Abstract:
An improved fire protection system that is of failsafe design for kitchen stoves with or without a range hood and other applications utilizing electrical power for generating heat and in which a fire condition such as a skillet of grease becomes ignited. Said system is activated thermally to release a quantity of fire suppressant material while simultaneously cutting off the electrical power. The system utilizes a reservoir containing the fire suppressant under pressure with a hose or pipe connected to one or a plurality of thermally activated nozzles. A second hose or pipe is connected to a pneumatically operated electrical interruption device.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This is a Continuation of application Ser. No. 11/647,055 Filing Date: Dec. 27, 2006 Art Unit 3752 
     
    
     FEDERALLY SPONSORED RESEARCH 
       [0002]    Not Applicable 
       SEQUENCE LISTING OR PROGRAMS 
       [0003]    Not Applicable 
       BACKGROUND OF THE INVENTION  
     Field of Invention  
       [0004]    This invention relates to an automatically actuated totally pressurized fire extinguishing system to fit all near wall kitchen stoves with or without a range hood. This invention includes a unique plug-in means for automatic shutoff of the heating electrical power to the stove. 
         [0005]    The use of automatically activated fire extinguishing devices for cooking stoves is known. Such devices provide a source of fire extinguishing compound to be released on to a stove surface in the event of a fire which occurs during use of the appliance. Virtually all prior art devices are designed and made only for installation within a range hood though preference today often calls for a microwave oven mounted over the cooking stove or such device without a traditional range hood, thereby eliminating the mounting space for the prior art devices. 
         [0006]    Even the smallest prior art device installed in a range hood leaves much to be desired in appearance due to the wires, pipes extinguishing nozzles and tanks that can be easily seen by persons near the stove and over time collect unsightly grease and dirt and are difficult to clean. 
         [0007]    Prior art automatic fire extinguishing installations sometimes include an automatic shutoff arrangement for shutting off the electricity to the stove upon detection of a fire. Known shutoff arrangements are generally complex, expensive, and present added components subject to faults and errors in installation and operation. Such devices quite often require professional services such as electricians for their installation, thus this also contributes to onsite installation time and expense. 
         [0008]    There is thus a need in the art for a fire extinguishing device which is unobtrusive in appearance, is fail safe, and lends itself to quick and easy installation without the need for professional services. 
         [0009]    The following discussed patents are a good representative sample of all prior art patents found. 
         [0010]    Prior inventors such as U.S. Pat. No. 4,313,501 to Eckert (1982) have relied on taught wires with fusible disks for their operation under a range hood while the fuel flow to the fire is shut off by a cable arrangement operating through a torturous path to a valve handle. Very little information is provided as to how this is to be done. 
         [0011]    Another invention, U.S. Pat. No. 4,979,572 to Mikulec, (1990) again requires a range hood for its operating space and electrical power to the stove is cut off by an arrangement to pull the electrical feed plug from the wall and is activated by a cable means similar to the previously mentioned patent by Eckert. This method was later seen as impractical and was later dropped in a succeeding patent, Mikulec U.S. Pat. No. 5,899,927 (1999), for a much more complicated interruption method. A gas valve for shutting off the gas supply to a gas operated stove is also operated by pulling a cable and releasing a spring powered valve. An alternate method of interrupting the gas supply is offered by Mikulec in U.S. Pat. No. 5,899,927 with an acoustically operated electronic system which introduces more complication and possibility of error unless the owner is well versed in testing and maintenance of the system. Both means of operation require considerable on site labor for both installation, adjustment, and some components could fail during an emergency. 
         [0012]    U.S. Pat. No. 4,984,637 by Finnigan (1991) again requires a range hood to hide the mechanism and uses a thermocouple and accompanying electronics to give a temperature display and sound an alarm. A brief mention is made that relays and valves can be used to cut off the stove heating energy. The main emphasis of this patent is that the system will turn off water or other suppressants when the temperature drops. This does not really solve the problem of a grease fire for water is the wrong material to use in such an instance and further the system is intended for a large liquid reservoir system to utilize the cycling on and off. 
