Overheat protection for fluid pump

• US 6,837,688 B2
• Filed: 11/01/2002
• Issued: 01/04/2005
• Est. Priority Date: 02/28/2002
• Status: Expired due to Fees

• Current Assignee: Standex International Corporation
• Original Assignee: Standex International Corporation
• Inventors: Harvey, Robert E. III, Jiang, Jie, Kimberlin, Robert R.
• Primary Examiner(s): FREAY, CHARLES GRANT
• Application Number:
  US10/286,083
• Publication Number:
  US 20030161732A1
• Time in Patent Office: 795 Days
• Field of Search: 417/32.13, 417/14.18, 417/53.63, 417/420, 417/423.7, 417/44.1, 337/3.16, 337/97
• US Class Current: 417/32
• CPC Class Codes: F04B 2201/0801 Temperature
• CPC Class Codes: F04B 2203/0205 Temperature
• CPC Class Codes: F04C 11/008 Enclosed motor pump units
• CPC Class Codes: F04C 14/06 specially adapted for stopping, starting, idling or no-load operation
• CPC Class Codes: F04C 14/26 using bypass channels
• CPC Class Codes: F04C 14/28 Safety arrangements; Monitoring
• CPC Class Codes: F04C 15/0042 Systems for the equilibration of forces acting on the machines or pump interstice adjustment other than by fluid pressure F01C21/102
• CPC Class Codes: F04C 15/008 Prime movers
• CPC Class Codes: F04C 15/0096 Heating; Cooling of machines or engines in general F01P
• CPC Class Codes: F04C 2/3446 the inner and outer member being in contact along more than one line or surface
• CPC Class Codes: F04C 2240/40 Electric motor
• CPC Class Codes: F04C 2270/18 Pressure
• CPC Class Codes: F04C 2270/19 Temperature
• CPC Class Codes: F04C 23/008 Hermetic pumps
• CPC Class Codes: F04C 29/023 Lubricant distribution through a hollow driving shaft F04C29/025 takes precedence
• CPC Class Codes: F04C 29/045 of the electric motor in hermetic pumps
• CPC Class Codes: F04D 13/064 Details of the magnetic circuit
• CPC Class Codes: F04D 29/106 especially adapted for liquid pumps
• CPC Class Codes: F04D 29/588 cooling or heating the machine F04D29/5886, F04D29/5893 take precedence
• CPC Class Codes: H02K 5/128 using air-gap sleeves or air-gap discs

Abstract

An apparatus for detecting the presence of an overheat condition in a fluid pump includes a pump head for receiving a fluid at a first pressure and outputting the fluid at a second pressure that is greater than the first pressure. A motor is positioned adjacent the pump head to drive the pump head to pressurize the fluid. A single overheat sensor senses an overheat condition in the pump head and an overheat condition in the motor. When a threshold temperature is sensed by the overheat sensor, a switch is activated to prevent operation of the motor. In one embodiment, the overheat sensor and switch are integral and may, for example, take the form of a bi-metal switch formed in the stator windings of the motor. In alternate embodiments, the overheat sensor and switch are separate.

Claims

1. An apparatus for detecting the presence of an overheat condition in a fluid pump, the apparatus comprising:

a pump head for receiving a fluid at a first pressure and outputting the fluid at a second pressure that is greater than said first pressure;

a motor positioned adjacent said pump head for driving the pump head to pressurize the fluid; and

an overheat sensor in direct thermal association with both the pump head and the motor temperatures for sensing overheat conditions of the pump head and for sensing overheat conditions of the motor.

2. The apparatus of claim 1 wherein the overheat sensor is located within the motor.

3. The apparatus of claim 1 further comprising an electric circuit for providing power to the motor, and wherein said overheat sensor modifies the electrical circuit to prevent operation of the motor when an overheat condition is sensed.

4. The apparatus of claim 1 wherein said overheat sensor includes a bi-metal switch formed in stator windings of the motor, said bi-metal switch including:

a closed position providing electrical continuity through the stator windings during normal operation of the motor; and

an open position preventing electrical continuity through the stator windings when an overheat condition is sensed by the bi-metal switch.

5. The apparatus of claim 1, further comprising a switch for preventing operation of the motor when an overheat condition is sensed.

6. The apparatus of claim 1 wherein said overheat sensor is configured to detect the presence of an overheat condition when a threshold temperature of about 320 degrees F. is sensed by the overheat sensor.

7. The apparatus of claim 1 wherein said pump head is a rotary vane pump head.

8. The apparatus of claim 1 wherein said pump head is a turbine pump head.

9. The apparatus of claim 1 wherein said pump head is a centrifugal pump head.

10. An apparatus for inhibiting damage to a fluid pump, the apparatus comprising:

a pump head for receiving a fluid at a first pressure and outputting the fluid at a second pressure that is greater than said first pressure;

a motor positioned adjacent said pump head for driving the pump head to pressurize the fluid; and

a sensor switch positioned in said motor adjacent the pump head for directly sensing the temperature of the pump head and the motor and preventing operation of the motor when a threshold temperature is sensed.

11. The apparatus of claim 10 wherein said threshold temperature is about 320 degrees F.

12. The apparatus of claim 10 wherein said sensor switch comprises a bi-metal switch formed in the stator windings of the motor, said bi-metal switch including:

a closed position providing electrical continuity through the stator windings during normal operation of the motor; and

an open position preventing electrical continuity through the stator windings when an overheat condition is sensed by the bi-metal switch.

13. The apparatus of claim 10 wherein said pump head is a rotary vane pump head.

14. The apparatus of claim 10 wherein said pump head is a turbine pump head.

15. The apparatus of claim 10 wherein said pump head is a centrifugal pump.

16. An apparatus for inhibiting damage to a motor pump, the apparatus comprising:

a pump head for receiving a fluid at a first pressure and outputting the fluid at a second pressure that is greater than said first pressure;

a motor positioned adjacent said pump head for driving the pump head to pressurize the fluid; and

a bi-metal switch formed in stator windings of the motor adjacent the pump head for sensing the temperature of the pump head and the motor and preventing operation of the motor when a threshold temperature is sensed, said bi-metal switch including;

a closed position providing electrical continuity through the stator windings during normal operation of the motor; and

an open position preventing electrical continuity through the stator windings when an overheat condition is sensed by the bi-metal switch.

17. The apparatus of claim 16 wherein said threshold temperature is about 320 degrees F.

18. The apparatus of claim 16 wherein said pump head is a rotary vane pump head.

19. The apparatus of claim 16 wherein said pump head is a turbine pump head.

20. The apparatus of claim 16 wherein said pump head is a centrifugal pump.