The Automatic Recording Regulator which measures the Brightness of Pulp Suspension

Abstract

The apparatus so far developed tend to have a defect not to give a true brightness of pulp in suspension because of the influence of the changes in the pulp consistency, the rate of flow and the variation of freeness in the beating processes etc. Thus, these apparatuses seem to be little useful.In this report, the principle and structure of the new successful apparatus which is capable of measuring a true brightness of pulp, the influences mentioned above beeing eliminated, is described, and also the experimental results obtained by using this apparatus, are given.It is characterized by employing not only the reflectance of light from the pulp suspension, but also the compensation light.It is devised so as to determine a true brightness without beeing influenced by changes as in consistency and so forth, since the compensation light is established so that both the amount of light transmission of the compensation light and of the reflected light from the light source are subject to changes and simultaneously the sum of them become constant, when-ever changes occur in the consistency of pulp.It is also devised so as to give in variable accuracy by employing the optical automatic balancing method which excludes such factors as the variation of voltage of the lamp of light source, the deterioration of luminous intensity and the change in the sensitivity of the receiving and amplification parts.The sensitivity of the apparatus is in a range of ±0.1% in the terms of the brightness of pulp, and the change caused by the elapsed time is within 0.1%.The total accuray is less than ±0.1% as converted to the brightness obtained by the Hunter Reflectometer, under the best condition.This apparatus is set in a certain position after the addition of a bleaching agent, and is much effective for regulating the amount of bleaching agents in the bleaching sequences.