A centrifugal blower is a fan designed to move air or gases in a confined area. The centrifugal blower has a number of blades mounted around the hub, which turns on a shaft that passes through the housing. The gas enters the side of the fan wheel and by use of centrifugal force(hence the name) accelerates over the fan blades. A centrifugal blower is usually used in factories or large open places that need air flow.This could be an underground carpark, a gymnasium or any other open space with static air. There are many different centrifugal blowers on the market today and choosing one will depend on a number of factors.

The centrifugal blower has a number of blades mounted around the hub, which turns on a shaft that passes through the housing.

A Centrifugal fan can come in three different types of fan blades. They can come with forward curved blades, backward curved blades and straight radial blades. The type you need will come down to what the conditions are within the area in which you intend to use the device.

When inquiring about purchasing a centrifugal fan you will more than likely need someone from the company in which your purchasing the fan to come and take a look at the conditions the fan will be placed and also to check what kind of air pressure there is within the area.

The size of the area in which the centrifugal blower is to be used will obviously play a major part in the decision of how large it needs to be and how much air it can actually blow through the area. There are many different sizes that you can get to cover any area but depending on your circumstances you may need more than one to do the job adequately.

The type of air that is in the premises will also play a large role in which type of Centrifugal Blower you need. If the centrifugal fan is to be used in an area where the air conditions are standard then no adjustments will need to be made to the actual fan itself. On the other hand if you are going to operate the fan in other types of air density then adjustments can be made to the static pressure and brake horsepower.

Another point to be made when you are interested in purchasing a centrifugal blower is where you intend to put it. There are many different styles of centrifugal blowers, they include roof and ceiling ventilators, pressure and volume blowers, duct fans and blowers or freestanding fans and plenum fans.

There is obviously an advantage with freestanding fans as you have the opportunity of moving it to different areas of the building/factory, which is an advantage. If you do have it mounted then it is out of the way and not taking up valuable room. Most Industrial fans come with a safety guard on them now which is made so that no human appendages can accidentally go into the fan. Most centrifugal fans come with an electric motor although they do make ones

now which run off an generator also. This is a huge advantage if there is a power failure within the premises.

Most industrial fans make some kind of noise but with a lot of the new models being released now the noise level is minimal. Some can make more noise than others but this depends on the size of the fan and also the conditions which it is working in.

The highlighting features of these centrifugal blowers are:

Range from 100 CFM. To 200000 CFM and pressure range up to 1300 MM WG. The fans are available in direct drive and V belt drive arrangement. Direct drive impeller is supported by the two ball bearings and is directly mount on the

motor shaft and shaft is driven with V belt. Centrifugal fan impellers are dynamically and statically balanced after fabrication. Operating efficiency Low energy consumption Quality air delivered Quality inspected as per the standard codes

AIR COMPRESSOR:

An air compressor increases the amount of air in a particular space. By packing in the air, the air pressure is increased which creates a force that is useful for a variety of purposes, from industrial and manufacturing to commercial and personal purposes.

The original air compressor is the lung. When you take a deep breath to blow out your birthday candles, for example, you're increasing the pressure of the air in your lungs, which effectively is an air compressor containing pressurized air. You then use the force of the air in your lungs to blow out the flames of your birthday candles.

Eventually, man-made air compressors were created. These fall generally fall into one of two types, positive displacement or dynamic, defined by its mode of operation. A positive displacement air compressor works by filling and then emptying an air chamber. Three common types of positive displacement air compressors are: reciprocating, rotary screw and rotary sliding vane. A dynamic air compressor, on the other hand, uses a a rotating device to accelerate and then decelerate air. This process uses the speed or velocity of the air to increase the air's pressure. Centrifugal air compressors are dynamic air compressors.

Compressed air can be used in a variety of ways. It can be used to alter the chemical composition as in the case of making fertilizer or it can be used for industrial purposes like production line manufacturing processes or it can be used to maintain industrial plants. Perhaps the most well known use of the air compressor is in the case of pneumatic tools like air powered nail guns, staplers, sanders, spray guns, or ratchet wrenches. Air compressors can also be used to move debris. These tools are commonly available at hardware stores for purchase or rental.

