Piston Compressors

Piston compressor is the most widely used compressor die in the refrigeration industry. Piston compressors are specially adapted for use with refrigerants, requiring relatively small displacements and condense at relatively high pressures. R-12, R-22, R-134a, R-500 and R-502, R-717 and die environmentally safe replacement for these refrigerants commonly used refrigerants with reciprocating compressors. Although reciprocating compressors are best applied in systems with evaporator pressure above atmospheric pressure, they successfully used in conditions of low temperature and ultra-low temperatures.

Piston compressors can be produced economically in a wide range of sizes and designs that are durable and effective under the most varied conditions. These characteristics given their popularity in the refrigeration field. They are available in sizes from fractional tonnage units used in small domestic applications over 250 tons of industrial machines. As a rule, reciprocating compressors are economically employed with low-pressure refrigerants. These applications require a large volumetric displacement per unit of cooling capacity, which can not be satisfied with the limited valve port areas of piston compressors.

In addition to their classification as either open or closed, piston compressors can be single - or double-acting device. Simple steps compressor is designed so vapor compression occurs only on one side of the piston. A sectional view of the simple actions of the compressor. Double-acting compressors for vapor compression with both sides of their pistons, switch high pressure surface of the piston changes direction. This design allows the compression occur twice during each rotation of the crankshaft, while single-acting compressors only permit compression times a shaft revolution. While several of the double-acting compressors are still being used, they are no longer selected for cooling duty.

Each piston in a single-acting compressor reciprocates dirough action of the rod, what drives die, rotating the crankshaft. Connecting rod and crankshaft are enclosed in a hermetically sealed compressor crankcase. Internal compressor components come into contact with system refrigerant. This strategy provides cooling of the moving components through overheating process.

Piston compressor design altered to fit the requirements of the process. Number of cylinders, pistons, valves, bore and stroke, speed and materials used in construction are modified to produce a cost effective, efficient compressor for this application..