Patent GB-699909-A (GB)
Title: Improvements relating to the control of the mixing of liquids
Inventor: BLIGHT FRANK CHARLES
IPC: G01N21/80
Filed: 1950-09-04
Abstract: A method of controlling a mixing process in which acid is added to an aqueous alkaline solution to reduce the alkali content of the solution is characterized in that methyl orange or other indicator responsive in its colour to acidity or alkalinity is added to two samples of the mixture of solution and acid, to one of which such an amount of additional acid is added that if the mixture is satisfactory the sample becomes slightly acid and so in the presence of the indicator changes colour; the proportions of acid mixed with the solution is corrected if the colour of either sample is not that corresponding to ordinary mixing.  In a process of blending alkaline water with acidic water to produce a mixture of substantially constant alkalinity, two samples are continuously bled from the mixture and methyl orange or other colour indicator is added to each sample.  A further quantity of acidic water is added to each sample, the further quantities being different from each other so that if blending is being correctly performed, one sample will just be rendered acid and the other sample will have its alkalinity reduced nearly to the neutral point, and in the presence of the colour indicator the samples will be of different colour.  The blending proportion of the mixture is corrected upon the colour of either sample changing.  The samples may be used to control two photo electric devices responsive to the two colours in that if either changes the device in question will provide an electric impulse for operation of a relay by which the blending proportion is corrected.ALSO:In a process of blending alkaline water with acidic water to produce a mixture of substantially constant alkalinity two samples are continuously bled from the mixture and methyl orange or other colour indicator is added to each sample.  A further quantity of acidic water is added to each sample, the further quantities being different from each other so that if the blending is being correctly performed, one sample will just be rendered acid and the other sample will have its alkalinity reduced nearly to the neutral point, and in the presence of the colour indicator the samples will be of different colour.  The blending proportion of the mixture is corrected upon the colour of either sample changing.  The samples may be used to control two photo-electric devices responsive to the two colours in that if either changes the device in question will provide an electric impulse for operation of a relay by which the blending proportion is corrected.ALSO:A method of controlling a mixing process in which acid is added to an aqueous alkaline solution to reduce the alkali content of the solution is characterized in that methyl orange or other indicator responsive in its colour to acidity or alkalinity is added to two samples of the mixture of solution and acid, to one of which such an amount of additional acid is added that if the mixture is satisfactory the sample becomes slightly acid and so in the presence of the indicator changes colour; the proportion of acid mixed with the solution is corrected if the colour of either sample is not that corresponding to ordinary mixing.  In a process of blending alkaline water with acidic water to produce a mixture of substantially constant alkalinity, two samples are continuously bled from the mixture and methyl orange or other colour indicator is added to each sample.  A further quantity of acidic water is added to each sample, the further quantities being different from each other so that if the blending is being correctly performed, one sample will just be rendered acid and the other sample will have its alkalinity reduced nearly to the neutral point, and in the presence of the colour indicator the samples will be of different colour.  The blending proportion of the mixture is corrected upon the colour of either sample changing.  The samples may be used to control two photo electric devices responsive to the two colours in that if either changes the device in question will provide an electric impulse for operation of a relay by which the blending proportion is corrected.