Patent GB-808027-A (GB)
Title: System for extracting oil from metal chips
IPC: C22B1/00
Filed: 1956-01-31
Abstract: 808,027. Centrifugal strainer separators. TURBINE EQUIPMENT CO. Jan. 31, 1956 [Feb. 24, 1955], No. 3028/56. Class 46. [Also in Group XXX] In a system for extracting cooling or cutting compounds, e.g. oil, from metal turnings or chips in a crushed condition in a centrifugal separator, the turnings are supplied intermittently to the separator by a hopper which is fed by a pneumatic conveyer and provided with means whereby on the occurrence of a predetermined high level of turnings in it, a feeder delivering the turnings to the pneumatic conveyer is rendered inoperative. An endless-belt conveyer 6a, Fig. 1, driven by a motor 8 delivers wet chips to the feed hopper 7 of a crusher 11. The broken chips fall from the crusher into a surge hopper 12, from which they are conveyed by a screw conveyer 13a to means for feeding them into a pneumatic conveyer 15, This conveyer delivers them to a surge hopper 16 which discharges into a screw conveyer 20a feeding the basket 26, Fig. 2, of a centrifugal extractor 21. Liquid separated from the chips passes through the pipe 23d to a collecting tank. The chips fall through the outlet 26c into a surge hopper 30 when the centrifugal force becomes insufficient to hold them against the wall of the basket. Chips pass from the hopper 30 into a screw conveyer 31a which feeds them to means 32 for feeding them into a pneumatic discharge pipe 33. The energizing circuit 9 for the motor 8 includes a manually-actuated switch 9b, an automatically-actuated switch 9c and an overload switch 11b associated with the motor 11a of the crusher 11. The switch 9c is connected to a level-responsive device 12a in the hopper 12 and is opened when the chips reach it to stop the conveyer 6a. The conveyer is also stopped when the crusher motor 11a becomes overloaded by the opening of the switch 11b. This switch is operated by a relay in series with the motor 11a. The hopper 16 has level responsive devices 16b, 16c which control a circuit 18 energizing the motor 13c driving the conveyer 13a. The circuit 18 includes a manually-actuated switch 18b, a switch 18c connected to a pressure-responsive device 15b in the conveying conduit 15, a switch 18d connected to the level-responsive device 16c and a relay switch 18e. These switches effect the stopping of the motor 13c when the air pressure in the conduit 15 rises above a predetermined value. When the air pressure in the conduit 15 becomes normal, the device 15b recloses the switch 18c and the conveyer 13a resumes operation. When the amount of chips in the hopper 16 rises sufficiently to actuate the device 16b, the latter closes the switch 19a without affecting the circuit 18 until the chips rise to the level of the device 16c. When this occurs the circuit 18 is opened at the switch 18d and the conveyer 13a is stopped. The circuit 18 is also opened at switch 18e and closed at switch 19e. When the level falls sufficiently for the device 16c to reclose the switch 16d and reopen the switch 19c, the relay 19d remains energized and the circuit 18 remains de-energized since the switch 18e is open. When the level further falls, a device 16b is operated, the holding circuit for the relay 19d is broken, relay switches 18e, 19e return to normal positions to re-energize the motor circuit 18 and the conveyer 13a is restarted. A lower responsive device 16d operates to maintain in a minimum level of chips in the hopper. The extractor 21, Fig. 2, comprises a rotor housing 23 which is mounted in a frame 22 and contains a centrifugal basket 26. The basket is supported and driven by a shaft 25 which is mounted for rotation in the head of the frame. The housing and basket have aligned top openings 23b, 26a through which the chips fall. The shaft 25 carries axiallyspaced discs 25a, 25b and 25c of progressively increasing diameter which deflect the chips outwardly against the perforated cylindrical wall of the basket. The lower frusto-conical end 26b of the basket also is perforated and is open at the bottom 26c. The shaft is driven by an electric motor 27. At the commencement of each cycle, the basket is driven at a relatively low speed while chips are being fed to it, this speed being sufficient to hold the chips against the wall. When it is full, the basket is driven at full speed for a time sufficient for the extraction of all the oil. At the end of this time the drive is interrupted and a brake applied so that the chips fall through the outlet 26c into the hopper 30 when the centrifugal force becomes insufficient to hold them against the wall. The motor 31b driving the conveyer 31a is controlled by a switch 34c which is connected to a pressureresponsive device 33a in the pipe 33. When pressure exceeds a predetermined value due to partial stoppage, the switch 34c is opened and the motor is stopped until the pressure drops to normal. The driving means for the extractor 21 and its feeder 20a are controlled by a switch 35 actuated by the level-responsive device 16d, a zero-speed switch 36 which opens only when the basket comes to a full stop, a basket unbalance switch 37 which closes only in response to excessive lateral movements of the shaft 25, and a normally-closed level-responsive switch 38 at the upper part of the hopper 30.