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  Burner shut offUSPTO Application #: 20060234176Title: Burner shut off Abstract: A burner shutoff for a burner, the burner shutoff including a solenoid moveable between an open position permitting fuel supply to the burner and a closed position cutting off fuel supply to the burner. The burner shutoff including a thermocouple in communication with the solenoid, wherein the thermocouple producing a voltage output signal when heated by the burner for maintaining the solenoid in the open position. The burner including a safety timer for selectively generating and communicating a reverse polarity voltage signal to the solenoid such that the voltage signal received by the solenoid is altered sufficiently to move the solenoid to the closed position, thereby shutting off the burner. (end of abstract) Agent: Mark A Koch - Hamilton, ON, CA Inventor: Eric Willms USPTO Applicaton #: 20060234176 - Class: 431080000 (USPTO) Related Patent Categories: Combustion, Timer, Programmer, Retarder Or Condition Responsive Control, By Combustion Or Combustion Zone Sensor, Of Shutdown By Response To Sensed Combustion Failure Or Overheat, By Electrical Control Circuit, Thermoelectric Generator Sensor The Patent Description & Claims data below is from USPTO Patent Application 20060234176. Brief Patent Description - Full Patent Description - Patent Application Claims
FIELD OF THE INVENTION [0001] The present invention generally relates to a safety automatic shut off device for gas burners. BACKGROUND OF THE INVENTION [0002] Heaters often utilize gas fired burners which normally operate with propane fuel, however can also have other sources of fuel, including but not limited to natural gas, butane and heating oil. Most portable heaters having gas fired burners are fitted with a safety thermocouple which communicates electrically with a solenoid valve in order to detect a flame out condition. The thermocouple mounted proximate the flame or heat source develops a millivolt signal which in turn is communicated back to the solenoid valve. The millivolt signal maintains the solenoid valve in the open position. When a flame out condition occurs, the thermocouple cools downs and the millivolt signal decreases which in turn closes off the solenoid valve once the signal from the thermocouple has dropped to a certain predetermined level. [0003] Small heaters having gas fired burners are often used in very small enclosed spaces and under the right conditions, the gas fired burners may deplete the amount of oxygen within the enclosed space and under certain conditions may give off carbon monoxide which can be hazardous to the occupant of the enclosed space. [0004] Therefore it is desirable to have a safety device and/or a safety feature which will prevent or minimize the possibility of oxygen depletion within small enclosed spaces and/or the development of carbon monoxide in order to prevent hazardous conditions from forming within small enclosed spaces in which the heaters are located. BRIEF DESCRIPTION OF THE DRAWINGS [0005] The embodiments now be described by way of example only with reference to the following diagrams in which: [0006] FIG. 1 is a schematic diagram of the burner shut off as shown deployed with a heater. [0007] FIG. 2 is a schematic wiring diagram of the burner shut off showing details of the wiring of the safety timer. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT [0008] The present embodiment of burner shut off is shown generally as 100 in FIGS. 1 and 2. In FIG. 1, burner shut off 100 is shown deployed together with a heater 102. In one example heater 102 is a portable space heater of the type having a high intensity ceramic type gas burner. Burner shut off 100 may also be applicable to other heaters. [0009] Burner shut off 100 includes safety timer 202 which includes circuit board 214 having the following major components, namely a timer 204, a micro processor 206, a power storage device 208 and a power supply preferably a battery 212. [0010] The burner shut off 100 further includes a thermocouple 220 having thermocouple wires 222 in electrical communication with solenoid valve 230 which also has a manual push button 232. [0011] Safety timer 202 is in electrical communication with thermocouple wires 222 via timer wires 216. [0012] Typical heater 102 includes a gas supply 110, burner 116 producing a flame 118. [0013] Certain components of heater 102 are not shown for simplicity sake for example, the mixing of air with gas supply 110 is not shown and also the ignition source for lighting flame 118 is also not shown. The components of heater 102 which interact with burner shut off 100 are generally shown namely burner 116 having flame 118 as well as solenoid valve 230. In Use [0014] Heater 102 is started in the manner generally