Water sensor system

• US 4,987,408 A
• Filed: 05/10/1989
• Issued: 01/22/1991
• Est. Priority Date: 05/10/1989
• Status: Expired due to Fees

• Current Assignee: Leakgard, Inc.
• Original Assignee: Robert C. Barron
• Inventors: Barron, Robert C.
• Primary Examiner(s): Orsino, Joseph A.
• Assistant Examiner(s): NEGASH, KINFE MICHAEL
• Application Number:
  US07/351,455
• Time in Patent Office: 622 Days
• Field of Search: 340/604, 340/605, 340/618, 340/620, 200/61.04, 307/118, 323/239, 323/245, 455/602, 250/551
• US Class Current: 340/604
• CPC Class Codes: G08B 21/20 responsive to moisture

Abstract

The disclosure relates to a water sensor unit wherein a plurality of water related appliances or equipment can be simultaneously monitored and in the event of sensing water with respect to any one of the several items being monitored appropriate action is taken such as shutting off the power to the unit and simultaneously shutting off the water supply to that particular unit. The sensor unit comprises a plurality of electronic circuits which include a "memory" permitting retention of a ground fault even through a power failure for up to 500 hours.

Claims

1. A water detector system for the detection of standing water indicative of an abnormal condition in a building or other habitable structure, said system comprising:

a power circuit comprising at least two electrically conducting leads, each of said leads electrically connected at one end to an input which is electrically connected to a source of alternating current, each of said leads electrically connected at their respective other ends to an output which is electrically connected to an electrical appliance which is to be protected, said electrical appliance receiving its electrical power through said leads of said power circuit;

means, electrically connected intermediate said power circuit input and output and connected to each lead of said power circuit, for providing control of said power circuit, said means for providing control including isolating means for protecting personnel from the hazards of electrical shock from contact with said source of alternating current;

means, connected to said means for providing control, for initiating alarm signals and control signals responsive to the detection of standing water, said control signals triggering said means for providing control of said power circuit to disconnect said protected electrical appliance from said source of alternating current; and

,

a plurality of water sensors connected to said means for initiating alarm signals and control signals, said water sensors capable of detecting standing water.

2. A water detector system as claimed in claim 1, in which said means for providing control of said power circuit includes triac means electrically connected to said leads between said input and said output for control of current from said input to said output whereby said control signals generated in response to the detection of standing water cause said triac means to prevent electrical current from flowing along said leads.

3. A water detector system as claimed in claim 2, which includes means for sensing a ground fault in said power circuit or said electrical appliance and initiating a control signal which causes said triac means to electrically disconnect said appliance from said source of alternating current.

4. A water detector system as claimed in claim 1, in which said isolating means for protecting personnel include light emitting diodes and associated phototransistors placed between said power circuit and said means for providing control of said power circuit whereby personnel are electrically isolated from the electrical current present in said power circuit.

5. A water detector system as claimed in claim 1, in which said water sensors include means for converting alternating current, provided from said isolating means for protecting personnel, to direct current, means for creating a continuous electrical current path only in the presence of standing water whereby said standing water becomes an integral, electrically conducting element of said continuous electrical current path, said standing water thereby electrically completing said continuous current path;

and, means for communicating the presence of said continuous electrical current path to said means for initiating alarm signals and control signals, thereby indicating the presence of water.

6. A water detector system as claimed in claim 5, in which said means for providing a continuous electrical current path includes two spaced apart water probes;

wherein said means for converting alternating current to direct current includes a full wave diode rectifier positioned across the drain and source of a field effect transistor, said full wave diode rectifier electrically connected to said isolating means for protecting personnel; and

, wherein said means for providing a continuous electrical current path also includes two resistors operating as a voltage divider biasing the gate of said field effect transistor causing said field effect transistor to conduct electrical current from said drain to said source in the absence of water between said water probes, each of said water probes respectively electrically connected to each side of said resistor positioned between said gate and said source of said field effect transistor so that an electrical circuit containing said water probes is in parallel with said resistor positioned between said gate and said source, whereby the presence of water between said water probes dissipates the bias of said gate of said field effect transistor, thereby shutting off said field transistor, whereby in the presence of water between said water probes, the only electrical current flowing through said water sensor flows through said resistor positioned between said drain and said gate and through said water probes and the water therebetween, which electrical current flows in a reduced amount in comparison to the electrical current flowing through said water sensor in the absence of water between said water probes.

