elevator to ascend. The elevator also used a system of counterbalancing so that the plunger did not have to lift the entire weight of the elevator and its load. The plunger, however, was not practical for tall buildings, because it required a pit as deep below the building as the building was tall. Later, a rope-geared elevator with multiple pulleys was developed.

Henry Waterman of New York is credited with inventing the "standing rope control" for an elevator in 1850. Elisha Otis' elevator patent drawing, 15 January 1861.

In 1852, Elisha Otis introduced the safety elevator, which prevented the fall of the cab if the cable broke. The design of the Otis safety elevator is somewhat similar to one type still used

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today. A governor device engages knurled roller(s), locking the elevator to its guides should the elevator descend at excessive speed. He demonstrated it at the New York exposition in the Crystal Palace in a dramatic, death-defying presentation in 1854.

On March 23, 1857 the first Otis passenger elevator was installed at  488 Broadway in New York City. The first elevator shaft preceded the first elevator by four years. Construction for Peter Cooper's Cooper Union Foundation building in New York began in 1853. An elevator shaft was included in the design, because Cooper was confident that a safe passenger elevator would soon be invented.  The shaft was cylindrical because Cooper felt it was the most efficient design. Later, Otis designed a special elevator for the building. Today the Otis Elevator Company, now a subsidiary of United Technologies Corporation, is the world's largest manufacturer of vertical transport systems.

The Equitable Life Building completed in 1870 in New York City was the first office building to have passenger elevators. The first electric elevator was built by Werner von Siemens in 1880 in Germany.

The safety and speed of electric elevators were significantly enhanced by Frank Sprague who added floor control, automatic elevators, acceleration control of cars, and safeties. His elevator ran faster and with larger loads than hydraulic or steam elevators, and 584 electric elevators were installed before Sprague sold his company to the Otis Elevator Company in 1895. Sprague also developed the idea and technology for multiple elevators in a single shaft.

The development of elevators was led by the need for movement of raw materials including coal and lumber from hillsides. The technology developed by these industries and the introduction of steel beam construction worked together to provide the passenger and freight elevators in use today.

In 1874, J.W. Meaker patented a method which permitted elevator doors to open and close safely. 

In 1882, when hydraulic power was a well established technology, a company later named the London Hydraulic Power Company was formed. It constructed a network of high pressure mains on both sides of the Thames which, ultimately, extended to 184 miles and powered some 8,000 machines, predominantly lifts (elevators) and cranes.

In 1887, American Inventor Alexander Miles of Duluth, Minnesota patented an elevator with automatic doors that would close off the elevator shaft.

In 2000 a vacuum elevator was offered commercially in Argentina.

2.2. Design Of Elevator:

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Some people argue that elevators began as simple rope or chain hoists (elevators). An elevator is essentially a platform that is either pulled or pushed up by a mechanical means. A modern day elevator consists of a cab (also called a "cage" or "car") mounted on a platform within an enclosed space called a shaft or sometimes a "hoistway". In the past, elevator drive mechanisms were powered by steam and water hydraulic pistons or by hand. In a "traction" elevator, cars are pulled up by means of rolling steel ropes over a deeply grooved pulley, commonly called a sheave in the industry.

The weight of the car is balanced by a counterweight. Sometimes two elevators are built so that their cars always move synchronously in opposite directions, and are each other's counterweight. The friction between the ropes and the pulley furnishes the traction which gives this type of lift its name.

Hydraulic elevators use the principles of hydraulics (in the sense of hydraulic power) to pressurize an above ground or in-ground piston to raise and lower the car. Roped hydraulics use a combination of both ropes and hydraulic power to raise and lower cars. Recent innovations include permanent magnet motors, machine room-less rail mounted gearless machines, and microprocessor controls.

The technology used in new installations depends on a variety of factors. Hydraulic elevators are cheaper, but installing cylinders greater than a certain length becomes impractical for very high lift hoistways. For buildings of much over seven storys, traction lifts must be employed instead. Hydraulic elevators are usually slower than traction lifts.

Elevators are a candidate for mass customization. There are economies to be made from mass production of the components, but each building comes with its own requirements like different number of floors, dimensions of the well and usage patterns.

2.2.1. Elevator Doors:

Elevator doors protect riders from falling into the shaft. The most common configuration is to have two panels that meet in the middle, and slide open laterally. In a cascading telescopic configuration (potentially allowing wider entryways within limited space), the doors run on independent tracks so that while open, they are tucked behind one another, and while closed, they form cascading layers on one side.

This can be configured so that two sets of such cascading doors operate like the center opening doors described above, allowing for a very wide elevator cab. In less expensive installations the elevator can also use one large "slab" door: a single panel door the width of the doorway that opens to the left or right laterally. Some buildings have elevators with the single door on the shaft way, and double cascading doors on the cab.

2.2.2. Machine room-less (MRL) elevators:

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Machine room-less elevators are designed so that most of the components fit within the shaft containing the elevator car; and a small cabinet houses the elevator controller. Other than the machinery being in the hoist way, the equipment is similar to a normal traction elevator. The benefits are:

Creates more usable space Use less energy (70-80% less than hydraulic elevators) Uses no oil All components are above ground similar to roped hydraulic type elevators (this takes

away the environmental concern that was created by the hydraulic cylinder on direct hydraulic type elevators being stored underground)

Slightly lower cost than other elevators Can operate at faster speeds than hydraulics but not normal traction units.

Detriments

Equipment can be harder to service and maintain. No code has been approved for the installation of residential elevator equipment.

Facts

Noise level is at 50-55 dBA (A-weighted decibels), which can be lower than some but not all types of elevators.

Usually used for low-rise to mid-rise buildings The motor mechanism is placed in the hoistway itself The US was slow to accept the commercial MRL Elevator because of codes

2.3. Types of Elevators Mechanism:

There are at least four means of moving an elevator:

2.3.1. Traction elevators:

Geared Traction Elevators:

Geared traction machines are driven by AC or DC electric motors. Geared machines use worm gears to control mechanical movement of elevator cars by "rolling" steel hoist ropes over a drive sheave which is attached to a gearbox driven by a high speed motor. These machines are generally the best option for basement or overhead traction use for speeds up to 500 ft/min (2.5 m/s).

In order to allow accurate speed control of the motor, to allow accurate levelling and for passenger comfort, a DC hoist motor powered by an AC/DC motor-generator (MG) set was the preferred solution in high-traffic elevator installations for many decades. The MG set also

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typically powered the relay controller of the elevator, which has the added advantage of electrically isolating the elevators from the rest of a building's electrical system, thus eliminating the transient power spikes in the building's electrical supply caused by the motors starting and stopping (causing lighting to dim every time the elevators are used for example), as well as interference to other electrical equipment caused by the arcing of the relay contactors in the control system.

Contemporary cheaper installations, such as those in residential buildings and low-traffic commercial applications generally used a single or two speed AC hoist machine. The widespread availability of cheap solid state AC drives has allowed infinitely variable speed AC motors to be used universally, bringing with it the advantages of the older motor-generator based systems, without the penalties in terms of efficiency and complexity. The older MG-based installations are gradually being replaced in older buildings due to their poor energy efficiency.

Gearless traction Elevators:

Gearless traction machines are low speed (low RPM), high torque electric motors powered either by AC or DC. In this case, the drive sheave is directly attached to the end of the motor. Gearless traction elevators can reach speeds of up to 2,000 ft/min (10 m/s), or even higher. A brake is mounted between the motor and drive sheave (or gearbox) to hold the elevator stationary at a floor. This brake is usually an external drum type and is actuated by spring force and held open electrically; a power failure will cause the brake to engage and prevent the elevator from falling .

In each case, cables are attached to a hitch plate on top of the cab or may be "under slung" below a cab, and then looped over the drive sheave to a counterweight attached to the opposite end of the cables which reduces the amount of power needed to move the cab. The counterweight is located in the hoist-way and rides a separate railway system; as the car goes up, the counterweight goes down, and vice versa. This action is powered by the traction machine which is directed by the controller, typically a relay logic or computerized device that directs starting, acceleration, deceleration and stopping of the elevator cab. The weight of the counterweight is typically equal to the weight of the elevator cab plus 40-50% of the capacity of the elevator. The grooves in the drive sheave are specially designed to prevent the cables from slipping. "Traction" is provided to the ropes by the grip of the grooves in the sheave, thereby the name.

As the ropes age and the traction grooves wear, some traction is lost and the ropes must be replaced and the sheave repaired or replaced. Sheave and rope wear may be significantly reduced by ensuring that all ropes have equal tension, thus sharing the load evenly. Rope tension equalisation may be achieved using a rope tension gauge, and is a simple way to extend the lifetime of the sheaves and ropes.

Elevators with more than 100 ft (30 m) of travel have a system called compensation. This is a separate set of cables or a chain attached to the bottom of the counterweight and the bottom of the elevator cab. This makes it easier to control the elevator, as it compensates for the differing weight of cable between the hoist and the cab. If the elevator cab is at the top of the

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hoist-way, there is a short length of hoist cable above the car and a long length of compensating cable below the car and vice versa for the counterweight. If the compensation system uses cables, there will be an additional sheave in the pit below the elevator, to guide the cables. If the compensation system uses chains, the chain is guided by a bar mounted between the counterweight railway lines.

2.3.2. Hydraulic elevators:

Conventional hydraulic elevators . They use an underground cylinder, are quite common for low level buildings with 2–5 floors (sometimes but seldom up to 6–8 floors), and have speeds of up to 200 feet/minute (1 meter/second).

Hole less hydraulic elevators  were developed in the 1970s, and use a pair of above ground cylinders, which makes it practical for environmentally or cost sensitive buildings with 2, 3, or 4 floors.

