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Mech_intBy Avinash Sir
Why?
Where?
Which?
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Pressure Ratio
Ratio of absolute discharge press. / absolute inlet pressure
Compressor capacity
It is the quantity of actual free air delivered by the compressor
Free air delivered(FAD)
It is the volume of air actually delivered under the conditions of temperature and pressure existing at the compressor intake.
Swept volume
It is the volume swept by the recip. compressor piston during suction or delivery stroke
Pneumatics, the use of pressurized gases to do work. See compressed air energy storage.
Vehicular transportation using a compressed air vehicle
Energy storage
Scuba diving, to inflate buoyancy devices.
Cooling using a vortex tube.
Gas dusters for cleaning electronic components that cannot be cleaned with water.
Railway braking systems
Road vehicle braking systems
Diesel engine cranking
Paintball ammunition propulsion
Airsoft ammunition propulsion
Air tools
Cleaning the insides of electronics
SINGLE STAGE
One suction and one delivery
MULTI STAGE
One actual suction and multiple sub suctions and sub-deliveries
SINGLE ACTING
One piston delivers from only one side
DOUBLE ACTING
Piston delivers from both sides
Construction
Volumetric efficiency
1. Depends on clearance(IP)2. Piston ring leakage3. Speed of compressor(IP)4. Fresh air coming in contact with hot wall
expands and decreases Vol. Eff.
Isothermal efficiency
Mechanical eff. = IP / SP
Vol. eff. Increases
Power IP decreases
Uniform torque and flywheel size reduced
Max. temp reduced so less lubrication
Reduced leakage loss due to reduced pressure difference across piston and valves
Reduced wt. of cylinders.
Screw compressors Positive displacement compressors
Driver and driven rotor (sometimes only one rotor)
Air is sucked form one side and compressed in the variable space between the rotors both axially and radially
Advantages:
1. High volumetric eff.
2. Uniform and continuous flow
3. Perfect balancing due to pure rotary motion
Same as screw compressor
Both rotors have mating geometric profiles
Air is compresses in the variable space in the mating of the blowers
Spring fitted vanes to vary the space between the vanes
The rotor is fitted eccentrically to obtain the variable area
Reversibly and irreversibly compressed
Low speeds are suitable