Fuel cap leakage tester

• US 5,996,402 A
• Filed: 02/16/1998
• Issued: 12/07/1999
• Est. Priority Date: 08/16/1995
• Status: Expired due to Fees

• Current Assignee: Stant Manufacturing Incorporated
• Original Assignee: Stant Manufacturing Incorporated
• Inventors: Harris, Robert S.
• Primary Examiner(s): LARKIN, DANIEL SEAN
• Application Number:
  US09/029,004
• Time in Patent Office: 659 Days
• Field of Search: 73/40, 73/49.7, 73/49.8
• US Class Current: 73/49.7
• CPC Class Codes: G01M 3/26 by measuring rate of loss or gain of fluid, e.g. by pressure-responsive devices, by flow detectors
• CPC Class Codes: G01M 3/3263 using a differential pressure detector G01M3/3245, G01M3/3272 take precedence

Abstract

A fuel cap leakage tester including a first and a second passage having equal restrictions connected to an inlet which receives a source of pressure. A restriction is placed at the outlet of first passage and the cap to be tested is placed at the outlet of the second passage. An indicator is connected to the first passage between the inlet restriction and outlet restriction and to the second passage between the inlet restriction and the outlet for indicating if the leakage at the outlet with the cap therein is greater or less than the flow rate of the other outlet restriction. The other outlet restriction is set to a desired standard.

Claims

1. A fuel cap leakage tester comprising:

an inlet for receiving a source of pressure,

a first outlet connected to said inlet by a first passage having a first restriction,

a second outlet for removably receiving a fuel cap to be tested and connected to said inlet by a second passage having a second restriction equal to said first restriction,

a third restriction in said first passage between said first restriction and said first outlet having a flow rate, and

an indicator connected to said first passage between said first and third restrictions and to said second path between said second restriction and said second outlet for indicating if the leakage at said second outlet with a cap therein is greater or less than the flow rate of said third restriction.

2. The tester of claim 1, wherein said indicator is a U-shaped manometer having each leg connected to a respective first and second passage.

3. The tester of claim 1, wherein said indicator is a pneumatic differential pressure gauge.

4. The tester of claim 1, wherein said indicator is an electrical differential pressure gauge.

5. The tester of claim 1, including a valve at said inlet connecting and disconnecting said source of pressure to said first and second passages for initiating and terminating a test.

6. The tester of claim 1, wherein said indicator qualitatively indicates if the leakage at said second outlet with said cap therein is greater or lesser than the flow rate of said third restriction.

7. The tester of claim 1, including a charged reservoir as said source of pressure and a valve at said inlet connecting and disconnecting said reservoir to said first and second passages for initiating and terminating a test.

8. The tester of claim 7, including a pump for charging said reservoir.

9. A fuel cap leakage tester comprising:

a reservoir containing a supply of pressurized air,

a base including a base chamber for receiving a fuel cap to be tested,

a master orifice having a first specified flow rate at a specified test pressure and communicating with the atmosphere,

a first supply conduit conducting pressurized air from the reservoir to the master orifice through a first control orifice having a second specified flow rate at the specified test pressure, the first supply conduit including a first passage interconnecting the first control orifice and the master orifice,

a second supply conduit conducting pressurized air from the reservoir to the base chamber formed in the base through a second control orifice having the second specified flow rate equivalent to the first specified flow rate at the specified test pressure, the second supply conduit including a second passage interconnecting the second control orifice and the base chamber, and

pass/fail indicator means connected to the first and second passages for indicating a failed fuel cap when a fuel cap to be tested is coupled to the base and the pressure level of pressurized air in the first passage is greater than the pressure level of pressurized air in the second passage and for indicating a passed fuel cap when a fuel cap to be tested is coupled to the base and the pressure level of pressurized air in the first passage is lesser than the pressure level of pressurized air in the second passage.

10. The tester of claim 9, further comprising a housing containing the reservoir, the master orifice, and the first and second supply conduits and a pressurized air supply hose interconnecting the second supply conduit in the housing and the base chamber in the base.

11. The tester of claim 10, further comprising a pump for pressurizing air contained in the reservoir, the pump being coupled to the housing.

12. The tester of claim 10, further comprising an electronics module appended to the housing and wherein the pass/fail indicator means includes a cap leakage detector positioned in the electronics module and coupled to the first and second passages.

13. The tester of claim 12, wherein the cap leakage detector includes a differential pressure transducer having a first input coupled to the first passage to communicate with air in the first passage and a second input coupled to the second passage to communicate with air in the second passage and the pass/fail indicator means further includes a signaling device positioned in the electronics module and coupled to the differential pressure transducer to provide a cap-failing signal when the air pressure at the first input is greater than the air pressure at the second input and a cap-passing signal when the air pressure at the first input is lesser than the air pressure at the second input.

