Fire prevention system

Claim 1

In combination with a hood that includes sidewalls and end walls of substantially the same height that merge on their upper ends into an upwardly extending duct; a. a grease and water receptacle of V-shape transverse a cross section and of shorter length than said hood longitudinally disposed in a fixed position therein and extending under said duct, said receptacle having a plurality of longitudinally spaced openings formed in the upper portion thereof through which air, smoke and fumes may flow to said duct, said openings having a total transverse area at least as great as the interior of said duct to permit a free flow of said smoke and fumes to said duct; b. a first water spray pipe longitudinally disposed at a fixed position in said receptacle, said pipe adapted to spray water on the interior surfaces of said receptacle below said opening; c. a second water spray pipe extending upwardly from said first pipe and positioned inside said duct, said second pipe adapted to spray water on the interior surface of said duct; d. first means for supplying heated water to said first and second pipes; e. second means for metering an aqueous detergent solution into said heated water prior to said water discharging from said first and second pipes; f. a normally closed solenoid operated valve in said first means; g. a normally open thermostat in said duct that closes at a temperature above that temperature normally encountered in said duct; h. electrically driven timer means; i. first and second relays; j. at least one electric circuit connected to a source of power, said circuit including said solenoid operated valve, thermostat, timer means and first and second relays, with said thermostat when closed due to being subjected to an elevated temperature energizing said first relay and deenergizing said second relay in such a manner as to complete a portion of said circuit to said solenoid operated valve to open said valve for detergent containing water to be sprayed from said first and second pipes to extinguish any fire in said hood, duct or receptacle, said timer means periodically completing said portion of said circuit to said solenoid operated for a predetermined period of time, and said thermostat when subjected to a temperature less than said predetermined temperature and said timer means after one of said periods for which it is set returning said circuit to a condition where said solenoid valve is deenergized and said motor is energized to drive said blower; and k. drain means connected to the lower portion of said receptacle through which water and grease flow by gravity to a location remote from said hood.