Working Principle of Air Compressor Elgi.pptx

Working Principle of Air Compressors

1. INTRODUCTION OF COMPRESSOR & WORKING PRINCIPLE OF SCREW COMPRESSOR Ash Handling Plant Ravi Vijay Sahu

2. Contents:- Introduction To Compressor Classification Of Compressors Screw Compressor Conveying Air Compressor EG90W-5.5 Checking Efficiency Ƞ Of Compressor Comparison Of Compressor Energy Saving Of Compressed Air Measurement Of System Leakages Major Players In Compressor Manufacturing In India

3. INTRODUCTION OF COMPRESSOR

4. Purposes Of Compressor Compression of Gas has one basic goal – To deliver gas at a pressure higher than that originally existing. The Original Pressure level may vary from few Kg/cm 2 to Hundred Kg/cm 2 . The Rise of Pressure may vary from few Kg/cm 2 to Hundred Kg/cm 2 . Similarly Volume handled from a few cubic feet per minute to Hundred of Thousands. Uses To transmit power, as in compressed air system for operating pneumatic tools. To provide air for combustion. To transport & distribute gas, as in natural gas pipelines & city gas distribution system. To circulate a gas through a process or a system.

5. Most Commonly Known Compressor

6. Compressor We Carry Lungs

7. Classification Of Compressors On Method Of Compression Positive Displacement Type Dynamic Type On Medium Of Compression Air Compressors Gas Compressors On Motive Power Electric Motor Driven Engine Driven Turbine Driven

8. Classification Of Compressors On Mobility Stationary Type Mobile Type On Cooling Medium Used Air Cooled Type Water Cooled Type On Degree Of Oil Contamination Type Oil Free Type Lubricated Type

9. Classification Of Compressors On Working Pressure Low Pressure ( Upto 4 Bar) Medium Pressure (4 To 10 Bar) High Pressure (10 To 40 Bar) Very High Pressure (Above 40 Bar) On Capacity / Flow Rate Or Power Used Low Capacity Medium Capacity High Capacity

10. Classification Of Compressors On Number Of Stages Single Stage Multi Stage On Application Garage Type Compressors Water Well Drilling Compressors Industrial Compressors Railway Brake Compressors

11. Methods Of Compression Four Methods are used to compress gas. Two are in the Intermittent Class . Two in the Continuous Flow Class . Trap consecutive quantities of gas in some type of enclosure, reduce the volume, thus increasing the pressure, then push the compressed gas out of the enclosure. (Reciprocating) Trap consecutive quantities of gas in some type of enclosure, carry it without volume change to the discharge opening, compress the gas by backflow from the discharge system, then push the compressed gas out of the enclosure. (Rotary) Compress the gas by the mechanical action of rapidly rotating impellers or bladed rotors that impart velocity & pressure to the flowing gas (Velocity is further converted into pressure in stationary diffusers or blades). (Centrifugal) Entrain the gas in a high velocity jet of the same or another gas (usually, but not necessarily, steam) & convert the high velocity of the mixture into pressure in a diffuser. (Ejector) 1 & 2 are in the Intermittent Class known as Positive Displacement 3 is known as Dynamic Compressors 4 is known as Ejector & normally operate with an intake below atm press.

12. Compressor Types:- Positive Displacement units are those in which successive volumes of gas are confined with in closed space and elevated to a higher pressure. Reciprocating Compressors are positive – displacement machine in which the compressing and the displacing element is a piston having a reciprocating motion with in cylinder. Rotary Positive Displacement compressor are machines in which compression and displacement is effected by the positive action of rotating elements. Sliding Vane Compressor are rotary positive displacement machines in which axial vanes slides radially in a rotor eccentrically mounted in a cylinder casing. Gas trapped between vanes is compressed and displace the gas handled. Liquid Ring Compressor are rotary positive- displacement machines in which water or other liquid is used as the piston to compress and displace the gas handled. Two-Impeller Straight- Lobe Compressor are rotary positive-displacement machines in which two straight mating lobed impellers trap gas & carry it from intake to discharge. There is no internal combustion.

