GB607974A - Steam injection type water heater - Google Patents

Abstract

607,974. Fluid-pressure servomotor-control systems. PICK MANUFACTURING CO. Dec. 10, 1945, No. 33354. Convention date, Jan. 11. [Class 135] [Also in Group XIII] In a water heater, steam is supplied internally to a tube T with a multitude of orifices 42, a variable number of which are opened for the escape of steam into the water flowing through a casing A surrounding the tube T, by movement of a piston P within the tube against the action of resilient means, such as a spring 44, in response to changes in steam pressure. A stop 46 limits the closing movement of the piston so that some orifices are always open for the escape of steam. The orifices have a slight inclination in the direction of water flow and, in a zone near the bottom of the tube, are progressively reduced in number downwardly so that equal small upward movements of the piston at the bottom of the tube expose progressively increasing numbers of orifices. Helical vanes 62 are provided on the inside of the casing A. Steel balls 56 retained in position by grids 57, 58 break-up the flow of steam through the conduit 38 to the tube T. The pressure of water supplied to the heater through the pipe 18, Fig. 1, is kept constant by a valve 17 operated by a diaphragm unit 21 responsive to pressure changes in the pipe 18. The pressure of steam supplied to the heater from a pipe 14 is varied to keep the temperature of the heated water constant by a valve 24 operated by a diaphragm unit 26 responsive to pressure changes transmitted through a tube 30 by a thermostatic device 27 which applies pressure from a pipe 31 or relieves it through a pipe 32 in response to temperature changes in a thermal element 28 which projects into the conduit 29 leading to the hot water outlet pipe 13. To prevent formation of large steam bubbles in the heater, a pump 63 recirculates water from the conduit 29 through the heater when the rate of withdrawal of hot water through the pipe 13 is so hot that the rate of water flow through the heater would otherwise fall below a predetermined minimum.