Liquid sensor for disabling an electrical device

• US 6,229,229 B1
• Filed: 05/24/1999
• Issued: 05/08/2001
• Est. Priority Date: 05/24/1999
• Status: Expired due to Term

• Current Assignee: Sharps Technology Inc.
• Original Assignee: Terry D. Sharp
• Inventors: Sharp, Terry D.
• Primary Examiner(s): Sherry, Michael J.
• Assistant Examiner(s): HUYNH, KIM NGOC
• Application Number:
  US09/317,745
• Time in Patent Office: 715 Days
• Field of Search: 361/78, 361/87, 361/271, 361/286, 361/280, 361/284, 361/285, 307/112, 307/116, 307/118, 307/125, 340/540, 340/603-605, 137/312
• US Class Current: 307/118
• CPC Class Codes: F24F 2140/30 Condensation of water from cooled air
• CPC Class Codes: G01F 23/242 Mounting arrangements for electrodes
• CPC Class Codes: H01H 35/42 Switches operated by change of humidity
• CPC Class Codes: Y10T 137/5762 With leakage or drip collecting

Abstract

A liquid sensor for disabling an electrical device includes upper and lower conductors, each preferably formed of wire mesh tape, separated by a water permeable insulating material such as foam. The electrical device to be disabled when the presence of a liquid is detected is preferably connected to a power source through a circuit breaker, and the upper conductor of the liquid sensor is connected to the same side of the circuit breaker as the electrical device. The lower conductor of the liquid sensor is preferably connected to ground. When water accumulates in the vicinity of the liquid sensor to the point that the water forms an electrical connection between the upper and lower conductors, the sensor will induce an excessive current through the circuit breaker, thus causing the circuit breaker to trip or blow, thus removing power to the electrical device. In one preferred embodiment, the electrical device is a thermostat for a climate control system, where disabling the thermostat will disable the climate control system. The circuit breaker may be resettable or may comprise a replaceable fuse.

Claims

1. In a climate control system including a thermostat and a power source for the thermostat, the improvement comprising a circuit breaker electrically connecting the thermostat to a line terminal of the power source, and a sensor operatively connected to the circuit breaker so as to electrically connect the circuit breaker to ground upon sensing a predetermined level of liquid in a vicinity of the sensor, thereby electrically connecting the line terminal of the power source to ground through the circuit breaker for opening the circuit breaker so as to disconnect the thermostat from the power source.

2. The system of claim 1 wherein the system is of a type capable of discharging a liquid.

3. The system of claim 2 wherein the circuit breaker is resettable.

4. The system of claim 2 wherein the circuit breaker is a replaceable fuse.

5. The system of claim 2 wherein the sensor comprises a first terminal electrically connected to the same side of the circuit breaker as the thermostat.

6. The system of claim 5 wherein the sensor comprises a second terminal electrically connected to ground.

7. The system of claim 6 wherein the sensor further comprises a first conductive surface electrically connected to the circuit breaker, a second conductive surface electrically connected to ground, and a water permeable insulator separating the first and second conductive surfaces.

8. A device for disabling a thermostat in a climate control system upon sensing a liquid in a vicinity of the device, the device comprising:

a circuit breaker having an input terminal for connection to a current source, an output terminal for connection to a positive terminal of the thermostat, and an electrical connection between the input terminal and the output terminal, the circuit breaker being configured to open the electrical connection between its input terminal and its output terminal when an electric current flowing through said electrical connection exceeds a predetermined current threshold; and

a liquid sensor having a first terminal connected to the circuit breaker output terminal and a second terminal for connection to ground, the liquid sensor being configured to electrically connect its first terminal to its second terminal upon sensing a liquid, thereby causing a current greater than said predetermined current threshold to flow through the electrical connection of the circuit breaker and causing the circuit breaker to open the electrical connection between the input and output terminals and remove power from the positive terminal of the thermostat when the second terminal of the liquid sensor is connected to ground, the input terminal of the circuit breaker is connected to the current source, and the output terminal of the circuit breaker is connected to the positive terminal of the thermostat.

9. The device of claim 8 wherein the circuit breaker is resettable.

10. The device of claim 8 wherein the circuit breaker is a replaceable fuse.

11. A method for disabling a thermostat in a climate control system upon sensing a liquid, the thermostat having a positive terminal for connection to a current source, the method comprising the steps of:

electrically connecting an input terminal of a circuit breaker to the current source;

electrically connecting an output terminal of the circuit breaker to the positive terminal of the thermostat so as to electrically connect the positive terminal of the thermostat to the current source through the circuit breaker; and

electrically connecting the output terminal of the circuit breaker to ground upon sensing a predetermined level of liquid, causing the circuit breaker to open the electrical connection between the positive terminal of the thermostat and the current source and thereby disable the thermostat.

12. The method of claim 11 wherein the step of electrically connecting the circuit breaker output terminal to ground includes electrically connecting the circuit breaker output terminal to a sensor having two conductors separated by a water permeable material.