Another way to group air compressor types is by the number of stages it has. A two-stage air compressor is usually used for heavy duty use. This type of unit offers a higher level of compression than smaller, single stage air compressors. A two-stage air compressor can store air for future use, and is more energy efficient since it produces more air per unit of horsepower than a single stage compressor. Also, less heat is generated in a two-stage compressor, which means that wear on the unit is reduced. Portable electric air compressors are also available for light-duty applications.

Depending on the type of air compressor, operation costs can be high, as in the case of plant maintenance. While air compressors can run on manual labor, like a hand powered air compressors, most run on either electricity or natural gas. It's the natural gas air compressor that is usually more cost-effective. If the air compressor is used in a small,

The American Society of Mechanical Engineers (ASME) attests to the quality and protective features of air compressors. Their rating can be considered in evaluating air compressors for purchase or rental. In some states, only ASME-certified air compressors may be sold. Some safety features include a safety relief valve, which lets air escape if the tank's pressure exceeds

the maximum. The air compressor should also have a belt guard for protection, and an enclosed air intake filtration system. As with all tools, proper safety should exercised when using an air compressor. When not being used, air compressors should be properly powered off and unplugged.

Air Compressor: Types

Air compressors are available in various types, which are designed to meet different requirements. Each of the type of air compressor may differ in cooling method, compression stages, lubrication and power source. Following are the three major types of air compressors:

Reciprocating (Piston) Air Compressor

Reciprocating air compressor makes use of piston to compress air and store it in a storage tank. Based on the number of compression stages, reciprocating type can be a single-stage or double-stage compressor. In single-stage, only one piston is used to compress air, whereas in double-stage compressor, there are two pistons for air compression.

Rotary Air Compressor

Rotary air compressor is similar to the positive displacement configuration of a reciprocating compressor. In rotary type, two spinning helical mated screws are used rather than piston(s). As the screws spin towards each other, air is compressed and pushed inside a storage tank.

Centrifugal Air Compressor

Centrifugal air compressor or dynamic compressor is applicable when the demand for compress air is high. In this air compressor, a high speed rotating impeller increases velocity of air, which is directed towards a diffuser that converts the velocity of air into pressure. Centrifugal air compressor requires more energy to operate than the other two air compressors.

Air Compressor: Working

Air compressor consists of two major components - compressing mechanism and a power source. The compressing mechanism can be a piston, rotating impeller or vane, whereas the power is supplied by an electric motor or other energy sources. The compressing mechanism, as the name suggests, helps in compressing atmospheric air by using energy from the power source.

The basic working principle of an air compressor is to compress atmospheric air, which is then used as per requirements. In the process, atmospheric air is drawn in through an intake valve; more and more air is pulled inside a limited space mechanically by means of piston, impeller or

vane. Since the amount of pulled atmospheric air is increased in the receiver or storage tank, pressure is raised automatically.

In simpler terms, free or atmospheric air is compressed after reducing its volume and at the same time, increasing its pressure. There is a pressure setting knob that can be manipulated as per the requirement of the operator. When the pressure increases to the maximum pressure setting in the receiver or tank, the pressure switch shuts off the intake of air in the compressor. When the compressed air is used, the pressure level falls. As the pressure drops to a low pressure setting, the pressure switch is turned on, thus allowing the intake of atmospheric air. Thus, the cycle continues in an air compressor.

Compressor powerOne of the factors used to designate compressor power is motor horsepower. However, this isn't the best indicator. You really need to know the amount of air the compressor can deliver at a specific pressure.

The rate at which a compressor can deliver a volume of air is noted in cubic feet per minute (cfm). Because atmospheric pressure plays a role in how fast air moves into the cylinder, cfm will vary with atmospheric pressure. It also varies with the temperature and humidity of the air. To set an even playing field, makers calculate standard cubic feet per minute (scfm) as cfm at sea level with 68 degrees F air at 36% relative humidity. Scfm ratings are given at a specific pressure–3.0 scfm at 90 psi, for example. If you reduce pressure, scfm goes up, and vice versa.

You also may run across a rating called displacement cfm. This figure is the product of cylinder displacement and motor rpm. In comparison with scfm, it provides an index of compressor pump efficiency.

The cfm and psi ratings are important because they indicate the tools that a particular compressor can drive. When choosing a compressor, make sure it can supply the amount of air and the pressure that your tools need.