Patent GB-556978-A (GB)
Title: Improvements in and relating to mobile fire fighting apparatus
IPC: A62C27/00
Filed: 1942-05-21
Abstract: 556,978. Fire-extinguishing apparatus. CARDOX (GREAT BRITAIN), Ltd. (Cardox Corporation) May 21, 1942, No. 6939. [Class 47 (ii)] A mobile fire extinguishing unit employing liquid carbon dioxide or water or both comprises a self-propelled wheeled truck, an insulated carbon dioxide liquid storage tank 26, a mechanical refrigerator device 32 operatively connected to the tank for lowering the temperature and pressure of the liquid carbon dioxide, means responsive to a pressure increase in the tank causing the refrigerator to operate and maintain the liquid at constant low temperature and pressure and a discharge device for the liquid carbon dioxide operable and adjustable from the driver's cab. A preferred low temperature is 32‹ F. and when this increases the increased vapour pressure conveyed along a pipe line 71 actuates a switch 70 to start the driving motor 65 of the refrigerator whereby refrigerant is supplied to an evaporator coil in the dome 37 of the tank 26, the refrigerator continuing in action until the resulting reduction of vapour pressure again actuates the switch 70 and cuts out the motor 65. The liquid carbon dioxide from the tank may be discharged through a hose 28 at the rear of the truck or through a pipe 49 and nozzle 31 at the front of the truck which nozzle is universally mounted and movable from side to side and up and down by control cables 131, 140 operated by a hand lever 138 in the driver's cab. The current for the refrigerator motor is supplied by a push plug at the parking position plugged in to a connector box 75. The truck is also equipped with a water tank 33 from which water may be delivered by a hose 35 under pressure of the carbon dioxide vapour pressure through the pipe 86 leading from the top of the tank 26 to the top of the tank 33. The modification shown in Fig. 12 provides for the discharge of mixed carbon dioxide and water through a nozzle consisting of a central bell 156 for the carbon dioxide and perforated ring 162 for the water under control of a trigger 150 and cable 164 which actuates a pilot valve 167 controlling the passage of carbon dioxide from the tank 26 through the pipe 157 and differential pressure valve 154 to the discharge pipe 155, the pressure thus established on the discharge side of the valve 154 acting through the pipe 175 to open a water control valve 176 so that water is delivered from the tank 33 to the discharge pipe 160; these discharge pipes are carried on a. support 146 mounted for universal movement in a fork 145 and provided with a pistol grip 149. Another modification, Fig. 16, has two such combined water and carbon dioxide discharging nozzles 206 mounted on long booms 201 carried by turntables actuated by handwheels 194 for swinging them laterally in a horizontal plane, the supporting forks 202 of the booms being pivoted to the turntables so that the booms may also be swung in vertical planes by means of cables 211 wound round spools 215 driven by an electric motor from the truck battery; the nozzles are also adjustable in vertical planes about their pivots 207 by control cables 209 connected to two-armed hand levers. Fig. 24 shows another modification with banks of combined water and carbon dioxide discharging nozzles at the sides and front of the truck, the nozzles 265 at the sides being fixed and the front ones 265a being adjustable about vertical axes by worm gearing 273. Specifications 549,441, [Group XXIX], and U.S.A. 2,248,270 are referred to.