JPS5531216A - Freeze preventing device for water boiler - Google Patents

Abstract

PURPOSE: To facilitate freeze prevention with the minimum amount of water discharge by establishing water discharge passage or air vent which closes automatically when water pressure exists within the water supply pipe at water boiler, and providing a freeze prevention valve which opens and closes by water temperature or atmospheric temperature at the hot water exit port.

CONSTITUTION: Water supply valve is provided in the water supply passage of the water boiler 2, while a water discharge passage 4, having valve 3 which opens when the water pressure at the water supply passage becomes below the prescribed value and closes when the water pressure becomes above the value, is provided at a position in the downstream of the water supply valve. On the hot water supply passage, a hot water supply faucet 5 is provided, while a water discharge passage 7 is installed at a position on the upstream of the faucet 5. The water discharge passage 7 has a freeze prevention valve 6 which opens when the temp. of the water or the atmospheric temp. lowers below the prescribed value and passes thru water necessary for preventing freezing. Under the ordinary situation, prevention for freezing is performed by closing water supply valve 1. That is, the two valves 3 and 6 do not open unless water temp. does not lower, which means unnecessary water discharge is not carried out. When the water temp. lowers close to the freezing point, the freeze prevention valve 6 opens, discharging water, making water pressure within the pipe equal to the atmosphere which opens the valve 3 and water discharge is performed as necessary.

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