Patent Publication Number: US-7896093-B2

Title: Localized fire suppression

Description:
RELATED APPLICATION INFORMATION 
     Priority Claim Under Rule 1.78(a)(4): This patent claims priority from the following provisional patent application Ser. No. 60/940,187, filed May 25, 2007, entitled “Automatic Fire Protection System With Audible Alarm for a Christmas Tree”. 
     Priority Claim Under Rule 1.78(a)(1): This patent claims priority from the following non-provisional patent applications: none. 
     Other related applications: none. 
    
    
     NOTICE OF COPYRIGHTS AND TRADE DRESS 
     A portion of the disclosure of this patent document contains material which is subject to copyright protection. This patent document may show and/or describe matter which is or may become trade dress of the owner. The copyright and trade dress owner has no objection to the facsimile reproduction by anyone of the patent disclosure as it appears in the Patent and Trademark Office patent files or records, but otherwise reserves all copyright and trade dress rights whatsoever. 
     BACKGROUND 
     1. Field 
     This disclosure relates to controlling a localized fire such as, for example, a fire in a Christmas tree. 
     2. Description of the Related Art 
     Most homes and commercial buildings have smoke detectors, but many homes and some commercial buildings may not have installed fire sprinklers or other fire suppression systems. Even in homes and other buildings having fire sprinklers, localized fires may cause significant damage and risk to occupants before the smoke detectors and/or sprinkler system sense the fire. 
     Faulty electric wiring on Christmas trees is a common cause of fires that are, at least initially, localized to the tree and its immediate environment. Other causes of localized fires include smoking (particularly while in bed), cooking appliances, and improperly placed space heaters. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic diagram of an apparatus for localized fire suppression. 
         FIG. 2  is a schematic diagram of an apparatus for localized fire suppression. 
         FIG. 3A  is a schematic diagram of an armed pneumatically-actuated valve. 
         FIG. 3B  is a schematic diagram of an activated pneumatically-actuated valve. 
         FIG. 4  is a view of a representative application of an apparatus for localized fire suppression. 
     
    
    
