By Shridevi Bhat 13/02/2016

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1 Reciprocating Air (Gas) Compressor By Shridevi Bhat 13/02/2016

2 Introducti on An air compressor is a device that converts power (using an electric motor, diesel or gasoline engine, etc.) into potential energy stored in pressurized air. Work required for increasing pressure of air is available from the prime mover driving the compressor. Generally, electric motor, internal combustion engine or steam engine, turbine etc. are used as prime movers. In industry, reciprocating compressors are the most widely used type for both air and refrigerant compression.

3 The US Department of Energy (2003) reports that 70 to 90 % of compressed air is lost in the form of unusable heat, friction, misuse and noise. For this reason, compressors and compressed air systems are important areas to improve energy efficiency at industrial plants.

4 History Human lungs the earliest air compressor Water organ 3rd century B.C. Ctesibius & Hero of Alexandria Water wheel driven blowing cylinder 1762 John Smeaton of England Bellows 1500 B.C. The first mechanical air compressors It was replaced in turn by the blasting machine invented by John Wilkinson in Wilkinson s blasting machine became the archetype for later mechanical air

5 Classificat ion Based on principles of operation

6 ocating air compressor is a positive displacement comp In positive displacement compressors the compression is realized by displacement of solid boundary and preventing fluid by solid boundary from flowing back in the direction of pressure gradient. Due to solid wall displacement these are capable of providing quite large pressure ratios. Non-positive displacement compressors also called as steady flow compressors use dynamic action of solid boundary for realizing pressure rise. Here fluid is not contained in definite volume and subsequent volume reduction does not occur as in case of positive displacement compressors.

7 Reciprocating compressors generally, employ piston-cylinder arrangement where displacement of piston in cylinder causes rise in pressure.

8 How it works?

Single acting and double acting compressors The reciprocating air compressor is considered single acting when the compressing is accomplished using only one side of the piston, i.e., has one discharge per revolution of crankshaft.

9 Single acting and double acting compressors The reciprocating air compressor is considered single acting when the compressing is accomplished using only one side of the piston, i.e., has one discharge per revolution of crankshaft. A compressor using both sides of the piston is considered double acting, i.e., completes two discharge strokes per revolutions of crankshaft.

10 Configurations Reciprocating compressors are available in many configurations, the four most widely used are horizontal, vertical, horizontal balance-opposed and tandem. Vertical type reciprocating compressors are used in the capacity range of cfm. Horizontal balance opposed compressors are used in the capacity range of cfm in multi-stage design and up to 10,000 cfm in single stage designs. Reciprocating air compressors are available either as air-cooled or water-cooled in lubricated and non- lubricated configurations, may be packaged, and provide a wide range of pressure and capacity selections.

11 Single stage and multistage compressors A compressor is considered to be single stage when the entire compression is accomplished with a single cylinder or a group of cylinders in parallel. Two stage machines are used for high pressures and are characterized by lower discharge temperature (140 to 160oC) compared to single-stage

12 Applicatio ns The majority of applications for reciprocating compressors are in the oil and gas industries. Oil refineries use these compressors for processes that require high pressure delivery of essential gases. The natural gas industry also utilizes reciprocating compressors to transport gas via cross country pipelines. These compressors can also be found in chemical plants, refrigeration plants, or air compressors for tooling.

13 Reference s elearning.vtu.ac.in/10/enotes/06me43/unit5-gp.p df df

Working principles of pumps

Working principles of pumps History of Reciprocating pumps In 17 th century Egyptians in Alexandria built reciprocating fire pump and and it had all the parts of today s pump. About 1805 Newcomen (Great