         [0013]    U.S. Pat. No. 5,127,479 by Stehling et al. (1992) is strictly a range hood system much like the previously mentioned patents by Mikulec which utilizes cables and chain with heat melting links. A 12 volt battery back up system is referred to for powering an undefined valve or relay to cut off gas or electricity to the stove. If the home owner does not check the battery system regularly the system could easily fail to shut off the stove energy source in a fire emergency. 
         [0014]    U.S. Pat. No. 5,207,276 by Scofield (1993) operates only with a range hood and utilizes a twisted pair of wires in which the insulation melts to allow the two wires to short. The operation of the system depends on a battery backed up system. Energy cut off to the stove, though critical, is not mentioned. 
         [0015]    U.S. Pat. No. 5,868,205 by Cunningham et al. (1999) is designed to be used only with a range hood and has no means to cut off energy to the stove. 
         [0016]    U.S. Pat. No. 5,697,450 by Stehling, et al. (1999) is a fully electronic system for a range hood with acoustic triggered cut off of gas or electric energy to the stove. This system is totally dependent on electrical power and is subject to many faults and consequently is not fail safe. Blocking any of the acoustical properties by accumulation of dirt behind the stove by the system could prevent the shut off of energy to the stove. 
         [0017]    U.S. Pat. No. 5,899,278 by Mikulec (1999) is a self contained unit for range hood mounting and has no provision for energy shut off to the stove. 
         [0018]    U.S. Pat. No. 6,044,913 by Stehling et al. (2000) is an electrical system for a range hood fully dependent on battery power and acoustically linked to the energy shut off. This system therefore has the same limitation as U.S. Pat. No. 5,697,450 by Stehling (1999) listed above. 
         [0019]    U.S. Pat. No. 6,276,461 by Stager (2001) is a mechanically operated system for a range hood and has no provision for disrupting energy to the stove which could make the system ineffective. 
         [0020]    U.S. Pat. No. 3,866,687 Banner 02-1975 Makes reference to operation with or without a range hood. the Banner system applied to a range hood utilizes a pressurized tank with piping to an electrically operated valve with nozzles within the range hood and beneath the burners. The pressurized tank is equipped with a pressure operated meter which is a requirement of approving authority when using unsealed pressurized fire extinguishing tanks. In applying the system to either a range hood or beneath the burner Banner uses electrically operated valves for discharge of the fire suppressant beneath the burners, which might prove less than effective. 
         [0021]    U.S. Pat. No. 4,356,870 Gaylord et al. Nov. 2, 1982 System is for hoods only and utilizes an electrically operated solenoid valve for cut off of the gas and presumably uses an electrically energized relay to cut off the electrical power, which usually requires wiring and electricians. The system utilizes a spray nozzle which is connected to the building water supply and is usually considered to be the wrong material to fight a grease fire. 
         [0022]    U.S. Pat. No. 4,830,116 Walden et al. May 16, 1989 System is for range hoods and utilizes electrical equipment to disconnect the power source. 
         [0023]    U.S. Pat. No. 5,351,760 Tabor Jr. Oct. 4, 1994 System is for range hoods. Tabor claims the system is pressurized but it is actually pressurized only to an electrically operated release valve adjoining the retardant tank. The spray nozzle of this system is a passive device and is not thermally actuated. Further the spray nozzle has to spray material of a viscosity of one, which is probably water and the nozzle is a cooling spray nozzle of limited capacity usually associated with cooling back porches. 
         [0024]    These prior art devices have the disadvantage of being designed only for under or within a range hood even though today thousands of kitchens are designed with a microwave oven in place of the range hood. Some require taught wires that require some experience to install and are in a position under a range hood to collect grease and dirt and with such pipes, wires, and other paraphernalia will be difficult to clean. Others rely on electronics for acoustically operating the disruption in electricity or gas and are inherently less reliable than a failsafe system. It must be kept in mind that the average home owner will seldom think of maintenance for such a system and therefore systems of such design can fail long before they are needed in an emergency. 
