Patent GB-836819-A (GB)
Title: Improvements in or relating to pneumatically operated gate valves
IPC: F16K39/04
Filed: 1956-07-26
Abstract: 836,819. Gate valves. MANUFACTURES DES GLACES ET PRODUITS CHIMIQUES DE SAINT - GOBAIN, CHAUNY & CIREY S.A., DES. July 26, 1956 [July 26, 1955], No. 23203/56. Class 135. In a pneumatically-operated gate valve provided with a deformable sealing element and an auxiliary gate the principal gate slides on tubular members 20 between plates 1, 2 which have apertures to allow the intioduction of articles into a vessel 8 which is supported thereby. The principal gate is formed by a dished member 12 secured to an annular collar 13 with an annular groove 14 therein to provide a cavity closed by a diaphragm 15 and fed with pressure or vacuum through the operating tube 34. The auxiliary gate orifice 26 is sealed by a piston 30 also operated by pressure or vacuum through the tube 34. The tube 34 is fitted with stops 34b contacting a gland 35 at the extremities of travel of the gate. An auxiliary piston 43 is secured to the end of the tube 34 and operates inside a main piston 44 which is acted upon by pressure fed from either of valves 76, 77. In the extreme open position of the gate the pistons 43, 44 engage a collar 67 on a sliding tube 64 to operate a signalling contactor 74. The movement of the auxiliary piston 43 is limited by a ring 43a and a control-valve 53, open on the extreme closed position of the principal gate, allows pressure to be fed to the chamber 47 from the valve 78 to open the auxiliary gate on excessive pressure in the treatment vessel 8. The valves 75 ... 78 are supplied with pressure through the ports 75b ... 78b and ports 76a, 78a are open to the atmosphere whilst port 75a is connected to a source of vacuum. The circuit also comprises a pressure/vacuum responsive switch 84, relays 79, 85, a flashing device 86, indicators 88, 89, a controller 80, a photoelectric cell 83 and a manometric contactor 87. When the power supply is connected, vacuum admitted by the valve 75 to the annular groove 14, the chamber 32 and the gauge 84 deflates the diaphragm 15, withdraws the piston 30 and contacts arm 84a with stud 84b. The relay winding 85c is energized ard switches 85a, 85b are closed. To close the gate the controller 80 is moved in the direction 81 closing contact 80c and establishing a circuit through valve 77 providing there is no foreign body in the path of the gate revealed by the photo-electric cell 83. Passage 77a is closed and passage 77c connected with 77b supplying pressure to the pistons 43, 44 to close the gate. At the end of the stroke the auxiliary piston 43 contacts a stop 66 on the tube 64 to close contacts 74c which energize the valve 75, closing the vacuum passage 75a and opening the pressure supply 75b. The pressure brings the contact of the pressure gauge 84 to stud 84c and short-circuits the relay 85 to put valve 76 out of action. At the same time pressure is directed to the diaphragm 15 and the auxiliary gate 28 to effect sealing. Closing of the contact 74c also lights the indicator lamp 89. To open the gate the controller 80 is moved in the direction 82 closing the contacts 80a, 80b and opening 80c. The relay 79 is energized to break the circuit to the valve 75 and connect the vacuum source at 75a to the passage 75c and hence the gauge 84, the diaphragm 15 and the auxiliary gate piston 30. Contacts 85a, 85b are re-established to operate the valve 76 and direct pressure to the piston 44 which opens first the auxiliary gate 28 and when the stop 34b contacts the member 12, the principal gate. During movement of the gate the contact 74b and flashing unit 86 cause the lamp 88 to flash. When fully open the signal contactor 74a is actuated to light the lamp 88.