GB829458A - Colour control of liquids - Google Patents

Abstract

829,458. Automatic dye colour control systems. PROCTOR & SCHWARTZ Inc. Aug. 9, 1957 [Sept. 17, 1956], No. 25155/57. Class 38 (4). In a system for mixing coloured liquids to obtain a predetermined colour in a mixing chamber the amounts of the component colours fed to the mixing chamber are controlled by a colour monitoring device which checks sequentially the quantity of each component colour in a sample and causes additional colours to be educted from the appropriate colour tank when a deficiency is detected. The colour of a dye sprayed on to stockings 50, Fig. 2a, in a dye tank 47 is maintained in accordance with the colour of a liquid in a standard cell in a colour monitoring device 25 by solenoid-operated valves 22<SP>1</SP>-24<SP>1</SP> in the conduits from the colour tanks 10-12 to the mixing tank 15 which respond respectively to the corresponding outputs arising from the sequential examination of different colour components. The dye from chamber 16 into which the mixed liquid from mix chamber 15 is spilled, is fed to the dyeing sprays 49 through a heater 45, the output temperatures of which is regulated, by a unit 117 controlling a valve 115 in response to the output of a temperature measuring device 119, and because of the possible changes of colour with temperature, the sample to the colour monitoring device 25 is temperature-controlled by a cooling coil 92. PH control is effected by a measuring cell 96 and a tank of phosphoric acid, the conduit 59 of which leads with the component colour conduits into a manifold 20<SP>1</SP>. The level in chamber 16 is maintained by a ballvalve 105 which controls through an air pipeline 106 water inlet valve 107, and the flow of dye to the tank 47 as measured by a Venturi 129 is caused to operate red and green lights 132, 133. A strainer 128 is included in the circuit, and the possibility of colour error arising from the presence of non-dyeing coloured material picked up from the sump of the tank is avoided by compensation in the monitoring device, a regular addition of dilutant to the system and a regular removal of a proportion of the accumulation in the sump of the dye tank serving to prevent a build-up of the non-dyeing material in suspension. The non-dyeing component may be measured by infra-red or ultra-violet absorption. The system includes a tank 54 in which a new colour can be prepared if a change of colour is desired and the possibility of adding di-sodium phosphate for pH correction is referred to. The dilutant may also be controlled in response to colour tests. Specifications 819,484 and 822,027 are referred to.