The Evaporator Pressure-Regulating Valves Operation

For any pressure sensitive valve for modulation for more open and closed positions, changes in the working pressure is not required. The unit change in the valve position on this change in the operating pressure is called valve gradient. Each valve has a gradient it is intended to achieve the best performance. Valve sensitivity and valveР‚'s capacity rating function : valve gradient. Thus, relatively sensitive valve is required when a large change in temperature of boiling, cannot be tolerated. Therefore, the valves have a nominal ratings based on 8-psi evaporator pressure changes, and not the full cycle.

The evaporator pressure-regulating valves respond only to differences in their input pressure (pressure in the evaporator). Therefore, the purpose for evaporator pressure-control valves-ORI (opens on the rise inlet pressure) (see Fig. 11-29).

Outlet pressure is on the bottom of the bellows, and on top of the seat disc. Effective bellows area equal to the area of the port. Thus, the pressure at the output input cancels and pressure acting on the bottom of the seat disk opposes adjustable springs. These two forces operational forces in the ICU. (ТЂќ added valve designation indicates that access valve on the inlet connection.) In the evaporator of load changes, ORIT opens or closes in response to the change in pressure in the evaporator. The increase in pressure above the installation of the valve, as a rule, to open the valves. If the load decreases, less is evaporating refrigerant in the evaporator, the condenser and evaporator pressure will decrease. Reduction of pressure in the evaporator tends to move in the ICU for more than the closed position. This, in turn, maintains the pressure in the evaporator. As a result of the evaporator pressure changes as the load changes. The valve functioning of this type of improved by antichatter a device built into the valve. Without this device, " OBIT " will be exposed compressor pulsation, which can shorten the life of the furs. This antichatter function allows ORIT operate under low-load conditions without talking or other operational difficulties.

..