Patent GB-832774-A (GB)
Title: Apparatus for adjusting intermittently operating mixing devices to continuously operating material-consuming installations
IPC: B28C7/04
Filed: 1956-07-09
Abstract: 832,774. Automatic control systems for mixing apparatus. EIRICH, W., and EIRICH, G. July 9, 1956 [July 9, 1955], No. 21202/56. Class 38 (4). [Also in Group XVIII] In an apparatus for adjusting an intermittently or continuously operating mixing apparatus to a material consuming installation which receives the mixed material either continuously or intermittently, an intermediate container is interposed between the mixing device and the material consuming installation and contains at least one device operating when a predetermined quantity of material is contained in the intermediate container and connected to electric switching means for stopping the supply of material to the said container when the predetermined quantity is exceeded. Means may be provided to stop the feed of material from the intermediate container when the contents have been reduced to a predetermined amount. In addition, means may be provided to regulate the discharge or introduction of material into the intermediate container in accordance with the temperature of the material therein. As shown, in an automatic concrete mixing installation, Fig. 1, a mixer 1 is provided with sand and gravel from bins 4 via worm conveyer 5 and basin 6 of an automatic weighing apparatus. The weighed materials are automatically discharged via closure device 8 to a hopper 9 which transports the materials to the mixer 1. Cement is stored in a bin 10 and via worm conveyer 11 and automatic weighing appliance 12 a measured quantity is discharged into the mixer. Water is brought in to the mixer from a reservoir 13 via cock 14 and water meter 15. Below the mixer the intermediate container 16 is arranged on an automatic weighing apparatus and receives the mixture and delivers it in a continuous flow on a conveyer 17. The sequence of operations is controlled by timing switches, and electrical interlock arrangements and limit switches provide the necessary safety measures, Fig. 2 (not shown). Instead of an automatic weighing device the intermediate container 16<SP>11</SP>, Fig. 2a, may include volumetric measuring devices comprising rotating paddle wheels 173 driven by motors 174 and operating torquecontrolled switches 175, 176, the switch 175 operating to stop the motor 131<SP>1</SP> to stop the supply of material from the mixer 1<SP>11</SP> to the container at the upper level and the switch 176 switching off the motor 133<SP>1</SP> at the lower level to stop the supply of material to the materialconsuming installation 134<SP>1</SP>. An automatic weighing apparatus for the intermediate container comprises a balance beam 183, Fig. 2b, mounted on a knife edge 182 and carrying knife edges 181 supporting the intermediate container. A two part weight 184, 185 is mounted on the other end of the beam and mercury switches 155, 169 are closed at the upper and lower limits respectively. In an arrangement for feeding three installations 134a, 134b, 134c from an intermediate container 16, Fig. 3a, via discharge apertures 27 controlled by tongues 201, each tongue 201 is connected to a pistonrod 203 of a compressed air or liquid cylinder 202, the length of the piston-rod being adjustable by hand wheel 214 through scissors-action levers 206 to 209. A control line 114<SP>11</SP> is energized via contact 169<SP>11</SP> operated by the automatic weighing apparatus when the minimum quantity of material in the intermediate container is reached, and energizes relays 217 which through motors 216 and valves 215 close all the discharge apertures 27. If one of the installations 134 is incapable of receiving further material operation of the appropriate switch 171 closes the discharge aperture 27 to that particular installation.