Fluid leak detector mechanism

• US 5,673,025 A
• Filed: 11/21/1996
• Issued: 09/30/1997
• Est. Priority Date: 11/21/1996
• Status: Expired due to Term

• Current Assignee: Deere & Company
• Original Assignee: Deere & Company
• Inventors: Refugio, Maria Rosalyn Bengua, Marquart, Gordon Le Roy, Lamb, Mark Edward
• Primary Examiner(s): Hofsass, Jeffery
• Assistant Examiner(s): Huang, Sihong
• Application Number:
  US08/753,200
• Time in Patent Office: 313 Days
• Field of Search: 340/605, 340/603, 340/619, 340/616, 73/49.2, 73/295, 73/290 R, 73/40
• US Class Current: 340/605
• CPC Class Codes: A01D 34/60 fluid
• CPC Class Codes: A01D 34/80 fluid
• CPC Class Codes: G01M 3/3245 using a level monitoring device G01M3/3272 takes precedence

Abstract

A fluid leak detector mechanism having a main fluid tank, an expansion tank for receiving fluid therefrom as the fluid becomes heated and expands, and a sensing chamber operatively coupled with the main tank. A signalling mechanism signals to an operator when the level of fluid in the sensing chamber has dropped significantly to alert the operator of the presence of a leak. An oil return valve is operatively coupled between the main tank and the expansion tank and has an open position that allows fluid to flow back to the main tank from the expansion tank and a closed position that blocks oil from flowing from the expansion tank to the main tank. A temperature sensor senses the temperature of fluid. A control mechanism shifts the oil return valve to its open position when the temperature sensor detects a significant drop in fluid temperature, thereby allowing the fluid levels to be reset with changes in fluid temperature.

Claims

1. A fluid leak detector mechanism, comprising:

a main fluid tank,

an expansion tank operatively coupled with the main tank for receiving fluid therefrom as the fluid becomes heated and expands,

a sensing chamber operatively coupled with the main tank,

a signalling mechanism which signals to an operator when the level of fluid in the sensing chamber has dropped significantly and that a fluid leak may be occurring,

an oil return valve operatively coupled between the main tank and the expansion tank, said oil return valve having an open position that allows fluid to flow back to the main tank from the expansion tank and a closed position that blocks oil from flowing from the expansion tank to the main tank,

a temperature sensor for sensing the temperature of fluid, and

a control mechanism operatively coupled with the temperature sensor and the oil return valve for shifting the oil return valve to its open position when the temperature sensor detects a significant drop in fluid temperature.

2. The invention of claim 1, and further comprising an expansion check valve operatively positioned between the main tank and the expansion tank for allowing fluid to flow from the main tank to the expansion tank as fluid in the main tank becomes heated and expands, and said expansion check valve blocks fluid from flowing from the expansion tank to the main tank.

3. The invention of claim 1, and further comprising an air vent check valve operatively coupled with the top portion of the sensing chamber for allowing air to enter the sensing chamber to replace oil that has exited the sensing chamber during operation.

4. The invention of claim 1, and further comprising an air vent valve operatively coupled with the top portion of the sensing chamber, said air vent valve having a closed position for blocking fluid from entering or exiting the sensing chamber via the air vent valve, said air vent valve being automatically shifted to an open position as fluid enters the sensing chamber to thereby allow air to be displaced from the sensing chamber as fluid enters the sensing chamber.

5. The invention of claim 1, and further comprising a hydraulic line which operatively extends between the top portion of the sensing chamber and the atmosphere, said hydraulic line extending in a serpentine route such that any fluid that may splash into said hydraulic line during operation will flow back into the sensing chamber.

6. The invention of claim 5, wherein said hydraulic line is operatively coupled to the upper portion of the expansion tank, and said expansion tank includes a vent which exposes the upper portion of the expansion tank to atmospheric pressure.

7. The invention of claim 1, wherein said control mechanism opens said oil return valve when the fluid temperature drops approximately two degrees Fahrenheit.

8. The invention of claim 4, wherein said control mechanism opens both the oil return valve and air vent valve when the fluid temperature drops a significant amount, said open valves allowing the fluid levels within the sensing chamber, main tank and expansion tank to reset themselves corresponding to the change in fluid temperature.

9. A hydraulic fluid leak detector mechanism adapted for detecting leaks in a hydraulic system of a vehicle adapted for mowing, comprising:

a main fluid tank operatively coupled with said hydraulic system,

an expansion tank operatively coupled with the main tank for receiving fluid therefrom as the fluid becomes heated and expands,

a sensing chamber operatively coupled with the main tank,

a signalling mechanism which signals to an operator when the level of fluid in the sensing chamber has dropped significantly and that a fluid leak may be occurring,

an oil return valve operatively coupled between the main tank and the expansion tank, said oil return valve having an open position that allows fluid to flow back to the main tank from the expansion tank and a closed position that blocks oil from flowing from the expansion tank to the main tank,

a temperature sensor for sensing the temperature of the fluid, and

a control mechanism operatively coupled with the temperature sensor and the oil return valve for briefly shifting the oil return valve to its open position when the temperature sensor detects a significant drop in fluid temperature, said brief opening of the oil return valve generally allowing the fluid levels in the main tank, expansion tank and sensing chamber to reset themselves in response to the change in fluid temperature and volume.

10. The invention of claim 9, and further comprising an expansion check valve operatively positioned between the main tank and the expansion tank for allowing fluid to flow from the main tank to the expansion tank as fluid in the main tank becomes heated and expands, and said expansion check valve blocks fluid from flowing from the expansion tank to the main tank.

