Internship Report

Pakistan Ordnance

Factories

Raheel

raheel_siddique@outlook.com

August 23, 2015

Transport Shop

TPT SHOPS

Petrol Shop (Petrol Engine) Diesel Shop (Diesel Engine)

Engine:

Engine is a device which converts heat energy into mechanical energy or work.

Types of Engine

IC Engine(efficiency 35%) EC Engine(efficiency 16%)

SI Engine CI Engine

IC Engine:

The engine in which the combustion takes place inside the cylinder and is ultimately responsible for

moving the piston up or down, within the cylinder. A/F is 1:7.

Difference b/w SI & CI Engine:

Petrol is used. Diesel is used.

Mixture of Air & Fuel are compressed. Air is compressed then fuel is injected.

Spark plug is used. Fuel injector is used.

Basic Parts of IC Engine:

Cylinder.

Piston.

Connecting Rod.

Crank Shaft.

Spark Plug(petrol engine).

Fuel Injector(diesel engine).

4-Stroke IC Engine:

4-stroke mean two revolutions of crank shaft & four piston strokes.

4-strokes are as follows:

1st stroke (Intake Stroke):

The engine cycle begins with the intake stroke as the piston is pulled towards the crankshaft . The

intake valve is open, and fuel and air are drawn past the valve and into the combustion chamber and

cylinder from the intake manifold located on top of the combustion chamber, exhaust valve is closed,

fuel/air mixture is at a relatively low pressure.

2nd

stroke (Compression Stroke):

With both valves closed, the combination of the cylinder and combustion chamber form a

completely closed vessel containing the fuel/air mixture. As the piston is pushed to the right, the volume is

reduced and the fuel/air mixture is compressed during the compression stroke, the pressure in the gas is

increased.

3rd

stroke (Power Stroke):

At the beginning of the power stroke, the electrical contact is opened. The sudden opening of the

contact produces a spark in the combustion chamber which ignites the fuel/air mixture. Rapid combustion

of the fuel releases heat, and produces exhaust gases in the combustion chamber, The combustion increases

the temperature of the exhaust gases.

4th

stroke (Exhaust Stroke):

At the end of the power stroke, the piston is located at the far left. Heat that is left over from the

power stroke is now transferred to the water in the water jacket until the pressure approaches atmospheric pressure.

The exhaust valve is then opened by the cam pushing on the rocker arm to begin the exhaust stroke, the exhaust

valve is open, the exhaust gas is pushed past the valve and exits the engine.

4-Stroke SI Engine:

Cylinder arrangement:

Common cylinder arrangements are from 1 to 6 cylinders in-line or from 2 to 16 cylinders in V-formation. Flat engines – like a V design flattened out – are common in small airplanes and motorcycles and were a hallmark of

Volkswagen automobiles into the 1990s. Flat 6s are still used in many modern Porsches, as well as Subarus. Many

flat engines are air-cooled. Less common, but notable in vehicles designed for high speeds is the W formation,

similar to having 2 V engines side by side. Alternatives include rotary and radial engines the latter typically have 7

or 9 cylinders in a single ring, or 10 or 14 cylinders in two rings.

Compression ratio:

The compression ratio is the ratio between the total volumes of the cylinder AND the combustion chambers – at the

beginning, and end of the compression stroke. Broadly speaking, the higher the compression ratio, the higher the

efficiency of the engine. However, compression ratio has to be limited to avoid pre-ignition of the fuel-air mixture

which would cause engine knocking and damage to the engine. Modern motor-car engine overall have compression

ratios of between 9:1 and 10:1, but this can go up to 11 or 12:1 for high-performance engines that run on higher

octane fuel.

Diesel shop:

A diesel engine (also known as a compression-ignition engine) is an internal combustion engine that uses

the heat of compression to initiate ignition to burn the fuel, which is injected into the combustion chamber. This is in

contrast to spark-ignition engines such as a petrol engine (gasoline engine) or gas engine (using a gaseous fuel as

opposed to gasoline), which uses a spark plug to ignite an air-fuel mixture. The engine was developed by Rudolf

Diesel in 1893.