known in the art namely, manual push button 232 of solenoid valve 230 is manually depressed in order to allow gas supply 110 to flow freely to burner 116. Not shown, gas is mixed in appropriate proportions with air in order to produce a combustible mixture of fuel and air which can be ignited at the end of burner 116 to produce flame 118. An ignition source not shown is used to ignite the combustible fuel mixture at the end of burner 116 to produce flame 118. Once flame 118 has been initiated, it heats thermocouple 220 and the heating of thermocouple 220 creates a millivolt output normally in the range between 0.007 to 0.020 volts (7 to 20 millivolts) and this potential produced by thermocouple 220 is electrically communicated back to solenoid 230. The millivolt out of thermocouple 220 is enough to hold the solenoid valve 230 in the open position allowing gas supply 110 to flow freely to burner 116. [0015] A person skilled in the art will recognize that once thermocouple 220 has been heated to the normal operating temperature by flame 118, enough millivolts and/or current are produced by thermocouple 220 to hold solenoid valve 230 in the open position, and therefore manual push button 232 can be released and the valve 230 is retained in the open position to ensure continuous firing of burner 116. [0016] Thermocouple 220 is there to ensure that should for some reason flame 118 be extinguished, thermocouple 220 will naturally cool down and therefore the millivolts produced by thermocouple 220 will decrease to a point where the current produced by thermocouple 220 can no longer hold solenoid valve 230 in the open position and therefore, gas supply 110 will be shut off. A person skilled in the art will recognize this as a normal safety feature that is found on many commercially available portable space heaters for safety purposes to ensure that the gas supply 110 is cut off should there be an interruption or an extinguishment of flame 118. [0017] A person skilled in the art will recognize that the electromotive force or the voltage output of thermocouple 220 is extremely low, normally in the range of 7 to 20 millivolts and once the voltage falls below about 5 millivolts the solenoid valve 230 will normally trip to the closed position. [0018] A person skilled in the art will also recognize that due to the small millivolt output of thermocouple 220, the electrical connections between thermocouple 220 and solenoid valve 230 are extremely sensitive, particularly to any contact resistance which may inhibit the flow of current between thermocouple 220 and solenoid valve 230 along thermocouple wires 222. Therefore, any mechanical contact which is introduced between thermocouple 220 and solenoid valve 230 may be undesirable in that it may introduce an unwanted contact resistance and falsely close solenoid valve 230 when in fact, flame 118 has not been extinguished. [0019] Therefore in one embodiment a burner shut off 100 is contemplated which will allow solenoid valve 230 to shut gas supply 110 without introducing any mechanical contact resistance of additional switches or contacts along thermocouple wires 222. In other words thermocouple wires 222 are continuous and free of intervening contacts between thermocouple 220 and solenoid valve 230 in order to ensure the most reliable operation of heater 102. This continuous aspect of thermocouple wires 222 means there are no mechanical contacts introduced between thermocouple 220 and solenoid 230 other than to accomplish connection between thermocouple 222 and solenoid 230. The connection between the timer wires 216 and thermocouple wires 222 does not introduce a mechanical contact and therefore no additional contact resistance along thermocouple wires 222. The timer wires 216 are connected to the thermocouple wires using a contact less connection 219. The contact less connection can be in any location provided a connection is made to the solenoid 230. In another embodiment it is contemplated that contacts may be used provided the contact resistance does not falsely close solenoid valve 230. Continue reading... Full patent description for Burner shut off Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Burner shut off patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. Start now! - Receive info on patent apps like Burner shut off or other areas of interest. ### Previous Patent Application: Air quality sensor/interruptor Next Patent Application: Time knob for gas and electric heater Industry Class: Combustion ### FreshPatents.com Support Thank you for viewing the Burner shut off patent info. IP-related news and info Results in 0.13841 seconds Other interesting Feshpatents.com categories: Qualcomm , Schering-Plough , Schlumberger , Seagate , Siemens , Texas Instruments , |
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