| 摘要 |
1,222,390. Valves. ELECTRICITE DE FRANCE (Service National). 19 Dec., 1968 [27 Dec., 1967], No. 60417/68. Heading F2V. A gas cock comprises a body portion 4 formed with an inlet 1 and an outlet 2 and with two coaxial bores 5, 7 of different diameters, the inlet being in communication with one of the bores and the outlet being in communication with the other bore, a piston 9 located in the larger diameter bore, sealing means 19, 20 arranged between the piston 9 and the body portion, a second piston 8 slidable within the smaller diameter bore 7 and secured to the piston 9 so as to move axially with it, a plurality of sealing rings 16 mounted on the piston 8 to seal the inlet from the outlet, screw means 12 for axially moving the piston 9, and a stop 18 adjustable to allow successive ones of the sealing rings 16 to engage the bore 7. The piston 9 houses anti-friction bearings 10, 11 so that rotation of the rod 12 does not cause rotation of the pistons 8, 9. An aperture 22 allows a chamber 21 to communicate with the atmosphere. The screw 23 is not initially tightened so that any gas leakage past the sealing ring 19 visibly expands an elastic sleeve 25. In an alternative construction, the outlet 2 is coaxial with the bores 5 and 7. |
