Refrigerant recovery system

• US 5,875,638 A
• Filed: 03/23/1995
• Issued: 03/02/1999
• Est. Priority Date: 05/03/1993
• Status: Expired due to Fees

• Current Assignee: Copeland Corporation LLC (Emerson Electric Company)
• Original Assignee: Copeland Corporation LLC (Emerson Electric Company)
• Inventors: Tinsler, Theodore E.
• Primary Examiner(s): Sollecito, John M.
• Application Number:
  US08/408,995
• Time in Patent Office: 1,440 Days
• Field of Search: 62/77, 62/85, 62/292, 62/149, 62/231, 62/151, 62/150
• US Class Current: 62/149
• CPC Class Codes: F25B 2345/002 Collecting refrigerant from a cycle
• CPC Class Codes: F25B 45/00 Arrangements for charging or discharging refrigerant

Abstract

A refrigerant recovery system and method for recovering refrigerant from a separate refrigeration system are disclosed which first employs a liquid recovery phase and then a subsequent vapor recovery phase. A liquid sensor monitors the incoming recovered refrigerant and produces a signal indicative of when all of the liquid refrigerant has been recovered from the separate refrigeration system. The timer relay continues the liquid refrigerant recovery phase of operation for an additional predetermined time period once the signal is sensed. Thereafter, the recovery system switches to the vapor recovery phase of operation for yet an additional time period. The system then switches between these two phases until a predetermined condition occurs. An alternative refrigeration system is ambient temperature sensitive for controlling the recovery modes of operation. A thermistor is electronically connected to the timer relay which in turn produces a delayed signal that is indicative of the sensed ambient temperature. Based upon the sensed temperature, the timer relay sequences the system between the two different modes of recovery and adjusts the time periods for operating each mode.

Claims

1. A refrigerant recovery system comprising:

a recovery compressor having a suction side and a discharge side;

a condenser connected to said compressor;

an insulated recovery tank for storing recovered refrigerant;

a controller connected to said system for automatically operating said system in a liquid recovery phase when the recovered refrigerant is liquid and a vapor recovery phase when the recovered refrigerant is a vapor;

a timer connected to the controller to maintain the refrigerant recovery system in the liquid recovery phase for an additional time period after the recovered refrigerant is no longer a liquid, and before the vapor recovery phase is activated; and

a sensor for measuring ambient temperature, the sensor electrically connected to the timer for operating the recovery system in the liquid recovery phase for a period of time that is proportional to the ambient temperature.

2. The refrigerant recovery system according to claim 1, wherein said controller includes a liquid/vapor sensor, connected upstream from said recovery tank, for sensing the presence of liquid refrigerant as it enters said recovery system.

3. The refrigerant recovery system according to claim 1, said system further comprising a recovery tank capacity fill sensor which is operable to produce a signal indicative of the recovery tank having a predetermined level.

4. The refrigerant recovery system according to claim 1, said system further comprising a throttling device located between the tank and the compressor for maintaining a discharge pressure of the recovery compressor by restricting the flow of refrigerant to the suction side of the compressor.

5. A device for recovering contaminated refrigerant from a refrigeration system comprising:

a compressor for compressing refrigerant that is delivered thereto, said compressor having an inlet and an outlet;

a storage tank for containing contaminated refrigerant;

a first conduit connected to said refrigeration system and said storage tank;

a fluid sensor located within said first conduit for sensing the presence of liquid and or gaseous refrigerant as it is being recovered from the refrigeration system, said sensor operable to produce an electrical signal indicative of liquid refrigerant being recovered;

a second conduit connected to said first conduit and to said compressor;

a condenser connected to the outlet of said compressor;

an expansion member located between said condenser and said storage tank;

a third conduit between said storage tank and said inlet of said compressor;

a first electrically operated valve located in said third conduit for controlling the flow of refrigerant therein;

a second electrically operated valve located in said second conduit for controlling the flow of refrigerant therein;

a third electrically operated valve located between said condenser and said storage tank for controlling the flow of refrigerant therebetween; and

an ambient temperature signal producing member connected to each said valve for controlling the operation of the device.

6. The device according to claim 5, said device further comprising a timing member for activating said device into a pump-down mode of operation.

7. The device according to claim 5, further comprising a timer that is operable to sequence the opening and closing of said valves at predetermined time periods.

8. The device according to claim 5, wherein the ambient temperature signal producing member is a thermistor that senses ambient temperatures and produces a signal that is indicative of the sensed ambient temperature.

9. The device according to claim 5, further comprising a storage tank float switch that is operable to produce a signal indicative of the storage tank being at capacity.

10. The device according to claim 5, further comprising an external pressure sensing regulator that is in communication with said compressor inlet and outlet and is operable to maintain a maximum compressor discharge pressure.

11. The device according to claim 5, wherein said fluid sensor produces a signal that is indicative of all liquid refrigerant having been recovered, said signal is relayed to a timer relay that delays the activation of a vapor recovery mode of operation.