11. The invention of claim 9, and further comprising an air vent check valve operatively coupled with the top portion of the sensing chamber for allowing air to enter the sensing chamber to replace oil that has exited the sensing chamber during normal operation of the hydraulic system.

12. The invention of claim 9, and further comprising an air vent valve operatively coupled with the top portion of the sensing chamber, said air vent valve having a closed position for blocking fluid from entering or exiting the sensing chamber via the air vent valve, said air vent valve being automatically shifted to an open position as fluid enters the sensing chamber to thereby allow air to be displaced from the sensing chamber as fluid enters the sensing chamber during normal operation of the hydraulic system.

13. The invention of claim 12, wherein said control mechanism is operatively connected with hydraulic cylinders driven by the hydraulic system, and said control mechanism opens the air vent valve when fluid is flowing out of the hydraulic cylinder and back into the hydraulic system.

14. The invention of claim 9, and further comprising a hydraulic line which operatively extends between the top portion of the sensing chamber and the atmosphere, said hydraulic line extending in a serpentine route such that any fluid that may splash into said hydraulic line during normal operation of the hydraulic system will generally flow back into the sensing chamber.

15. The invention of claim 14, wherein said hydraulic line is operatively coupled to the upper portion of the expansion tank, and said expansion tank includes a vent which exposes the upper portion of the expansion tank to atmospheric pressure.

16. The invention of claim 9, wherein said control mechanism opens said oil return valve when the fluid temperature drops approximately two degrees Fahrenheit.

17. The invention of claim 12, wherein said control mechanism opens both the oil return valve and air vent valve when the fluid temperature drops a significant amount and thereby allows the fluids levels within the sensing chamber, main tank and expansion tank to reset themselves corresponding to the change in fluid temperature.

18. The invention of claim 17, wherein said oil return valve and air vent valve include solenoids controlled by the control mechanism.

19. The invention of claim 9, wherein said temperature sensor is operatively coupled with the main tank for sensing the temperature of hydraulic fluid within the main tank.

20. A hydraulic fluid leak detector mechanism adapted for detecting leaks in a hydraulic system of a vehicle having at least one reel mower cutting unit usable for mowing golf courses, comprising:

a main fluid tank operatively coupled with the hydraulic system for serving as a reservoir,

an expansion tank operatively coupled with the main tank for receiving fluid therefrom as the fluid becomes heated and expands,

a sensing chamber operatively coupled with the main tank,

a signalling mechanism which signals to an operator when the level of fluid in the sensing chamber has dropped significantly and that a fluid leak may be occurring,

an oil return valve operatively coupled between the main tank and the expansion tank, said oil return valve having an open position that allows fluid to flow back to the main tank from the expansion tank and a closed position that blocks oil from flowing from the expansion tank to the main tank,

an expansion check valve operatively positioned between the main tank and the expansion tank for allowing fluid to flow from the main tank to the expansion tank as fluid in the main tank becomes heated and expands, and said expansion check valve blocks fluid from flowing from the expansion tank to the main tank,

an air vent check valve operatively coupled with the top portion of the sensing chamber for allowing air to enter the sensing chamber to replace oil that has exited the sensing chamber during normal operation of the hydraulic system,

an air vent valve operatively coupled with the top portion of the sensing chamber, said air vent valve having a closed position for blocking fluid from entering or exiting the sensing chamber via the air vent valve, said air vent valve being automatically shifted to an open position as fluid enters the sensing chamber to thereby allow air to be displaced from the sensing chamber as fluid enters the sensing chamber during normal operation of the hydraulic system,

a temperature sensor for sensing the temperature of the fluid, and

a control mechanism operatively coupled with the temperature sensor and the oil return valve for shifting the oil return valve to its open position when the temperature sensor detects a significant drop in fluid temperature, said opening of the oil return valve generally allows the fluid levels in the main tank, expansion tank and sensing chamber to reset themselves in response to the change in fluid temperature.

21. The invention of claim 20, and further comprising a hydraulic line which operatively extends between the top portion of the sensing chamber and the atmosphere, said hydraulic line extending in a serpentine route such that any fluid that may splash into said hydraulic line during normal operation of the hydraulic system will generally flow back into the sensing chamber.

22. The invention of claim 21, wherein said hydraulic line is operatively coupled to the upper portion of the expansion tank, and said expansion tank includes a vent which exposes the upper portion of the expansion tank to atmospheric pressure.

23. The invention of claim 22, wherein said control mechanism opens said oil return valve when the fluid temperature drops approximately two degrees Fahrenheit.

24. The invention of claim 23, wherein said control mechanism opens both the oil return valve and air vent valve when the fluid temperature drops a significant amount and thereby allows the fluids levels within the sensing chamber, main tank and expansion tank to reset themselves corresponding to the change in fluid temperature and volume.

25. The invention of claim 24, wherein said oil return valve and air vent valve include solenoids controlled by the control mechanism.

26. The invention of claim 25, wherein said temperature sensor is operatively coupled with the main tank for sensing the temperature of hydraulic fluid within the main tank.

27. The invention of claim 20, wherein said control mechanism is operatively connected with hydraulic cylinders driven by the hydraulic system, and said control mechanism opens the air vent valve when fluid is flowing out of the hydraulic cylinders and back into the hydraulic system.

28. The invention of claim 27, wherein said hydraulic cylinders are lift cylinders for shifting the reel mower cutting units between raised transport positions and lowered operating positions.