Fail-safe leak detector including independent and repetetive sensing means

• US 5,229,750 A
• Filed: 08/02/1991
• Issued: 07/20/1993
• Est. Priority Date: 08/02/1991
• Status: Expired due to Term

• Current Assignee: Demetrius Vassiliou, James G. Welch Jr, James W. Simmons
• Original Assignee: Demetrius Vassiliou, James G. Welch Jr, James W. Simmons
• Inventors: Simmons, James W., Vassiliou, Demetrius, Welch, James G. Jr.
• Primary Examiner(s): Mofsass, Jeffrey
• Application Number:
  US07/739,467
• Time in Patent Office: 718 Days
• Field of Search: 340/603, 340/604, 340/605, 340/618, 340/623, 340/624, 200/61.04, 200/61.05, 73/304 R, 73/305, 73/307, 73/308, 73/319, 73/40, 73/40.5, 137/551, 137/558
• US Class Current: 340/605
• CPC Class Codes: G01F 23/242 Mounting arrangements for electrodes
• CPC Class Codes: G01F 23/243 Schematic arrangements of probes combined with measuring circuits
• CPC Class Codes: G01F 23/70 for sensing changes in level only at discrete points
• CPC Class Codes: G01M 3/16 using electric detection means G01M3/045, G01M3/06, G01M3/12, G01M3/20, G01M3/24, G01M3/26 take precedence
• CPC Class Codes: G01M 3/186 for containers, e.g. radiators
• CPC Class Codes: G08B 21/20 responsive to moisture
• CPC Class Codes: Y10T 137/8158 With indicator, register, recorder, alarm or inspection means

Abstract

A fail-safe system for the detection of water leaks, and for the prevention of damage therefrom. In a home or building which includes a hot-water tank and a water tank for a toilet, e.g., the damage-prevention system comprises valves for shutting off the supply of water to the tanks, and other valves for draining the tanks through discharge lines to the outside of the home or building. At the same time, power to the hot-water tank is shut off. A fail-safe water detector comprises a float with a metal cap, a first pair of electrical probes below the float, and a second pair of electrical probes above the metal cap and separated from the cap by an air gap. A circuit is closed in any of three ways: (1) when water contacts the first pair of probes, (2) when water raises the float and makes contact between the metal cap and the second pair of probes, and (3) when water contacts the second pair of probes.

Claims

1. A fail-safe electrical sensor for detecting a water leak, the sensor comprising:

(a) a float having an electrically-conductive top;

(b) means for signalling a closed electrical circuit;

(c) a first pair of electrical conductors disposed below the float and electrically connected to a source of electricity; and

(d) a second pair of electrical conductors disposed directly above and spaced apart from the float'"'"'s conductive top, and electrically connected to the source of electricity;

the first and second pairs of conductors being connected in parallel to the source of electricity, the individual conductors of each pair of electrical conductors being spaced apart from one another to provide an open circuit in the absence of the detection of a water lead, the distance separating the individual conductors of the second pair of conductors being less than the width of the electrically-conductive top of the float to provide an open circuit in the absence of the detection of a water leak;

whereby

(e) a first electrical contact is made by water contacting the first pair of electrical conductors, thereby closing a first circuit and producing a first signal;

(f) a second electrical contact is made by rising water raising the float to a level at which electrical contact is made between the second pair of electrical conductors and the electrically-conductive top of the float, thereby closing a second circuit and producing a second signal; and

(g) a third electrical contact is made by rising water contacting the second pair of electrical conductors, thereby closing the second circuit and producing the second signal.

2. A device for detecting a water leak, the device comprising:

(a) a float having an electrically-conductive top;

(b) a first pair of electrical conductors disposed below the float; and

(c) a second pair of electrical conductors disposed directly above and spaced apart from the float'"'"'s conductive top;

the individual conductors of each pair of conductors being spaced apart from one another to form an open circuit in the absence of the detection of a water leak, the distance separating the individual conductors of the second pair of conductors being less than the width of the conductive top of the float, to provide an open circuit in the absence of a water leak, whereby a first electrical circuit is closed by water contacting the first pair of conductors, a second electrical circuit is closed by rising water raising the float to a level at which electrical contact is made between the second pair of conductors and the conductive top of the float, and the second electrical is closed by rising water contacting the second pair of conductors.