Roped hydraulic elevators  use both above ground cylinders and a rope system, allowing the elevator to travel further than the piston has to move.

The low mechanical complexity of hydraulic elevators in comparison to traction elevators makes them ideal for low rise, low traffic installations. They are less energy efficient as the pump works against gravity to push the car and its passengers upwards; this energy is lost when the car descends on its own weight. The high current draw of the pump when starting up also places higher demands on a building’s electrical system. There are also environmental concerns should either the lifting cylinder leak fluid into the ground.

The modern generation of low cost, machine room-less traction elevators made possible by advances in miniaturization of the traction motor and control systems challenges the supremacy of the hydraulic elevator in their traditional market niche.

2.3.3. Traction-Hydraulic Elevators:

The traction-hydraulic elevator has overhead traction cables and counterweight, but is driven by hydraulic power instead of an overhead traction motor. The weight of the car and its passengers, plus an advantageous roping ratio, reduces the demand from the pump to raise the counterweight, thereby reducing the size of the required machinery.

2.3.4. Climbing elevator   :

A climbing elevator is a self-ascending elevator with its own propulsion. The propulsion can be done by an electric or a combustion engine. Climbing elevators are used in guyed masts

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or towers, in order to make easy access to parts of these constructions, such as flight safety lamps for maintenance. An example would be the Moonlight towers in Austin, Texas, where the elevator holds only one person and equipment for maintenance. The Glasgow Tower - an observation tower in Glasgow, Scotland - also makes use of two climbing elevators.

2.4. Elevator modernization:

Most elevators are built to provide about 20 years of service, as long as service intervals specified and periodic maintenance/inspections by the manufacturer are followed. As the elevator ages and equipment become increasingly difficult to find or replace, along with code changes and deteriorating ride performance, a complete overhaul of the elevator may be suggested to the building owners.

A typical modernization consists of controller equipment, electrical wiring and buttons, position indicators and direction arrows, hoist machines and motors (including door operators), and sometimes door hanger tracks. Rarely are car slings, rails, or other heavy structures changed. The cost of an elevator modernization can range greatly depending on which type of equipment is to be installed.

Modernization can greatly improve operational reliability by replacing mechanical relays and contacts with solid-state electronics. Ride quality can be improved by replacing motor-generator-based drive designs with Variable-Voltage, Variable Frequency (V3F) drives, providing near-seamless acceleration and deceleration. Passenger safety is also improved by updating systems and equipment to conform to current codes.

2.5. Elevator safety:

Cable-borne elevators:

Statistically speaking, cable-borne elevators are extremely safe. Their safety record is unsurpassed by any other vehicle system. In 1998, it was estimated that approximately eight millionths of one percent (1 in 12 million) of elevator rides result in an anomaly, and the vast majority of these were minor things such as the doors failing to open. Of the 20 to 30 elevator-related deaths each year, most of them are maintenance-related 

For example, technicians leaning too far into the shaft or getting caught between moving parts and most of the rest are attributed to other kinds of accidents, such as people stepping blindly through doors that open into empty shafts or being strangled by scarves caught in the doors. In fact, prior to the September 11th terrorist attacks, the only known free-fall incident in a

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modern cable-borne elevator happened in 1945 when a B-25 bomber struck the Empire State Building in fog, severing the cables of an elevator cab, which fell from the 75th floor all the way to the bottom of the building, seriously injuring (though not killing) the sole occupant — the elevator operator. However, there was an incident in 2007 at a Seattle children's hospital, where a ThyssenKrupp ISIS machine-room-less elevator free-fell until the safety brakes were engaged. 

This was due to a flaw in the design where the cables were connected at one common point, and the Kevlar ropes had a tendency to overheat and cause slipping (or, in this case, a free-fall). While it is possible (though extraordinarily unlikely) for an elevator's cable to snap, all elevators in the modern era have been fitted with several safety devices which prevent the elevator from simply free-falling and crashing. An elevator cab is typically borne by six or eight hoist cables, each of which is capable on its own of supporting the full load of the elevator plus twenty-five percent more weight.

In addition, there is a device which detects whether the elevator is descending faster than its maximum designed speed; if this happens, the device causes copper brake shoes to clamp down along the vertical rails in the shaft, stopping the elevator quickly, but not so abruptly as to cause injury. This device is called the governor, and was invented by Elisha Graves Otis. In addition, a hydraulic buffer is installed at the bottom of the shaft to somewhat cushion any impact. However, In Thailand, in November 2012, a woman was killed in free falling elevator, in what was reported as the "first legally recognised death caused by a falling lift".

Hydraulic elevators:

Past problems with early hydraulic elevators meant those built prior to a code change in 1972 were subject to possible catastrophic failure. The code had previously required only single-bottom hydraulic cylinders. In the event of a cylinder breach, an uncontrolled fall of the elevator might result. Because it is impossible to verify the system completely without a pressurized casing (as described below), it is necessary to remove the piston to inspect it. The cost of removing the piston is such that it makes no economic sense to re-install the old cylinder; therefore it is necessary to replace the cylinder and install a new piston. Another solution to protect against a cylinder blowout is to install a "life jacket." This is a device which, in the event of an excessive downward speed, clamps onto the cylinder and stops the car. A device known as a rupture valve is often attached to the hydraulic inlet/outlet of the piston and can be adjusted for a maximum flow rate. If a pipe or hose were to break (rupture), the flow rate of the rupture valve will surpass a set limit and mechanically stop the outlet flow of hydraulic fluid, thus stopping the piston and the car in the down direction.

In addition to the safety concerns for older hydraulic elevators, there is risk of leaking hydraulic oil into the aquifer and causing potential environmental contamination. This has led to the introduction of PVC liners (casings) around hydraulic cylinders which can be monitored for integrity.

In the past decade, recent innovations in inverted hydraulic jacks have eliminated the costly process of drilling the ground to install a borehole jack. This also eliminates the threat of corrosion to the system and increases safety.

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Mine-shaft elevators :

Safety testing of mine shaft elevator rails is routinely undertaken. The method involves destructive testing of a segment of the cable. The ends of the segment are frayed, then set in conical zinc molds. Each end of the segment is then secured in a large, hydraulic stretching machine. The segment is then placed under increasing load to the point of failure. Data about elasticity, load, and other factors is compiled and a report is produced. The report is then analysed to determine whether or not the entire rail is safe to use.

2.6. Uses of elevators:

Table lifts, and positioners are used for positioning the work material such that the material to be worked on is placed at an ergonomically comfortable access points. Truck or vehicle lifts are used to lift materials for the purpose of lading them onto the trucks, which is done by lifting such materials to the height of the truck bed. Vehicle lifts come with attachments by which they can be mounted at the rear of a vehicle.

Transport companies, that transports heavy goods and machinery by roads commonly uses such lifts. A dock lift is similar to a vehicle lift; however, these are mounted at the docks and are used to position material and/or personnel for loading purpose.

Personnel lifts, as the name implies, are used to move workers to materials or the work area. This is done when it is more feasible to move personnel to the work area, rather than moving the work area to the workers. Such situations can arise when the work has to be done at great heights, or the work area is very large, and highly impossible to move.

Fork lifts and pallet lifts are used to lift the load from the base or pallets. Forklift trucks are a common sight at docks, as well as warehouses, and storage places. These trucks are mobile forklifts that are used to lift and transport goods at short distances. Fork lifts, and pallet lifts are used for loading, unloading, as well as storage and working purposes. Tilt table are hollow bins with four sides, and (usually) open at the top. These cannot only raise or lower the work piece, but can also tilt it an angle to place it in an ergonomically optimal position to be worked upon.

The main reason for the widespread use of the hydraulic lifts is the benefits it provides by creating ergonomically safe working conditions. This helps to greatly reduce, or even eliminate the large amount of injuries caused to workers due to repetitive stress.

Such injuries frequently occur when the job is much more physically demanding as compared to the physical limitations of the workers. Hydraulic lifts help to place the work material at positions that is not awkward to the workers, in an easy, and safe manner. The worker may not only benefit from the better posture for work, but the lifts can also help in placing the objects in such a manner that the worker would require the minimum force, and labor to get the job done. Due to creation of such work friendly environment, it not only results in reduced injuries, but also better productivity on the part of the workers.

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By using hydraulic lifts, this can be successfully achieved in a variety of conditions that are otherwise very demanding or dangerous. Hydraulic lifts can also be used to move materials horizontally, as well as vertically. Many hydraulic lifts come with wheel, and are thus mobile in nature, and thus can be used in various situations (the best example being the forklift truck). For sustained use in a repetitive work environment, hydraulic lifts can be permanently fixed, and be made a part of the process line. In a manufacturing workshop, smaller hydraulic lifts are commonly used for holding and moving various products.

2.7. Controlling elevators:

Early elevators had no automatic landing positioning. Elevators were operated by  elevator operators using a motor controller. The controller was contained within a cylindrical container about the size and shape of a cake container and this was operated via a projecting handle. This allowed some control over the energy supplied to the motor (located at the top of the elevator shaft or beside the bottom of the elevator shaft) and so enabled the elevator to be accurately positioned — if the operator was sufficiently skilled.

More typically the operator would have to "jog" the control to get the elevator reasonably close to the landing point and then direct the outgoing and incoming passengers to "watch the step". Some older freight elevators are controlled by switches operated by pulling on adjacent ropes. Safety interlocks ensure that the inner and outer doors are closed before the elevator is allowed to move. Most older manually controlled elevators have been retrofitted with automatic or semi-automatic controls.

