ORD valve

ORD valve pressure drop across the valve. It responds to changes in the pressure drop across the valve (see Fig. 11-34). Valve designation stands for open on the rise differential pressure. Therefore ORD depends on some other control valve or action for its operation. In this sense, it is used with either ORI'ORO for head-pressure control.

No matter how ORI'ORO valve starts to regulate the flow of liquid refrigerant from the condenser pressure drop created by ORD. If this difference reaches 20 psi, ORD starts to open and bypasses the hot gas in a liquid drain-line. As the differential increases, ORD opens on, up to its full speed is achieved with a differential of 30 psi. Thanks to the control of pressure, the full course can be used when choosing ORD. While capacity ORD increases as the pressure drop increases, paragraph rating of 30 psi considered satisfactory maximum value.

Standard pressure setting for ORD-20 pounds per square inch. For systems where the condenser pressure drop is higher than 10 or 12 psi, ORD with higher settings may be ordered.

Head-pressure control can be improved with the arrangement, as shown on Fig. 11-35. In this operation, the constant pressure in the receiver supported for normal system operation. ARI is regulated by more than the nominal range from 100 to 225 pounds per square inch. Thus, the desired pressure can be maintained for all commonly used refrigerants 12, 22, and 502, and as a last alternative.

ARI is in the liquid drain line between the condenser and receiver. ORD is " the hot line of the gas pipeline bypass capacitor. In periods of low temperature, the condensing pressure falls until it approaches the installation ORI valve. ORI then chokes, limiting the flow of liquid from the condenser. This causes the refrigerant in the condenser, thus reducing the active surface of the condenser. This raises the pressure of condensation. Because it really is a receiver pressure that needs to be maintained, the bypass line with ORD required.

ORD opened after the ORI proposed limit is sufficient reason for the difference between the condensing pressure and the pressure in the receiver exceed 20 pounds per square inch. Hot gas flowing through ORD heats the cold liquids transmitted by the ORI. Therefore, the liquid reaches the receiver, warm and with sufficient pressure to ensure proper expansion valve. Until enough of refrigerant in the system, two valves modulation of the flow automatically to maintain the correct pressure in the receiver, regardless of outside temperature of the environment.