Fluid handling – Ambient condition change responsive – Burner gas cutoff
Reexamination Certificate
1999-10-19
2001-01-09
Chambers, A. Michael (Department: 3753)
Fluid handling
Ambient condition change responsive
Burner gas cutoff
C251S067000, C251S068000, C251S074000, C251S292000
Reexamination Certificate
active
06170509
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a safety valve system for the prevention of gas leaks. More particularly it relates to an add-on safety device installed over a previously Installed valve controlling the gas flow in a gas pipe, designed to automatically shut off the valve when a gas leak is detected.
BACKGROUND OF THE INVENTION
Leakage of inflammable, explosive or toxic gasses and liquids is a major threat to human lives and properties. If unnoticed and not stopped and dealt with on time, It may result in ignition, explosion or inhalation of these dangerous substances, and subsequently in heavy casualties and damages.
Various leakage detectors are known both for industrial and home use. For example, many buildings are equipped with smoke detectors which detect the presence of smoke produced by flames and produce an alarm signal or activate water sprinklers to put out the fire. Gas detectors are also known, and widely used.
Simple types of detectors merely detect the presence of dangerous substances, whereas more sophisticated devices incorporate detection and activation of other systems generally aimed at preventing further leakage and/or removing or neutralizing the danger imposed by those leaked substances.
In EP 440828 (Gazzaz) a gas monitoring system with leak detection and flow cut off was disclosed for controlling the flow of gas from a pressurized gas container to a cooking range of a kitchen. Leaked gas is detected by a sensor which activates a visual and an audible alarm and which operates said valve to terminate the gas flow. It comprised a valve having a solenoid having an energized position for retaining the valve in an open position allowing gas to flow through the valve and a deenergized position in which the valve is shut off.
In EP 523655 (Feleppa), a safety device for detecting gas leaks was described, comprising a gas detection electronic circuit, which signals electro-magnetic waves with radio frequency, at the event of gas leak detection, to a second electronic circuit, and controls a solenoid valve for the opening and closing of the gas supply in said gas system.
UK Pat. Application publication no. 2159249 (Fuentetaja) it was disclosed a shut-off valve for the automatic closure of a gas supply, comprising a body, having an angled passage corresponding to the gas inlet, having a valve head or obturator which is urged towards an associated seat by a spring. A locking pin whose distal end is positioned inside a groove on a stem extending from the valve head, locks the valve-head in an open position. Upon the detection of a gas leak the locking pin is drawn out of the groove, by means of an electromagnet actuating the removal of the locking pin from the groove.
The abovementioned inventions seem like good solutions for the prevention of gas leaks in gas systems. But require a major adjustment to be carried out on existing gas systems, as the introduction of a new component (i.e. the automatic valve) into the existing system, and its installation is necessary. Moreover, the installation of such devices in existing gas systems require the employment of skilled specialist workers, and cannot be done by an ordinary person, who generally is the user of such gas systems.
BRIEF DESCRIPTION OF THE INVENTION
The present invention seeks to provide an add-on safety device that can be mounted on top of an existing gas valve knob and thus eliminate the need to make major changes in an existing gas system.
Further more it is the object of the present invention to provide such a safety device that would be easily installed and would permit unskilled persons to install the add-on device without the need for skilled worker's guidance and assistance.
The purpose of the gas safety add-on device of the present invention is to provide a reliable, simple to Install and to operate, add-on safety device mounted over an existing gas valve, for the controlling of gas supply and the automatic gas supply cut off in the event of gas leak detection.
It is therefore provided, in accordance with a preferred embodiment of the present invention, an add-on automatic safety gas device for shutting off a gas valve at the detection of a gas leak comprising:
An add-on adapter device comprising:
a first knob, mounted over an existing gas valve knob, and affixed to it;
a spindle coupled to said first knob, capable of rotating said first knob, and said gas valve knob, between an “open position”, which is the position of the gas valve being open, allowing gas to flow through the pipe, and a “closed position”, which is the position of the gas valve being closed, shutting off the gas valve;
a second knob rotatably mounted substantially perpendicular to said spindle, said second knob provided with firm cantilever which is extended to provide a firm support along side the gas valve knob, so as to cause the rotation of said gas valve knob when said second knob is rotated in one direction:
a spring attached to said second knob, wherein the spring is in a wound state when said second knob is parallel to said first knob, when said first knob is in the “open position”, and wherein the spring is in an unwound state, when said second knob is parallel to said first knob when said first knob is in the “closed position”, thus rendering the “closed position” a preferred state of said second knob;
a bracket capable of being springably forced into a groove on said second knob, when said second knob is aligned substantially parallel to the open position, and while inserted preventing said second knob from rotating;
a solenoid, which in its energized state retracts said bracket away from said groove, thus enabling said spring to force said second knob to rotate to the closed position;
fixing means for fixing said add-on adapter device and holding it in place when mounted over said existing gas valve knob;
a gas leak detector, capable of detecting predetermined concentrations of a predetermined gas, and upon such detection produce an electrical signal and send it via electrical connecting means to actuate said solenoid to its energized state.
Furthermore, in accordance with another preferred embodiment of the present invention, the fixing means is a clamp.
Furthermore, in accordance with another preferred embodiment of the present invention, the add-on adapter device is housed inside a housing.
Furthermore, in accordance with another preferred embodiment of the present invention, the add-on adapter housing is installed over the gas valve, and the spindle axis of rotation aligned with that of the gas valve handle.
Furthermore, in accordance with another preferred embodiment of the present invention, the add-on adapter device may be operated manually, switching said gas valve from closed position to open position and vice versa.
And finally, in accordance with another preferred embodiment of the present invention, the spring is a torsion spring.
REFERENCES:
patent: Re. 30135 (1979-11-01), Fitzwater et al.
patent: 118008 (1871-08-01), Gardiner, Jr.
patent: 2333370 (1943-11-01), Graham
patent: 3085781 (1963-04-01), LaPointe
patent: 3685790 (1972-08-01), Crowe
patent: 3923475 (1975-12-01), Stenzel et al.
patent: 3955186 (1976-05-01), Green et al.
patent: 4488567 (1984-12-01), Grant
patent: 4533114 (1985-08-01), Cory et al.
patent: 0440828 (1991-08-01), None
patent: 0523655 (1993-02-01), None
patent: 2159249 (1985-11-01), None
Century Investments Limited
Chambers A. Michael
Fulbright & Jaworski LLP
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