Patent Publication Number: US-5628368-A

Title: Fire fighting installation

Description:
The present invention relates to equipment for fighting fire, in particular for kitchen spaces and the like. 
     Fires in kitchen spaces, in particular in restaurant kitchens and comparable, with friteuses ie. french fryers and other objects liable to fire, are often disastrous. 
     The object of the invention is to provide new equipment for fighting fire, which is capable of efficiently extinguishing fires in such spaces. 
     The equipment of the invention comprises a number of preferably automatically releasable spray heads or sprinklers placed at suitable positions and to which extinguishing liquid is arranged to be delivered from at least one hydraulic accumulator preferably having a high charge pressure, e.g. 30-200 bar. 
     When at least one spray head has been released because of a fire broken out within its action range, the pressure in the hydraulic accumulator starts to decrease as extinguishing liquid is sprayed out of the released spray head. To the hydraulic accumulator is connected a pressure guard which, when the pressure in the hydraulic accumulator has decreased to a predetermined value, e.g. 20 bar and 150 bar, respectively, for the exemplifying limit values of 30 bar and 200 bar, respectively, mentioned above, is arranged to produce a signal in order to release also the other spray heads in the space. The pressure guard can also be arranged to produce a signal to disconnect the electric current to cooking and other apparatuses, as well as a signal for fire alarm. 
     The spray heads are preferably made according to what is described in the International Patent applications PCT/FI92/00060, PCY/FI/92/00155 and PCT/FI92/00156, in order to produce a fog-like liquid spray with a good penetration power. The drop diameter can preferably be within the interval 30-200 microns. 
     The release of all spray heads in the space effected by the pressure guard can preferably be arranged to take place by means of heat coils laid around release ampoules of the respective spray heads. 
     The initially released spray head, utlilizing the full capacity of the hydraulic accumulator, is in general alone capable of extinguishing the fire or at least of suppressing it; the continued spray of liquid with all spray heads prevents the fire from spreading and reignition and brings about general cooling. 
    
    
     The invention shall in the following be described with reference to a preferred embodiment shown in the attached drawing. 
    
    
     In the drawing a number of spray heads, most of which usually are positioned at the ceiling of the space, are indicated by the reference numeral 1. Extinguishing liquid is delivered to the spray heads by at least one hydraulic accumulator 2 via a line 3 in common for the spray heads 1. A pressure guard connected to the hydraulic accumulator 2 is indicated by 4. The release ampoules of the spray heads 1 are indicated by 5 and a heat coil laid around the respective ampoules is indicated by 6. 
     The hydraulic accumulator 2 is preferably made according to what is described in the Finnish patent application 924752, with an outlet pipe running within the accumulator and having apertures in its wall, in order to mix drive gas into the extinguishing liquid as the amount of liquid decrases in the accumulator. 
     The different electrical coupling included in the equipment do not present difficulties for a person skilled in the art and are therefore not shown in the drawing.