| 摘要 |
A valve unit for controlling the delivery of a combustible gas, in particular for delivery via a gas metering apparatus including a main gas through-flow pipe (2), the unit comprising a servovalve with a first valve seat (3) provided on the pipe and associated with a respective first shutter (6) with diaphragm control (7) for the opening of the seat (3) in opposition to a first return spring (22), an operating chamber (10) for controlling the servovalve, the chamber being in communication with an inlet section (4) of the main pipe (2), upstream of the first valve seat (3), one side (7a) of the diaphragm (7) being subjected to the pressure prevailing in the chamber (10), the other side (7b) being subjected to the pressure prevailing downstream of the first valve seat, in the region of an outlet section (5) of the pipe (2), the operating chamber (10) being in communication with the outlet section (5) via a second valve seat (9) co-operating with a second shutter (8). The unit also comprises an actuating rod (13) operatively associated with the first and the second shutter (6, 8), for controlling same for the opening or closing of the respective seats (3, 9), and a drive means (14) associated with the actuating rod (13) in order to move the shutters (6, 8) away from and towards the respective valve seats (3, 9), wherein the actuating rod (13) is secured to at least the first shutter (6) so as to be able to slide in a limited manner with respect thereto, with a predetermined play, such that the rod is movable by means of the actuation of the drive means (14), without interference with the first shutter (6) along at least a portion of the lifting stroke of the shutter (6) and also in opposition to the resilient action of a return means (15), in order to store energy in the return means (15) and transfer it to the first shutter (6) in order to urge this away from the valve seat (3) and ensure opening for the through-flow of gas in the main pipe (2). |