14. The tester of claim 9, wherein the pass/fail indicator means includes a cap leakage detector coupled to the first and second passages and a pass/fail signaling device coupled to the cap leakage detector.

15. The tester of claim 14, wherein the cap leakage detector includes a first differential pressure transducer having two inputs, a first transducer supply conduit communicating air from the first passage to one input of the differential pressure transducer, and a second transducer supply conduit communicating air from the second passage to another input of the first differential pressure transducer.

16. The tester of claim 15, wherein the pass/fail signaling device includes a pass light, a fail light, and circuit means coupled to the pass and fail lights for providing a cap-failing signal to illuminate the fail light when air pressure at said one input of the first differential pressure transducer is greater than the air pressure at said another input of the first differential pressure transducer and for providing a cap-passing signal to illuminate the pass light when air pressure at said one input of the first differential pressure transducer is lesser than the air pressure at said another input of the first differential pressure transducer.

17. The tester of claim 14, further comprising a reservoir pressure detector coupled to the reservoir and to the first passage and ready-to-test indicator means coupled to the reservoir pressure detector for providing a ready-to-test signal to a user once the air pressure in the reservoir reaches a predetermined minimum pressure.

18. The tester of claim 9, wherein the reservoir includes a reservoir chamber and test actuator means for selectively conducting pressurized air from the reservoir chamber to the first and second supply conduits.

19. The tester of claim 18, wherein the test actuator means includes a test actuator switch including a normally closed flow control valve, a switch intake conduit interconnecting the reservoir chamber and the flow control valve, a flow junction connected to the first and second supply conduits, and a switch discharge conduit interconnecting the flow control valve and the flow junction.

20. The tester of claim 19, wherein the normally closed flow control valve is movable between a closed position blocking flow of pressurized air from the switch intake conduit to the switch discharge conduit and an opened position permitting flow of pressurized air from the switch intake conduit to the switch discharge conduit and the test actuator switch further includes operator means for selectively moving the flow control valve from the closed position to the opened position to cause pressurized air in the reservoir chamber to be supplied to the master orifice through the first supply conduit and to the base chamber through the second supply conduit.

21. The tester of claim 19, further comprising a housing formed to include an interior region and a partition member mounted in the housing to divide the interior region into a first cavity defining the reservoir chamber and a second cavity containing the master orifice, the first and second supply conduits, and the test actuator means.

22. The tester of claim 13, further comprising a housing containing the reservoir chamber, the master orifice, the first and second supply conduits, and the test actuator means.

23. The tester of claim 22, wherein the test actuator means includes a passageway interconnecting the reservoir chamber and the first and second supply conduits, a valve positioned in the passageway for movement between passageway-opening and passageway-closing positions, and a valve operator mounted on the housing and connected to the valve.

24. The tester of claim 9, further comprising output means for connecting the pass/fail indicator means to a communication line adapted to communicate with a computer system so that cap-passing and cap-failing signals generated by the pass/fail indicator means are communicated to the computer system via the communication line.

25. A fuel cap leakage tester comprising:

a master orifice having a first specified flow rate at a specified test pressure corresponding to a predetermined acceptable fuel cap leakage specification,

a first control orifice having a second specified flow rate at the specified test pressure,

a second control orifice having the second specified flow rate at the specified test pressure,

a base including a base chamber for receiving a fuel cap to be tested,

a first passage conducting pressurized air from the first control orifice to the master orifice,

a second passage conducting pressurized air from the second control orifice to the base chamber so that a cap to be tested received in the base chamber is exposed to the pressurized air received in the base chamber,

an air supply generator providing a source of pressurized air at a selected pressure, the air supply being coupled to the first and second control orifices to discharge such pressurized air from the air supply simultaneously into the first passage through the first control orifice to reach the master orifice and into the second passage through the second control orifice to reach the base chamber, and

pass/fail indicator means connected to the first and second passages for indicating a failed fuel cap when a fuel cap to be tested is coupled to the base and the pressure level of pressurized air in the first passage is greater than the pressure level of pressurized air in the second passage and for indicating a passed fuel cap when a fuel cap to be tested is coupled to the base and the pressure levels of pressurized air in the first passage is greater than the flow rate of pressurized air in the second passage.

26. The tester of claim 25, wherein the first passage has a first volume receiving pressurized air and the second passage has a second volume receiving pressurized air equivalent to the first volume so that the flow rates of pressurized air introduced simultaneously into the first and second passage reach equilibrium substantially simultaneously.

27. The tester of claim 26, further comprising a meter block formed to include a damper chamber connected to the master orifice and to the first control orifice.

