Fire extinguishers – Fluid systems – Distributing systems
Reexamination Certificate
2000-07-19
2001-04-03
Douglas, Lisa Ann (Department: 3752)
Fire extinguishers
Fluid systems
Distributing systems
C169S037000, C169S042000, C239S209000, C137S074000
Reexamination Certificate
active
06209654
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to fire extinguishing systems adapted for inundating an entire fire hazard zone with water upon heat sensing of a fire ignition point within said zone.
BACKGROUND OF THE INVENTION
Closed head or closed orifice fire sprinkler systems are economically constructed, typically requiring no automatically opening deluge valve, and requiring no auxiliary heat sensitive deluge valve actuating means. Closed head fire sprinkler systems typically contain pressurized water, and closed orifice sprinkler heads at the terminal water output ends of such system withhold the water in the absence of fire. Upon exposure of one of the sprinkler heads of a closed head sprinkler system to heat from a fire, a heat fusible link incorporated in the sprinkler head fractures, opening such sprinkler head for local water dispersion.
A chief disadvantage of closed head sprinkler systems is that each sprinkler head of such system is individually responsive to heat. The opening of one of the sprinkler heads of a closed head sprinkler system does not open any other sprinkler head within the system. If a closed head sprinkler system were installed within a high risk fire hazard zone, such system would be unable to effectively suppress a rapidly spreading fire. Thus, closed head sprinkler systems are not commonly utilized in high risk fire hazard zones.
Fire sprinkler systems utilized in high risk fire hazard zones are necessarily adapted to instantly inundate an entire fire hazard zone with water in response to a localized fire ignition point within the zone. Through inundation of an entire zone, water flow is established in advance of a rapidly spreading fire, increasing the likelihood that the sprinkler system will effectively suppress the fire. Such fire sprinkler systems, commonly referred to a deluge systems, utilize open orifice sprinkler heads at the terminal water output ports of the system. The open terminal ends of a deluge system cannot withhold water under pressure. Therefore, an automatically opening deluge valve for restricting water flow at the input end of the system is normally utilized. The deluge valve of a deluge fire sprinkler system is normally closed, necessitating the provision of means for automatically opening such valve upon the occurrence of a fire at any point within the fire hazard zone. Known means for automatically opening such deluge valves comprise a fluid pressure actuated main valve installed in combination with a network of pressurized tubes, such network being co-extensive with the water pipes of the deluge system. The terminal ends of such network of tubes typically have heat sensing fluid release valves. Upon actuation of any one of the fluid release valves of the network of tubes, such network experiences an overall drop or rise in fluid pressure, actuating the deluge valve to allow a flow of pressurized water throughout the water pipes of the system, causing substantially simultaneous emission of water from the system's open sprinkler heads.
Another known means for automatically opening the deluge valve of a deluge sprinkler system comprises an electrically actuated main valve installed in combination with a network of electric lines installed co-extensively with the network of water pipes. The terminal ends of the network of electric lines commonly include electric switches sensitive to heat, ultraviolet or infra-red radiation, the closing or opening of any one of which opens the deluge valve, releasing a flow of pressurized water throughout the system.
Open head deluge fire extinguishing systems typically are more expensive to install and maintain than closed head systems because of the requirement of installing and maintaining a fire sensing network of tubes or electrical lines in addition to the fire extinguishing water distribution piping. The instant inventive deluge fire sprinkler system eliminates such additional expense by allowing fluid contained within the water pipes of the system to serve as an integral part of its means for automatically opening its deluge valve. By eliminating the need of a separate heat sensing network, the expense of the instant inventive deluge fire sprinkler system may be equal or less than that of a closed head system.
BRIEF SUMMARY OF THE INVENTION
A preferred embodiment of the instant inventive deluge fire sprinkler system comprises a main water supply pipe providing water at a pressure of approximately 90 p.s.i., or other pressure appropriate to hydraulic design. Water flow provided by the main pipe is preferably controlled by a diaphragm valve, such valve having a ventable upper chamber, a water input port, and a lower chamber annularly surrounding the water input port, the lower chamber having a water output port. The diaphragm of such valve separates the two chambers and normally closes the water input port. Under normal circumstances, water pressure within the upper chamber biases the diaphragm to close the valve, preventing a flow of water into the pipe network of the sprinkler system. Upon venting of water from the upper chamber of such valve, the diaphragm moves to open the valve, allowing water from the main pipe to spill into the lower chamber, through its output port, and into the network of pipes. The upper chamber of such diaphragm valve preferably has a vent tube which is normally closed by a fluid pressure actuated valve or by an electric solenoid valve. Where a fluid pressure actuated valve is utilized, it is preferable that a fluid pressure pilot line extend from such valve to a convenient point in the water pipe network, such pilot line serving to communicate a rise in fluid pressure within the pipe network to the fluid pressure actuated valve. Where an electric solenoid valve is utilized to control water flow from the vent of the upper chamber of the diaphragm valve, it is preferable that such solenoid valve be actuated by a fluid pressure sensing electric switch installed at some convenient point upon the water pipe system, such pressure sensing switch being adapted to open the electric solenoid actuated valve upon a rise in fluid pressure within the water pipe network. In either case, whether a fluid pressure actuated valve or an electric solenoid valve is utilized, a rise in fluid pressure within the water pipe network results in venting of water from the upper chamber of the diaphragm valve, opening such valve to a flow of pressurized water throughout the deluge system.
While it is preferred that a diaphragm valve be selected as the inventive system's automatic deluge valve, other types of deluge valves actuatable by a rise in fluid pressure within the system may be utilized. For example, an electric servo motor actuated gate valve controlled by a pressure sensing electric switch may be utilized. As further examples, pneumatic or electric release deluge valves as manufactured by the Viking Company or by the Reliable Automatic Sprinkler Co., Inc., may be suitably utilized to release a flow of pressurized water into the deluge system in response to a rise in fluid pressure within the pipe network. The pinch valve described in U.S. Pat. No. 3,759,331 issued on Sep. 18, 1973 to Livingston provides a further example. Other valves responsive to and actuatable by a pressure rise within the pipe network fall within the scope of the invention and may be suitably utilized.
In order for the network of water pipes of the instant inventive system to be capable of experiencing a rise in fluid pressure, it is necessary that a negative pressure differential exist between the interior fluid, typically gas, of the system and the outside atmosphere. When a negative pressure differential is maintained, the internal fluid pressure of the system is depressed below that of the outside atmosphere. A preferred means of inducing such negative pressure differential is to utilize a pump to draw fluid from a fluid output port extending through the wall of one of the pipes of the system. Less desirably, though suitably, mechanical means for increasing the internal volume of the pipe
Davis & Jack, L.L.C.
Douglas Lisa Ann
Jack Kenneth H.
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