THE ROLE OF RECIPROCATING COMPRESSORS

Here are a few observations regarding the current role and future prospects of the piston compressors in the industrial process refrigeration. For several decades, its falling market, some manufacturers reciprocating compressors disbanded their production. The result is that only the strong producers reciprocating compressors remain today. Sale of reciprocating compressors seems to have stabilized at this lower level in North America, while in Europe and Asia reciprocating compressors maintained a strong position. Maintenance and repair requirements remain less complicated for reciprocating compressors.

Clients often prefer to screw compressor due to lower maintenance costs. Screw compressor can work 30,000 to 60,000 hours prior to the overhaul, while the plant operators have traditionally serviced reciprocating compressors in year. However, many manufacturers reciprocating compressors recommend, while the cylinder heads should be solved in a year for a checkup that machines can be operated between 10 000 and 20 000 hours to repair. What happened requirement annual overhaul? Largely this was a tradition, and in some cases, it is recommended by the manufacturer for further profitable sale of spare parts. When operating conditions are not offensive, the annual repair of compressors may not be necessary in connection with improvement of quality of materials and production processes available today.

The efficiencies of reciprocating and screw compressors have the same order of magnitude at full load. The cooling capacity is less than 350 kW (100 tons of cooling systems) reciprocating compressor is slightly more efficient. At partial load, piston compressor with cylinder higher and higher, almost always has a higher efficiency than the screw compressor. The first one costs of reciprocating compressors is typically smaller than the screw compressor the same pumping capacity. The first comparison of the cost of switches in favor of the screw compressor in large amounts, when one screw compressor can provide several power of reciprocating compressors. Screw compressor can work against higher compression ratios than reciprocating compressor. Thus, screw compressor can run one phase from the low temperatures of the evaporator in a two-stage system in the periods of low capacity demands.

Maximum cooling capacity of the largest piston compressor available on the market in the ordinary middle stage of application is approximately 900 kW (250 tons of refrigeration), while one big screw compressor can supply more than 4000 kW (1,200 tons). The owner of a large power plant will allow to reduce capital costs by choosing a screw compressors, and place machines much less space. If the refrigerating demand at the plant more than what is capable of being provided by one of piston compressors, two units would be needed, which is more expensive than the one screw compressors, reciprocating compressors, has the advantage of having a single unit as a backup, if the other will not work.

It must be accepted that the piston compressors provide only part of the performance of the compressor for the industry of the future. His place is likely to be in plants with less than 1000 kW (300 tons), and many of these plants exist. In many packaged refrigeration, such as ice generators, reciprocating compressors typically support. Treatment of reciprocating compressors in this book reflects the assessment, reciprocating compressors, although providing much fewer opportunities for the industry than a screw compressor, still extremely important. In addition, some of the analysis of efficiency of piston compressors translate directly with screw compressors as well...