Leak damage prevention system

• US 5,008,650 A
• Filed: 09/21/1989
• Issued: 04/16/1991
• Est. Priority Date: 09/21/1989
• Status: Expired due to Fees

• Current Assignee: Dane A. Hoiberg
• Original Assignee: Dane A. Hoiberg
• Inventors: Hoiberg, Dane A.
• Primary Examiner(s): Orsino, Joseph A.
• Assistant Examiner(s): Hofsass, Jeffery A.
• Application Number:
  US07/410,641
• Time in Patent Office: 572 Days
• Field of Search: 340/604, 340/605, 340/618, 340/620, 200/61.05, 200/61.04, 73/304 R
• US Class Current: 340/604
• CPC Class Codes: G01F 23/241 for discrete levels
• CPC Class Codes: G01M 3/18 for pipes, cables or tubes; for pipe joints or seals; for valves; for welds; for containers, e.g. radiators

Abstract

A battery-powered, liquid-detection alarm and shut-off system includes an elongated sensor, an electronic controller, and a spring biased shut-off valve assembly. The sensor comprises two partially exposed conductors separated by protruding ridges of insulation. The protruding-ridge configuration enables the sensor to detect small quantities of surface water and yet be insensitive to humidity. The electronic controller maximizes battery life and protects against false alarms caused by electrical interference. The shut-off valve assembly comprises a 1/4-turn ball valve and a valve-actuating assembly. The valve is set by being manually cocked to an open position, engaging a lever actuated cam and preloading a valve shut-off spring. The valve is then closed by momentarily passing an electrical current through a temperature-activated memory-shaped spring located on the valve assembly. The current is supplied by the electronic controller in response to detection of liquid by the sensor. The heating of the spring from the induced current causes the tension of the memory-shaped spring to increase, releasing the lever actuated cam and permitting the preloaded valve shut-off spring to close the valve.

Claims

1. A liquid detection system comprising:

means for detecting the presence of a liquid on a normally dry surface area, the detecting means including a helically wound elongated sensor comprising at least two conductors each being partially surrounded by a body of electrically insulating material, so that an elongated exposed portion having a continuous extent along the length of the sensor is formed on each conductor and the exposed portions are exposed to the environment continuously in alternating fashion while remaining electrically isolated from each other by protruding ridges of insulation along the length of the sensor, whereby the presence of liquid on the surface area to which the conductors are exposed can bridge the exposed portions of a pair of conductors independent of orientation of the sensor; and

electrical circuit means operatively connected to the sensor for detecting electrical resistance changes in the sensor in response to the liquid bridging the exposed portions of the conductors of the sensor.

2. The system according to claim 1 in which the conductors and their insulating material are wound in a double helix configuration.

3. An improved sensor for use in a liquid detection system, in which the sensor is exposed to the presence of water or other liquid to complete an electrical circuit to activate an alarm or other warning or electrical device, or to activate a controller for the source of the water or other liquid, the improved sensor comprising at least two helically wound, elongated, continuous electrical probe members comprising electrical conductors each having an outer jacket of electrical insulation partially surrounding the conductor so that each conductor has a partially exposed portion to the environment, and said portion being an elongated slot having a continuous extent along the length of the probe member, at least two probe members being connected to one another to form an elongated, helically wound, continuous, filament-like sensor, the sensor being characterized by the insulating jacket of each probe member protruding so that the exposed portion of each conductor is electrically isolated from the exposed portion of the other conductor in the sensor, the probe members of the sensor forming portions of exposed electrical conductor closely spaced apart from each other, electrically isolated from each other, and extending in an alternating series along the sensor, whereby the presence of surface liquid on a surface to which the conductors are exposed can bridge exposed portions of an adjacent pair of conductors independent of the orientation of the sensor, and thereby complete an electrical circuit to which the conductors of the sensor are electrically connected, while the protruding insulating jacket, or jackets, separate and elevate adjacent conductors so as to prevent ambient condensation from bridging the adjacent conductors.