       OBJECTS AND ADVANTAGES 
       [0025]    There is a need in the art for a fire extinguishing system which will satisfy the needs of those kitchen type stoves that do not have range hoods and to provide a system that will be of low cost to install, have high reliability, and not require professional services in its installation. Accordingly, several objects and advantages of the present invention are: 
         [0026]    (a) to provide a fire extinguishing system for a cooking type stove that is fail safe; 
         [0027]    (b) to provide a fire extinguishing system that can be installed without the need for professional services; 
         [0028]    (c) to provide a fire extinguishing system that will be versatile and allow installation of components in other than a single type of application; 
         [0029]    (d) to provide a fire extinguishing system that can interface with a number of different thermally actuated extinguisher nozzles to meet differing requirements; 
         [0030]    (e) to provide a fire extinguishing system in which its electrical power interruption requires only minimal plug in type installation; 
         [0031]    Still further objects and advantages will become apparent from a consideration of the ensuing description and drawings. 
       SUMMARY 
       [0032]    In accordance with the present invention a fire extinguishing system of failsafe design for kitchen type stoves utilize electric power for cooking energy that not only provides fire sensing and extinguishing but also provides effective disconnection of the energy source for heating and does not require professional services in its installation. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0033]    For a full understanding of the invention the following detailed description should be read in conjunction with the drawings, wherein: 
           [0034]      FIG. 1  is a perspective view of the fire extinguishing apparatus of the present invention applied in this instance to an electric stove with a range hood. 
           [0035]      FIG. 2  is a perspective view of the control unit showing its associated parts. 
           [0036]      FIG. 3  is a perspective view of the control unit mounted typically in a cabinet. 
           [0037]      FIG. 4  is a perspective view of the electrical interruption device showing a front view. 
           [0038]      FIG. 4B  is perspective view of the electrical interruption device showing a back view. 
           [0039]      FIG. 4C  exploded perspective view of the electrical interruption device in a partially assembled condition. 
           [0040]      FIG. 4D  exploded perspective view of the electrical interruption device. 
           [0041]      FIG. 4E  perspective view of the electrical interruption device. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0042]    The preferred exemplary embodiments of the invention are illustrated in  FIG. 1  through  FIG. 4E  wherein like numerals represent like parts. In the drawings closely related figures have the same number but different alphabetic suffixes. Each segment of the system is discussed in detail individually. 
         [0043]      FIG. 1  illustrates an application to an electric stove  38  of the preferred embodiment with a range hood  44  and with the control unit  100  located in a cabinet  49  and connected by high pressure hose or piping  20  to a pressure operated electrical interruption device  300  which is plugged by male connector prongs  336  into an electrical wall outlet  16  and the said electrical interruption device then provides internal female receptors for an outlet  394  for the stove electrical plug  14  to be plugged in to supply electrical current through cable  36  to the said electric stove heating elements  51 . 
         [0044]    Fire suppressant under pressure in the hoses and piping  28   FIG. 1  and originating in the said control unit supplies pressurized gas and extinguishment by hose or piping  28  to a thermally actuated spray head  500 . The said control unit may be mounted in a cabinet over the said stove  25  or in a side cabinet  49   FIG. 1  as illustrated, or any nearby space within an engineer approved distance. Said hoses or piping would be generally installed inside the wall space on both existing and new construction. 
         [0045]    In the event of a skillet  56   FIG. 1  or other container being left on the said stove and becoming overheated a fire  52   FIG. 1  will soon result activating the said thermally activated spray head thereby releasing the pressurized extinguishing agent  32  within the said hoses or piping and vessel containing fire extinguishing material under pressure in the said control unit spraying the top  47  of said stove, thereby extinguishing said fire. The resulting loss of pressure within the system releases a latching device in said electrical interruption device cutting off the flow of electrical current to the said stove thereby removing the source of the heat to the said skillet. The loss of pressure also causes an alarm pressure operated switch  400  to activate switches to transmit an alarm to a remotely monitored location. 
