Refrigeration positive displacement compressors

Positive-Displacement Compressors Reciprocating compressors are built in different sizes (up to about one megawatt refrigeration capacity per unit). Modern compressors are high-speed, mostly direct-coupled, single-ac ting, from one to mostly eight, and occasion-aUy up to sixteen c inders. 

Compressors used in a typical refrigerator/freezer are of the positive displacement type, utilizing either reciprocating or rotary motion (Eig. 5) and... 

The spiral-lobe and helical-screw compressors are rotary positive-displacement machines and quite adaptable to a wide assortment of process and refrigeration gases. This class of equipment is usually built to comply with the American Petroleum Institute Standard 619. These units oper-... 

Positive displacement pumps and compressors—12 months Vessels with corrosive chemicals—12 months Process vessels with heat or refrigeration sources—12 months Boilers (usually controlled by State law)—12 months Steam headers— 24 months Storage vessels (clean)—24 months Instrument air manifolds— 36 months Lubricating relief valves— 36 months... 

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