The diesel engine has the highest thermal efficiency of any regular internal or external combustion engine due to its

very high compression ratio. Low-speed Diesel engines (as used in ships and other applications where overall engine

weight is relatively unimportant) often have a thermal efficiency which exceeds 50 percent.

Basic Parts Of IC Engine:

POWER HOUSE

THERMAL POWER PLANT

Demineralization of Water:

Demineralization is a process of removal of minerals from the raw water.

Flow Chart of Demineralization of Water:

Air + CO2 caustic

soda

Degassed pump

Pump Air blower

Raw water

Chemical & mechanical process is used to remove O2.

Zeolite chemical is used to remove minerals.

Chemical is change after 1 year.

BOILER:

Boiler is a device used to generate steam at high pressure & high temperature.

In POF D-Type water tube boiler is used.

Natural Gas is used as a fuel.

Starva-

tion

unit

Cati

on

+

c 225

Ani

on

–

A

162

Mix

ed

bed

unit

(A+

C)

Storage Tank

After starvation unit Acidic Water.

Before starvation unit Raw Water.

Combustion can take place when Air mix with Natural gas.

Steam capacity is 27 ton/hr.

Temperature of steam 405 deg C.

Steam pressure is 370psi or 26bar.

SCADA System:

It is the tripping control system or through which we can distribute the current from control room.

STEAM TURBINE:

It is a device which converts high temperature & high pressure steam into the

mechanical energy.

Ten bearings are used i.e 4bearings on reduction gears, 2bearings on generators,

4bearings on rotor.

Three turbines are used in power plant.

Turbine #1 Turbine #2 Turbine #3

CAPACITY: 6/8MW 10MW 6/8MW

RPM: 8000rpm 5684rpm 9923rpm

Types of Steam Turbine:

Impulse Turbine Reaction Turbine

Pressure Velocity Compounding:

Pressure Velocity Compounding is the combination of pressure compounding &

velocity compounding.

Compounding is used for reduction of turbine speed.

In pressure compounding pressure drops from boiler pressure to condenser pressure

takes place in more than one steps.

In velocity compounding pressure drops from boiler pressure to condenser pressure

takes place in one steps.

Rings of moving blades, fixed blades & nozzles are present.

Rings Row of Moving Blades:

Gas Generators:

Generator is a device which converts mechanical energy into electrical energy.

Wartsila SG220.

SG means Super Charged.

Dia is 220mm.

V –Type 12 cylinder engine is used.

In A Type 6 cylinders & in B Type 6 cylinders are present.

Air is compressed at 28bar.

MCC (main combustion chamber) + PCC(pre combustion chamber )

Capacity 11kv.

10 MW

2MW 2MW 2MW 2MW 2MW

FABRICTION SHOP: D-24

Fabrication :

A process in which sheets or plates, angle iron, rods & strips are cut, bend, rolled & joint manually or by

machines to manufacture a required workpiece is called Fabrication.

Following machines are present in this shop:

Warco press:

This press is used for bending operations according to the requirement, dies & punches can be

changed according to the shape of desired workpiece.

Capacity : 100 ton

Stroke : 30/min.

Hydraulic Rolling Machine:

This machine is used for rolling operations at 360 deg angle.

It has capacity to roll 12.5mm thick plate.

Shearing Machine:

This machine is used for cutting operations.

It has capacity to cut the sheets having thickness 0.5in MS & 3/8in SS.

2ND Shearing machine is used to cut 3.5mm thickness of sheet.

Radial Type Drilling Machine:

This machine is used for heavy work,the property of machine is that it can move 360deg along

its axis.It can be operated by both ways, manually as well as mechanically.

Rolling Machine:

This machine is used for rolling operations mechanically.It has capacity to roll the sheets of

4mm thickness.

Spot Welding Machine:

It is a type of resistance welding. Spot welding operation is performed on thin sheets.

Universal Cutting Machine:

This machine is used to cut rods, square & angle iron of 3 by 3in(w to d)

Bending Machine:

This machine is used for bending operations.It has capacity to bend the sheets having thickness upto 2mm at 0deg to

180deg.