Automatic elevators began to appear as early as the 1930s, their development being hastened by striking elevator operators which brought large cities dependent on skyscrapers (and therefore their elevators) such as New York and Chicago to their knees. These electromechanical systems used relay logic circuits of increasing complexity to control the speed, position and door operation of an elevator or bank of elevators. The Otis Autoerotic system of the early 1950s brought the earliest predictive systems which could anticipate traffic patterns within a building to deploy elevator movement in the most efficient manner. Relay-controlled elevator systems remained common until right up until the 1980s, and their gradual replacement with solid-state microprocessor based controls which are now the industry standard

CHAPTER- 3

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TYPES OF ELEVATORS

3.1. Types of Elevators:

There are various types of elevators. Some of them are as follows:

3.1.1. Passenger service:

A passenger elevator is designed to move people between a building's floors.

Passenger elevators capacity is related to the available floor space. Generally passenger elevators are available in capacities from 1,000 to 6,000 pounds (450–2,700 kg) in 500 lb (230 kg) increments. Generally passenger elevators in buildings eight floors or less are hydraulic or electric, which can reach speeds up to 200 ft/min (1.0 m/s) hydraulic and up to 500 ft/min electric. In buildings up to ten floors, electric and gearless elevators are likely to have speeds up to 500 ft/min (2.5 m/s), and above ten floors speeds begin at 500 ft/min (2.5 m/s) up to 2000 ft/min (10 m/s).

Sometimes passenger elevators are used as a city transport along with  funiculars. For example, there is a 3-station underground public elevator in Yalta, Ukraine, which takes passengers from the top of a hill above the Black Sea on which hotels are perched, to a tunnel located on the beach below. At Casco Viejo station in the Bilbao Metro, the elevator that provides access to the station from a hilltop neighbourhood doubles as city transportation: the station's ticket barriers are set up in such a way that passengers can pay to reach the elevator from the entrance in the lower city, or vice versa. See also the Elevators for urban transport service. 

3.1.2. Freight elevator:

A specialized elevator from 1905 for lifting narrow gauge railroad cars between a railroad freight house and the Chicago Tunnel Company tracks below

A freight elevator, or goods lift, is an elevator designed to carry goods, rather than passengers. Freight elevators are generally required to display a written notice in the car that the use by passengers is prohibited (though not necessarily illegal), though certain freight elevators allow dual use through the use of an inconspicuous riser. In order for an elevator to be legal to carry passengers in some jurisdictions it must have a solid inner door. Freight elevators are typically larger and capable of carrying heavier loads than a passenger elevator, generally from 2,300 to 4,500 kg. Freight elevators may have manually operated doors, and often have rugged

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interior finishes to prevent damage while loading and unloading. Although hydraulic freight elevators exist, electric elevators are more energy efficient for the work of freight lifting.

3.1.3. Sidewalk elevators:

A sidewalk elevator is a special type of freight elevator. Sidewalk elevators are used to move materials between a basement and a ground-level area, often the side walk just outside the building. They are controlled via an exterior switch and emerge from a metal trap door at ground level. Sidewalk elevator cars feature a uniquely shaped top that allows this door to open and close automatically.

3.1.4 Stage lifts:

Stage and orchestra lifts are specialized lifts, typically powered by hydraulics, that are used to lift entire sections of a theatre stage. For example, Radio City Music Hall has four such lifts: an "orchestra lift" that covers a large area of the stage, and three smaller lifts near the rear of the stage. In this case, the orchestra lift is powerful enough to raise an entire orchestra, or an entire cast of performers (including live elephants) up to stage level from below.

3.1.5. Vehicle elevators:

Vehicular elevators are used within buildings or areas with limited space (in lieu of ramps), typically to move cars into the parking garage or manufacturer's storage. Geared hydraulic chains (not unlike bicycle chains) generate lift for the platform and there are no counterweights. To accommodate building designs and improve accessibility, the platform may rotate so that the driver only has to drive forward. Most vehicle elevators have a weight capacity of 2 tons.

Rare examples of extra-heavy elevators for 20-ton lorries, and even for railcars (like one that was used at Dnipro Station of the Kiev Metro) also occur.

3.1.6. Boat elevators :

In some smaller canals, boats and small ships can pass between different levels of a canal with a boat lift rather than through a canal lock.

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3.1.7. Aircraft elevators:

Elevators for aircraft

On aircraft carriers, elevators carry aircraft between the flight deck and the hangar deck for operations or repairs. These elevators are designed for much greater capacity than other elevators, up to 200,000 pounds (90tonnes) of aircraft and equipment. Smaller elevators lift munitions to the flight deck from magazines deep inside the ship.

Elevators within aircraft

On some passenger double-deck aircraft such as the Boeing 747 or other widebody aircraft, lifts transport flight attendants and food and beverage trolleys from lower deck galleys to upper passenger carrying decks.

3.1.8. Residential elevator

The residential elevator is often permitted to be of lower cost and complexity than full commercial elevators. They may have unique design characteristics suited for home furnishings, such as hinged wooden shaft-access doors rather than the typical metal sliding doors of commercial elevators. Construction may be less robust than in commercial designs with shorter maintenance periods, but safety systems such as locks on shaft access doors, fall arrestors, and emergency phones must still be present in the event of malfunction.

3.1.9. Limited use / limited application:

The limited-use, limited-application (LU/LA) elevator is a special purpose passenger elevator used infrequently, and which is exempt from many commercial regulations and accommodations. For example, a LU/LA is primarily meant to be handicapped accessible, and there might only be room for a single wheelchair and a standing passenger.

3.1.10. Dumbwaiter: 

Dumbwaiter  are small freight elevators (or lifts) intended to carry objects rather than people. Dumbwaiters found within modern structures, including both commercial, public and private buildings, are often connected between multiple floors. When installed in restaurants, schools, hospitals, in private homes, the lifts generally terminate in a kitchen.

3.1.11. Scissor Lift:

A scissor lift is a type of platform that can usually only move vertically. The mechanism to achieve this is the use of linked, folding supports in a criss-cross "X" pattern, known as a pantograph (or scissor mechanism). The upward motion is achieved by the application of

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pressure to the outside of the lowest set of supports, elongating the crossing pattern, and propelling the work platform vertically.

3.1.12. Rack-and-pinion lift

Rack-and-pinion lifts are powered by a motor driving a pinion gear. Because they can be installed on a building or structure's exterior and there is no machine room or hoist way required, they are the most used type of lift for buildings under construction (to move materials and tools up and down).

3.1.13. Material Carrying Lift:

Lift illustrates the use of one or more simple machines to create mechanical advantage. The lever, a balance lift contains a horizontal beam (the lever) pivoted about a point called the fulcrum.

The principle of the lever allows a heavy load attached to the shorter end of the beam to be lifted by a smaller force applied in the opposite direction to the longer end of the beam. The ratio of the load's weight to the applied force is equal to the ratio of the lengths of the longer arm and the shorter arm, and is called the mechanical advantage

CHAPTER-4

Dumbwaiter Lift:

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4.1. Introduction:

Dumbwaiters are small freight elevators (or lifts) intended to carry objects rather than people. Dumbwaiters found within modern structures, including both commercial, public and private buildings, are often connected between multiple floors. When installed in restaurants, schools, hospitals, in private homes, the lifts generally terminate in a kitchen.

The mechanical dumbwaiter was invented by George W. Cannon, a New York inventor. Cannon first filed for the patent of a brake system that could be used for a dumbwaiter on January 6, 1883. Cannon later filed for the patent on the mechanical dumbwaiter on February 17, 1887.

A simple dumbwaiter is a movable frame in a shaft, dropped by a rope on a pulley, guided by rails. Most dumbwaiters have a shaft, cart, and capacity smaller than those of passenger elevators, usually 45 to 450 kg.  Before electric motors were added in the 1920s, dumbwaiters were controlled manually by ropes on pulleys.

Early 20th-century codes sometimes required fire proof dumbwaiter walls and self-closing fire proof doors and mention features such as buttons to control movement between floors and locks on doors preventing them from opening unless the cart is stopped at that floor.

(fig 4.1)

4.2. Specification Of The Dumbwaiter:-

A) - LOAD/ CAPACITY (in kg): 100

B) - MOTOR: Electric

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C) - CAR & DOOR MATERIAL:

Galvanized steel sheet finished Door opening (height & width) exactly corresponding to interior car dimensions.

D) - LANDING DOORS:-

TYPE: By- parting shelf loading or floor loading HIGHT H (in mm): 600 - 800

E) - SPEED ( in m/s): 0 , 4

F) - MAIN OPTIONS:

Stainless steel finish Overload device Machine below or on side Entrance on 2 sides Corner post arrangements Car door

G) - CAR DIMENSIONS:

CAR WALL (in mm): 400 - 1000 B)- CAR DOOR (in mm): 400 - 1000

H) - CAR MODULAR INCREMENTS (in mm): 25

I) - TOTAL HIGHT OF THE LIFT (in m): 5 - 6

4.3. Advantages:

Practical and simple to use in every environment. Robust and reliable design. Quiet operation. Flexible design dimensions due to 25 mm car increments.

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Compact design. Machine and controller incorporated in pylone. Fitting and decoration flexibility.

4.4. Dis-advantage:

The actual lift is not portable as the apparatus is been fixed. The setup is quite costly. The availability of the motor was difficult. A gearbox was compulsory to be installed. Due to stainless steel the initial cost of the material was high.

CHAPTER-5

The Material Carrying or Bucket Lift

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5.1. Introduction:

An elevator or lift is a type of vertical transport equipment that efficiently moves people or goods between floors/ level of a building, vessel or other structures. Elevators are generally powered by electric motors that either drive traction cables or counterweight systems like a hoist,

or pump hydraulic fluid to raise a cylindrical piston like a jack.

