| 摘要 |
<p>A shut-off valve for the automatic closure of a gas supply comprises a body (1) having an angled passage therethrough, a first sector of the said passage, corresponding to the gas inlet, having a valve head or obturator (5) which is urged towards an associated seat (7) by a spring (4), the valve head (5) carrying, on the opposite side of the valve to the said spring, a stem (8) which passes in a leak-proof manner through the valve body and accommodates at its free end an actuator (13), a peripheral groove or channel (11) of dihedral cross- section being formed in the said stem (8) in the vicinity of the actuator (13), a locking pin (20) interacting with the said groove (11), this pin (20) being actuated by the moveable core (18) of an electromagnet (15) and engaging at right angles on the said stem (8), the arrangement being such that the valve is opened by depressing the actuator (13) whereupon the electrical supply to the electromagnet (15) is connected thereby actuating the locking pin (20) to engage in the said groove (11) in the stem, and furthermore the electromagnet (15) being connected to an atmospheric analyser which, on detecting the presence of gas in the atmosphere, interrupts the electrical supply to the electromagnet (15) whereupon the locking pin (20) releases the stem (8) and the valve head (5) is returned to its closed position by the said spring (4). <IMAGE></p> |
