| 摘要 |
1,141,006. Hot water boilers; central heating systems. JUNKERS & CO. G.m.b.H. 9 Feb., 1966 [9 Feb., 1965 (2)], No. 5579/66. Headings F4A and F4U. The flow and return lines 13, 15 respectively of a circulating water heater 10 fired by a gas burner 11, are interconnected by a cross connection line 32 leading into a Venturi intake device 30 in the return line 15. The Venturi intake device 30 is bridged by short circuit pipe 34 containing a three way valve 351 controlled by a thermostat 36 downstream in the return line 15. A further cross connection line 40 connects the short circuit line 34 at the three way valve 351 with the flow line 13. In operation, when a room thermostat (not shown) calls for heat to start circulating pump 12 and light the burner 11, the water from pump 12 flows in parallel both through section 151 of return line 15 and through section 341 of short circuit line 34. The water flow through Venturi intake device 30 includes a flow of heated water from flow line 13 along cross connection line 32 past non-return valve 33 whereby the temperature of the water flowing to the heater 10 is increased to avoid condensation of combustion products from the burner 11 thereon. The water flow through pipe section 341 is diverted through the further cross connection line 40 to the flow line 13, downstream of the take off point of the first cross connection line 32, whereby an excessive temperature difference across the radiators 14 may be avoided throughout the start up period. When the water temperature at the inlet to the heater 10, as measured by thermostat 36, has achieved a sufficient value to avoid condensation of the combustion products, valve 351 is actuated to close the further cross connection line 40 and open line 34, whereby due to the great pressure drop in Venturi intake device 30, practically all the flow from circulating pump 12 passes through the short circuit line 34 and the flow from the flow line 13 through the first cross connection line 32 ceases. High and low pressure tappings 38, 39 are taken from section 151 of return pipe 15 and pipe 32 respectively, to either side of a diaphragm 19 in a pressure box 18, and used to operate a gate valve 24 in the gas supply line 25 in the event of water deficiency. |