7. A water detector system as claimed in claim 5, in which said means for providing a continuous electrical current path includes two spaced apart water probes;

wherein said means for converting alternating current to direct current includes a full wave diode rectifier positioned across the drain and source of a field effect transistor, said full wave diode rectifier electrically connected to said isolating means for protecting personnel; and

, wherein said means for providing a continuous electrical current path also includes two resistors positioned so as to bias the gate of said field effect transistor between the drain and gate of said field effect transistor, to turn on said field effect transistor in the event of the presence of water between said water probes, said water probes electrically connected in series with said resistor positioned between said gate and said drain, said water probes and the water therebetween being integral electrically conducting elements of the circuit between said gate and said drain of said field effect transistor.

8. A water detector system as claimed in claim 5 wherein said means for communicating the presence of said continuous electrical current path to said means for initiating alarm signals and control signals includes means for detecting the reduction in electrical current flowing through said water sensors in response to water present between said water probes.

18. A water detector system as claimed in claims 1, 9, or 13 further comprising:

means for initiating alarm signals and control signals in response to a blown fuse.

19. A water detector system as claimed in claims 1, 9, or 13 further comprising:

means to "remember" the state of the system during a power failure and return the system to the pre-power failure state when power returns.

9. A water detector system for the detection of standing water indicative of an abnormal condition in a building or other habitable structure, said system comprising:

a power circuit comprising at least two electrically conducting leads, each of said leads electrically connected at one end to an input which is electrically connected to a source of alternating current, each of said leads electrically connected at their respective other ends to an output which is electrically connected to an electrical appliance to be protected, said electrical appliance receiving its electrical power through said leads of said power circuit, said power circuit having a triac switch means electrically connected in each of said leads whereby the flow of electrical current through said leads is controlled by the operation of said triac switch means;

means electrically connected to said triac switch means, including optical isolator control means, for controlling each of said triac switch means;

a low voltage power supply connected between said electrically conducting leads of said power circuit;

an alarm circuit, said alarm circuit including optical isolator means to electrically isolate said alarm circuit from said power circuit;

and, means powered by said low voltage power supply, including a plurality of water sensors and associated circuitry, for detecting standing water and generating a control signal at said sensor, whereby said control signal enables said alarm circuit and causes said triac switch means to discontinue the flow of electrical current through said leads, thereby protecting said electrical appliance from electrically related damage and alerting persons near said electrically protected device to the presence of the standing water condition.

10. A water detector system as claimed in claim 9, further comprising means for disconnecting the water supply to said electrical appliance in response to said control signal.

11. A water detector system as claimed in claim 9, which includes means for sensing a ground fault in said power circuit or said electrical appliance and initiating a control signal which causes said triac switch means to electrically disconnect said appliance from said source of alternating current.

12. A water detector system as claimed in claim 11, in which, once a ground fault has been sensed, and alarm and control action has been taken, normal operation of said water detector system may not be restored except by manual resetting of the control circuits involved.

13. A water detector and cutoff system for detecting the presence of moisture in the immediate vicinity of a water consuming appliance an cutting off the supply of power and water thereto, said system comprising:

a power circuit comprising at least two electrically conducting leads, each of said leads electrically connected at one end to an input which is electrically connected to a source of alternating current, each of said leads electrically connected at their respective other ends to an output which is electrically connected to an appliance to be protected, said appliance receiving its electrical power through said power circuit;

means, electrically connected intermediate said power circuit input and output and connected to each lead of said power circuit, for providing control of said power circuit;

means for providing control of a solenoid valve to control the supply of water to said appliance;

means, connected to said means for providing control of said power circuit, for initiating alarm signals and control signals responsive to the presence of moisture, said control signals triggering said means for providing control of said power circuit to disconnect said water consuming appliance from said source of alternating current;

means, connected to said means for providing control of a solenoid valve, for initiating alarm signals and control signals responsive to the presence of moisture to trigger said means for providing control of a solenoid valve to cut off the supply of water to said appliance; and

a plurality of water sensors operatively connected to said means for initiating alarm signals and control signals, for detecting standing water.

14. A water detector and cutoff system as claimed in claim 13 wherein said means for providing control of said power circuit includes isolating means placed between said power circuit and said means for providing control of said power circuit for protection of personnel from said source of alternating current.

15. A water detector and cutoff system as claimed in claim 14 wherein said means for initiating alarm signals and control signals is connected to said means for providing control of said power circuit through electrically isolating means for protecting personnel.

16. A water detector and cutoff system as claimed in claim 13 wherein said alarm signal actuates an audible alarm.

17. A water detector and cutoff system as claimed in claim 13 wherein said alarm signal actuates an audible and visual alarm.