| 摘要 |
Gas/air ratio control apparatus for a temperature control loop for gas appliances The invention relates to a gas/air ratio control apparatus for a temperature control loop for household gas appliances, in particular for domestic/direct hot water units and combined direct hot water/central heating units, for temperature control of domestic and/or heating water. The invention is particularly suitable for household appliances up to 120 KW. The gas/air ratio control apparatus comprises a controllable fan (3) for supplying a predetermined air stream (2-2) to a burner (4) in dependence on the detected actual temperature (TActual) and the desired target temperature (TTarget) of the heating and/or domestic hot water; and a pressure-controllable valve (8) for controlling the supply of a specified fuel quantity (1) to the burner (4) in dependency exclusively on the absolute pressure of the air stream (2-2) produced by the controllable fan (3). The inventive temperature control apparatus operates in an air/fuel regulating range of 20% to 100%, the controllable valve (8) supplying a fuel quantity (1) to the burner (4) having a pressure at a ratio of 1:1 to the absolute pressure of the air stream (2-2) produced by the controllable fan (3). The system uses only one pressure sensing line (11) and can always be brought into a safe condition when faults appear in the burner (4). (Fig. 2)
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