초록 ▼

Apparatus for and a method of automatically adjusting the superheat setting of a thermostatic expansion valve of a refrigeration system is disclosed in which the superheat of the refrigeration system is maintained at a low superheat level so as to maximize the operating efficiency of the refrigerati

Apparatus for and a method of automatically adjusting the superheat setting of a thermostatic expansion valve of a refrigeration system is disclosed in which the superheat of the refrigeration system is maintained at a low superheat level so as to maximize the operating efficiency of the refrigeration system, and yet which prevents the return of excessive amounts of liquid refrigerant to the compressor which would be likely to cause damage to the compressor. This apparatus includes an electric heater for biasing the thermostatic sensing bulb of the thermostatic expansion valve and a control for the heater which is responsive to a refrigeration system parameter, such as the temperature of the lubricant in the compressor sump, so as to effect an increase in the temperature of the thermostatic bulb above the refrigerant temperature upon an indicated change in the parameter being monitored thereby to, in effect, reduce the superheat setting of the thermostatic expansion valve and to increase the flow of refrigerant through the refrigeration system. Upon sensing another indicated change in the parameter, the heater is de-energized (or at least the heater power is reduced) thereby to effect an increase in the superheat setting of the thermostatic expansion valve and to reduce the flow of refrigerant.

대표청구항 ▼

In a heat pump system comprising a compressor having an inlet and an outlet, a first coil located out of doors, a second coil located indoors, said indoor and outdoor coils being in communication with one another, a shiftable valve connected to the outlet and the inlet of the compressor and to the o

In a heat pump system comprising a compressor having an inlet and an outlet, a first coil located out of doors, a second coil located indoors, said indoor and outdoor coils being in communication with one another, a shiftable valve connected to the outlet and the inlet of the compressor and to the outdoor and indoor coils, said valve being selectively shiftable between a first position in which refrigerant is delivered from the outlet of the compressor to the outdoor coil such that the heat pump system is operated in a cooling mode and a second position in which refrigerant is delivered from the outlet of said compressor to said indoor coil such that said heat pump system is operated in a heating mode, and a thermostatic expansion valve between said indoor and said outdoor coils, said thermostatic expansion valve having a thermostatic sensor in heat transfer relation with the refrigerant discharged from one of said coils for automatically varying the flow of refrigerant through said thermostatic expansion valve so as to maintain the refrigerant entering said compressor at a predetermined superheat level, said thermostatic expansion valve being pre-set at a predetermined superheat setting, wherein the improvement comprises: an electric heater in heat transfer relation with said thermostatic sensor, and control means responsive to an operating parameter of said heat pump system operating parameter for varying the heat output of said heater thereby to vary said superheat setting of said thermostatic expansion valve, said control means including means responsive to said heat pump system operating parameter when the heat pump system is in its heating mode for operating said heater along a first heater power output versus said operating parameter value function and being further responsive to said heat pump refrigeration system operating parameter when the heat pump system is in its cooling mode for operating said heater along a second heater power output function versus said operating parameter value function.