5.2. Working principle :

Lift illustrates the use of one or more simple machines to create mechanical advantage. The lever, a balance lift contains a horizontal beam (the lever) pivoted about a point called the fulcrum.

The principle of the lever allows a heavy load attached to the shorter end of the beam to be lifted by a smaller force applied in the opposite direction to the longer end of the beam. The ratio of the load's weight to the applied force is equal to the ratio of the lengths of the longer arm and

the shorter arm, and is called the mechanical advantage.

5.3. Specifications :

Supporting Frames(U- Shaped) Bucket Electric Motor (1/2 hp) Cables Pulley(V- Shaped) Weight Carrying Capacity 75 -100 kgs. Height for lifting the weight 10-12 ft.

5.4. Designs of the lift:

(Top view) -

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(side view)-

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5.5. Types of Drives & Controls:

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There are 2 types of drives & control systems:

AC motor control techniques DC motor control techniques

AC motor control techniques, The AC variable voltage drive is suitable for lift speeds up to 2 mis. For speeds of 1 mis or less, and small lift cars (i.e. less than 8-person), a simple AC drive without re-levelling may be satisfactory. A drive with re-levelling should always be specified for larger lift cars and higher speed applications or where small wheeled trolleys etc. may beused. Compared to variable voltage control only, variable voltage, variable frequency drives provide better all-round drive performance for lift speeds from 0.4 mis to 10 mis. They give near unity power factor operation and draw lower acceleration currents (e.g. twice the full load current) requiring smaller mains feeders. Provided that it is correctly designed and filtered, the variable voltage, variable frequency drive produces the lowest harmonic current and voltage values in the supply of all the various types of solid-state drive.

DC motor control techniques, DC gearless machines are still the most common type of drive for lift speeds greater than 2 mIs. There are two basic methods of controlling DC motors: the Ward Leonard set and the static converter drive. Static converter drives are the most economical in operation with energy costs up to 60% less than those for equivalent Ward Leonard drives.

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CHAPTER- 6

SCISSOR LIFT

6.1. Introduction:

A scissor lifts mechanism for use on a coil car or the like, the lift having scissor legs connected to each other by a shaft. The lift is raised and lowered by a means for providing a generally vertical force to the shaft. The means may be provided by a hydraulic cylinder and a bell crank mechanism. The bell crank mechanism redirects the force from a hydraulic cylinder to a generally vertical force on a hinge connecting the scissor legs of the lift. The bell crank mechanism allows the strength of the lift to be maximized while retaining a low profile design

Scissor lift are meant for temporary works and can be transported to site either loaded onto a trailer or under their own power. There are several types of fuel available, including diesel, battery, bio fuel, LPG and air-powered units. Scissor lifts come in a variety of sizes to suit different applications - compact and micro scissor lifts are available for tight access areas.

6.2. Principle Of Scissor Lift :

A scissor lift is a type of platform that can usually only move vertically. The mechanism to achieve this is the use of linked, folding supports in a criss-cross "X" pattern, known as a pantograph (or scissor mechanism). The upward motion is achieved by the application of pressure to the outside of the lowest set of supports, elongating the crossing pattern, and propelling the work platform vertically.

The platform may also have an extending "bridge" to allow closer access to the work area, because of the inherent limits of vertical-only movement.

The contraction of the scissor action can be hydraulic, pneumatic or mechanical (via a  lead screw or rack and pinion system). Depending on the power system employed on the lift, it may require no power to enter "descent" mode, but rather a simple release of hydraulic or pneumatic pressure. This is the main reason that these methods of powering the lifts are preferred, as it allows a fail-safe option of returning the platform to the ground by release of a manual valve.

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6.3. Parts Of Scissor Lift:

1.  Flat or tear pattern deck top. The top roll over edges are square for greater strength, smoother load transfer and flush mounting of handrail, conveyors etc.

2.  A perimeter safety trip frame is fitted to the undersides of the platform to prevent further should an obstruction be encountered. For added safety, operator reset is standard.

3.  The scissor arms for lift tables up to 3 meters in length are usually profiles, solid steel. For larger lifts, steel hollow section is used to provide greater stability. 

4.  Pre-lubricated, replaceable type bearing bushes are standard features. For heavy duty work we recommend chrome plating heavy wear parts, including grease points or grease free spherical plain bearings with seals.

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5. A built in high pressure filter helps protect the lowering valve from malfunction. The lowering speed is adjustable on site and is controlled by a pressure compensating valve. The control station is on 3 meters of flexible cable complete with Emergency Stop and dead man UP and DOWN push buttons.

6. Steel swivel stops or posts are provided to mechanically support the lift in a raised or semi-raised position to allow access for maintenance purposes.

7. The steel arm roller bearings are replaceable.

6.4. Advantages:

It is a portable lift. No oil tank is required. Easy operation

6.5. Disadvantages

Low safety factor High maintenance required Complex Structure

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CHAPTER-7

MULTI-STAGE HYDRAULIC LIFT

7.1. Introduction:

This type of hydraulic lift is also called as Multi-Stage Hydraulic Lift. This lift basically comprises of a multi-stage hydraulic cylinder, which should be single acting type, a hydraulic gear pump which helps the cylinder to perform its operations, a platform attached to the top of the multi-stage cylinder on which the material to be lifted is placed, working fluid i.e. hydraulic oil, and a hose pipe which connects the pump and multi-stage hydraulic cylinder.

(fig.7.1)

7.2. Multi-Stage Single Acting Hydraulic Cylinder:

These cylinders are also referred to as Telescopic Cylinders. Telescopic cylinders are commonly restricted to a maximum of 6 stages. 6 stages are commonly thought to be the practical design limit as stability problems become more difficult with larger numbers of stages. Telescopic cylinders require careful design as they are subjected to large side forces especially at

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full extension. The weight of the steel bodies and the hydraulic oil contained within the actuator create moment loads on the bearing surfaces between stages. These forces, combined with the load being pushed, threaten to bind or even buckle the telescopic assembly. Sufficient bearing surfaces must therefore be incorporated in the design of the actuator to prevent failure in service due to side forces. Telescopic cylinders must only be used in machinery as a device for providing force and travel.

Hydraulic telescopic cylinders are often limited to a maximum hydraulic pressure of 2000 -3000 psi. This is because the outward forces produced by internal hydraulic pressure tends to expand the steel sleeve sections.

fig.7.2 pneumatic telescoping cylinder, 8-stages, single-acting, retracted and extended

Too much pressure will cause the nested sleeves to balloon outward, bind the mechanism and stop moving. The danger exists that a permanent deformation of the outer diameter of a sleeve could occur, thus ruining a telescopic actuator. For this reason, care must be taken to avoid shock pressures in a hydraulic system using telescopic cylinders. Often such hydraulic systems are equipped with shock suppressing components, such as hydraulic accumulators, to absorb pressure spikes.

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7.3. Hydraulic Pump:

Hydraulic pumps are used in hydraulic drive systems and can be hydrostatic or hydrodynamic. Hydrostatic pumps are positive displacement pumps, while hydrodynamic pumps can be fixed displacement pumps, in which the displacement (flow through the pump per rotation of the pump) cannot be adjusted, or variable displacement pumps, which have a more complicated construction that allows the displacement to be adjusted.

Gear pump are simple and economical pumps. The swept volume or displacement of gear pumps for hydraulics will be between about 1 cm3 (0.001 litre) and 200 cm3 (0.2 litre). They have the lowest volumetric efficiency (about 90%). These pumps create pressure through the meshing of the gear teeth, which forces fluid around the gears to pressurize the outlet side. For lubrication, the gear pump uses a small amount of oil from the pressurized side of the gears, bleeds this through the (typically) hydrodynamic bearings, and vents the same oil either to the low pressure side of the gears, or through a dedicated drain port on the pump housing.

.

(fig. 7.3)

Some gear pumps can be quite noisy, compared to other types, but modern gear pumps are highly reliable and much quieter than older models. This is in part due to designs incorporating split gears, helical gear teeth and higher precision/quality tooth profiles that mesh and un-mesh more smoothly, reducing pressure ripple and related detrimental problems. Another positive attribute of the gear pump, is that catastrophic breakdown is a lot less common than in most other types of hydraulic pumps. This is because the gears gradually wear down the housing and/or main bushings, reducing the volumetric efficiency of the pump gradually until it is all but useless. This often happens long before wear causes the unit to seize or break down.

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7.4. Hydraulic Fluid (Oil):

Hydraulic fluids, also called hydraulic liquids, are the medium by which power is transferred in hydraulic machinery. Common hydraulic fluids are based on mineral oil or water. The primary function of a hydraulic fluid is to convey power. In use, however, there are other important functions of hydraulic fluid such as protection of the hydraulic machine components. The original hydraulic fluid, dating back to the time of ancient Egypt, was water.

(fig.7.4)

Beginning in the 1920s, mineral oil began to be used more than water as a base stock due to its inherent lubrication properties and ability to be used at temperatures above the boiling point of water. Today most hydraulic fluids are based on mineral oil base stocks.

7.5. Specifications:

Load capacity: 1 Ton Height: 6 ft Pump: Hydraulic Gear pump\ Discharge: 1 cm3 (0.001 litre) and 200 cm3 (0.2 litre)

7.6. Advantages:

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The multi-stage lift could easily raise heavy equipments. More stroke length is obtained. Lift could be portable.

7.7. Disadvantages:

These lift could not be operated by small hand operated hydraulic pumps because high pressure is required.

Telescopic cylinders must only be used in machinery as a device for providing force  and travel.

For continuous flow of oil at high pressure separate large oil tank is required The setup is quite costly. Skilled operators are required.