         [0046]      FIG. 2  illustrates a control unit  100  while  FIG. 3  illustrates a control unit as it would normally be housed in a cabinet  122 . The said control unit includes a vessel  112  under pressure and containing fire suppressant. 
         [0047]    The said vessel  112  is initially installed with full design pressure as indicated with pressure gauge  102 . When placing the system in operation after installation and verifying its integrity, the fire suppressant release lever  104 A is depressed against the fixed device  104  and permanently locking an internal valve in an open condition by applying a locking device  106  which will sufficiently hold the internal valve of the vessel  104 B in a potentially dischargeable condition. 
         [0048]    The said vessel is in communication with the said suppressant system by hose or pipe  108  through a connector  110  to piping connecting to a connection device for hose or piping  114  allowing passage of gas propellant from said vessel to the said thermally actuated device through said hose or piping  FIG. 1 . 
         [0049]    Pressure within the said vessel also feeds through connecting piping  140  through a conventional in line filter  116  to a hose barb or connector  120  to apply pressure to the pressure activated electrical interruption device  300   FIG. 1 . 
         [0050]    Said pressure also is applied through said connecting piping to the pressure operated alarm monitoring switch  400  and to a pressure gauge  124  whose purpose is for initial leak detection and setup operation with the initial gas for testing being induced through valve stem  118  prior to opening said valve  104 B. 
         [0051]    A cabinet  122   FIG. 3  constructed of material adequate for the purpose provides restraining strapping  128  for restricting movement of the said suppressant vessel. Additional restraining devices  126  hold the companion piping and devices in a restrained and vertical position to limit the effect of any powdery suppressant that may pass through the filter  116 . 
         [0052]    Said cabinet  122   FIG. 3  shall include a cover with a means of holding the cover in a closed position with the aid of latching device  132  engaging another cabinet mounted device  134  to hold said cover in a closed position when not being serviced. A penetration  138  is provided within the said cabinet for connection of the fire suppressant discharge hose or piping  28   FIG. 1  and another penetration  136  is provided for the pressure line  20   FIG. 1 . An additional penetration  130   FIG. 3  is provided for installing an alarm monitoring cable for connection to the said alarm monitoring switch  400 . 
         [0053]    The said extinguishing unit can be placed in any other convenient space such as an adjoining room or even an attic space with reasonable access provided such location is within a predetermined maximum distance provided through engineering calculations that is adequate for transmission of the fire suppressant by means of the high pressure hose or piping  28   FIG. 1 . 
         [0054]    Electrical interruption device identified as item  300  in  FIG. 4A  is housed in a case  302 ,  304  of which the front of case  302  is affixed to the case back  304  by screws  392  and provides openings  394  on the said front of case  394  for plugging in a three prong male electrical plug. Channels  391 ,  390  are made in the said case parts to allow a hose barb or other connector  372  to protrude for access to a pressure source such as the said pressurized vessel of the control unit  FIG. 2 . 
         [0055]    The upper most part of the said case back in  FIG. 4A  has an opening  306  for access to a reset device  308 . The most outstanding uniqueness of the present device is shown by the protrusion from the rear by male connector prongs  336 ,  340  through ports  338  in the back side of the said case  304  for directly plugging into an electrical power outlet  16   FIG. 1  thereby causing the total electrical installation to consist of plugging said electrical interruption device into a wall socket and a male socket  14  into the front portion of the electrical interruption device  300  and into internal female receptors as in  FIG. 1 . 
         [0056]      FIG. 4D  is an exploded view of all operating parts of said electrical interruption device. Gas pressure enters a hose barb or connector  372  and applies pressure within the cylinder  374  on piston  378  while o-rings  380  restrict leakage by sealing yet sliding against the Walls of said cylinder. Said piston, with sufficient pressure applied, forces against a connecting rod  382  which controls the movement of a hold release lever  358  with force through a spherical shaped  370  slide in connector. 
