Fire extinguishers – Portable vessels
Reexamination Certificate
1999-08-10
2003-03-04
Mar, Michael (Department: 3752)
Fire extinguishers
Portable vessels
C169S074000, C239S288300
Reexamination Certificate
active
06527058
ABSTRACT:
BACKGROUND
This invention relates generally to fire extinguishers, and more particularly to a portable wet chemical fire extinguisher for kitchen applications.
Kitchen cooking fires represent the single most common reason restaurants are damaged by fire. The origin of these fires is typically associated with commercial cooking appliances, such as deep fat flyers. The potential for severe restaurant fires continues to grow as the restaurant industry moves toward larger, more efficient cooking appliances which utilize higher heating rates and more unsaturated fats. Moreover, some combustible cooking materials, such as animal and vegetable fats and oils, can retain their auto re-ignition temperature for an extended period of time, up to twenty minutes. Thus, kitchen cooking fires represent a unique fire protection hazard that requires special fire suppression agents and equipment.
The National Fire Protection Association recently designated a new Class “K” portable wet chemical fire extinguisher for use in commercial kitchen areas, and particularly for commercial “combustible cooking media” fire hazards (NFPA-10 Standard For Portable Fire Extinguishers 1998 Edition).
The conventional K class fire extinguisher comprises a pressurized cylinder containing a fire suppressing agent and an outlet hose having an 18 to 20 inch long metal discharge wand. At the end of the wand is a nozzle for delivering the agent in a fine mist so as not to splash the liquid cooking media. The fire suppressing agent is a low pH, potassium acetate solution which does not react with the liquid cooking media during application. The agent saponifies on the liquid surface creating a thick, heavy foam blanket to seal out oxygen for extended periods of time until the liquid cooking media cools below its auto re-ignition temperature. The agent also helps cool appliance surfaces.
The problem with the conventional K class fire extinguisher is the discharge wand presents potential misuse and safety concerns. The wand is designed to give the user an extended reach and a longer agent discharge range, which is initially limited due to delivery of the agent as a mist. However, the wand allows the user to get too close to the fire. If the user places the end of the wand through the flames into the cooking media and discharges the agent, the initial discharge of the pressurized, cool agent could produce a burst of burning, hot grease which blows up and out of the fryer. Even after the fire is out, if the wand tip is brought into contact with the grease the discharge will blow the foam blanket off the liquid surface thereby minimizing the effectiveness of the suppressing agent and possibly burning the user. In addition, utilizing the metal discharge wand near energized electrical equipment raises electrical shock concerns. K class fire extinguishers are typically used by kitchen personnel with little or no fire extinguishment training.
For the foregoing reasons, there is a need for a new portable wet chemical fire extinguisher for kitchen applications which eliminates the possibility of contacting the agent discharge outlet of the fire extinguisher with burning or hot cooking media. The new fire extinguisher should also minimize or eliminate the possibility of electrical shock when used around cooking appliances. Preferably, the new device should be simple enough to use so that the above goals are met even with novice users
SUMMARY
An object of the present invention is to provide a new fire extinguisher for kitchen applications that satisfies these needs and having one or more of the novel features of this invention as hereinafter shown or described.
Another object of the present invention is to minimize the safety risks to the user in extinguishing kitchen cooking fires, including preventing the possibility of fire blow ups or splashing hot cooking media.
Still another object of the present invention is to minimize the possibility of electrical shock when extinguishing fires around energized electrical appliances.
A further object of the present invention is providing the user, whether novice or experienced, with exceptional fire fighting safety and comfort.
A portable, wet chemical fire extinguisher for kitchen applications having features of the present invention comprises a pressurized container for housing the fire suppressing wet chemical, a discharge assembly having an outlet in fluid communication with the container, and means mounted on the discharge assembly for requiring a hand position adjacent the outlet for delivery of fire suppressing agent. The required hand position thereby prevents the user from moving closer than a safe distance from the fire and from the placing the outlet in, or adjacent to, the fire area even when the fire is out.
The hand positioning means may comprise a guard surrounding the agent delivery outlet. The guard can be cup-shaped, but may be any configuration which promotes natural hand placement adjacent the outlet. Preferably, the guard is made of a non-conductive, heat-resistant material such as plastic.
The present invention overcomes the drawbacks of present K class fire extinguishers through the provision of the hand positioning means such as the nozzle guard. With the user's hand adjacent the nozzle, the user cannot safely get too close to a cooking media fire, much less place the hose outlet in or near the cooking media. Moreover, by making the guard out of non-conductive material and large enough so that the guard does not fit into small places, the danger of electrical shock is significantly minimized. It has been found that these results can be achieved with the fire extinguisher of the present invention even though the user is a novice.
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Johnston Michael G.
Mar Michael
Moore & Van Allen PLLC
Nguyen Dinh Q.
Walter Kidde Portable Equipment Inc.
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