GB566477A - Improvements in or relating to suspended centrifugal machines - Google Patents

Abstract

566,477. Hydraulic couplings. CLARK, G. M. (Western States Machine Co.). Sept. 3, 1943, No. 14431. [Class 69 (ii)] [Also in Group II] A machine of the suspended basket type used in the manufacture of sugar is driven by an electric motor with high and low speeds, through a hydraulic coupling, and the torque-transmission is regulated by controlling the flow of oil to the coupling, smooth acceleration preventing overheating of 'the driving motor. The centrifugal basket 10 may be driven at a speed differing from that of the motor 22, by the incorporation of a speed-changing unit just above a flexible coupling. The hydraulic coupling oil is cooled externally to absorb heat due to slippage in the coupling 30. Under a sudden heavy torque demand the .motor frame 22a is allowed slight rotary movement against spring or pressure-oil resistance, the movement displacing a valve 50 to shut off the oil supply to the coupling and allowing the coupling 30 to slip. When a two-speed motor is provided, the motor may be used for regenerative braking during the first part of the braking period of each cycle, and the basket 10 brought to rest between cycles without having to stop or disconnect the motor, by using a brake 17. A head 16 contains bearings and a ball-andsocket joint to allow the basket 10 to gyrate. A rotor 24, of the driving motor, is fixed to a hollow shaft 26 connected to an impeller 32, Fig. 3, of the coupling 30. The runner 34 of coupling is fixed to the top of a solid driven shaft 28 which drives the basket through the flexible coupling. Oil for the coupling 30 is supplied from a tank 46 by a pump 48 through a cooler 49, three-way valve 50 and pipe 36. Oil passes through bleeder holes 44 constantly during operation, to secure cooling of the coupling, the bled oil being drained off through a font 40. The valve 50, Fig. 6, normally allows oil to pass from a pipe 52 to the pipe 36 by way of a pipe 54, but when the electric motor has to supply a heavy torque, the frame 22a mounted on bearings 94, rotates slightly and an arm 80, and screw 82, presses on the end of a spindle 72. This closes valve seat 62 shutting off the oil supply to the coupling, and opens a valve seat 64 allowing oil to flow through a pipe 56 back to tank 46. The motor is held down on an adaptor plate 22b by bolts 86 and springs 90. The bolt holes 88 are enlarged to allow the movement of the frame 22a. A second radial arm 80a may be provided to bear, through a screw 82a, on a spring 66a. Fig. 7 - shows another arrangement using fluid pressure on. the end of a plunger 160 in place of the spring-pressure. A pump 148 drains oil from a tank 146 and pumps it through a cooler 149 to pipes 165 and 172. The plunger has enlarged portions 161, 162, for closing or opening ducts 163, 164. A set-screw 82 bears on the end 162. Fluid flow is controlled by relief valves 174, 178 which are set to open at approximate pressures of 30 lbs. per sq. inch and 10-20 lbs. per sq. inch, respectively. In a further arrangement, a number of centrifugal machines are controlled by fluid lines connected to manifolds.