Patent GB-396558-A (GB)
Title: Improvements in connection with apparatus for the separation of materials of differing densities
IPC: B03B11/00
Filed: 1932-08-05
Abstract: 396,558. Control of two motors. GENERAL ELECTRIC CO., Ltd., Magnet House, Kingsway, London.-(Chance, T. ; Merion, Pennsylvania, U.S.A.) Aug. 5, 1932, No. 22055. [Class 38 (iii).] In apparatus for separating materials of different densities by means of a fluid medium, in which heavy matter is discharged from a settling-chamber through a second chamber, which is separated from the settling-chamber by a power-operated valve and is provided with a power-operated discharge valve, means, operated by movement of the valves, are provided for permitting the application of power to either valve to effect. opening thereof only when the other valve is closed. The invention may be applied in connection with apparatusas described in Specification 119,038. As shown in the Figure, the rods 8, 9 of the two valves. are connected to cranks on shafts 73, 74 driven respectively through worms 81, 82 by threephase electric motors 83, 84. Current is supplied to the motors from mains 106, 107, 108 through. leads 111, 112, 113, and switches 114, 115 closed respectively by means of coils 116, 117. Connected to the rod 8 is a pawl 93 which near one end of its travel engages a switch 134 and near the other end engages a link 101 connected to a spring-mounted switch-bar 103 so as to disengage a contact point 126 thereon from a contact point 125 and bring it into engagement with a contact point 132. A similar pawl 94 connected to the rod 9 engages a switch 136 and moves the bar 103 in the reyerse direction. The circuit of the coil 116 includes a wire 120, contactors 121, 122, a switch 123, closed when pressure is maintained in a chamber 4, the contact points 125, 126 and a wire 127. When this circuit is closed the motor 83 operates to open the upper valve. As the pawl 93 approaches its extreme position it closes the switch 134 and thus energizes a coil 133 to open contactor 121 and close contactor 122. The contactor 122 is under the influence of a time-delay, such as a dashpot, and there is therefore a short period during which the circuit of the coil 116 is closed and the motor 83 at rest, this corresponding to the full opening of the upper valve. The return movement follows, the pawl 93 when reaching the other end of its travel moving over the bar 103 to bring together the contact points 126, 132, and close the circuit of the coil 117 to start the motor 84 and thus operate the lower valve. Overload circuit-breakers 109, 110 are provided so that the motors are reversed if either of the valves are obstructed. In the position shown the switch 110 is closed. Overload will cause coils 140, 141 to break a contact 142 and deenergize a coil 144, thus allowing the switch 110 to open under gravity. Contacts 145 are closed and a coil 154 energized to close the switch 109 including contacts 156 in the circuit of a coil 143, which resets the contact 142. On further overload the switch 109 is similarly opened and the switch 110 closed, the motors being again reversed. There is a contact 146 in series with the coil 154 and a contact 148 in series with the coil 144, both contacts being closed by a shunt coil 147, but the contact 146 being subject to a dashpot or other coil delay. This arrangement ensures that if the current is shut down the switch 110 will close first and in doing so will open contacts 145 and thus prevent closing of the switch 109.