         [0057]    An opposing force supplied by spring  384  pressing against the interior of the end cap  388  and the base of said piston will return said piston to its uppermost position when gas pressure within the said cylinder is relaxed. The maximum travel of said piston is restricted by a limit washer  386  which limits said piston travel by the top surface of said limit washer pressing on the said piston bottom surface while the said limit washer bottom surface presses against inside bottom surface of the said end cap therefore limiting the maximum travel of the piston during periods of substantial gas pressure on the said piston. 
         [0058]    Said cylinder is formed to a mounting plate  376  which is anchored by screws  364  to a front mounting block  398  which includes a hinge bracket  396 . Attached to said hinge bracket by means of a hinge pin  356  is the said hold release lever  358 . Said spherical shaped connector engages the said hold release lever by sliding the said spherical shaped connector into and being held within a catchment  368  and thereby controlling the movement of said hold release lever. A latch protrusion  366  engages a notch  320  in a contact riser assembly  318  and when so engaged locks said contact riser assembly firmly in a downward position. 
         [0059]    The said contact riser assembly,  FIG. 4D , is sandwiched between the said front mounting block and rear mounting block  314  in a groove  352  and  352 A. Said contact riser assembly is pressed upward by stored kinetic energy in spring  312  resting one end on the top of said front mounting block and top of said rear mounting block. The top portion of the contact riser assembly  308  serves the purpose as a push to reset device and holds a locking pin  310  which restrains the top portion of said spring by pressing on the interior of said rear portion of case  304 . 
         [0060]    The said front mounting block and said rear mounting block along with the said mounting bracket for cylinder  374  are secured together by screws  364  which engage screw threads in holes  362  in said rear mounting block which is actually molded as an integral part of the case back  304 . 
         [0061]    When pressure decreases sufficiently on said cylinder, the said piston rises due to the urging of said spring  384   FIG. 4D  which thereby causes the said hold release lever  358   FIG. 4C  to rotate around said hinge pin and disengage from notch  320  thereby allowing the contact riser assembly  318  to quickly move upward propelled by compression spring  312 . The contact riser assembly continues its upward travel until the flat surface area  316  strikes the limit surface  350 , as seen in  FIG. 4D . 
         [0062]    The said contact riser assembly includes two electrical contacts  324  mounted to contact connector lugs  328  that mount through holes  328 A  FIG. 4D  in the extension arms  318 A of the said contact riser assembly. Said lugs can move freely within the said holes of the said extension arms. When the said contact riser assembly is in the locked down position the said moveable contact  324  becomes mated to a fixed contact  326  with proper contact pressure being supplied by coil springs  322  pressing on the said extension arms and the moveable contacts  324 . 
         [0063]    The fixed mating contact  326  is part of a prong mounting bracket  348  which serves to provide electrical conduction to male contact prong  336  and also serves as a mounting means for the said prong in the front of case  302  in openings  348 A  FIG. 4E . 
         [0064]    Male contact prong  340   FIG. 4C  is for ground or neutral conduction and is electrically connected to one internal female receptor ground or neutral connector  344  through tabs  342  with push on connectors  330  with wire conductor  355 . Two additional internal female receptors  345  for connection by means of tabs  342 A utilize two additional push on connectors  330  with wires  354  to connect to the said electrical moveable contacts  324  through the contact connector lugs  328 . 
         [0065]    The receiving end of the female receptors  344 ,  345  are in line with openings  394   FIG. 4C  and fitting into their respective restraining pockets  344 A and  345 A  FIG. 4E  molded in the front case  302   FIG. 4E . 
