Basic Mechanical Engineering (3110006)

BE | Semester-1   Summer-2020 | 11-06-2020

Q4) (b) 

Distinguish between Reciprocating and Rotary Compressor.

Sr. No. Parameters Reciprocating Rotary
1 Discharge pressure Very high i.e. 1000 bar Very low i.e. 10 bar
2 Free air delivered The maximum free air delivery is about 300 m3/min. The maximum free air delivery is as high as 3000 m3/min.
3 Air supply The air supply is intermittent The air supply is continuous.
4 Balancing Balancing problem is major. No major balancing problem.
5 Speed Cannot run at high speed & directly coupled with the shaft of prime mover. Can be run at high speed & directly coupled with the shaft of prime mover.
6 Lubrication system Complicated Simple
7 Purity of air The air delivered is not clean as it comes in contact with lubrication oil. The air delivered is clean as it comes in contact with lubrication oil.
8 Size of compressor Large size for a given discharge. Small size for a given discharge.
9 Efficiency Isothermal efficiency is used as standard for reciprocating compressor. Isentropic efficiency is used as standard in rotary compressor.
10 Suitability Suitable for low discharge of air at very high pressure. Suitable for large discharge of air at low pressure.

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