Pretrip device for testing of a refrigeration system compressor

• US 6,176,095 B1
• Filed: 01/19/1999
• Issued: 01/23/2001
• Est. Priority Date: 01/19/1999
• Status: Expired due to Term

• Current Assignee: Carrier Corporation (Carrier Global Corporation)
• Original Assignee: Carrier Corporation (Carrier Global Corporation)
• Inventors: Porter, Kevin J.
• Primary Examiner(s): Tanner, Harry B.
• Application Number:
  US09/234,041
• Time in Patent Office: 735 Days
• Field of Search: 621/25, 621/26, 621/27, 621/29, 622/283, 621/961, 621/962, 621/963, 622/285, 621/31
• US Class Current: 62/126
• CPC Class Codes: B60H 1/3225 characterised by safety arrangements, e.g. compressor anti-seizure means or by signalling devices
• CPC Class Codes: F04B 2205/05 Pressure after the pump outlet
• CPC Class Codes: F04B 2205/07 Pressure difference over the pump
• CPC Class Codes: F04B 2205/15 By-passing over the pump
• CPC Class Codes: F04B 49/022 by means of pressure
• CPC Class Codes: F25B 2400/074 with multiple cylinders
• CPC Class Codes: F25B 2600/026 by controlling unloaders
• CPC Class Codes: F25B 49/022 Compressor control arrangements

Abstract

A refrigeration/heating system for cooling or heating an area includes a condenser for removing heat from the system to an external environment, an evaporator for receiving heat from the area to be cooled or delivering heat to the area to be heated, and a compressor for raising the pressure and the temperature of a refrigerant. The compressor has at least one cylinder bank and an unloader connected to the cylinder bank for loading and unloading the cylinder bank. Pressure transducers measure the suction and discharge pressures of the compressor when the state of a cylinder bank is changed from a loaded to an unloaded state. A processor uses the suction and discharge pressures in the various states to determine the operational condition of either unloader. By varying the loading and unloading of a pair of cylinder banks, the processor can also use various suction and discharge pressures to determine if a problem exists within either cylinder bank or unloader.

Claims

1. A method for testing a compressor of the type having at least one unloader, a first cylinder bank, and a second cylinder bank, said method comprising the steps of:

measuring a first pressure differential indicator;

loading said first cylinder bank;

measuring a second pressure differential indicator subsequent to said first cylinder bank loading step;

unloading said first cylinder bank;

loading said second cylinder bank;

measuring a third pressure differential indicator subsequent to said second cylinder loading step; and

determining a location of a problem within said compressor based at least in part on at least two of said pressure differential indicators.

2. The method of claim 1, wherein said pressure differential indicators are pressure differential readings between discharge pressures and suction pressures of said compressor.

3. The method of claim 1, wherein said pressure differential indicators are discharge pressures of said compressor.

4. The method of claim 1, wherein said pressure differential indicators are suction pressures of said compressor.

5. The method of claim 1, wherein said determining step includes the step of finding a difference between said second and first pressure differential indicators to determine whether a problem exists in a first unloader of said compressor.

6. The method of claim 1, wherein said determining step includes the step of finding a difference between said third and said first pressure differential indicators to determine whether a problem exists in a second unloader of said compressor.

7. The method of claim 2, wherein said determining step includes the step of analyzing said first, second and third pressure differential indicators to determine whether a problem exists within said first cylinder bank of said compressor.

8. The method of claim 7, wherein said determining step includes the step of analyzing said first, second and third pressure differential indicators to determine whether a problem exists within said second cylinder bank of said compressor.

9. The method of claim 1, wherein said determining step includes the step of determining whether a problem exists within a specific component of said compressor, said specific component selected from the group consisting of a rear unloader, a front unloader, a rear cylinder bank and a front cylinder bank of said compressor.

10. The method of claim 1, wherein said determining step includes the step of analyzing at least two of said pressure differential indicators to determine if a problem exists within a specific unloader of said compressor.

11. The method of claim 10, wherein said determining step includes the step of analyzing said first, second and third of said pressure differential indicators to determine if a problem exists within a specific one of said cylinder banks of said compressor.

13. The method of claim 11, wherein said pressure differential indicators are pressure differential readings between discharge pressures and suction pressures of said compressor.

14. The method of claim 13, wherein said pressure differential indicators are discharge pressures of said compressor.

15. The method of claim 14, wherein said pressure differential indicators are suction pressures of said compressor.

16. The method of claim 15, wherein said determining step includes the step of finding a difference between said second and first pressure differential indicators to determine whether a problem exists in a rear unloader of said compressor.

17. The method of claim 16, wherein said determining step includes the step of finding a difference between said fourth and said third pressure differential or between said fifth and said fourth of said pressure differential indicators to determine whether a problem exists within a front unloader of said compressor.

18. The method of claim 14 wherein said determining step includes the step of analyzing said first, second, fourth and fifth pressure differential indicators to determine whether a problem exists within said rear cylinder bank of said compressor.

19. The method of claim 14, wherein said determining step includes the step of analyzing said second, third and fourth pressure differential indicators to determine whether a problem exists within said front cylinder bank of said compressor.

20. The method of claim 19, wherein said determining step includes the step of determining whether a problem exists within a specific component of said compressor, said specific component selected from the group consisting of a rear unloader, a front unloader, a rear cylinder bank and a front cylinder bank of said compressor.

21. The method of claim 20, wherein said determining step includes the step of analyzing at least two of said pressure differential indicators to determine if a problem exists within a specific unloader of said compressor.

22. The method of claim 14, wherein said determining step includes the step of analyzing said first, second and third of said pressure differential indicators to determine if a problem exists within a specific one of said cylinder backs of said compressor.

12. A method for testing a compressor of the type having a front unloader, a rear unloader, a front cylinder bank and a rear cylinder bank, said method comprising the steps of:

measuring a first pressure differential indicator;

loading said rear cylinder bank;

measuring a second pressure differential indicator subsequent to said rear cylinder bank loading step;

unloading said rear cylinder bank; and

measuring a third pressure differential indicator subsequent to said rear cylinder bank unloading step;

loading said front cylinder bank;

measuring a fourth pressure differential indicator subsequent to said front cylinder loading step;

unloading said front cylinder bank;

measuring a fifth pressure differential indicator subsequent to said front cylinder unloading step; and

determining a location of a problem within said compressor based at least in part on at least two of said pressure differential indicators.

23. A refrigeration system comprising:

a compressor having a front unloader a rear unloader, a front cylinder bank, and a rear cylinder bank;

an evaporator;

a condenser for removing heat from said refrigeration system;

means for measuring a first pressure differential indicator of said system;

means for loading said rear cylinder bank;

means for measuring a second pressure differential indicator subsequent to said rear cylinder bank loading means loading said rear cylinder bank;

means for unloading said rear cylinder bank;

means for loading said front cylinder bank;

means for measuring a third pressure differential indicator subsequent to said front cylinder loading means loading said front cylinder bank; and

means for determining a location of a problem within said compressor by considering at least two of said pressure differential indicators.