Patent GB-427756-A (GB)
Title: Improvements in or relating to centrifugal machines
IPC: B04B13/00
Filed: 1933-11-16
Abstract: 427,756. Centrifugal machines. SHARPLES SPECIALTY CO., 23rd Street, Phila. delphia, U.S.A.-(Assignees of Jones, L. D.; 23rd Street, Philadelphia, U.S.A.) Nov. 16, 1933, No. 31985. Convention date, Nov. 17, 1932. [Class 23] In a centrifugal machine for separating solids from liquids, the holder for the tool, which acts to discharge separated solids from the drum, controls and operates the means which determine its own axial and rotary movement. Automatic means are used to supply a quantity of mixture to the drum, to allow the drum to rotate with the supply cut off, to supply a quantity of wash water, to allow the drum to rotate for washing and drying the solids, and then to operate the tool for the discharge of the solids. The shaft 15, Fig. 1 carries the rotor 10, which may be perforate or imperforate, and is supported in bearings on the frame 18. A pipe 21 with discharge openings 22 projects into the drum and is connected to pipes 150, 151, for the mixture and the washing liquid respectively, the supplies of which are controlled by valves 152, 153. The tool 25 for dislodging deposited solids is mounted in the holder 28 which can reciprocate in bearings 29, 30, Fig. 4, a stuffing box with packing 311 compressed by the member 32 being provided to prevent materials passing from the rotor into the bearing 30. The tool 25 is moved to or from the inner surface of the drum 10 by rotation of the holder 28 through worm gearing 39, 40, and rack gearing 46, 44. The rack 46 is attached to a piston 51 working in a cylinder 52 supplied with pressure fluid at one of its ends according to the angular position of the holder 28. The holder is reciprocated to carry the tool 25 axially in the drum 10 by means of two cylinders, one 60 of which is shown in Figs. 1, 19 with a piston 61. The arrangement of pipes and circuits for the combined hydraulic and electric operation of the control gear is shown in Fig. 19. A motor driven pump supplies liquid, preferably oil, under pressure to the pipe 86 leading to the four way valve 88 from which it is supplied to either end of the cylinder 60 according to the position of the valve. The supply also extends through the valve 92 and the double piston valve 94 to the ends of the cylinder 52, the valve 94 being subject to the control of the solenoid 201. This valve also carries a stem with an adjustable collar 55 which is engaged by a series of circumferentially spaced lugs 119 on the tool holder 28 during the operation of the tool 25. The valve 152 through which the mixture is supplied is operated by a torque motor 156 controlled by the switch 166 operated by the solenoid 168, and the valve 153 for the washing water is operated by the solenoid 159. To start the cycle of operations, the main switch 160 is closed after the drum has been run up to speed by its driving motor. Current passes through the mercury contact switch 132 and the solenoid 167 to lift contacts 164, 165 into engagement with contacts 169, 171 to complete the circuit of the torque motor 156 and open the valve 152 to supply mixture to the drum. The solenoid 177 is energized at the same time as the relay 167 but its armature is only lifted after the lapse of a predetermined time and then it breaks the circuit of the relay 167 so that the valve 152 closes to stop the supply of mixture. The armature of the solenoid 177 closes the circuit of the solenoid 182, and, after a predetermined time during which the cake on the drum is drying, the armature of the latter solenoid closes the circuit of the solenoid 159 to open the valve 153 to supply washing water to the drum. This circuit is broken after sufficient water has been supplied by the lifting of the core of the solenoid 192 and the valve is closed by the spring 158. After an interval for the drying of the cake the relay 197 closes the circuit of the solenoid 201 which moves the piston of the valve 94 to the left from the position shown in Fig. 19. Oil under pressure then flows from the pipe 86 through the valves 88, 92, 94 to the right hand end of the cylinder 52 so that the piston 51 moves to the left. This movement permits the closure of the valve 58 and the opening of the switch 132 to deenergize the relays ; it also rotates the tool holder 28 to bring the tool 25 into the cutting position. The first lug 119, Fig. 12 on a ring carried by the holder 28 operates lever mechanism to actuate the valve 88 so that oil under pressure flows from the pipe 86 through the pipe 90 to the left hand end of the cylinder 60 ; the movement'of the piston 61 then carries the tool 25 into the drum. As the tool moves inwards the movement of the plate 78 with the holder permits the spring 92b to close the valve 92 to cut off the flow of oil to the cylinder 52. As the tool 25 nears the inner limit of its travel a lug 101 engages the right-hand collar 99, Fig. 4, thereby causing the valve 88 to be returned to the position shown in Fig. 19. As the valve 92 is closed the oil passes from the valve 88 to the right hand end of the cylinder 60 causing the piston 61 to withdraw the tool from the drum. Near the end of the outer movement the plate 78 opens the valve 92 and this permits oil to flow again to the right hand end of the cylinder 52 to move the piston 51 to the left. This causes a further rotation of the tool holder 28 and the second lug 119 operates the lever mechanism to actuate the valve 88 so that the tool 25 is reciprocated again. The third action of the piston 51 brings it to the limit of its movement and the third rotational step of the tool holder brings the lug 119<a>, Fig. 12, into position to engage the collar 55. This engagement returns the valve 94 to the position shown in Fig. 19, and when the tool holder returns to its outer position the plate 78 opens the valve 92 so that oil flows from the valve 88 through the valves 92, 94, to the left hand end of the cylinder 52. The rack 46 is thus moved to return the tool 25 to its original position, to open the valve 58, and to close the mercury switch 132, so that the series of operations is repeated while the main switch 160 remains closed. In a modification of the control system the valve 152 is operated hydraulically instead of electrically. An automatic stopping device may be employed to come into operation if the drum becomes unbalanced owing to an uneven deposit of solids. A plate 236, Fig. 27, is linked to the frame of the machine and its end projects into a housing 237 in proximity to a partition 240. A source of light 238 is fixed in one end of the housing and a photoelectric cell 239 in the other. Apertures are made in the plate 236 and the partition 240 and are normally out of register. When the drum vibrates however, the apertures are brought into register and light passes to the cell 239. This causes the relay 241 and the solenoid 204 to be energized so that the circuit of the solenoid 201 is completed to set the discharge mechanism in operation.