GB1534061A - Installation for controlling the weight of tablets during the manufacture thereof - Google Patents

Abstract

1534061 Automatic control of size ATELIERS DE CONSTRUCTION ED COURTOY 12 March 1976 [14 March 1975] 10000/76 Heading G3R [Also in Division B5] The weight of tablets is kept constant by retroactive control of their size when compressed at substantially constant pressure during manufacture. Synchronously rotating platforms 27 ... 29 carry a number of dies 31 and associated plungers 32, 33 to a station at which each die is filled by an amount depending upon the height of a ramp 38 acting on the lower plunger and thence to a compression station, at which pressure is applied to the lower plunger by hydraulic fluid in a chamber 1 of the piston and cylinder arrangement shown, acting through a roller 24. An upper pressure roller 25 is fixed. The piston contains the core 12 of a differential transformer forming a position measuring device, whose output is separately compared with four reference voltages which set upper and lower limits respectively for corrective action or rejection of the tablet. The two comparators for correction are connected to respective shift registers; when one is full (due to a predetermined number of over or under size tablets) a motor 45 is energized to adjust the height of the ramp 38 at the filling station. The two comparators for rejection are both connected to a further shift register having as many stages as there are positions of the platforms between the compression stage and a reject take-off point. Thus, if any tablet exceeds the reject limits it is automatically ejected when it reaches this point. All the registers are stepped once per cycle of the machine. If a predetermined number of rejects occur in succession the machine is stopped. The reject signals are also supplied to a device by which the operation of any given die can be monitored as to whether it is producing reject tablets.