CHAPTER- 8

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HYDRAULIC LIFT

8.1 INTRODUCTION Hydraulic lift is a heavy goods lifting machinery which utilizes mechanical advantage of hydraulic cylinder. The basic principle of lift depends upon Pascal's Law. It utilizes incompressible fluid for the transfer of force equally in all direction. Lifting capacity is more as compared to power supplied.

Two main parts are used in lift-

1. Hydraulic Cylinder

2. Hydraulic Pump

8.2. HYDRAULIC CYLINDER:

8.2.1 INTRODUCTION:

Cylinders are linear actuators which convert fluid power into mechanical power. They are also known as JACKS or RAMS.

Hydraulic cylinders are used at high pressures and produce large forces and precise movement. For this reason they are constructed of strong materials such as steel and designed to withstand large forces.

Because gas is an expansive substance, it is dangerous to use pneumatic cylinders at high pressures so they are limited to about 10 bar pressure. Consequently they are constructed from lighter materials such as aluminium and brass. Because gas is a compressible substance, the motion of a pneumatic cylinder is hard to control precisely. The basic theory for hydraulic and pneumatic cylinders is otherwise the same.

8.2.2. THEORY:

8.2.2.1 FORCE:

The fluid pushes against the face of the piston and produces a force. The force produced is given by the formula: F = p.A

p is the pressure in N/m2 and A is the area the pressure acts on in m2.

This assumes that the pressure on the other side of the piston is negligible. The diagram shows a double acting cylinder. In this case the pressure on the other side is usually atmospheric so if p is a gauge pressure we need not worry about the atmospheric pressure.

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(Figure8.1)

Let A be the full area of the piston and a be the cross sectional area of the rod. If the pressure is acting on the rod side, then the area on which the pressure acts is (A - a). F = pA on the full area of piston. F = p(A-a) on the rod side. This force acting on the load is often less because of friction between the seals and both the piston and piston rod.

8.2.2.2 SPEED

The speed of the piston and rod depends upon the flow rate of fluid. The volume per second entering the cylinder must be the change in volume per second inside. It follows then that:

Q m3/s = Area x distance moved per second

Q m3/s = A x velocity (full side)

Q m3/s = (A-a) x velocity (rod side)

Note in calculus form velocity is given by v = A dx/dt and this is useful in control applications.

In the case of air cylinders, it must be remembered that Q is the volume of compressed air and this changes with pressure so any variation in pressure will cause a variation in the velocity.

8.2.2.3 POWER

Mechanical power is defined as Force x velocity. This makes it easy to calculate the power of a cylinder. The fluid power supplied is more than the mechanical power output because of friction between the sliding parts.

P = F v Watts

8.2.4 TYPES OF HYDRAULIC CYLINDER:

8.4.1 SINGLE ACTING CYLINDERS

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A simple single acting cylinder is shown below. The cylinder is only powered in one direction and needs another force to return it such as an external load (e.g. in a car hoist or jack) or a spring. No hydraulic fluid is present on the low pressure side.

Single Acting Cylinder for Pushing (figure8.2) Single Acting Cylinder for Pulling

8.2.5 DOUBLE ROD CYLINDERS

The basic design of a double rod cylinder is shown below. The design allows equal force and speed in both directions. It is useful in robotic mechanisms were the rod is clamped at both ends and the body moves instead.

2

(figure 8.3)

8.2.6 TELESCOPIC CYLINDERS

These cylinders produce long strokes from an initial short length. Each section slides inside a larger section. These cylinders have from 2 to five stages. They are typically used in refuse lorries for ejecting the compacted refuse. They are also used for lifts, tipping platforms, lifting platforms and other commercial vehicle applications.

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(figure 8.4)

8.3. PARTS OF HYDRAULIC CYLINDER:A hydraulic cylinder consists of the following parts.

Cylinder barrel 

Cylinder base or cap 

Cylinder head 

Piston

Piston rod 

Seal gland 

Seal

Other parts

Cylinder base connection Cushions

8.3.1 Cylinder barrel :   The main function of cylinder body is to hold cylinder pressure. The cylinder barrel is mostly made from a seamless tube. The cylinder barrel is ground and/or honed internally with a typical surface finish of 4 to 16 micro inch. Normally hoop stress is calculated to optimize the barrel size.

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8.3.2Cylinder base or cap: The main function of the cap is to enclose the pressure chamber at one end. The cap is connected to the body by means of welding, threading, bolts, or tie rod. Caps also perform as cylinder mounting components [cap flange, cap trunnion, cap clevis]. Cap size is determined based on the bending stress. A static seal / o-ring is used in between cap and barrel (except welded construction).

8.3.3 Cylinder head:  The main function of the head is to enclose the pressure chamber from the other end. The head contains an integrated rod sealing arrangement or the option to accept a seal gland. The head is connected to the body by means of threading, bolts, or tie rod. A static seal / o-ring is used in between head and barrel.

8.3.4 Piston:

The main function of the piston is to separate the pressure zones inside the barrel. The piston is machined with grooves to fit elastomeric or metal seals and bearing elements. These seals can be single acting or double acting. The difference in pressure between the two sides of the piston causes the cylinder to extend and retract. The piston is attached with the piston rod by means of threads, bolts, or nuts to transfer the linear motion.

8.3.5 Piston rod:  The piston rod is typically a hard chrome-plated piece of cold-rolled steel which attaches to the piston and extends from the cylinder through the rod-end head. In double rod-end cylinders, the actuator has a rod extending from both sides of the piston and out both ends of the barrel. The piston rod connects the hydraulic actuator to the machine component doing the work. This connection can be in the form of a machine thread or a mounting attachment....

8.3.6 Seal gland:

The cylinder head is fitted with seals to prevent the pressurized oil from leaking past the interface between the rod and the head. This area is called the seal gland. The advantage of a seal gland is easy removal and seal replacement. The seal gland contains a primary seal, a secondary seal / buffer seal, bearing elements, wiper / scraper and static seal. In some cases, especially in small hydraulic cylinders, the rod gland and the bearing elements are made from a single integral machined part.

\

8. 3.7. SEALS : The seals are considered / designed as per the cylinder working pressure, cylinder speed, operating

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temperature, working medium and application. Piston seals are dynamic seals, and they can be single acting or double acting. Generally speaking, Elastomer seals made from nitrile rubber, Polyurethane or other materials are best in lower temperature environments, while seals made of Fluorocarbon Viton are better for higher temperatures. Metallic seals are also available and commonly use cast iron for the seal material. Rod seals are dynamic seals and generally are single acting. The compounds of rod seals are nitrile rubber, Polyurethane, or Fluorocarbon Viton. Wipers / scrapers are used to eliminate contaminants such as moisture, dirt, and dust, which can cause extensive damage to cylinder walls, rods, seals and other components. The common compound for wipers is polyurethane. Metallic scrapers are used for sub zero temperature applications, and applications where foreign materials can deposit on the rod. The bearing elements / wear bands are use to eliminate metal to metal contact. The wear bands are designed as per the side load requirements. The primary compounds for wear bands are filled PTFE, woven fabric reinforced polyester resin and bronzeThe detailed diagram shows a double acting cylinder. The main seals used are

1. Piston seals to prevent leakage from one side to the other2. Rod seal to prevent leakage from the rod end.3. Static seals to prevent leakage from joints between the barrel and end caps. 4. Wiper seal to stop dirt being drawn inside with the rod.

(figure8.5)

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8.3.8 Bearings:

The bearings are

1. The rod end bearing made of brass or bronze. This takes the side loads on the rod and ensures lubrication and reduced wear. It also prevents the seal distorting and leaking.

2. The pistons bearing to take the sideways forces and reduce wear.

(fig.8.6)

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8.3.9. CUSHIONING:

The fluid is normally expelled through the outlet port direct but when the cushioning boss enters the recess, the fluid around the piston is trapped. The only way the fluid can escape is through the secondary path, which is restricted by a needle valve. The needle valve is adjusted so that the piston is slowed up over the last part of its stroke by a pressure build up in the fluid escaping past the needle valve.

8.3.10. QUICK START:

The problem with cushioning is that when you try to move the piston back the other way, fluid only has the cushioning boss to push on and because it is a small area the force may not be enough to move it or it may only move slowly until the boss clears the recess. To get around this a one way check valve is placed in parallel with the needle valve so that fluid can easily get into the space behind the piston and push on the full area.

8.3.11. BUCKLING

Buckling occurs when the rod bends or bows out sideways under load. The longer and thinner the rod, the more likely it is for buckling to occur. When selecting a cylinder from a catalogue, the manufacturer will show information to enable you to determine the buckling load.

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8.4. CONSTRUCTION:

The detailed diagram shows the main construction details. Hydraulic cylinders are built to withstand substantial pressures and so are expensive compared to pneumatic cylinders. The body is a tube or barrel with a smooth finish to prevent seals wearing out. Steel is usually used for the strength required. The fluid ports are contained in the end caps. One end cap has a hole for the rod. The end caps must be sealed to the barrel. The picture shows cylinders with tie rods for holding the end caps in place.

(figure8.7)

The next picture shows cylinders with the end caps screwed onto the barrel

(Figure 8.8)

Other methods of construction use welding and swaging techniques. These types cannot be disassembled for servicing. In some applications no fasteners are needed and external restraints prevent the end caps blowing out.

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8.5. END FIXINGS:

The diagram shows typical ways of mounting cylinders and attaching them to machines.

(Figure 8.9)

8.6. CYLINDER SPEED CONTROL:

The basic method of controlling the speed is by controlling the flow in or out of the cylinder. The simplest way is to place a restrictor on the appropriate port but this reduces the thrust and wastes energy through friction.

