| 摘要 |
<p>The valve unit described is for automatically regulating the flow-rate of a fuel gas to a device for heating a fluid in dependence on variations in the flow-rate of the fluid through the heating device. The unit comprises means (36) for bringing about, in the fluid, a pressure differential correlated with the flow-rate of fluid flowing through a pipe (36a), actuator means (35a) which are supplied with the pressure differential in order to generate a signal correlated with the pressure-differential value, and means (4,10), controlled by the actuator means (35a), for regulating the flow-rate of fuel gas in order to vary the flow-rate of gas in a manner correlated with the fluid-pressure differential; the means for regulating the flow-rate of gas comprise a pressure regulator (4, 10) with a diaphragm (19), and the actuator means (35a) act on the regulating means by means of the control mediated by the pressure regulator (4, 10). <IMAGE></p> |
