The actual compression cycle

When the pressure in the tank exceeds the discharge pressure, discharge valve opens and gas discharged into the system. Direct line D-gas is discharged from the cylinder, the piston ends its move up. In the upper part of his journey, there still remains about 4% (in this case) volume of the cylinder, as the gap between the upper part of the piston and cylinder end. Its quantity will vary from one compressor design to another; but, in the interest of efficiency, it is always kept at the minimum distance, in accordance with the rules of safe operation.

The graphs shown so far have assumed that no pressure loss as a refrigerant gas passes through the inlet and exhaust valves of the compressor. Real compression cycle, as shown here shows that the real pressure is higher than the direct line D-and the real suction pressure is lower than the straight line B-C. the differential pressure valves on discharge and suction caused by valve springs and turbulent gas flow around the valve and through the hole.

At point D, at the end of the compression stroke, it is necessary for the cylinder pressure exceed the discharge pressure to force open the valve against spring pressure. So with point B, at the end of the re-enlargement process just before the gas is taken into the cylinder, the cylinder pressure drop below the suction pressure to force open the valve against spring pressure. The actual wavy lines, not smooth because of the turbulent gas flow, as she passes through the valve hole. This is especially true when you first open the valves.

When the whole cycle of compression in the cylinder is considered, its outline (ABCD shown here) shows the performance of the compressor. The work done directly linked to performance of the compressor.

Several factors can reduce the amount of work compressor refrigerant gas. For example, shown here, in the area РЁРђРђР‘'CD which is caused by increased clearance volume. He is obviously much less than in the previous field ABCD. Compression cycle shows a similar reduction in the area when the discharge pressure may be increased to a suction it helped to reduce or small amounts of liquid refrigerant get compression in the cylinder. In each case, the percent of the cylinder stroke, are required to re-expand the clearance volume of the gas increases. As a result of decreases the performance of the compressor, the capacity of the system and the system of energy efficiency...