     Throughout this description, elements appearing in figures are assigned three-digit reference designators, where the most significant digit is the figure number and the two least significant digits are specific to the element. An element that is not described in conjunction with a figure may be presumed to have the same characteristics and function as a previously-described element having a reference designator with the same least significant digits. 
     DETAILED DESCRIPTION 
     Description of Apparatus 
     Referring now to  FIG. 1 , an apparatus  100  for localized fire suppression may include a tank  110  of fire suppressant  112  coupled through a hose  132  to a valve  130  through which the fire suppressant  112  may be dispensed in case of a localized fire.  FIG. 1  shows, as an example, the valve  130  disposed at the top of a Christmas tree  105 . It should be recognized that the apparatus for localized fire suppression  100  is not limited to suppressing Christmas tree fires. The apparatus for localized fire suppression  100  may be disposed in a kitchen, bedroom, garage, or other location that may have a risk of a localized fire. 
     The tank  110  may contain a quantity of fire suppressant  112 , which may be water or another fire suppressant material. The tank  110  may contain a quantity of precursor material that turns into a fire suppressant foam when released through the valve  130 . The tank  110  may be pressurized such that, when the valve  130  releases the fire suppressant, the fire suppressant  112  may be forced out of the tank  110  through a siphon tube  116 . Thus the apparatus  100  may dispense fire suppressant without the use of a pump or other mechanism that requires electricity. To suppress a fire in a Christmas tree, for example, the tank  110  may hold 3 to 4 gallons of fire suppressant  112 . The tank  110  may hold a greater or smaller amount of fire suppressant  112 . 
     The tank  110  may be pressurized by gas from a gas bottle  120 . The gas bottle  120  may be coupled to the tank  110  by a gas pipe  122 , which may include one or more valves  124 . The tank  110  may include a volume  114  of pressurizing gas, which may be air, nitrogen, carbon dioxide or other nonflammable gas. The volume  114  of pressurizing gas may be separated from the fire suppressant  112  by a flexible diaphragm (not shown in  FIG. 1 ) or other mechanism, if necessary to prevent absorption of the pressuring gas into the fire suppressant or other undesired interaction between the fire suppressant and the pressurizing gas. 
     The valve  130  may be adapted to distribute the fire suppressant  112  over an appropriate area for the anticipated localized fire. The valve  130  may be controlled by a pneumatic fire sensor which may include a tube  140  containing a gas at a pressure above a predetermined pressure level and a first pressure-detecting mechanism  150  to detect a reduction in the gas pressure within the tube  140 . The first pressure-detecting mechanism  150  may be linked to the valve  130  such that the valve  130  is opened when the first pressure-detecting mechanism  150  detects that the gas pressure within the tube  140  falls below the predetermined pressure level. 
     In the absence of a fire, the tube  140  may be filled with a gas at a pressure greater than the predetermined pressure level. The predetermined pressure level may be, in turn, greater than atmospheric pressure. The tube  140  may be pre-filled with a gas at a pressure greater than the predetermined pressure level and closed or sealed at each end. The tube  140  may be pressurized by a gas supply, which may be the gas bottle  120  used to pressurize the tank  110 . The tube may be coupled to the gas bottle  120  as shown by the dashed line  126 . 
     The tube  140  may be fabricated from a polymer or other material that is incapable of retaining a gas at a pressure greater than the predetermined pressure level when exposed to a fire. Continuing the example of an apparatus to suppress Christmas tree fires, the tube  140  may be draped around the tree and hidden among the decorations. When exposed to a fire, the tube  140  may soften and burst, leak, melt, burn through, or otherwise fail, resulting in a drop in the pressure of the gas within the previously pressurized tube. When the tube is exposed to fire, the internal gas pressure may drop to atmospheric pressure or to some other pressure level below the predetermined pressure level. The first pressure-detecting mechanism  150  may respond to the drop in the pressure within the tube by causing or enabling the valve  130  to open and thus dispense the fire suppressant. 
     Referring now to  FIG. 2 , an apparatus  200  for localized fire suppression may include a tank of fire suppressant  210  coupled through a hose  232  to a valve  230  through which the fire suppressant may be dispensed in case of a localized fire. The apparatus  200  may include a pneumatic fire sensor including a tube  240  containing a gas at a pressure above a predetermined pressure level, a first pressure-detecting mechanism  250  to detect a drop in the gas pressure within the tube  240 , and a second pressure-detecting mechanism  270  to also detect a drop in the gas pressure within the tube  240 . 
     The tube  240  may be fabricated from a polymer or other material that is incapable of retaining a gas at a pressure greater than the predetermined pressure level when exposed to a fire. The tube  240  may include a section  244  to couple the second pressure-detecting mechanism  270  and the first pressure-detecting mechanism  250 . 
     The first pressure-detecting mechanism  250  may detect when the pressure within the tube  240  falls below the predetermined pressure level, causing or enabling the valve  230  to open and thus dispense the fire suppressant. The second pressure-detecting mechanism  270  may respond to the drop in the pressure within the tube section  244  by causing or enabling an air horn  280  or other audible alarm to sound to alert persons to the fire. The first pressure-detecting mechanism  240  and the second pressure-detecting mechanism  270  may be coupled to and activate a valve, an air horn, or another device. 
     The air horn  280  or other audible alarm, the tank  210 , the gas bottle  220 , and the associated tubes and piping may be contained within an enclosure  290 . For example, the enclosure  290  of an apparatus specifically intended to suppress Christmas tree fires may appear to be a present that can be inconspicuously placed beneath the tree. For further example, the enclosure  290  of an apparatus specifically intended to suppress bedding fires may serve an additional function as a night stand or lamp table. 
       FIG. 3A  is a schematic diagram of a valve  330  and a pressure-detecting mechanism  350 . The valve  330  may be suitable for use as the valve  130  or  230 . The pressure-detecting mechanism  350  may be suitable for use as the pressure-detecting mechanism  150  or  250 . The schematic diagram shows the functional components of the valve  330  and the pressure-detecting mechanism  350  without showing the structure that supports and connects those components.  FIG. 3A  shows the valve  330  in the armed or ready condition. A hose  332  extending from a tank of fire suppressant (not shown) is coupled to a sprinkler head which may include a valve body  334 , a frangible glass bulb  336 , and a deflector  338 . In the absence of a fire, a valve within the valve body  334  may be held in a closed position by the frangible glass bulb  336 . The frangible glass bulb  336  may be filled with a liquid that expands when heated, such that the frangible glass bulb  336  may break due to the expansion of the liquid when the temperature exceeds a predetermined activation temperature. Breaking the frangible glass bulb  336  allows the valve  330  to open, dispensing the fire suppressant. 