         [0066]      FIG. 4C  is a partially exploded perspective of the operating units of the said electrical interruption device. The electric plug  14   FIG. 1  plugs into the female receptor  394 . The male connector prongs  340 ,  336   FIG. 4B  are plugged into the wall mounted electrical outlet  16   FIG. 1 . With sufficient gas pressure applied to the hose barb or connector  372  the reset  308   FIG. 4C  can be manually pushed sufficiently which will cause the contacts  324  to engage the fixed contacts  326  while the gas pressure on the piston  378  will cause it&#39;s catchment  368  to move in the opposite direction causing the said catch  366  to engage the notch  320  thereby locking the said contact riser assembly  318  in a condition where with spring force from the contact pressure springs  322  will cause proper pressure to be applied to the contacts  324  making firm contact with the fixed contacts  326 . Electrical conduction is then complete from the male connector prongs  336  through the prong mounting brackets  348  to the fixed contacts  326 , through the moveable contacts  324  to the connector lugs  328 . Electrical conduction is then through the connectors  330  and wires  354  to connectors  330  pushed onto tabs  342 A of the internal female receptors thereby completing the electrical circuit through the electrical interruption device  300  and connecting to an external electrical plug  14  and cord  36   FIG. 1 . 
         [0067]    Upon the loss of pressure on the said cylinder  374   FIG. 4C  the said connector rod  382  will rise causing the piston connector sphere  370  to lift and thereby rotate the hold release lever catchment  368  freeing the catch  366  from the notch  320  of the connector riser assembly  318 . The said connector riser assembly quickly rises urged by the spring  312  and thereby removing pressure on the said contacts  324  causing them to separate a sufficient distance to break the electrical conduction between said contacts  324  and  326  and any carryover arching. 
         [0068]    This totally pressurized fire protection system is provided with a pressure operated alarm switch  400   FIG. 3  that can be used for remote alarm monitoring. 
         [0069]    The fire protection system of this invention can utilize a multitude of conventional thermally actuated spray nozzles of several vendors to be selected according to the space to be covered with the fire suppressant. 
       ADVANTAGES 
       [0070]    From the description above, a number of advantages of my kitchen type fire protection system become evident: 
         [0071]    (a) The control unit cabinet that houses the suppressant vessel and provides the pressurized fire suppressant does not require extensive installation and can be placed in any number of locations in the near vicinity of the protected area. This unit provides a pressure gauge for checking the pressure integrity of the system prior to placing the system in service. 
         [0072]    (b) The system can be installed in instances either with or without a range hood. 
         [0073]    (c) All components will be out of the view of persons near the stove except for one or more small thermally actuated nozzles. Collection of grease and dust on the operating components is severely minimized in comparison with others. Systems as described earlier have much of their equipment easily seen which detracts from the appearance of the kitchen and the pipes and wires are exposed for the collection of grease and dirt. 
         [0074]    (d) Installation of the electrical interruption device to remove the source of the heat to the stove is by simple plug in means. Installation of tubing or piping to this device for operation of the interruption device utilizes only a small tube easily installed even to pulling the said tubing or piping inside a wall. 
         [0075]    (e) Connection of the thermally activated spray nozzle to the control unit is by means of flexible hose or by piping. 
         [0076]    (f) A very important feature of this invention is that it is continually pressurized and failure of the system such as a leak in the two hoses or piping will cause interruption of the electrical power to the stove therefore making it fail safe. 
         [0077]    (g) Due to the simplicity of the installation the cost of this system for electric stoves should be well within the average home owners&#39; affordability. 
       CONCLUSIONS, RAMIFICATIONS, AND SCOPE 
       [0078]    Thus the reader will see that the fire extinguishing system presented here provides a highly reliable, easily installed system that can save property and lives. 
         [0079]    While the above description contains much specificity these should not be construed as limitations on the scope of the invention but rather as an exemplification of the preferred embodiment thereof. Many other variations are possible. For example, the system can be installed as a protective system in confined instrument cabinets or in many other such applications where the fire extinguishment and the cutoff of electricity is imperative. 
         [0080]    The operational design of the equipment as presented herein is the presently preferred embodiments and variations of the basic designs might well result in future cost savings. The electrical interruption device could be made smaller and with a variation of the presently designed cocking mechanism could result in other savings in both space and cost. However, the simplicity of installation of the electrical power interruption is the systems main attributes. 
         [0081]    Accordingly, the scope of the invention should be determined not by the embodiments illustrated but by the appended claims and their legal equivalents.