Patent GB-402840-A (GB)
Title: Controlling device for automatically acting machines, particularly for centrifuges
IPC: B04B13/00
Filed: 1933-06-10
Abstract: 402,840. Valves. TER MEER, G., 3, Seestrasse, Munich, Germany. June 10, 1933, No. 16674. Convention date, June 11, 1932. [Class 135.] Servo-motors employed to make a sequence of operations during the running of automatically operating machines, especially centrifuges, are controlled by reversing valves having three stepped pistons actuated by the pressure medium supplied to the servo-motors ; the pressure acting on the pistons can be varied by means of members coupled to mechanism operated by the timing device. The servomotors are shown in the form of cylinders 1, 2, 3 with pistons 4, and they initiate the various operations of the centrifuge, such as the filling of the drum, the washing of the material, the emptying of the drum or like operations. The spaces on each side of the pistons 4 are connected by pipes 6, 7 to the reversing valves 8, 9, 10. The three pistons 11, 12, 13 in each valve have different diameters and each stem has radial bores 14 and an axial bore 15. The space below the smallest piston 13 communicates through the pipe 17 with the reservoir 18, and the space 19 above the largest piston communicates with an opening 20 controlled by a disc 21 with recesses 37 at its periphery. The valve 8 is connected by a pipe 34 to the gear pump 24 driven by the electric motor 25. A pipe 38 connects the suction side of the pump to the reservoir 18. The motor 25 also drives the timing or control disc 26 which has a number of stops 27 fixed at appropriate places on its periphery. These stops engage a spring pin 28 which operates a pawl 29 to rotate a ratchet wheel 30 on the shaft 31 which carries the discs 21 above each valve. During normal working the parts are in the position shown in Fig. 1. Oil from the reservoir 18 is pumped through the pipes 34, 23. The ports 20 at the top of the valves 8, 9 are closed by the discs 21 and the oil flows through the channels 14, 15 to the spaces above the pistons 11. This depresses the pistons and closes the outlets 17. At the same time the pressure fluid flows through the pipes 6 to the servo-motors 1, 2, and moves their pistons to the positions shown, since their discharge pipes 7 are in communication with the discharge openings 22. In the case of the third valve 10 the disc 21 is in a position to leave the port 20 open, so that the pressure fluid is discharged and the valve pistons are in the raised positions ; fluid therefore passes through the pipe 7 to the servo-motor 3 the pipe 6 of which is connected to the outlet 17. When the rotation of the disc 26 causes a stop 27 to depress and release the spring pin 28 the pawl and ratchet 29, 30 rotate the discs 21 and cause the closure of the port 20 of the valve 10. The valve pistons drop to their lower position and fluid passes through the pipe 6 to operate the servo-motor 3. The stops 27 and the discs 21 may be arranged to obtain any desired sequence of operations. The gearing between the motor 25 and the control disc 26 is worm and worm-wheel, and toothed gearing. The toothed wheels of the gear may be changed to vary the time of revolution of the disc 26. A hand-wheel 43, Fig. 5, is provided so that the disc 26 can be rotated manually after it has been uncoupled from the gearing by the removal of the coupling pin 48. The stops 27 may be mounted on screwthreaded pins 71 locked by wing nuts 73 in an annular dovetail groove in the rim of the disc 26. Any one of the valves 8, 9, 10 can be brought to its upper position by opening the hand operated valve 32 to release the pressure fluid above the top piston 11. Two controlling mechanisms of the kind shown in Fig. 1 may be arranged in one casing and used to control a double centrifuge plant.