GB938442A - Improvements in and relating to automatic dispensing machines - Google Patents

Abstract

938,442. Automatic control of container filling machines. INDUSTRIAL NUCLEONICS CORPORATION. July 6, 1961, No. 24569/61. Class 38 (4). In an automatic control system for a dispensing machine, through which a plurality of containers pass in succession, an adjusting device for varying the volume of material placed in each container is controlled by a detecting device producing a signal indicative of the average height to which the material is placed in the containers so as to maintain the fill height at a predetermined level. As shown, a row of containers 40, Fig. 2, to be filled, pass into an automatic dispensing machine 20 and the filled containers 41 are scanned by a staggered arrangement of a cesium source 10 and G.M. tubes 11 positioned so that the cans present a continuous barrier to the radiation. The output of the G.M. tubes is fed to a measuring bridge circuit 8 energizing a contactmeter 150 arranged to operate a low-fill controller 70 or a high-fill controller 72. The controllers are connected to a reversible motor 58 varying the volume dispersed so as to maintain the height of material in the container constant. In the measuring bridge circuit, Fig. 7, the output of parallel-connected G.M. tubes 11a-11c is fed through an integrating circuit 104 to a bridge circuit comprising triode valves 1, 2 and having a contact-meter 150 as a bridge-balance indicator, a coil 150a being in series with a rheostat 119, controlling sensitivity, across the output of the bridge. The bridge is set at the desired fill-height by a rheostat 110. Movement of the contact-meter pointer 150c outside of the set limits closes a switch 150d, 150c to energize a hold-on coil 150f, 150g through contacts 120a of a delay timer 120 to bias a grid 128, 142 and render a thyratron 3, 4 conductive. A relay 140, 160 is energized by the thyratron to open contacts 140a, 160a in the supply to the other thryatron 4, 3 and close contacts 140b, 160b to energize the appropriate field winding of a motor 58 so as to tend to correct the variation in the fill-height. The delay-timer 120 runs continuously and is arranged so that contacts 120a disconnect the hold-on coils and the grid bias to the thyratrons for a sufficient period in each cycle for the results of a previous corrective action to be measured by the bridge. Specification 938,441 is referred to.