28. The tester of claim 27, further comprising a housing formed to include an interior region and a partition member mounted in the housing to divide the interior region into a reservoir chamber and a metering chamber, and wherein the meter block is formed to provide the damper chamber with an open mouth and is positioned to lie in the metering chamber in engagement with the partition member to cause the partition member to close the open mouth of the damper chamber.

29. The tester of claim 27, wherein the meter block is also formed to include the master orifice, the first control orifice, and the second control orifice.

30. The tester of claim 25, further comprising a meter block formed to include the master orifice, the first control orifice, and the second control orifice.

31. The tester of claim 30, wherein the meter block is also formed to include the first passage and a portion of the second passage.

32. The tester of claim 30, further comprising a housing containing the air supply generator and including an internal wall and wherein the meter block is positioned to lie within the housing in engagement with the internal wall.

33. The tester of claim 25, further comprising a meter block formed to include the first passage.

34. The tester of claim 33, wherein the meter block is formed to include a damper chamber communicating with the master orifice and an internal passage interconnecting the damper chamber and the first control orifice and cooperating with the damper chamber to define the first passage.

35. The tester of claim 34, wherein the meter block is formed to include the master orifice and the first control orifice.

36. The tester of claim 25, further comprising a meter block formed to include an air supply conduit defining a portion of the second passage.

37. The tester of claim 36, wherein the second passage further includes a pressurized air supply hose interconnecting the air supply conduit formed in the meter block and the base chamber formed in the base.

38. The tester of claim 37, further comprising a housing containing the meter block and wherein the base lies outside of the housing and the pressurized air supply hose extends from the housing to the base.

39. The tester of claim 25, wherein the air supply generator includes a reservoir chamber and test actuator means for selecting conducting pressurized air from the reservoir chamber to the first and second passages.

40. The tester of claim 39, wherein the test actuator means includes a test actuator switch including a normally closed flow control valve, a switch intake conduit interconnecting the reservoir chamber and the flow control valve, and switch discharge means for discharging pressurized air from the flow control valve simultaneously into the first passage through the first control orifice and into the second passage through the second control orifice.

41. The tester of claim 40, wherein the normally closed flow control valve is movable between a closed position blocking flow of pressurized air from the switch intake conduit to the switch discharge means and an opened position permitting flow of pressurized air from the switch intake conduit to the switch discharge means and the test actuator switch further includes operator means for selectively moving the flow control valve from the closed position to the opened position to cause pressurized air in the reservoir chamber to be supplied to the master orifice through the first passage and to the base chamber through the second passage.

42. The tester of claim 41, further comprising a housing formed to include an interior region and a partition member mounted in the housing to divide the interior region into a first cavity defining the reservoir chamber and a second cavity containing the master orifice, the first and second control orifices, the first and second passages, and the test actuator means.

43. The tester of claim 39, further comprising a housing containing the reservoir chamber, the master orifice, the first and second control orifices, the first and second passages, and the test actuator means.

44. The tester of claim 43, wherein the test actuator means includes a passageway interconnecting the reservoir chamber and the first and second passages, a valve positioned in the passageway for movement between passageway-opening and passageway closing positions, and a valve operator mounted on the housing and connected to the valve.

45. The tester of claim 39, wherein the air supply generator further includes a pump for charging the reservoir chamber and further comprising a reservoir pressure detector connected to the reservoir chamber and to the first passage to sense the level of pressure in the reservoir chamber.

46. The tester of claim 25, further comprising output means for connecting the pass/fail indicator means to a communication line adapted to communicate with a computer system so that cap-passing and cap-failing signals generated by the pass/fail indicator means are communicated to the computer system via the communication line.

47. A fuel cap leakage tester comprising:

a reservoir containing a supply of pressurized air,

a base including a base chamber for receiving a fuel cap to be tested,

a master orifice having a first specified flow rate at a specified test pressure and communicating with the atmosphere,

a first supply conduit conducting pressurized air from the reservoir to the master orifice through a first control orifice having a second specified flow rate at the specified test pressure, the first supply conduit including a first passage interconnecting the first control orifice and the master orifice,

a second supply conduit conducting pressurized air from the reservoir to the base chamber formed in the base through a second control orifice having the second specified flow rate equivalent to the first specified flow rate at the specified test pressure, the second supply conduit including a second passage interconnecting the second control orifice and the base chamber,

a cap leakage detector coupled to the first and second passages, and

a pass/fail signaling device coupled to the cap leakage detector.

48. The tester of claim 47, wherein the cap leakage detector includes a first differential pressure transducer having two inputs, a first transducer supply conduit communicating air from the first passage to one input of the differential pressure transducer, and a second transducer supply conduit communicating air from the second passage to another input of the first differential pressure transducer.

