| 摘要 |
1,256,881. Valves. MARTONAIR Ltd. 24 March, 1969 [8 April, 1968], No. 16780/68. Heading F2V. [Also in Division Fl] A double-acting valve piston 2 is held in the position shown against inlet 3 by inlet pressure acting on annular shoulder 9. Movement to the left is initiated by a pressure signal admitted to port 18 and continues until the piston seats upon outlet 4. The piston is held in this position by inlet pressure acting on area C 2 until return movement is initiated by a pressure signal applied to port 17. The piston ends may alternatively engage within the inlet 3 and outlet 4 to close these, the arrangement being such that the inlet is closed before the outlet is opened; in either case the ends may act as piston valves rather than lift valves. The external conduit 20 can communicate with inlet-outlet ports of a single or double-acting motor; piston 2 can also provide a direct mechanical output. |
