| 摘要 |
816,756. Vatves. LEWIS, E. C., and ALUMASC Ltd. May 2, 1957 [Jan. 5, 1957; Feb. 16, 1957], Nos. 528/57 and 5333/57. Class 135. A two-stage fluid pressure reducing valve is characterized by each stage consisting of a spring-loaded piston 12 or 24 slidable in a fluidtight manner in a chamber 4 or 6 and about a tubular inlet member 2 or 7 for admitting fluid under pressure into the chamber, the piston carrying a valve member 19 or 32 adapted to close an orifice 21 or 33 of the tubular inlet member on the piston being moved against its spring loading when the outlet pressure of each stage acting on the top surface of the piston exceeds the spring rating of the piston, the fluid passing from the orifice 21 or 33 into the chamber 4 or 6 via a port 20 or 35 in the axial extension of the piston. The valve member consists of a pad of rubber, plastic or like material and is clamped to the axial extension of the piston by means of a screwed cap 17 or 31. Adjustment of the spring loading of the second stage piston 24 is provided by a rotatable abutment member 29 in threaded engagement with the second stage inlet member 7. The periphery of the abutment member 29 may be notched to engage with a " C " spanner inserted through a hole in the housing after a segmental portion 41 has been removed. Instead of the spanner adjustment the periphery of the abutment member may be provided with worm-wheel teeth to engage a tangentially disposed worm mounted in the housing and operated externally. To permit easy dismantling of the valve for cleaning purposes the end plug 1 is secured by a spigoted engagement. The first stage body part 3 has also a similar engagement with the second stage body part 5. A dust cap 11 may be provided to blank off the outlet 9 when the valve is not in use. The invention may consist of a single, double or multi-stage arrangement.
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