Patent GB-516878-A (GB)
Title: Improvements in or relating to automatic control mechanism for water gas and other cyclic processes
IPC: C10J3/24
Filed: 1938-07-11
Abstract: 516,878. Automatic control -mechanism for industrial plants RAMSEY, A. R. J. (Koppers Industrieelc Maatschappij, N.V., H.), July 11, 1938, No. 20503. [Class 135] Automatic control mechanism for actuating the control valves of fluid pressure actuators for the valves or other regulating members of water gas plants, intermittently - operated gas filtering plants of the active carbon type, plants for the decomposition of hydrocarbons or like apparatus and in which the control valves are opened and closed in a predetermined sequence by a continuously rotating cam shaft includes a series of timing cams whereby thrust bars coupled to the valves are moved at appropriate times into the path of the corresponding actuating cam. The invention is described in its application to a water gas plant the valves of which are operated by hydraulic cylinders each connected by pipes 53, 54 to a set of control valves 2 having a common inlet pipe 50 and a common exhaust pipe 51, each valve being operated by the rotation of a stem 57. This arrangement is described more fully in Specification 357,001, [Group XII]. The mechanism for timing the operation of the valves is contained in a casing 16 and comprises a gear 65 for each stem 57, the gear meshing on opposite sides with a pair of racks 12 each pivotally connected to a push bar 14 so that a movement of one push bar produces a reverse movement of the other push bar. The push bars are actuated at timed intervals by double-ended cams 20 on a constant speed shaft 18 driven through gearing by a motor 17. The timing devices comprise a series of cams 19, one for each push bar, driven from a timing shaft 78. The latter is driven by the motor 17 through gearing which includes change speed gear to adjust the speed of the timing shaft. The timing shaft 78 may also be operated by a hand crank 17<1>. The timing cams 19 normally depress the push bars out of path of the actuating cams 20 by means of keys 21, but are each provided with a recess 22 which permits the corresponding push bar to rise. Each push bar can reciprocate a limited distance in a slide 23 of U-section constantly pressed upwardly by a spring plunger 29 engaging a notch 28 in its base and has inclined slots 27 engaging rollers 26 carried by the sli'des 23. After a key 21, secured to the top of the slide 23, has engaged its recess 22 so as to bring the corresponding push bar into the path of its actuating cam 20, the movement of the push bar, due to the inclined slots 27, depresses the key 21 below its upper edge before the key can foul the side of the recess 22. This movement actuates the corresponding stem 57 to position its control valve and also returns the other push bar of the pair so that the rollers 26 are at the top of the slots 27 and the key 21 of this bar by engaging its cam 19 maintains the push bar clear of its actuating cam but ready for actuation of the stem 57 in the reverse direction. The push bars 14 have recesses 32 to permit their movement relative to the keys 21. The timing cams 19 are adjustably mounted on a hub 36 fixed to the timing shaft against a graduated disc 38 integral with the hub, and are clamped by nuts 35. In the modification shown in Fig. 5, the timing cams 19 are connected to the timing shaft 78 through epicyclic gearing 84, 83, 85, the planet gears 83 being carried by worm wheels 82 adjustable from outside the casing 16 by worms 144. The ring gears 85 which carry the cams 19 are graduated and co-operate with a pointer 41. In both forms, the automatic operation may be stopped by a handle 42 on a shaft 43 which in the first form carries a series of shut down cams 44 and in the modification, Fig. 5, carries tappets adapted to engage similar tappets on the cam 44. The cams of each pair of push rods. are joined by a shut down arm 46 and normally engage the bars 14 by the flats 73. The cam surfaces 45 depress the push bars 14 whichever way the handle 42 is turned but in one direction the arm 46 engages a pin 47 on one of each pair of push bars so as to put the corresponding valve stem 57 into the shut down position. If the handle is oppositely rotated each valve stem may be separately actuated by a hand lever 48 connected to a clevis 59 on the valve stem 57 by a link 60. The form shown in Fig. 5 permits also selective shut down of individual valves. Each pair of cams 44 and their arm 46 can be operated by rack and pinion gear 64, 67 from a push rod 62. The rack 64 has recesses 68 for engagement by a locating ball' in its end position. The casing 16 is provided with a removable glass or like cover 39 and carries a cycle indicator 165 as described in Specification 357,001, [Group XII].