| 摘要 |
The present invention relates to a valve for use in central heating and domestic hot water 10 systems, to control the flow of water in the circuits of such systems. In particular the invention provides a valve comprising a valve body of the rotary type and an electrical valve actuator the salient elements of which are an electrical motor, an electrical latch, an electrical switch and interconnecting circuitry terminating in a pair of electrical terminals, the application of a voltage to said terminals serving to energise the motor thus driving the valve to its open state, to latch the valve in said open state and to de-energised the motor. The advantage of the invention is improved longevity of the actuator motor compared to actuators which use the motor to both drive the valve to its open state and to hold the valve in said open state. <Figure 1> |
