GB1275491A - Fume cupboards - Google Patents

Abstract

1275491 Fume cabinets PIELKENROODVINITEX NV 11 May 1970 [12 May 1969] 22616/70 Heading F4X A fume cupboard having an access opening 1 closable by a sliding window 2 connected by cables 3 to a counter-weight 5 incorporates an automatic safety arrangement operative, when fire or like hazardous conditions prevail in the cupboard, to (a) close the access opening 1 and the discharge duct 8 and (b) spray extinguishing agent such as CO 2 through a nozzle 17 into the cupboard. A sensing device 14 responsive to a predetermined increase in temperature per unit time actuates a knife 15 which severs the cable 3 causing the window to drop and close the opening 1. An auxiliary cable 19 is also severed causing a normally open valve 18 in the duct 8 to close. In addition the supply of auxiliary air through channels located near the cupboard bottom is terminated, e.g. by closing valves located in these channels. Operation of an exhaust blower communicating with the duct 8 and the supply of services such as air, water, gas &c. to the cupboard are terminated by cutting off the power supply (see Fig. 3). A flow meter (39, Fig. 3) sensing lack of air flow in the exhaust duct 8 actuates a warning device (41). In the event of an explosion occurring a hinged safety hatch 9 opens to relieve the excess pressure. The cupboard is provided with a double-walled construction (Fig. 4, not shown) comprising an outer wall (43) and an inner wall (44) of fire-proof flexible material with insulating material (45) therebetween. Gauzes 12 and 13 prevent flames from spreading.