| 主权项 |
1. A valve for a pressurised fluid cylinder, the valve comprising:
a housing with a bore containing a valve assembly, the valve assembly comprising:
a shut off valve biased against a seat to seal the cylinder;an actuation element movable linearly to open the valve against the biasing force; anda linkage element coupling the actuation element to the shut off valve;a first piston towards the top of the linkage element sealed with a first portion of the bore having a first diameter,a second piston towards the bottom of the linkage element sealed in a first position with a second portion of the bore having a second diameter less than the first diameter, the linkage element being movable to a second position in which the second piston enters a third portion of the bore having a diameter greater than the second diameter, such that the second piston is no longer sealed with the bore;a gas refill inlet communicating with the second portion of the bore; the first piston having a face exposed to the gas refill inlet which is larger than a face of the second piston exposed to the gas refill inlet, such that refill gas pressure biases the linkage element away from the valve; wherein the actuation element in a depressed position pushes against the linkage element to hold the linkage element down and the valve open so that the cylinder can be refilled; and wherein when the actuation element is in a non-depressed position, the linkage element is free to move with the refill gas pressure so that it is spaced from the valve. |