One of the problems with pneumatics is the compressibility of the air which makes it unsuitable for precise movement control in applications such as machine tools and robots. This problem is overcome by the use of air/oil systems (covered later). The cylinder is filled with oil and both ports are connected to a storage vessel with oil in them. The oil in these vessels has air supplied to the top. When air pressure is supplied to one tank, the oil is forced into the cylinder. The pressures are low and the cylinders are often pneumatic cylinders. The speed is controlled by a one way variable restrictor on each port. This system has the cost benefit and flexibility of a pneumatic system but with the precise and steady motion of hydraulics.

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8.3. Hydraulic Hand Pump

8.3.1. Introduction:

The Hydraulic Hand Pump is a hand-held hydraulic sealant injection pump that is rated to 10,000 PSI and operates in any position. It is very portable making it easy to keep one in your pickup for quick top-ups and emergency sealing jobs between regular maintenance intervals. It is perfect for pumping small quantities of cleaners, sealants and lubricants into valves.Features include: Locking handle to prevent damage to the pump. Easy to handle, very portable. Self-priming hydraulic action makes manual injection simple. Generates up to 10,000 PSI when required. Easily reloads with cartridge, bag or stick type products. Discharges one (1) ounce of product easily with every fifty (50) strokes Easy to read high pressure gauge Button head coupler quickly attaches to and releases from fittings

The Hydraulic Hand Pump ships with an eighteen (18) inch long hose, Giant Button head Coupler #17G and 15,000 PSI Gauge with Guard #17B. It is ready to load and use right out of the box.

(Figure 8.3.1)

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8.3.2. Operating Instructions:

8.3.2.1. How to Operate a Hydraulic Hand Pump

The components of a Hydraulic Hand Pump are shown in fig. 1.1.To operate the Hydraulic Hand Pump:The Hydraulic Hand Pump must first be loaded. Inspect the Giant Button head Coupler #17G for damage and contaminants. Clean using a mild

solvent and a clean cloth if required.Attach the Giant Button head Coupler #17G to a button head fitting on the valve being

serviced. Close By-Pass Valve #7 hand-tight only.Pull back the Stem and Knob #16A to release the Handle #10.Lift the Handle #10 up until it reaches it full height.Pull the Handle #10 all the way down. Steps six (6) and seven (7) together is one (1) stroke.By stroking the Handle #10, product is injected into the valve and pressure will begin to build.

It could require 10 - 15 full strokes before pressure begins to builds up in the pump. As you stroke, monitor the pressure on the 15,000 PSI Gauge #17B.

The Hydraulic Hand Pump requires fifty (50) strokes to transfer approximately one (1) fluid ounce of product. Once you have injected the required amount of product, open the By-Pass Valve #7 and slide the Giant Button head Coupler #17G off the fitting on the valve.

The 15,000 PSI Gauge #17B must have a zero (0) reading before the Giant Buttonhead Coupler #17G can be easily removed. If a zero (0) reading cannot be obtained it could indicate that:

The check valves in the button head fitting and in the valve have failed creating a dangerous situation.

Product has entered the bourdon tube of the15,000 PSI Gauge #17B. Repeat this procedure as required for each valve to be serviced.

8.3.2.2 Working Principle:

The working principle of Hydraulic hand pump is shown in fig.1.1.The working principle is simple; As the Handle #10 is stroked hydraulic fluid pushes the Piston Assembly #2 in the Sealant

Barrel #3 forcing product out through the High-pressure Hose Assembly #17. Continue stroking the Handle #10 and pressure will continue to increase. Once the valve line pressure is exceeded product will begin to flow into the valve. When a sufficient quantity of product has been injected the Hydraulic Hand Pump may be

removed by opening the By-Pass Valve #7 then slipping off the Giant Button head Coupler #17G from the button head fitting.

8.3.3. Components Of Hydraulic Pump:

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There are many components used in a Hydraulic Pump. Each & every component have their importance in hydraulic hand pump. Some of them are as follows; Sealant Barrel Cap Piston Assembly Piston O-Ring Sealant Barrel Barrel O-Ring Hydraulic Pump Cylinder Pump Piston Pump Piston O-Ring By-Pass Valve Hydraulic Relief Valve Handle Hydraulic Fluid Hydraulic Pump Hose Assembly

8.3.3.1. Hydraulic Fluid

a. Introduction:

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Hydraulic fluids, also called hydraulic liquids, are the medium by which power is transferred in hydraulic machinery. Common hydraulic fluids are based on mineral oil or water. Hydraulic fluid heats, cools, lubricates, and sometimes corrodes mechanical components, picks up and releases gases, and sweeps sludge into supposedly free clearances. The fluid is just as important as any other part of the hydraulic system. In fact, a major portion of hydraulic problems stem from the use of improper types of fluids or fluids containing dirt and other contaminants. To understand the fluids used in today’s industry, you have to divide them into two general areas: petroleum fluids and fire resistant fluids. These in turn break down into a number of different types with different properties.

b. Composition:

Base Stock :

The original hydraulic fluid, dating back to the time of ancient Egypt, was water. Beginning in the 1920 mineral oil began to be used more than water as a base stock due to its inherent lubrication properties and ability to be used at temperatures above the boiling point of water. Today most hydraulic fluids are based on mineral oil base stocks.

Natural oils such as rapeseed (also called canola oil) are used as base stocks for fluids where biodegradability and renewable sources are considered important.

Other base stocks are used for specialty applications, such as for fire resistance and extreme temperature applications. Some examples include: glycol, esters, organophosphate ester, polyalphaolefin, propylene glycol, and silicone oils.

Biodegradable hydraulic fluids:

Environmentally sensitive applications (e.g. farm tractors and marine dredging) may benefit from using biodegradable hydraulic fluids based upon grape seed (Canola) vegetable oil when there is the risk of an oil spill from a ruptured oil line. Typically these oils are available as ISO 32, ISO 46, and ISO 68 specification oils. ASTM standards ASTM-D-6006, Guide for Assessing Biodegradability of Hydraulic Fluids and ASTM-D-6046, Standard Classification of Hydraulic Fluids for Environmental Impact are relevant.

3.1.3 Safety:

Because industrial hydraulic systems operate at hundreds to thousands of PSI and temperatures reaching hundreds of degrees Celsius, severe injuries and death can result from component failures and care must always be taken when performing maintenance on hydraulic systems. Fire resistance is a property available with specialized fluids.

Function Property

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Medium for power transfer and

control

No compressible (high bulk modulus)

Fast air release

Low foaming tendency

Low volatility

Medium for heat transfer Good thermal capacity and conductivity

Sealing Medium Adequate viscosity and viscosity index

Shear stability

Lubricant

Viscosity for film maintenance

Low temperature fluidity

Thermal and oxidative stability

Hydrolytic stability / water tolerance

Cleanliness and filterability

Anti-wear characteristics

Corrosion control

Pump efficiency Proper viscosity to minimize internal leakage

High viscosity index

Special function

Fire resistance

Friction modifications

Radiation resistance

Environmental impact Low toxicity when new or decomposed

Functioning life Material compatibility

c. Function & Property

8.3.3.1. High Pressure Hose:

a. Introduction:

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High Pressure Hose is an important part of Hydraulic Hand Pump. It is used to develop high pressure inside the cylinder. NEVER carry the Hydraulic Hand Pump by the high pressure hose.

A hose is a hollow tube designed to carry fluids from one location to another. Hoses are also sometimes called pipes (the word pipe usually refers to a rigid tube, whereas a hose is usually a flexible one), or more generally tubing. The shape of a hose is usually cylindrical (having a circular cross section).

Hose design is based on a combination of application and performance. Common factors are Size, Pressure Rating, Weight, Length, Straight hose or Coil hose and Chemical Compatibility.

Hoses are made from one or a combination of many different materials. Applications mostly use nylon, polyurethane, polyethylene, PVC, or synthetic or natural rubbers, based on the environment and pressure rating needed. In recent years, hoses can also be manufactured from special grades of polyethylene (LDPE and especially LLDPE). Other hose materials include PTFE (Teflon), stainless steel and other metals.

(Figure 2.3)

b. Factors affecting Hose: Hose life is reduced by factors that include: Environment - Temperature extremes, UV light, chemicals, ozone, etc. will degrade the

rubber used in hydraulic hoses. Abrasion and Cuts - Wear against other hoses or objects will wear off the outer cover and

lead to corrosion of the reinforcing mesh. Extreme Pressure Fluctuations - Pressure surges above the hose’s working pressure will

damage hose components. Improper Length/Routing - Excessive bending of the high pressure hose causes high

stresses in the hoses components that may also reduce pressure capacity (avoid multi-planebending, small bend radii, tension in hose, etc.). Hose life can be reduced by 90% when subject to these type of stresses.

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8.3.3.3 Seals of hydraulic pump

i. Introduction :

The seals are considered / designed as per the cylinder working pressure, cylinder speed, operating temperature, working medium and application. Piston seals are dynamic seals, and they can be single acting or double acting. Generally speaking, Elastomer seals made from nitrile rubber, Polyurethane or other materials are best in lower temperature environments, while seals made of Fluorocarbon Viton are better for higher temperatures. Metallic seals are also available and commonly use cast iron for the seal material. Rod seals are dynamic seals and generally are single acting. The compounds of rod seals are nitrile rubber, Polyurethane, or Fluorocarbon Viton. Wipers / scrapers are used to eliminate contaminants such as moisture, dirt, and dust, which can cause extensive damage to cylinder walls, rods, seals and other components. The common compound for wipers is polyurethane. Metallic scrapers are used for subzero temperature applications, and applications where foreign materials can deposit on the rod. The bearing elements / wear bands are used to eliminate metal to metal contact. The wear bands are designed as per the side load requirements. The primary compounds for wear bands are filled PTFE, woven fabric reinforced polyester resin and bronzeThe detailed diagram shows a double acting cylinder. The main seals used are 1. Piston seals to prevent leakage from one side to the other2. Rod seal to prevent leakage from the rod end.3. Static seals to prevent leakage from joints between the barrel and end caps. 4. Wiper seal to stop dirt being drawn inside with the rod. Hydraulic seals can be made from a variety of materials such as polyurethane, rubber or PTFE. The type of material is determined by the specific operating conditions or limits due to fluid type, pressure, fluid chemical compatibility or temperature.

