Refrigeration system including head pressure control means

Claim 2

A refrigeration system comprising in combination: a compressor, condenser, capillary flow restrictor and evaporator series connected to form a closed refrigerant circuit in which the portion of said circuit from said compressor to said expansion means defines the high pressure side of said refrigerant circuit; fans respectively driven by separate fan motors for passing a cooling stream of outdoor air over said condenser, one of said fan motors being a multi-speed motor; a circuit for controlling the energization of said second multispeed motor including an autotransformer having high, medium and low voltage taps, first and second time delay relays each including two position switches, and first and second pressure actuated switch means respectively responsive to lower and higher operating pressures in said high pressure side of said refrigerant circuit; said first switch connecting said second multi-speed motor to said low voltage tap at a high side pressure sensed by said first pressUre actuated switch means which is below said lower pressure and to said second switch at pressures above said lower pressure; said second switch connecting said second multi-speed motor to said medium voltage tap at pressures below said higher high side pressure and to said high voltage tap at pressures above said higher high side pressure; said time delay relays having time delays sufficient that upon initial energization of said compressor, said multi-speed fan motor will be sequentially connected to said low, medium and high voltage taps with sufficient delay while connected to said low voltage tap to permit the high side pressure to reach the highest level for the existing outdoor temperature.

Claim 3

A refrigeration system comprising in combination: a compressor, condenser, expansion means and evaporator series connected to form a closed refrigerant circuit in which the portion of said circuit from said compressor to said expansion means defines a high pressure side of said refrigerant circuit; first and second fans respectively driven by first and second fan motors for passing outdoor air over said condenser, said second fan motor being a multi-speed motor; control circuitry for controlling the operation of said fan motors comprising: means for energizing said first fan motor only when the outdoor temperature is above a predetermined temperature; a circuit for operating said second fan motor at high, medium and low speeds, including first and second time delay relays and first abd second pressure actuated switch means respectively responsive to lower and higher pressures in said high pressure side of said refrigerant circuit for respectively energizing said first and second relays; said time-delay relays having time delays sufficient that upon initial energization of said compressor, with said second fan motor operating at low speed, the system high side pressure will go to the highest level the system will experience at existing outdoor temperatures before said second fan motor operates at its higher speed.

Claim 4

A refrigeration system comprising in combination: a compressor, condenser, expansion means and evaporator series connected to form a closed refrigerant circuit in which the portion of said circuit from said compressor to said expansion means defines a high pressure side of said refrigerant circuit; first and second fans respectively driven by first and second fan motors for passing outdoor air over said condenser, said second fan motor being a multi-speed motor; control circuitry for controlling the operation of said fan motors comprising: means for energizing said first fan motor only when the outdoor temperature is above a predetermined temperature; a circuit for operating said second fan motor at high, medium and low speeds, including first and second time delay relays and first abd second pressure actuated switch means respectively responsive to lower and higher pressures in said high pressure side of said refrigerant circuit for respectively energizing said first and second relays; said time-delay relays having time delays sufficient that upon initial energization of said compressor, with said second fan motor operating at low speed, the system high side pressure will go to the highest level the system will experience at existing outdoor temperatures before said second fan motor operates at its higher speed.

Claim 5

A refrigeration system comprising in combination: a compressor, condenser, capillary flow restrictor and evaporator series connected to form a closed refrigerant circuit in which the portion of said circuit from said compressor to said expansion means defines the high pressure side of said refrigerant circuit; first and second fans respectively driven by first and second fan motors for passing a cooling stream of outdoor air over said condenser, said second fan motor being a multi-speed motor; control circuitry for controlling the operation of said fan motors comprising: an outdoor thermostat for energizing said first fan motor when the outdoor temperature is above a predetermined temperature and for de-energizing said first fan motor when the temperature falls below said predetermined temperature; a circuit for controlling the energization of said second fan motor including an autotransformer having high, medium and low voltage taps, first and second time delay relays each including two position switches, and first and second pressure actuated switch means respectively responsive to lower and higher operating pressures in said high pressure side of said refrigerant circuit; said first switch connecting said second fan motor to said low voltage tap at a high side pressure sensed by said first pressure actuated switch means which is below said lower pressure and to said second switch at pressures above said lower pressure; said second switch connecting said second fan motor to said medium voltage tap at pressures below said higher high side pressure and to said high voltage tap at pressures above said higher high side pressure; said time delay relays having time delays sufficient that upon initial energization of said compressor, said second fan motor will be sequentially connected to said low, medium and high voltage taps with sufficient delay while connected to said low voltage Tap to permit the high side pressure to reach the highest level for the existing outdoor temperature.

Claim 6

A refrigeration system comprising in combination: a compressor, condenser, capillary flow restrictor and evaporator series connected to form a closed refrigerant circuit in which the portion of said circuit from said compressor to said expansion means defines the high pressure side of said refrigerant circuit; first and second fans respectively driven by first and second fan motors for passing a cooling stream of outdoor air over said condenser, said second fan motor being a multi-speed motor; control circuitry for controlling the operation of said fan motors comprising: an outdoor thermostat for energizing said first fan motor when the outdoor temperature is above a predetermined temperature and for de-energizing said first fan motor when the temperature falls below said predetermined temperature; a circuit for controlling the energization of said second fan motor including an autotransformer having high, medium and low voltage taps, first and second time delay relays each including two position switches, and first and second pressure actuated switch means respectively responsive to lower and higher operating pressures in said high pressure side of said refrigerant circuit; said first switch connecting said second fan motor to said low voltage tap at a high side pressure sensed by said first pressure actuated switch means which is below said lower pressure and to said second switch at pressures above said lower pressure; said second switch connecting said second fan motor to said medium voltage tap at pressures below said higher high side pressure and to said high voltage tap at pressures above said higher high side pressure; said time delay relays having time delays sufficient that upon initial energization of said compressor, said second fan motor will be sequentially connected to said low, medium and high voltage taps with sufficient delay while connected to said low voltage Tap to permit the high side pressure to reach the highest level for the existing outdoor temperature.