49. The tester of claim 48, further comprising a reservoir pressure detector including a second differential pressure transducer having two inputs, a third transducer supply conduit communicating air from the reservoir to one input of the second differential pressure transducer, and a fourth transducer supply conduit communicating air from the first passage to another input of the second differential pressure transducer.

50. The tester of claim 49, wherein the fourth transducer supply conduit is connected to the first transducer supply conduit at a junction with the first passage.

51. The tester of claim 47, further comprising a reservoir pressure detector coupled to the reservoir and wherein each of the cap leakage detector and the reservoir pressure detector includes a differential pressure transducer.

52. The tester of claim 47, wherein the pass/fail signaling device includes a pass light, a fail light, and circuit means coupled to the pass and fail lights for providing a cap-failing signal to illuminate the fail light when air pressure at said one input of the first differential pressure transducer is greater than the air pressure at said another input of the first differential pressure transducer and for providing a cap-passing signal to illuminate the pass light when air pressure at said one input of the first differential pressure transducer is lesser than the air pressure at said another input of the first differential pressure transducer.

53. The tester of claim 47, wherein the reservoir includes a reservoir chamber and test actuator means for selectively conducting pressurized air from the reservoir chamber to the first and second supply conduits.

54. The tester of claim 47, wherein the reservoir includes a reservoir chamber and a reservoir flow control device communicating pressurized air from the reservoir chamber to the first and second supply conduits.

55. The tester of claim 54, wherein the reservoir flow control device includes a test actuator switch including a normally closed flow control valve, a switch intake conduit interconnecting the reservoir chamber and the flow control valve, a flow junction connected to the first and second supply conduits, and a switch discharge conduit interconnecting the flow control valve and the flow junction.

56. The tester of claim 55, wherein the normally closed flow control valve is movable between a closed position blocking flow of pressurized air from the switch intake conduit to the switch discharge conduit and an opened position permitting flow of pressurized air from the switch intake conduit to the switch discharge conduit and the test actuator switch further includes operator means for selectively moving the flow control valve from the closed position to the opened position to cause pressurized air in the reservoir chamber to be supplied to the master orifice through the first supply conduit and to the base chamber through the second supply conduit.

57. The tester of claim 55, further comprising a housing formed to include an interior region and a partition member mounted in the housing to divide the interior region into a first cavity defining the reservoir chamber and a second cavity containing the master orifice, the first and second supply conduits, and the test actuator switch.

58. The tester of claim 54, further comprising a housing containing the reservoir chamber, the master orifice, the first and second supply conduits, and the reservoir flow control device.

59. The tester of claim 58, wherein the reservoir flow control device includes a passageway interconnecting the reservoir chamber and the first and second supply conduits, a valve positioned in the passageway for movement between passageway-opening and passageway-closing positions, and a valve operator mounted on the housing and connected to the valve.

60. The tester of claim 54, further comprising a pump for charging the reservoir chamber and reservoir pressure detector connected to the reservoir chamber and to the first passage for sensing the level of pressure in the reservoir chamber.

61. The tester of claim 60, further comprising ready-to-test indicator means connected to the reservoir chamber and to the reservoir pressure detector for providing a ready-to-test signal to a user once the air pressure in the reservoir chamber reaches a predetermined minimum pressure.

62. A fuel cap leakage tester comprising:

a reservoir containing a supply of pressurized air,

a base including a base chamber for receiving a fuel cap to be tested,

a master orifice having a first specified flow rate at a specified test pressure and communicating with the atmosphere,

a first supply conduit conducting pressurized air from the reservoir to the master orifice through a first control orifice having a second specified flow rate at the specified test pressure, the first supply conduit including a first passage interconnecting the first control orifice and the master orifice,

a second supply conduit conducting pressurized air from the reservoir to the base chamber formed in the base through a second control orifice having the second specified flow rate equivalent to the first specified flow rate at the specified test pressure, the second supply conduit including a second passage interconnecting the second control orifice and the base chamber,

a housing containing the reservoir, the master orifice, and the first and second supply conduits,

an electronics module coupled to the housing, and

a cap leakage detector positioned in the electronics module and coupled to the first and second passages.

63. The tester of claim 62, further comprising a pressurized air supply hose interconnecting the second supply conduit in the housing-and the base chamber in the base.

64. The tester of claim 62, wherein the cap leakage detector includes a differential pressure transducer having a first input coupled to the first passage to communicate with air in the first passage and a second input coupled to the second passage to communicate with air in the second passage.

65. The tester of claim 64, wherein the cap leakage detector further includes a signaling device positioned in the electronics module and coupled to the differential pressure transducer to provide a cap-failing signal when the air pressure at the first input is greater than the air pressure at the second input and a cap-passing signal when the air pressure at the first input is lesser than the air pressure at the second input.