(Figure 2.4)

ii. Seals, fittings and connections :  In general, valves, cylinders and pumps have female threaded bosses for the fluid connection, and hoses have female ends with captive nuts. A male-male fitting is chosen to connect the two. Many standardized systems are in use.

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Fittings serve several purposes;

To bridge different standards; O-ring boss to JIC, or pipe threads to face seal, for example. To allow proper orientation of components, a 90°, 45°, straight, or swivel fitting is chosen as

needed. They are designed to be positioned in the correct orientation and then tightened. To incorporate bulkhead hardware. A quick disconnect fitting may be added to a machine without modification of hoses or

valves

A typical piece of heavy equipment may have thousands of sealed connection points and several different types:

Pipe fittings , the fitting is screwed in until tight, difficult to orient an angled fitting correctly without over or under tightening.

O-ring boss, the fitting is screwed into a boss and orientated as needed, an additional nut tightens the fitting, washer and o-ring in place.

Flare fittings , are metal to metal compression seals deformed with a cone nut and pressed into a flare mating.

Face seal , metal flanges with a groove and o-ring are fastened together. Beam seals are costly metal to metal seals used primarily in aircraft. Swaged  seals, tubes are connected with fittings that are swaged permanently in place.

Primarily used in aircraft.

Elastomeric seals (O-ring boss and face seal) are the most common types of seals in heavy equipment and are capable of reliably sealing 6000+ psi (40+ MPa) of fluid pressure

8.3.3.4 Types Of Seals : There are various types of seals used in hydraulic pump.

BUNA N SEAL: This type of seal is excellent with petroleum products. The seal is rated for a temperature range from -20°F to +200°F, but when used for low temperatures, it is necessary to sacrifice some low temperature resistance. It is a superior material for compression set, cold flow, and tear and abrasion resistance. This seal is generally recommended for petroleum, water, digester and water-glycol. POLYURETHANE SEAL: The polyurethane seal provides excellent mechanical and physical properties. Polyurethane does not provide a good low pressure seal, due to its poor compression and permanent set properties. This seal is generally recommended for petroleum, water/oil, and phosphate ester. ETHYLENE PROPYLENE this seal is excellent when used with Skydrol 500 and Phosphate Ester Fluids. The seal is rated for a temperature range from -65° F to +350° F. This seal is generally recommended for phosphate ester, steam (to 400° F), water, and ketones. VITON SEAL: Viton seals are compatible with a wide range of fluids. This seal is rated

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for a temperature range from 15° F to +350°F. This seal is generally recommended for petroleum, silicate ester, digester, halogenated hydrocarbons, and most phosphate esters.

3.3.3 Material:

Hydraulic seals can be made from a variety of materials such as polyurethane, rubber or PTFE. The type of material is determined by the specific operating conditions or limits due to fluid type, pressure, fluid chemical compatibility or temperature

8.3.3.4 Pressure Relief Valve:

1. Introduction :

The relief valve (RV) is a type of valve used to control or limit the pressure in a system or vessel which can build up by a process upset, instrument or equipment failure, or fire.

The pressure is relieved by allowing the pressurized fluid to flow from an auxiliary passage out of the system. The relief valve is designed or set to open at a predetermined set pressure to protect pressure vessels and other equipment from being subjected to pressures that exceed their design limits. When the set pressure is exceeded, the relief valve becomes the "path of least resistance" as the valve is forced open and a portion of the fluid is diverted through the auxiliary route.

The diverted fluid (liquid, gas or liquid–gas mixture) is usually routed through a piping system known as a flare header or relief header to a central, elevated gas flare where it is usually burned and the resulting combustion gases are released to the atmosphere. As the fluid is diverted, the pressure inside the vessel will drop. Once it reaches the valve's reseating pressure, the valve will close. The blow down is usually stated as a percentage of set pressure and refers to how much the pressure needs to drop before the valve reseats. The blow down can vary from roughly 2–20%, and some valves have adjustable blow downs.

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(Figure8.9)

In high-pressure gas systems, it is recommended that the outlet of the relief valve is in the open air. In systems where the outlet is connected to piping, the opening of a relief valve will give a pressure build up in the piping system downstream of the relief valve. This often means that the relief valve will not re-seat once the set pressure is reached. For these systems often so called "differential" relief valves are used.

This means that the pressure is only working on an area that is much smaller than the openings area of the valve. If the valve is opened the pressure has to decrease enormously before the valve closes and also the outlet pressure of the valve can easily keep the valve open. Another consideration is that if other relief valves are connected to the outlet pipe system, they may open as the pressure in exhaust pipe system increases. This may cause undesired operation.

In some cases, a so-called bypass valve acts as a relief valve by being used to return all or part of the fluid discharged by a pump or gas compressor back to either a storage reservoir or the inlet of the pump or gas compressor. This is done to protect the pump or gas compressor and any associated equipment from excessive pressure. The bypass valve and bypass path can be internal (an integral part of the pump or compressor) or external (installed as a component in the fluid path). Many fire engines have such relief valves to prevent the over pressurization of fire hoses.

In other cases, equipment must be protected against being subjected to an internal vacuum (i.e., low pressure) that is lower than the equipment can withstand. In such cases, vacuum relief valves are used to open at a predetermined low pressure limit and to admit air or an inert gas into the equipment so as control the amount of vacuum.

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2. Operating Principle :

The action of pressure-reducing valves always generates heat energy because of the throttling effect. This heat generation must be taken into account when considering their application. Where two separate pressures are continuously required in a circuit, a two-pump system may prove a better solution than one using pressure-reducing valves. This will depend upon the flow and pressures required.

3. Materials :Standard models of Relief Valves are constructed of 316 stainless steel with selected components made of anti-galling stainless steel material for optimum economy and ruggedness.

8.3.3.5 Sealant Barrel

Artificial lift refers to the use of artificial means to increase the flow of liquids, such as crude oil or water, from a production well. Generally this is achieved by the use of a mechanical device inside the well (known as pump or velocity string) or by decreasing the weight of the hydrostatic column by injecting gas into the liquid some distance down the well.

Artificial lift is needed in wells when there is insufficient pressure in the reservoir to lift the produced fluids to the surface, but often used in naturally flowing wells (which do not technically need it) to increase the flow rate above what would flow naturally. The produced fluid can be oil, water or a mix of oil and water, typically mixed with some amount of gas.

8.3.4. Hydraulic pumping systems:

Hydraulic pumping systems transmit energy to the bottom of the well by means of pressurized power fluid that flows down in the wellbore tubular to a subsurface pump. There are at least three types of hydraulic subsurface pump:

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A reciprocating piston pump, where one side is powered by the (injected) drive fluid while the other side pumps the produced fluids to surface

A jet pump, where the (injected) drive fluid passes through a nozzle-throat venture combination, mixes with produced fluids and by the venture effect creates a high pressure at the discharge side of the pump.

A hydraulically driven down hole turbine (HSP), whereby the down hole drive motor is a turbine, mechanically connected to the impeller-pump section which pumps the fluid.

These systems are very versatile and have been used in shallow depths (1000 ft) to deeper wells (18,000 ft), low rate wells with production in the tens of barrels per day to wells producing in excess of 20,000 bbl (3,200 m3) per day. In most cases the drive (injected) fluid can be water or produced fluids (oil/water mix). Certain chemicals can be mixed in with the injected fluid to help control corrosion, paraffin and emulsion problems. Hydraulic pumping systems are also suitable for deviated wells where conventional pumps such as the rod pump are not feasible.

Like all systems, these systems have their operating envelopes, though with hydraulic pumps these are often misunderstood by designers. Some types of hydraulic pumps may be sensitive to solids, while jet pumps for example can pump solids volume fractions of more than 50%. They are considered the least efficient lift method, though this differs for the different types of hydraulic pumps, and also when looking at full system losses the differences in many installations are negligible.

The life-cycle cost of these systems is similar to other types of artificial lift when appropriately designed, bearing in mind that they are typically low maintenance, with jet pumps for instance having slightly higher operating (energy) costs with substantially lower purchase cost and virtually no repair cost.

8.3.5. Care and Maintenance:

By following these five (5) easy steps the Hydraulic Hand Pump will operate for many years without requiring any further maintenance. Carefully follow all Operating Instructions and the Simple Rules provided Perform Testing the Pump annually. Keep all threaded connections tight. Use a mild solvent or penetrating fluid and a clean rag to keep the Hydraulic Hand Pump

clean. Replace or repair any leaking or failed components

CHAPTER - 9

COST ESTIMATION OF HYDRAULIC LIFT

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S.NO. COMPONENTS QTY. COST(in Rs.)

1. HYDRAULIC CYLINDER 1 2900.00

2. HYDRAULIC PUMP 1 5000.00

3. HYDRAULIC OIL- 68 3 lt. 700.00

4. HOSE PIPE 1 325.00

5. UPPER PLATFORM * 1 1500.00

6. LOWER BASE * 1 1200.00

TOTAL 11,625.00

* Including Labour Charges

CHAPTER-10

DESIGN CALCULATION & ANALYSIS

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5.1       THE PISTON ROD            The piston rod is circular in shape & has length of 700mm.  The piston rod is made up of mild steel SA 36 Grade A. The compressive stress of SA 36 mild steel is 407.7 MPa.            Since the oil concentrates in the cylinder when pumped by plunger pump. This oil creates pressure in the cylinder and as the piston is free to move in the cylinder, the whole pressure acts on the cross sections of the piston.

