Patent GB-717899-A (GB)
Title: Improvements in or relating to loading control mechanism for cyclical centrifugal apparatus
IPC: C25D7/06
Filed: 1952-12-11
Abstract: 717,899. Centrifugal separators. WESTERN STATES MACHINE CO. Dec. 11, 1952 [Dec. 12, 1951], No. 31436/52. Class 23 Loading control mechanism for a separator preferably used in refining sugar includes a rotary basket 1, which is supplied with material from a tank 3 by way of a gate 5, which is closed progressively through means actuated by a feeler 15 in contact with the surface 2b of the material being centrifuged. Fig. 1 shows one construction wherein a gate-actuating link 9 is controlled by a piston in a cylinder 10 through fluid, preferably air under pressure, supplied by a pipe 55 to either line 11, 12 under control of a servo-piston valve 45, the second pipe 11 or 12 venting the cylinder 10 to atmosphere. A hand-lever 72 may be used to control the valve 45. The latter is carried on a frame 41, pivotable about a point 42, under control of a link 18. The piston valve 45 is normally biased by a compression spring 48 to a gate-opening position but is movable backwards, first to a gate inactivating position then to a gate-closing position. A control bar 60 is movable with the frame 41 but is also movable relatively to the frame in order to position the valve 45 and is connected with the feeler mechanism 20 by a link 17. When a solenoid 62 is energized, a plunger 63 moves to thrust forward the bar 60, against the tension of a spring 64, which normally biases the bar 60 and valve 45 to gate-closing position when the solenoid 62 is de-energized. The spring 64 is stronger than the spring 48. A further spring 66 yieldingly couples the bar 60 to the frame 41 for movements with the frame 41 in response to movements of the gate 5. A slot 67, in the bar 60, engages a pin 68 on a shaft 69 which is slidable relatively to the frame 41. When the lever 72 is pushed to the left, Fig. 1, a pin 78 thrusts a collar 76 backward against a compression spring 74, and the pin 68 travels backward until it engages the end of the slot 67 and moves the bar 60 and the valve 45. Connections between parts 21, 23, 24 cause these, as well as a shaft 16 and the feeler 15, to move together yieldably about the axis of the shaft 16. Adjustable stops limit the outward movement of the feeler 15. A fixed limit switch 31, having a movable switch arm 32 co-operates with a switch-operating cam 23d, on the member 23, to bring about a quick final closing of the gate, acting through the solenoid 62 see Fig. 3 (not shown). An electrical timer may be used to control the loading of the basket. Fig. 4 shows a modified arrangement in which the gate is closed step by step in response to charge-induced movements acting through a feeler 15a and an electric motor 17a. A series of slider bars, springs and links are actuated when the gate 5a moves in response to air pressure in the cylinder 10a, under control of the valve 45a, which may be moved manually by means of a lever 70a. When it is time to complete the closing of the gate 5a, this is accomplished automatically by de-energizing a solenoid 85a, a solenoid 62a having previously been de-energized A spring 84a then shifts an arm 77a and abutment 78a out of engagement with the control member 60a and allows the spring 64a to dispose this member and the air valve at gate-closing position. The condition of actuation of the solenoids 62a, 85a are determined by the charge feeler assembly 20A which includes two limit switches 21a, 31a respectively. When the motor 17a is energized it acts to move the feeler 15a outward into working position, after' which the material building up on the wall of the basket 1 presses the feeler inward acting against the motor torque. A third arrangement, Figs. 5, 6 (not shown), resembles that described in connection with Fig. 1 but has a forked lever controlled by the feeler shaft, the ends of the fork bearing on the valve controlling the fluid supply to the gate-operating cylinder. The cover for the basket has a safety lock preventing the automatic opening of the loading gate unless the cover is in the open position. In another arrangement, Fig. 8 (not shown) a link connects the frame 41 with a piston in a cylinder, the position of which is influenced by the pressure head of the material in the supply tank 3. A flexible diaphragm, on the side of the tank 3, is under pressure of the material within and on the other side to air under pressure. Movement of the diaphragm acts on a rockable member which controls needle valves and thus regulating the suppy of compressed air to the piston in the cylinder.