General Education - Compressors PDF

General Education: Compressors Maintenance Department Rev 0  Compression Basics Gases are fluids that take shape of their container and are highly compressible Compressor is a machine that receives gas at a lower density and pressure and compresses it...

General Education: Compressors Maintenance Department Rev 0  Compression Basics Gases are fluids that take shape of their container and are highly compressible Compressor is a machine that receives gas at a lower density and pressure and compresses it, resulting it into higher density and higher pressure Gas can be compressed by – Rotation of impeller – Reciprocation of piston  Compression principle This cycle It repeats. Discharge Pressure p Expansion P-V Diagram Compression Suction P-V Diagram Classification of general compressor Feature of compressor and main usage Compressor name Working pressure Feature Main usage MPa (kgf/cm2) *Comparatively has high pressure *Low pressure air Centrifugal 0.490～34.3 and large capacity. *Separation unit compressor (5～350) *Ammonia *Strong against dust and the mist. *Methanol synthesis *Jet engine *With the development of jet engine Axial 0.098～0.98 *Gas turbine compressor (1～10) *Mass air *Suitable for a large flow rate. *Pressure source *Wet process is highly effective, and an Discharge temperature. *Freezer Screw 0.147～3.43 *Oil mixing of dry *General pneumatic Compressor (1.5～35) *Suitable for disposal gas *Semiconductor relation *No pulse. *Noise size of high frequency. *Food relation *All usages and all pressures *General pneumatic *Used within the range of power. *Hydrogen Reciprocation 0.490～343 *Suitable for a high-pressure small *Oxygen Compressor (5～3500) volume. *Low-temperature *Cause constructional and pulse gas Compression Ratio  Compressor Discharge Temp Based on this, what is the relationship between compression ratio and Discharge temperature? Reciprocating Compressors Motion of reciprocating compressor 3) Reciprocating type compressor 1 Ream 2 Ream Four strings Cylinder part  Compressor Load Valve locknuts O-ring (gasket) Guide pins Spring plates Lift washers Guide ring Center bolt Compressor Unloader How does it work? 1. It keeps suction valve in “OPEN” condition. 2. As piston moves, gas returns back to suction side again. 3. Hence no increase in pressure (no load)  Reciprocating Compressor Animated Double Acting Compressor Cylinder – YouTube how Compressor Loaders Valves works.mp4 - YouTube  Screw Compressor Usually used for high capacity and high compression ratio. In OCIM, refrigerator Compressors utilise screw compressors.  Oil lubricated type and refueling Screw Compressor- wet process - (Oil screw-threaded) ⚫Consist of speeding up gear, bearing, mechanism seal, casing, male rotor, female rotor, and input shaft ⚫The power supplied by the electric motor ⚫It is transmitted to male rotor through the speeding up Refueling type single stage gear, and tooth form. with built-in speeding up gear ⚫The female rotor rotates by engagement. Mechanical seal Input axis ⚫It is lubricated by the oil between rotors Gas inlet Built-in gear Enlarged view of rotor Female rotor Female rotor Radial bearing Male rotor Radial thrust bearing Male rotor: Four piece teeth of convex Lubricant oil pump Casing Female rotor: Six piece teeth Gas outlet Male rotor of concave type  4. Compression mechanism (For the wet process) ① Inlet process ③ Compression completion Inlet The male rotor is The injected oil also connected with electric motor, and becomes mist by the the female rotor is rotor rotation and gas rotated by rotating stream, and not only the male rotor. increase temperature by The gas is aspirated the gas compression but from the inlet in a also it does highly Female Male part of the casing effective compression. according to the groove. ④ Discharge process ② Compressed process Oil injection The inlet port is sealed, When the rotor rotates and it and the capacity of the reaches the exhaust slot, groove decreases compressed gas mixed with gradually, and it is oil will be exhausted. compressed by rotating the rotor. Pulses don’t occur ,when The cooled oil is injected suction and discharge, from the injection port because the rotation of the provided for the casing atExhaust rotor is fast. slot the same time.  Screw Compressor Capacity Control Reciprocating compressors can use unloader Screw compressors uses Slide valve Slide valves increase the volume at the compression area thus reducing the pressure at the initial compression area. CSH Screw Compressor - Slider Valve - YouTube  What should an operator look for during patrol? 1. Net flow through compressor 2. Suction and discharge pressure. Compression ratio 3. Suction and discharge temperatures 4. High discharge temperatures or surging conditions 5. Oil pressures and levels 6. Gas seal panel 7. Bearing temperatures 8. Vibration 9. Power loading 10. Signs of surging Let’s go to site!!! Observe – Wonder – Infer