Compression-ignition process
Piston type, very widely used, being flexible, size, number of cylinders, the speed and the way drive. It works on the two-stroke cycle (see Fig. 4.4). Automatic pressure-driven suction and discharge valves are used as shown in Fig. 4.4. As the piston descends on the suction stroke, the intake valve opens to recognize gas from the evaporator. At the bottom of the stroke, the valve closes again, as the compression stroke begins. When the cylinder pressure becomes higher than in the discharge pipe, the discharge valve opens and compressed gas, reports the condenser.
Gas left in the lumen at the top of the kick must be redistributed before a fresh charge can log into the cylinder, see Fig. 4.4d. Suction valve will not close until the pressure in the tank is lower than the suction pressure. More re-expansion or clearance volume means the piston must go beyond the cylinder before the pressure falls below the suction pressure. The further course of the piston, without opening the valve, the greater the loss.
The process is shown in the pressure-volume or indicator diagram (Fig. 4.5). Chart area necessary for the compression and gas discharge.
 ....
|
Compressors 
....