Refrigeration – Refrigeration producer – Compressor-condenser-evaporator circuit
Reexamination Certificate
2002-06-14
2003-11-11
Jones, Melvin (Department: 3744)
Refrigeration
Refrigeration producer
Compressor-condenser-evaporator circuit
C062SDIG001
Reexamination Certificate
active
06644066
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to a cooling system, and, more particularly to a method and apparatus to relieve liquid pressure from a receiver to a condenser when the receiver is filled with liquid refrigerant due to ambient temperature cycling.
BACKGROUND OF THE INVENTION
Electronic equipment in a critical space, such as a computer room or telecommunication room, requires precise, reliable control of room temperature, humidity and airflow. Excessive heat or humidity can damage or impair the operation of computer systems and other components. For this reason, precision cooling systems are operated to provide cooling in these situations.
Precision cooling systems are often operated year round. Maintaining pressure levels in precision cooling systems that operate year round presents a number of challenges. Under low, ambient temperature conditions, the condenser may be exposed to a temperature as much as 75 degrees Fahrenheit lower than the evaporator temperature. To operate efficiently when the condenser is significantly cooler than the evaporator, head pressure in the condenser must be maintained.
When outdoor temperature conditions are warmer, refrigerant in the condenser may be warmed during an off-cycle and may undergo thermal expansion. Refrigerant may then accumulate in parts of the cooling system, such as a receiver. The pressure may rise above a maximum level, causing a relief valve to open and vent the excess pressure from the system.
The present invention is directed to overcoming, or at least reducing the effects of, one or more of the problems set forth above.
SUMMARY OF THE INVENTION
One aspect of the present invention provides a cooling system, including a condenser, a receiver and a means for balancing pressure between the condenser and the receiver. The receiver is connected to the condenser. The pressure-balancing means maintains a desired pressure differential between the receiver and the condenser and prevents pressure in the receiver above a maximum pressure level.
Another aspect of the present invention provides a cooling system, including a condenser, a receiver, a check valve and a pressure-balancing valve. The receiver is connected to the condenser. The check valve is connected between the condenser and the receiver and permits refrigerant flow from the condenser to the receiver. The pressure-balancing valve is connected between the condenser and the receiver and permits refrigerant flow from the receiver to the condenser in response to a predetermined pressure differential between the receiver and the condenser.
Yet another aspect of the present invention provides a method of balancing pressure in a cooling system. The method includes the step of maintaining a desired pressure differential between a receiver and a condenser by allowing refrigerant flow from the condenser to the receiver when a first pressure differential occurs between the condenser and the receiver. The method also includes preventing receiver pressure above a predetermined level by allowing refrigerant flow from the receiver to the condenser when a second pressure differential occurs between the receiver and the condenser.
The foregoing summary is not intended to summarize each potential embodiment, or every aspect of the invention disclosed herein, but merely to summarize the appended claims.
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Howrey Simon Arnold & White , LLP
Jones Melvin
Liebert Corporation
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