13. Helical Or Spiral-lobe Compressors are rotary positive-displacement machines in which two intermeshing rotors, each with a helical form, compress & displace the gas. Dynamic Compressors are rotary continuous-flow machine in which the rapidly rotating element accelerates the gas as it passes through the element, converting the velocity head into pressure, partially in the rotating element and partially in stationary diffusers or blades. Centrifugal Compressors are dynamic machines in which one or more rotating impellers, usually shrouded on the sides, accelerate the gas. Main gas flow radial. Axial Compressors are dynamic machines in which gas acceleration is obtained by the action of the bladed rotor shrouded on the blade ends. Main gas flow is axial. Mixed-flow Compressors are dynamic machines with an impeller form combining some characteristics of both the centrifugal and axial types.

14. Reciprocating Rotary Compressor Continuous - Flow Positive Displacement (Intermittent Flow) Dynamic Ejector Centrifugal Mixed - Flow Axial Flow Sliding - Vane Straight - Lobe Liquid - Piston Helical - Lobe

15. Reciprocating Compressor

16. Root Blower

17. Double Tooth Compressor

18. Vane Compressor

19. Liquid Ring

20. Scroll Compressor

21. Axial Compressor

22. Three Stage Internal Gear Centrifugal Compressor

23. SCREW COMPRESSOR

24. Invention of Screw Compressors Svenska Rotor Maskiner (SRM), Sweden ……Inventor of Screw Compressor 90 years in the development of screw 400 compressors build as prototype 25 licensees world wide More than….

25. HELICAL SCREW COMPRESSOR The helical lobe compressors are rotary positive displacement machines in which two intermeshing rotors i.e. Male & Female each with a helical Lobe & Flute form respectively, compress & discharge the air or gas. COMBINATION OF LOBE & FLUTE Following are combination of male lobe & female flute Lobe Flute 4 & 6 } Common 5 & 7 } Rarely 6 & 8 } Rarely In lub comp Male drive the Female rotor hence in combination of 4 to 6 female rotor will have lesser speed of 2/3 times of male rotor .

26. CAPACITY OF SCREW COMPRESSOR Capacity of compressor is depend on rotor diameter, length & it’s tip speed (d x l x tp). TIP SPEED OF ROTOR TIP SPEED LIMITS Maximum 50 to 52 m/sec Minimum 18 to 20 m/sec EFFECT OF OUT OF LIMIT TIP SPEEDS (a) High tip speed above 52 m/sec - Lack of suction effect (b) Less tip speed below 18 m/sec - More leakage through rotor & casing It is velocity of point farthest on circle of rotor from center.

27. ROTOR DIAMETER TO LENGTH RATIO l/d ratio of length to diameter of rotor should be between 1. 6 to 1. 8. Excess ratio more than 2 i.e length of rotor will cause deflection of rotor resulting in scoring of rotor casing. Screw to Screw Gap- 3 to 4 micron Screw to Casing Gap- 3 to 4 micron

28. WRAP ANGLE This is an angle provided on rotors for lobe & flute for mating suction & delivery port in suction & delivery casing respectively General wrap angle is 300 degree Maximum recommended is 330 degree 360 degree wrap angle will simultaneously connect suction & delivery port through rotor causing blow back hence same is not permitted.

29. COMPRESSION CYCLE

30. SECTIONAL ARRANGEMENT BARE COMPRESSOR

31. Typical Oil Lubricated Screw Compressor

32. A Modern Integrated Drive Oil Lubricated Screw Compressor

33. CONVEYING AIR COMPRESSOR EG90W-5.5 Elgi Equipments Ltd. Lubricated Water Cooled With After Cooler With Full Load / No Load Regulator. Press 5.5 Bar 17.2 m³/min 110 KW 2978 rpm

34. Operating Parameter Load Pressure 4.5 Bar UnLoad Pressure 5.5 Bar Air Outlet /Element Temp Fan 85°C Warning 105 °C Shut Down 110 °C Δ Delay 10 sec Inlet Pressure 1.8 to 2kg/cm2

35. Oil Injected Screw Compressor Flow diagram

36. Replacement Schedule Oil Every 4000hr Oil Filter Every 4000hr Air Filter Every 4000hr Air Oil Separator Every 4000hr Set Wearing Part EWD Every 8000hr Check Valve Maintenance kit Every 8000hr Stop Valve Maintenance kit Every 8000hr