Fly Press or Hand Press:

This machine is used for bending operations by the use of dies & punches.It has capacity to bend the sheets having

thickness upto 1mm.

Hydraulic Saw:

It is used for cutting the bars , channels, pipes etc in fabrication shop various number of

hydraulic machines are installed which are capable of cutting 1 ½ `` - 2 `` thick pipes, sheets etc.

Universal Rolling Machine:

This machine is used for the rolling of angle iron, rods & strips especially for manufacturing of flanges.

Hydraulic Pipe Bending Machine:

It has four parts:

1. Former 2. Counter Die 3. Mandrel 4. Bed.

It has capacity to bend the pipes having dia 6in.

In fabrication shop there is another section which is known as the Duct Section. In the duct section

following machines are installed.

1. Spot Welding Machine

2. Notching Machine

3. Grooving Machine

4. Bending Machine

Refrigeration Shop:

Air Condition (AC):

It has basic three parts:

1. Compressor.

2. Condenser.

3. Evaporator.

Gas freeon 22.

Gas properties:

High temperature & high pressure air is compressed.

Through Condenser it convert into liquid, it condense & cooled.

The liquid come into the capillaries & evaporates in big tubes.

Safety : suction sustainer.

Current : 11 A

Material: Cu & Al.

Machine Shop:D-21

INTRODUCTION:

This is basically maintence shop and provide services to whole POF. There are certain groups of machines are installed on

the shop floor they are:

Milling Machines

Lathe Machines

Planning Machine

Shaper Machine

Drilling Machine

Gear Hobbing Machines

Universal Milling Machine

Capstan Lathe

Milling Copying Machine

1. Turning group:

Turning group consists of following machines

Centre lathe

Turning/boring mill

Capstan lathe

2. Milling group:

Milling group consists of following machines

Horizontal milling

Vertical milling

Universal milling

Gear hobbing machine

Copy milling machine

Cam milling machine

Gear chamfering machine

3. Shaping Group:

Shaping group consists of following machines

Shaping group consists of following machines

Vertical shaper machine

Horizontal shaper machine

4. Grinding Group:

Grinding group consists of following machines

Universal grinding machine

Cam-shaft grinding machine

Surface grinding machine

Crank-shaft grinding machine

Details of some basic machines:

Centre lathe:

Centre lathe is a machine tool which spins a block of material to perform various operations such as cutting, sanding, knurling, drilling, or deformation with tools that are applied to the work piece to create an object

which has symmetry about an axis of rotation.

Lathes are used in woodturning, metalworking, metal spinning, and glass working. Lathes can be used to

shape pottery, the best-known design being the potter's wheel.

Capstan lathe: The turret lathe is a form of metalworking lathe that is used for repetitive production of duplicate

parts (which by the nature of their cutting process are usually interchangeable). It evolved from earlier lathes with the

addition of the turret, which is an index able tool holder that allows multiple cutting operations to be performed, each with a

different cutting tool, in easy, rapid succession, with no need for the operator to perform setup tasks in between (such as

installing or uninstalling tools) nor to control the tool path. (The latter is due to the tool path’s being controlled by the

machine, either in jig-like fashion [via the mechanical limits placed on it by the turret's slide and stops] or via IT-directed

servomechanisms [on CNC lathes].)

Universal milling machine: This machine is used for making helical gears. This machine is called

universal because its table can be tilted.

Gear hobbing machine: This machine is used for the mass production of gears.

Cam milling machine: This machine is used for making a cam.

Universal grinding machine: This machine is used for internal and external grinding. Grinding

allowance of this machine is .5mm.

Crankshaft grinding machine: This machine is used for grinding crankshaft.

Cylindrical grinding machine: This machine is used for only external grinding.

Cutters used in Milling machines:

Spur gear

Helical gear

Hub gears

Double helical gears

Worm gears

Rack and pinion

Materials: MS, 3% nickel chrome, 1.5% nickel chrome, copper, brass, phosphorous bronze, cast iron,

stainless steel, carbon steel oil hard, water hard, Gun Metal.