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Improvements in and relating to control valves for hydraulic presses

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  • Title:
    Improvements in and relating to control valves for hydraulic presses
  • Author: Towler John Maurice ; Towler Frank Hathorn
  • Subjects: Performing Operations ; Transporting ; Presses ; Presses In General ; Medicine ; Sciences ; Chemistry
  • Language: English
  • Description: 696,823. Hydraulic presses; valves. ELECTRAULIC PRESSES, Ltd. Aug. 3, 1951 [Aug. 26, 1950], No. 21163/50. Classes 69(ii) and 135 A combined control, prefill and exhaust valve for a hydraulic press comprises a valve seat member 11 secured between pipe members 9, 10 respectively connected to a reservoir and one or more press cylinders the arms of which are upwardly acting. A prefill valve 16 is held on the seat against the liquid head by a spring member 17 and includes a cylindrical bore 21 communicating with the pipe section 10 through a small hole 28. Slidable in the bore 21 is a relief valve comprising a piston 20 having a valve face seating on the prefill valve, communicating on one side with the pipe section 9 through an opening 22 and with the pipe section 10 through passages 23. The piston 20 has a stem 26 slidable in the member 11, terminating in an enlarged head 25 between which and the member 11 is compressed a spring 24. The piston 20 and stem 26 are bored to accommodate a small mushroom valve 30 seating on the head of the piston 20 and bored to provide communication, when it is opened, between the bore 21 and the pipe section 9 through parts 39 in the stem 26. The piston 20 is reduced in diameter to provide a shoulder 29 exposed to the pressure in pipe section 10. A spindle 32 slidable in the stem 26 is connected through an adjustment 33 with the piston 1 of a control valve comprising a cylinder 2 having a pump pressure supply port 8 and mounted on the pipe section 9. A handle 3 controls the piston 1. In the position shown the supply from port 8 is connected to the reservoir via pipe section 9. In the press operating position this connection is closed and pressure acts on approach cylinders to raise the platen, the main cylinders drawing liquid through the prefill valve 16. At a given pressure in the approach cylinders an automatic admission valve admits pressure to the main cylinders through a port 8a in the pipe section 10. At the end of the operation the piston 1 is returned to the position shown and the pump and approach cylinders are by-passed to the reservoir. Pressure in the main cylinders leaks through a decompression valve to the approach cylinder line until the press is held in balance. The handle 3 is then moved to the right and the stem 32 opens the valve 30 which releases the pressure in the bore 21 and pressure acting on the shoulder 29 opens the relief valve 20. In a modification the piston 20 is parallel sided and after pressure is relieved in the bore 21 the relief valve is manually opened by the adjustment 33 contacting the head 25 of the relief valve stem 26. The control valve may be pilot operated or remotely controlled.
  • Creation Date: 09 September 1953

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