초록 ▼

In a space cooling system having an evaporator in heat exchange relationship with a space to be cooled, a condenser external to the space, a compressor for circulating heat transfer fluid between the evaporator and condenser, an expansion valve for controlling the flow rate of heat transfer fluid th

In a space cooling system having an evaporator in heat exchange relationship with a space to be cooled, a condenser external to the space, a compressor for circulating heat transfer fluid between the evaporator and condenser, an expansion valve for controlling the flow rate of heat transfer fluid through the evaporator, apparatus for automatically closing the expansion valve in response to a loss of electrical power to the system. The apparatus includes a storage capacitor for storing electrical energy when power is being supplied to the system, a voltage detector for detecting a loss of electrical power and a controller for controlling a step motor to close the expansion valve in response to a loss of system power. The capacitor automatically discharges in response to a power loss condition to supply power to the controller and step motor to enable the expansion valve to be closed. Therefore, refrigerant migration in the system, which can damage the compressor upon restart, is substantially inhibited.

대표청구항 ▼

[ What is claimed is:] [1.]1. A space cooling system having an evaporator in heat exchange relationship with a space to be cooled, a condenser external to the space, a compressor for circulating heat transfer fluid between the evaporator and the condenser, and an expansion valve between an outlet si

[ What is claimed is:] [1.]1. A space cooling system having an evaporator in heat exchange relationship with a space to be cooled, a condenser external to the space, a compressor for circulating heat transfer fluid between the evaporator and the condenser, and an expansion valve between an outlet side of the condenser and an inlet side of the evaporator for controlling flow of heat transfer fluid through the evaporator, an electrically operable device for opening and closing the expansion valve, and an electrical power source, apparatus for automatically closing the expansion valve in response to a substantial loss of electrical power from the source, said apparatus comprising:a capacitor coupled to the electrical power source for being charged by the power source;a regulator device intermediate the power supply and said capacitor for regulating voltage across said capacitor;a detector for detecting a substantial loss of electrical power from the power source and for generating an electrical signal indicative thereof; anda controller responsive to said electrical signal for generating a control signal to control the electrically operable device to close the expansion valve, said capacitor being operable to automatically discharge in response to a substantial loss of electrical power to provide electrical power to said controller and to the electrically operable device.