37. A C B A C B 40385 40409 40721 40385 48385 52385 COMPRESSOR RUNNING HOUR

38. CHECKING EFFICIENCY Ƞ OF COMPRESSOR

39. Receiver Filling Method V1= Air Receiver Volume V2= Volume of pipe from comp discharge to air receiver P1= Load Pressure ie Intial Press in the tank. P2= Unload Pressure ie Final Press in the tank. T = Time taken to reach Final Press. Test Capacity= (V1+V2) (P2-P1) P atm x Time Ƞ = Test Capacity x 100 Actual Capacity as per name plate

40. Theoretical Method Vr= Air Receiver Volume m³ Pf= Intial Press in the tank ie 1kg/cm² Pi= Final Press in the tank. Pa= Atm Press. Time Practical= Time taken from 1 kg/cm² to max press. Time Theoretical = Vr (Pf - Pi) Pa x FAD Ƞ = T Pra x 100 T The Ƞ of Screw Compressor is 99 % Ƞ of Recep Compressor is 85- 90 %

41. COMPARISON OF COMPRESSOR TYPES

42. GENERAL COMPARISON BETWEEN RECIPROCATING, SCREW & CENTRIFUGAL COMPRESSORS

43. COMPARISON OF COMPRESSORS CHARACTERISTICS INFLUENCE ON THE SELECTION

44. GENERALISED PERFORMANCE ENVELOPES DIFERENT TYPES OF COMPRESSORS

45. ENERGY SAVING OF COMPRESSED AIR

46. System Air Leakage Pneumatic System Equivalent Electrical System 42 m³/hr Leakages @ 7.0kg/cm² 40 Nos 100 watts Bulbs Pressure Through 3 mm Hole. Kept ‘ON’ Continuously. Surrounding Air which we breathe is of Zero Cost gas but compressed air is not!. As a power source it is nine times more expensive to use than electricity! Power cost over the service life is many times of the first cost of compressor. A plant with 100 m³/min installed capacity, 3000 hr/year working and 20% leakage rate to pay Rs 20 lacs extra in power bill.

47. Air Leakages and Losses

48. MEASUREMENT OF SYSTEM LEAKAGES

49. Measure time T1 sec to raise receiver pressure from 6 kg/cm ² to 7 kg/cm ² , when consumption points are closed. Then after stopping the compressor, record time T2 sec for fall in receiver press from 7 kg/cm ² to 6kg/cm ² . % of leakage= T1 X 100 T1 + T2 If installation with poor maintenance management, this ratio is upto 25%. 10% leakage are very common and 5% are considered as ideal installations.

50. Industrial Example Compressed Air Uses Apparel Conveying, clamping, tool powering, controls and actuators, automated equipment Automotive Tool powering, stamping, control and actuators, forming, conveying Chemicals Conveying, controls and actuators. Food Dehydration, bottling, controls and actuators, conveying, spraying coatings, cleaning, vacuum packing. Furniture Air piston powering, tool powering, clamping, spraying, controls and actuators General Clamping, stamping, tool powering and cleaning, control and actuators Lumber and Wood Sawing, hoisting, clamping, pressure treatment, controls and actuators Metals Fabrication Assembly station powering, tool powering, controls and actuators injection moulding, spraying Petroleum Process gas compressing, controls and actuators Primary Metals Vacuum melting, controls and actuators, hoisting Pulp and Paper Conveying, controls and actuators Rubber and Plastics Tool powering, clamping, controls and actuators, forming, mold press powering, injection moulding. Stone, Clay, Conveying, blending, mixing, controls and actuators, glass blowing and moulding, cooling and Glass. Textiles Agitating liquids, clamping, conveying, automated equipment, controls and actuators, loom jet weaving, spinning, texturizing.

51. Major Players In Compressor Manufacturing In India Atlas Copco (I) Ltd, Pune. Chicago Pneumatic, Pune. Ingersoll Rand, Naroda, Ahmedabad. Kirloskar Pneumatic Ltd, Hadapsar Pune. Elgi, Coimbatore. Kaeser, Pune.

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