| 摘要 |
883,462. Stopping pipes. RHEINISCHES METALLWERK G.m.b.H. Feb. 12, 1958 [Feb. 13, 1957], No. 4649/58. Class. 99(1). [Also in Group XXIX] An auxiliary shut-off valve apparatus for a main valve housing 10 comprises an auxiliary casing 14 screwed on to a connecting stub pipe 13 and a closure member 18 which can be advanced into the flow passage of the main valve housing 10. The closure member consists of a rubber bag surrounding a hollow pin 17 which in turn is secured to a piston 15 in a chamber 20 in the auxiliary casing 14. A further piston 16 is attached to a spindle 21 in threaded engagement with an end cap of the easing 14. A flat link chain 22 connects the two pistons. The space between the pistons is filled with an hydraulic pressure medium. On screwing in the spindle 21 the piston 16 attached thereto causes the piston 15 to move the closure member 18 accross the flow passage of the main valve housing 10. Further movement of the pistons 16 causes an increase in fluid pressure in the space between the pistons and this increased pressure inflates the rubber bag 18 surrounding the pin 17 in to sealing engagement with the walls of the passage through the main valve. The main valve housing 10 is threaded at 11 into a clip, which is then clamped around a gas or water main. The pipe is bored through the housing 10 and when this is done the boring machine is moved back as far as possible and the passage sealed by the auxiliary shut-off valve apparatus as described above. The boring machine can then be removed and the closure member of the main valve fitted. The auxiliary shut off valve apparatus can be then unscrewed and a branch pipe substituted. |