12. An automatic refrigerant recovery system having a refrigerant tank volume fill sensor member, said system comprising:

a recovery compressor powered by an electrical power source;

a refrigerant storage tank for containing recovered refrigerant;

a volume fill sensor member including a float switch contained in said refrigerant storage tank, said switch being normally closed and producing a first signal when said tank is less than approximately 80% filled in volume with recovered refrigerant, said switch opening and producing a second signal when said tank is approximately 80% filled in volume with recovered refrigerant;

an electrical circuit including said float switch and a relay that is normally closed which causes an electrical connection between said recovery compressor and said power source;

a timer connected to said electrical circuit for delaying the activation of a vapor recovery mode of operation; and

a temperature sensor that produces signals indicative of the ambient temperature, the sensor connected to the timer to control activation of the vapor recovery mode of operation.

13. The recovery system according to claim 12, wherein said electrical circuit further includes a storage tank full capacity indicator that is activated when said second signal is detected.

14. The recovery system according to claim 12, further comprising a fluid sensor that is external to the storage tank that senses the presence of liquid refrigerant being recovered from a separate refrigeration system.

15. A refrigerant recovery system comprising:

a recovery compressor having a suction side and a discharge side;

a condenser connected to said compressor;

an insulated recovery tank for storing recovered refrigerant;

a liquid vapor control unit producing a first signal for operating said recovery system in a first phase a liquid recovery and for producing a second signal for operating said recovery system in a second phase of vapor recovery;

an external pressure regulating device located between the recovery tank and the suction side of the compressor for maintaining the discharge pressure of the compressor by restricting the flow of refrigerant to the suction side of the compressor;

a delay device connected to the liquid vapor control unit for a delay period that is sufficient to ensure that there is insufficient liquid being recovered by the recovery system so as to not damage the compressor; and

a sensor for measuring ambient temperature, the sensor electrically connected to the delay device for operating the recovery system in the first phase for a time period that tis proportional to the ambient temperature.

23. The system as claimed in claim 15, wherein the delay period is more than sixty seconds.

16. A refrigerant recovery system comprising:

a recovery compressor having a suction side and a discharge side;

a condenser connected to said compressor;

an insulated recovery tank for storing recovered refrigerant;

a controller operable to produce a signal indicative of liquid refrigerant being recovered in order to maintain a first phase of liquid recovery;

a timer device electrically connected to the controller for initiating a second phase of vapor recovery after the controller no longer produces said signal; and

a sensor for measuring ambient temperature, the sensor electrically connected to the timer device for operating the recovery system in the first phase for a time period that is proportional to the ambient temperature.

18. The device according to claim 16, wherein said fluid sensor produces a signal that is indicative of all liquid refrigerant having been recovered, said signal being relayed to said timing member for delaying the activation of the pump-down mode of operation.

17. A device for recovering contaminated refrigerant from a refrigeration system comprising:

a compressor for compressing refrigerant that is delivered thereto, said compressor having an inlet and an outlet;

a storage tank for containing contaminated refrigerant;

a first conduit connected to said refrigeration system and said storage tank;

a fluid sensor located within said first conduit for sensing the presence of liquid and or gaseous refrigerant as it is being recovered from the refrigeration system;

a second conduit connected to said first conduit and to said compressor;

a condenser connected to the outlet of said compressor;

an expansion member located between said condenser and said storage tank;

a third conduit between said storage tank and said inlet of said compressor;

a first electrically operated valve located in said third conduit for controlling the flow of refrigerant therein;

a second electrically operated valve located in said second conduit for controlling the flow of refrigerant therein;

a third electrically operated valve located between said condenser and said storage tank for controlling the flow of refrigerant therebetween;

a timing member for activating said device into a pump-down mode of operation; and

a thermistor that senses ambient temperatures and produces a signal that is indicative of the sensed ambient temperature, said thermistor being electrically connected to said timing member to control said valves.

19. An automatic refrigerant recovery system having a refrigerant tank volume fill sensor member, said system comprising:

a recovery compressor powered by an electrical power source;

a refrigerant storage tank for containing recovered refrigerant;

a volume fill sensor member including a float switch contained in said refrigerant storage tank, said switch being normally closed and producing a first signal when said tank is less than approximately 80% filled in volume with recovered refrigerant, said switch opening and producing a second signal when said tank is approximately 80% filled in volume with recovered refrigerant;

an electrical circuit including said float switch and a relay that is normally closed which causes an electrical connection between said recovery compressor and said power source;

a fluid sensor that is external to the storage tank for sensing the presence of liquid refrigerant recovered by the automatic refrigerant recovery system; and

a temperature sensor located within the electrical circuit, the sensor being operable to produce a third signal indicative of the ambient temperature for controlling the performance of the recovery system.

20. The automatic refrigerant recovery system according to claim 19, wherein said fluid sensor produces a fourth signal that is indicative of all liquid refrigerant having been recovered, said fourth signal is relayed to a timer relay that delays the activation of a vapor recovery mode of operation.

21. The automatic refrigerant recovery system according to claim 19, further comprising insulation means positioned around the tank.

22. The automatic refrigerant recovery system as claimed in claim 19, wherein said timer is programmable.