SOLID STATE FLUID LEVEL SENSOR

• US 20080095637A1
• Filed: 12/13/2007
• Published: 04/24/2008
• Est. Priority Date: 07/09/2004
• Status: Active Grant

• Current Assignee: Touchsensor Technologies LLC (Methode Electronics Incorporated)
• Original Assignee: Touchsensor Technologies LLC (Methode Electronics Incorporated)
• Inventors: Reniger, Bruce, Burdi, Roger
• Granted Patent: US 8,291,761 B2
• Time in Patent Office: Days
• US Class Current: 417/36
• CPC Class Codes: F04B 17/03 driven by electric motors
• CPC Class Codes: F04B 49/02 Stopping, starting, unloading or idling control
• CPC Class Codes: F04D 15/0218 the condition being a liquid level or a lack of liquid supply
• CPC Class Codes: G01F 23/261 for discrete levels
• CPC Class Codes: G01F 23/265 for discrete levels
• CPC Class Codes: G01F 23/266 measuring circuits therefor
• CPC Class Codes: G01F 23/268 mounting arrangements of probes
• CPC Class Codes: H05K 1/0268 for electrical inspection or testing
• CPC Class Codes: H05K 1/16 incorporating printed electric components, e.g. printed resistor, capacitor, inductor
• CPC Class Codes: Y10T 29/4913 Assembling to base an electrical component, e.g., capacitor, etc.

Abstract

A sensor system for sensing liquid level in a bilge, for use in automatic bilge pump actuation. First and second field effect sensors are potted or sealed within a container or the bilge wall and are aligned in a vertical array and each comprise a substantially planar pattern of “electrodes” or conductive traces disposed on a printed circuit board (PCB) along with integrated circuits used to create a loop or arc-shaped electric field. As bilge liquid rises to the proximity or level of the field effect sensors, a change in the arc-shaped electric field is sensed and, in response, a bilge pump is automatically actuated to pump liquid out of the bilge. Optionally, the pump control can be programmed by use of a microprocessor to permit control of on-off timing and is prevent undesirable effects of “sloshing.”

Claims

1-25. -25. (canceled)

26. A method of operating a bilge pump, comprising the steps of:

a) positioning within a bilge a sealed housing having therein at least a first field effect sensor;

b) generating an electromagnetic field with the sensor; and

c) sensing the presence of fluid proximate the sensor by detecting variations in the electromagnetic field.

27. The method of claim 26, further including the step of:

d) operating the bilge pump when a fluid is detected.

28. The method of claim 27, further including the step of:

e) stopping operation of the bilge pump when the fluid is no longer detected.

29. The method of claim 27, further including the step of:

e) stopping operation of the bilge pump when the fluid level is determined to be at a selected lower level.

30. The method of claim 26, further including the steps of:

d) starting a timer and measuring the duration of the interval for which fluid is present, and, if fluid is present for an interval indicating that the sensed condition is not a result of sloshing fluid; and

e) operating the bilge pump.

31. A method of manufacturing a pump with a solid state fluid level sensor, comprising the steps of:

disposing a first electrode pattern and a second electrode pattern on a dielectric substrate;

disposing a current switching device on the dielectric substrate;

electrically coupling the first and second electrode patterns to the current switching device to form a printed wiring board assembly;

electrically coupling the printed wiring board assembly to the pump and a power supply for the pump;

providing a housing;

disposing the printed wiring board assembly in the housing; and

sealing the printed wiring board assembly within the housing.

32. The method of manufacturing according to claim 31, further comprising the steps of:

disposing an upper center electrode on the dielectric substrate; and

disposing an upper outer electrode substantially around the upper center electrode to form the first sensor electrode pattern.

33. The method of manufacturing according to claim 31, further comprising the steps of:

disposing a lower center electrode on the dielectric substrate; and

disposing a lower outer electrode substantially around the lower center electrode to form the second sensor electrode pattern.

34. The method of manufacturing according to claim 32, further comprising the step of electrically coupling an active electrical component to the upper center electrode and the upper outer electrode.

35. The method of manufacturing according to claim 33, further comprising the step of electrically coupling an active electrical component to the lower center electrode and the lower outer electrode.

36. The method of manufacturing according to claim 31, further comprising the step of balancing the first and second electrode patterns.

37. The method of manufacturing according to claim 31, further comprising the step of disposing a ground ring substantially around at least one of the first or second electrode patterns on the dielectric substrate.

38. The method of manufacturing according to claim 31, further comprising the step of providing an N-channel field effect transistor as the current switching device.

39. The method of manufacturing according to claim 31, further comprising the step of providing two cables to form a wire assembly for electrically coupling the printed wiring board assembly to the pump and the power supply for the pump.

40. The method of manufacturing according to claim 31, further comprising the steps of:

programming a microprocessor with a predetermined delay for pump actuation to overcome sloshing;

disposing the microprocessor on the dielectric substrate; and

electrically coupling the microprocessor to the first and second electrode patterns and the current switching device such that the microprocessor controls a state of the current switching device based on the fluid level sensed by the first and second electrode patterns.

41. A method of operating a pump, comprising the steps of:

electrically coupling a current switching device to the pump and a power supply for the pump;

electrically coupling an electrode pattern to the current switching device;

generating an electromagnetic field with the electrode pattern;

sensing the level of a fluid to be pumped by detecting variations in the electromagnetic field due to changes in the fluid level; and

changing the state of the current switching device to operate the pump based on the sensed fluid level.

42. The method of operating a pump according to claim 41, further comprising the step of electrically coupling a second electrode pattern to the current switching device.

43. The method of operating a pump according to claim 42, further comprising the steps of:

disposing the electrode pattern in a first predetermined position; and

disposing the second electrode pattern in a second predetermined position,

wherein the first predetermined position is above the second predetermined position.

44. The method of operating a pump according to claim 42, further comprising the steps of:

electrically coupling a microprocessor to the electrode pattern and the second electrode pattern;

transmitting the sensed fluid level from the electrode pattern and the second electrode pattern to the microprocessor; and

actuating the pump when the microprocessor determines that both the electrode pattern and the second electrode pattern sense fluid for a predetermined number of reads.

45. The method of operating a pump according to claim 44, further comprising the step of current scalping the power supply to the pump to provide power to the microprocessor.

46. The method of operating a pump according to claim 41, further comprising the step of providing two cables to electrically couple the pump, the power supply for the pump, and the current switching device.

47. The method of operating a pump according to claim 41, further comprising the step of sending current through the current switching device to actuate the pump.

48. The method of operating a pump according to claim 41, further comprising the step of removing heat from the current switching device to the fluid to be pumped.

49. The method of operating a pump according to claim 41, further comprising the step of providing an N-channel field effect transistor to form the current switching device.