COMPRESSORS… : COMPRESSORS… Kanwar Dhaliwal 1 Compressor is……….. : Compressor is……….. 2 compressor is a mechanical device that increases the pressure of a gas by reducing its volume. Compression of a gas naturally increases its temperature.
Compressors are closely related to pumps: both increase the pressure on a fluid and both can transport the fluid through a pipe. As gases are compressible, the compressor also reduces the volume of a gas. Liquids are generally incompresible, so the main result of a pump is to move the liquid elsewhere. Kind Of Compressors are……. : Kind Of Compressors are……. Reciprocating Compressor
Rotary Screw Compressor
Axial Flow Compressor
Diaphragm Compressor 3 Reciprocating Compressor…. : Reciprocating Compressor…. use pistons driven by a crankshaft. They can be either stationary or portable, can be single or multi-staged, and can be driven by electric motors or internal combustion engines. Small reciprocating compressors from 5 to 30 horsepower (hp) are commonly seen in automotive applications and are typically for intermittent duty. Larger reciprocating compressors up to 1000 hp are still commonly found in large industrial applications, but their numbers are declining as they are replaced by less costly rotary screw compressors. Discharge pressures can range from low pressure to very high pressure (>5000 psi or 35 MPa). 4 Reciprocating Compressor…. : Reciprocating Compressor…. 5 Rotary Screw Compressor….. : Rotary Screw Compressor….. use two meshed rotating positive-displacement helical screws to force the gas into a smaller space.
These are usually for continuous operation in commercial and industrial applications and may be either stationary or portable.
Their application can be from 5 hp (3.7 kW) to over 500 hp (375 kW) and from low pressure to very high pressure (>1200 psi or 8.3 MPa).
They are commonly seen with roadside repair crews powering air-tools.
This type is also used for many automobile engine superchargers because it is easily matched to the induction capacity of a piston engine. 6 Rotary Screw Compressor….. : Rotary Screw Compressor….. 7 Axial-Flow Compressor….. : Axial-Flow Compressor….. use a series of fan-like rotating rotor blades to progressively compress the gasflow. Stationary stator vanes, located downstream of each rotor, redirect the flow onto the next set of rotor blades. The area of the gas passage diminishes through the compressor to maintain a roughly constant axial Mach number.
Axial-flow compressors are normally used in high flow applications, such as medium to large gas turbine engines.
They are almost always multi-staged. Beyond about 4:1 design pressure ratio, variable geometry is often used to improve operation. 8 Axial-Flow Compressor….. : Axial-Flow Compressor….. 9 Axial-Flow Compressor….. : Axial-Flow Compressor….. 10 Centrifugal Compressor….. : Centrifugal Compressor….. use a vaned rotating disk or impeller in a shaped housing to force the gas to the rim of the impeller, increasing the velocity of the gas. A diffuser (divergent duct) section converts the velocity energy to pressure energy.
These are for continuous, heavy industrial uses and are usually stationary.
Their application can be from 100 hp (75 kW) to thousands of horsepower. With multiple staging, they can achieve extremely high output pressures greater than 10,000 lbf/in² (69 MPa).
Many large snow-making operations (like ski resorts) use this type of compressor. They are also used in internal combustion engines as superchargers and turbochargers.
Centrifugal compressors are used in small gas turbine engines or as the final compression stage of medium sized gas turbines. 11 Centrifugal Compressor….. : Centrifugal Compressor….. 12 Centrifugal Compressor….. : Centrifugal Compressor….. 13 Mixed-Flow Compressor….. : Mixed-Flow Compressor….. are similar to a centrifugal compressor, but have a radial and axial velocity component at the exit from the rotor. The diffuser is often used to turn diagonal flow to the axial direction. The diagonal compressor has a lower diameter diffuser than the equivalent CF compressor.
A diagonal flow compressor is used in the Pratt & Whitney Canada PW600 turbofan. 14 Mixed-Flow Compressor….. : Mixed-Flow Compressor….. 15 Scroll Compressor…….. : Scroll Compressor…….. similar to a rotary screw device, it includes two interleaved spiral-shaped scrolls to compress the gas.
Its output is more pulsed than that of a rotary screw compressor, and this has caused its declining industrial use.
It can be used as an automotive supercharger, and in an air conditioner condensing unit. 16 Scroll Compressor…….. : Scroll Compressor…….. 17 Diaphragm Compressor….…. : Diaphragm Compressor….…. Diaphragm compressor is used for hydrogen and compressed natural gas (CNG). 18 Diaphragm Compressor….…. : Diaphragm Compressor….…. 19 Applications…….. : Applications…….. in pressurised aircraft to provide a breathable atmosphere of higher than ambient pressure
in jet engines to provide the great mass of operating fluid and, at high altitudes, a high enough concentration of oxygen for combustion of the air and fuel mixture. The power to turn the compressor comes from the jet's own turbines.
in many various industrial, manufacturing and building processes to power all types of pneumatic tools.
in medicine and manufacturing to store purified or manufactured gases in a small volume
as a medium for transferring energy, such as to power pneumatic equipment
in refrigeration and air conditioner equipment to move heat from one place to another in refrigerant cycles: see heat pump. 20 Applications……. (2) : Applications……. (2) in pipeline transport of domestic gas to move the gas from the production site to the consumer
in SCUBA diving, hyperbaric oxygen therapy and other life support devices to store breathing gas in a small volume such as in diving cylinders
in submarines to store gas for later use as buoyancy
in turbochargers and superchargers to increase the performance of internal combustion engines by concentrating oxygen
providing compressed air for filling pneumatic tires
in a Biogas powerplant to raise the gas pressure for the gas turbines
in rail and heavy road transport to provide compressed air for operation of rail vehicle brakes or road vehicle brakes and various other systems (doors, windscreen wipers, engine/gearbox control etc). 21 Slide 22: 22 THANK’S FOR YOUR ATTENTION Slide 23: ChE - FTUI 2006 SEE YOU AGAIN!!!