     Temperature-sensitive frangible bulb sprinkler heads are commercially available with a range of activation temperatures. A sprinkler head having an activation temperature of 135 F, commonly used in residences, may be suitable for use as the valve  330 . The deflector  338  may be adapted to distribute the fire suppressant over the expected size of a localized fire and may be different from the deflectors normally used with ceiling-mounted sprinkler heads. 
     Breaking the frangible glass bulb  336  due to excess temperature may be a secondary, back-up, mechanism for opening the valve  330 . The primary mechanism for opening the valve  330  may be the pneumatic fire sensor  350 . In the event of a fire, the pneumatic fire sensor  350  may mechanically break the frangible glass bulb with a spring-loaded breaker bar  360 . The breaker bar  360  may be coupled to first spring  364  and may have a hole, slot, lip, or other feature that engages a retaining pin or bar  362 . When the breaker bar  360  is engaged with the retaining pin  362 , the breaker bar  360  is held in position with the first spring  364  under substantial tension. 
     A tube  340 , normally filled with gas under pressure, is coupled to a cylinder  352 . A piston  354  is disposed within the cylinder  352 . The piston  354  may form a seal with the interior wall of the cylinder  352  to effectively seal the end of the tube  340 . The tube  340  may terminate in an inflatable bladder (not shown) disposed in the cylinder  352 . In this case, the piston  354  may not form a seal with the interior wall of the tube  352 . The position of the piston  354  within the cylinder may be maintained by the balance of the gas pressure within the tube  340  and the pressure of a second spring  356  which is normally compressed by the pressure of the gas upon the piston  354 . The piston  354  may be coupled to a hook  358  which may, in turn, be coupled to the breaker bar  360 . 
     Refer now to  FIG. 3B , which is a schematic diagram of a valve  330  in an activated condition, shortly after a loss of pressure within the tube  340 . Upon a reduction of gas pressure within the tube  340 , the force exerted by the previously compressed second spring  356  is no longer balanced by the gas pressure, allowing the second spring to expand and force the piston  354  upward within the cylinder  352 . Note that upward is a relative direction consistent with  FIG. 3 , but does not imply any absolute orientation of the valve  330 . The upward motion of the piston  354  is coupled to the hook  358  which, in turn, lifts the breaker bar  360  free of the retaining pin  362 . Once the breaker bar  360  is free of the retaining pin  362 , the first spring  364  contracts, pulling the breaker bar  360  into and through the frangible glass bulb  336 . Breaking the frangible glass bulb  336  allows the valve  330  to open to dispense the fire suppressant. 
     Safety pin  366  may be engaged, as shown by the arrow  368  in  FIG. 3A , to restrain the breaker bar and prevent activation of the valve regardless of the pressure within the tube  340 . 
     The combination of cylinder  352 , the piston  354 , the first and second springs  356 / 364 , the breaker bar  360 , and the retaining pin  362  is an example of a pressure-detecting mechanism to detect a loss in pressure within the tube  340 . The use of the spring loaded breaker bar to break the frangible glass bulb of a sprinkler head is an example of a linkage between the first pressure detecting mechanism and a valve. These components may be assembled in numerous physical configurations in addition to the configuration illustrated in  FIGS. 3A and 3B . Additionally, other combinations of springs, levers, linkages, and other mechanical components may be employed. For example, if the back-up mechanism provided by the temperature-sensitive sprinkler head is not required, the valve  330  may be a spring-loaded valve held in the closed position by a retaining pin which may be released by the action of the piston  354 . 
       FIG. 4  is a view of a exemplary deployment of an apparatus  400  for localized fire suppression to suppress a fire in a Christmas tree  405 . The apparatus  400  may include a enclosure  490 , which may be disguised as a present, containing a pressurized reservoir of fire suppressant (not visible). The reservoir may be coupled to a valve  430 , which may be disguised as an ornament, by a hose  432 . The vale  430  may be coupled to a pneumatic fire sensor which is hidden within the tree  105  and its decorations. The fire  495  may cause the pneumatic fire sensor to open the valve  430 , releasing the fire suppressant  485 . 
     Closing Comments 
     Throughout this description, the embodiments and examples shown should be considered as exemplars, rather than limitations on the apparatus and procedures disclosed or claimed. Although many of the examples presented herein involve specific combinations of method acts or system elements, it should be understood that those acts and those elements may be combined in other ways to accomplish the same objectives. With regard to flowcharts, additional and fewer steps may be taken, and the steps as shown may be combined or further refined to achieve the methods described herein. Acts, elements and features discussed only in connection with one embodiment are not intended to be excluded from a similar role in other embodiments. 
     For means-plus-function limitations recited in the claims, the means are not intended to be limited to the means disclosed herein for performing the recited function, but are intended to cover in scope any means, known now or later developed, for performing the recited function. 
     As used herein, “plurality” means two or more. 
     As used herein, a “set” of items may include one or more of such items. 
     As used herein, whether in the written description or the claims, the terms “comprising”, “including”, “carrying”, “having”, “containing”, “involving”, and the like are to be understood to be open-ended, i.e., to mean including but not limited to. Only the transitional phrases “consisting of” and “consisting essentially of”, respectively, are closed or semi-closed transitional phrases with respect to claims. 
     Use of ordinal terms such as “first”, “second”, “third”, etc., in the claims to modify a claim element does not by itself connote any priority, precedence, or order of one claim element over another or the temporal order in which acts of a method are performed, but are used merely as labels to distinguish one claim element having a certain name from another element having a same name (but for use of the ordinal term) to distinguish the claim elements. 
     As used herein, “and/or” means that the listed items are alternatives, but the alternatives also include any combination of the listed items.