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摘要

1,041,685. Automatic temperature control. HOVAL ING. G. HERZOG & CO. April 14, 1965 [April 21, 1964], No. 16071/65. Heading G3R. In a system in which boiler water is circulated for space heating and in heat exchange relationship with a hot water tank producing a running hot water supply, a thermostatic changeover switch sets a liquid or gaseous fuel burner in operation when the temperature of the boiler water falls below a predetermined value and opens a valve in the supply pipe from the boiler to the space heating when the temperature of the boiler water exceeds the predetermined value and solid fuel firing is in use. A control circuit is described which may be switched to a "solid fuel only" condition to introduce a draught regulator and start a circulating pump for the room heating water. A valve in the circulating system remains closed, however, to prevent room heating until the water in the running hot water tank reaches say 55‹C. at which temperature a thermostat opens the valve. A room thermostat then controls electrothermal operation of the valve to maintain the room at say 20‹C. Rise in the temperature of the boiler water above say 75‹C. is prevented by a boiler thermostat over-riding the room thermostat and opening the valve in the circulating system. If the system is switched to a "burner only (Winter)" state, fuel is supplied to the burner and there is no solid fuel firing or draught. Automatic control of the running hot water and room temperatures is otherwise as for solid fuel firing but the boiler thermostat controls the burner instead of the valve in the circulating system. If, in an attempt to rise room temperature in cold weather the valve opens sufficiently to operate a limit switch, this renders the boiler water thermostat ineffective so that the circulating water temperature can rise up to the limit, say 90‹C., set by an additional safety thermostate controlling the burner. When the system is switched to a "burner only (Summer)" state, the circulating pump is switched off and running hot water only is provided.