VIBRATION DETECTION IN A TRANSPORT REFRIGERATION SYSTEM THROUGH CURRENT SENSING

• US 20030061825A1
• Filed: 09/28/2001
• Published: 04/03/2003
• Est. Priority Date: 09/28/2001
• Status: Active Grant

• Current Assignee: Carrier Corporation (Carrier Global Corporation)
• Original Assignee: Carrier Corporation (Carrier Global Corporation)
• Inventors: Sullivan, Dennis Wayne
• Granted Patent: US 6,550,260 B1
• Time in Patent Office: Days
• 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: F04C 18/0215 where only one member is moving
• CPC Class Codes: F04C 23/008 Hermetic pumps
• CPC Class Codes: F04C 28/28 Safety arrangements; Monitoring
• CPC Class Codes: F25B 1/04 with compressor of rotary type F25B1/005, F25B1/10 take precedence
• CPC Class Codes: F25B 2700/151 of the compressor motor
• CPC Class Codes: F25B 49/005 of safety devices F25B49/02 and F25B49/04 take precedence

Abstract

A current sensor positioned on a power line monitors current draw associated with an electrical motor driven shaft based device, such as a scroll compressor. Mechanical vibrations in the scroll compressor force stress on the motor shaft of the scroll compressor, directly influencing current draw. By monitoring current draw, vibrations resulting from problems in the compressor, such as a broken mounting bracket, can be detected. A controller receives the current values and indicates if a current value exceeds a threshold current value or if a plurality of current values exceed a threshold value.

Claims

1. A refrigeration system comprising:

a compressor, a condenser, an evaporator and an expansion device for circulating a refrigerant; and

at least one sensor used to sense at least one system value representative of a level of vibration in a component of said refrigeration system.

2. The refrigeration system as recited in claim 1 wherein said compressor is a scroll compressor.

3. The refrigeration system as recited in claim 1 wherein said component is said compressor.

4. The refrigeration system as recited in claim 3 wherein said system value is a current value being delivered to a motor of said compressor.

5. The refrigeration system as recited in claim 4 wherein said compressor is mounted to a container unit by a mounting bracket, said at least one current sensor sensing an increase in said at least one current value and said level of vibration when said mounting bracket is broken.

6. The refrigeration system as recited in claim 1 further including a controller which receives said at least one system value, and said system value is a current value.

7. The refrigeration system as recited in claim 6 wherein said controller indicates when said at least one current value exceeds a threshold current value.

8. The refrigeration system as recited in claim 6 wherein said controller indicates when a plurality of said at least one current value exceeds a threshold current value in a timeframe.

9. The refrigeration system as recited in claim 1 wherein said refrigeration system is incorporated into a transport refrigeration unit.

10. The refrigeration system as recited in claim 1 wherein said component is an electrical motor driven shaft based device.

11. A transport refrigeration system comprising:

a compressor to compress a refrigerant to a high pressure, said compressor being provided with an electric current to drive a motor of said compressor;

a heat rejecting heat exchanger for cooling said refrigerant;

an expansion device for reducing said refrigerant to a low pressure;

a heat accepting heat exchanger for evaporating said refrigerant;

a refrigeration container for being cooled by said heat accepting heat exchanger; and

at least one current sensor to sense at least one current value representative of a level of vibration being delivered to said compressor motor.

12. The transport refrigeration system as recited in claim 11 wherein said compressor is a scroll compressor.

13. The transport refrigeration system as recited in claim 11 wherein said at least one current value is current draw associated with said compressor.

14. The transport refrigeration system as recited in claim 11 wherein said compressor is mounted to a container unit by a mounting bracket, said at least one current sensor sensing an increase in said at least one current value and said level of vibration when said mounting bracket is broken.

15. The transport refrigeration system as recited in claim 11 further including a controller which receives said current value.

16. The transport refrigeration system as recited in claim 15 wherein said controller indicates when said at least one current value exceeds a threshold current value.

17. The transport refrigeration system as recited in claim 15 wherein said controller indicates when a plurality of said at least one current value exceeds a threshold current value in a timeframe.

18. The transport refrigeration system as recited in claim 11 wherein said component is an electrical motor driven shaft based device.

19. A method for monitoring operation of a refrigeration system comprising the steps of:

(1) providing a refrigerant cycle including a compressor, a heat accepting heat exchanger, an expansion device and a heat rejecting heat exchanger, supplying electric current to a motor for driving said compressor;

(2) monitoring a current draw to said compressor motor, and detecting when said current draw exceeds predetermined conditions; and

(3) identifying undue vibration is said compressor when said monitored current exceeds said predetermined value in step (2).