5.2       CALCULATING LOAD BEARING CAPACITY OF PISTON ROD            In our case the pressure is applied by on one face of the piston while the other cross section of the piston faces the fixed wall.  This means that the failure or breakage of piston rod will occur only due to excessive compressive stress developed in the piston rod.            As we know that the maximum limit of compressive stress that a mild steel specimen can bear is 407.9 MPa.            Since the diameter of the piston is 47 mm therefore we can lastly calculate the amount of maximum load which can be beard by the piston.

=>                               σ =      F                                                          A

Where,                                        R = radius of the piston rod,                                        σ = stress,                                        A = area of the piston head.But,                                 A   =    πD 2 4

Area    =  π x (47) 2                                                             4

          A   =  1734 mm2

stress (σ) = 407.9 N/mm2

                   force   = stress x Area                                               = 407.9 x 1734                                               = 707325.11 N

We know,                                      1 Kg force = 9.81 N

                      Force (F) =  707325.11                                                                                                                9.81

                                 F   = 70732.5 KgAlso we know,

            =>                          1 Tone = 1000 kg.=>                          F = 70.73 Tones

This means that 70.73 is the last limit of our piston rod.  But our aim is to design the hydraulic cylinder which can easily with stand with 3 to 5 tones.

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5.3       CALCULATING THE MAXIMUM INSIDE PRESSURE OF BARREL Let’s assume a weight of 5 tones acts on the piston.  Therefore the pressure created by the piston in the cylinder or barrel can be calculated by the following formulae

                                                Pressure = Force                                                                  Area

Where area is the cross section of the piston rod.=>                   Area = πD 2

                                                 4                                            = π (47) 2  mm2

4                                            = 1734 mm2

               Pressure = Force                            Area

=>             Force = 5 tonnes

We know,              1tonnes = 1000 kg=>                      force = 5000 kg.

Again, we know                                            1 kg force = 9.81N                                                    Force = 9.81 x 5000N

=>                   Pressure = 9.81x5000   N/mm2

                                                        1734  =>                   Pressure = 28.28 N/mm2

This means that pressure of 28.28 MPa or 28.28 N/mm2 walls of the cylinder barrel when the hydraulic cylinder will loaded with 5 tones force.

5.4       CALCULATING THE THICKNESS OF THE BARREL

The lame's equations are:-σr   =  b     -  a

                     r2

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σc   =  b     +  a                      r2

Where,σr = The radial stressσc = The circumferential stressa and b  =  constantsr   =   radius

Since the internal diameter of the barrel is 47 mm as per design. Now we have to calculate the outer diameter of the barrel.

Inner radius = r1 = Di          =    47     =    23.5 mm                               2               2Since the material used for making cylinder barrel is mild steel SA36 there maximum tensile stress for this material is 410 MPai.e.    σc  at inner radius (ri) equal to 410 MPa

=>                   σc = 410 =        b         + a                                                       (23.5)2

=>                     b       +   a   =   410                                                     ………….  (1)                                 (23.5)2

Also,=>                   σ r  =  b   -   a

                                             (ri)2      

Since pressure at inner surface is 28.28 MPaσr at inner radius is equal to 28.28 N/mm2

=>                     b     -  a =  28.28 ………………………(2)                   (23.5)2

adding equation (1) & (2) we get,=>            b     + a +   b       -  a  =  410 + 28.28

                       (23.5)2       (23.5)2

=>      2b    =    438.28                    (23.5)2

=>        b   =     438.28 x   23.5 2                                           2

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=>        b = 121020

Put the value of b in Equation 2 & we get

=>        121020   -   a   =   28.28                         (23.5)2

=>                   a =      121020    -   28.28                                               (23.5)2

=>                    a = 191 N/mm2

Therefore, Lame’s equation for our case become

=>       σc = 121020  +  191                                   r2

and,=>       σr   =   121020    -   191

                                       r2

Now the barrel was must be strong enough to absorb all the stress such that the stress at the outer surface of the barrel must be zero.i.e.

=>       σr = 0  (at radius ro)

=>       σr =  121020  -  191   =  0                                   (ro)2

 =>     121020   -   191   = 0                          (ro)2

=>        ro2   =   121020   

                                       191        

=>        (ro2) = 733.621

=>         ro = 27.75 mm=>         ro = 28 mm=>        outer diameter (do) = 28 x2  = 56 mm

Barrel wall thickness (t) = Outer radius - Inner radius=>        t  =  ro – ri   =  28 -23  =  5     mm

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5.5       CALCULATING THE CAPACITY OF OIL REQUIRED BY HYDRAULIC CYLINDER In order to decide the oil capacity and the reserve oil capacity we need to calculate the minimum amount of oil used in the horizontal and vertical cylinder as well as the oil reserves in the hydraulic pips which completes the hydraulic diagram.

5.5.1   OIL REQUIRED OF HORIZONTAL CYLINDER

Oil required to run the piston out of the cylinder describes the oil capacity of he hydraulic cylinder.  This oil capacity can be figured out by calculating the working stroke volume at the cylinder.  The formula for calculating the stroke volume of the hydraulic cylinder is given as

Stock volume   =  π  x      (dia. of cylinder)2  x  (Stock length)           4

=>                   VN            =   π   (dH)2   x  SH

                                                      4Where,VN   =   Stock volume of horizontal cylinder.dH   =   Inner diameter of Horizontal cylinderSH   =   Stock length of horizontal cylinderdH   =   47 mmSh   =   350 mm

  VH             =   π  (47)2   x  700  mm 4

       =   1.214  x  103  M3

We know,

                                    1 L  =  1  dm3

And=>      (1 dm)3  =  (10 cm)3

=>             1 L   =  1000 cm3

=>    ( 1 cm )3  =  { 1    m }3

                                                       100                        =>                                     1 L = 1000 x  1           M3                                                                    (100)3            

=>            1 L   =    1000         M3

                             1000000=>           1m3  =  1000 L

=> 1.214 x 103  M3  =  1000 x 1.214 x 103

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=>                       VH  =  1.214 LWe also know,                           1  L  =  1000 mL

=>            VH  =  1214  mL

5.5.2.   OIL REQUIRED FOR VERTICAL RAM :

Let,VV   =  Stock volume for vertical cylinder dv  =  inner diameter of vertical cylinder SV =  stock length of vertical  cylinder

=>       VV  =  π     (dv)2   x sv

                                   4Here,                dV  =  47 mm

VV   =   π   (47)2   x 700 mm                           4       

VV  =  1214461.18  MM3

We know                        1 mm3 =   (   1       )3   M3

                                          1000

   VV       =   1.2144 x 10-4  M3       We know,                         1 m3   =   1000 L

    VV  =  1.2144 x 10-4 x 1000 L    VV  =  0.12144  L

Or,=>       VV  = 0.12144x1000 mL

=>       VV  = 121.44 mL

5.5.3   CALCULATING THE AMOUNT OF OIL IN PIPES & VAINSSince total length of pipe is about 1 m which will be cut and use for transferring oil to the hydraulic rams.  The diameter of this pipe is about 15 mm or 0.015 m. Therefore volume of oil which remains in the pipe can be calculated as under

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Volume of pipe =   π   x  (dia of pipe)2 x (length of pipe)                                           4

=>   VP   =   π   (0.015)2 x (1)                               4

   = 1.77 x 10-4  m3

=>       1M3  = 1000 L=>         VV   = 1.77 x 10-4   x 1000 L=>          VV  =  0.177 L

Or,=>       VV   = 177 ML approx.

5.8.4   CALCULATING TOTAL OIL CAPACITY REQUIRED FOR HYDRAULIC HAND PUMP:

The net capacity of the hydraulic hand pump must satisfy the oil demand of horizontal and vertical hydraulic cylinder as well as the pipes. Therefore the capacity of the pump tank must be equal to the sum of volume of the two rams and the pipe reserves i.e. the capacity of the tank must be greater than the oil civilized by the project.

V =  VH + VV  +  VP  +  VR

Where,               VR  =  Reserve  oil in tank               = 1000 ml for being in safe unit.=>        V = 1214 +121 + 177 + 1000=>        V = 2512 ml=>        V = 3 L approx.

CHAPTER-11

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CONCLUSION

A fundamental feature of hydraulic systems is the ability to apply force or torque multiplication in an easy way, independent of the distance between the input and output, without the need for mechanical gears or levers, either by altering the effective areas in two connected cylinders or the effective displacement (cc/rev) between a pump and motor.

The popularity of hydraulic machinery is due to the very large amount of power that can be transferred through small tubes and flexible hoses, and the high power density and wide array of actuators that can make use of this power.

Furthermore, these systems offer other advantages, such as:

 

continuously variable speed setting of drive within wide limits, easy to reverse direction of movement easy to generate very great forces and torques safe and fast-acting overload protection by means of pressure relief valve Implementation of parallel or rotator output elements (Hydraulic cylinders or hydro

motors) with a primary component (pump) in a combined system, producing the effect of a differential without additional effort.

long service life, since the fluid is self-lubricating and acts as a cooling medium Simple regulatory concept to make the best use of the drive motor with widely varying

performance requirements of the working machine. very precise adjusting simple display of load by pressure measurement device start-up from standstill to full load corrosion protection by hydraulic liquids (except water)

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REFERENCES

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