JPS5553878A - Electrolyte-concentration detector for lead storage battery - Google Patents

Abstract

PURPOSE: To detect the electrolyte-concentration with high precision without being influenced by the variations and fluctuations of the electrolyte surface, by receiving the light reflected from the bottom surface of a prism contacting the electrolyte by an array of light receiving elements, and detecting the change of the index of refraction of the electrolyte due to the change of the electrolyte-concentration.

CONSTITUTION: The detector is formed of a point light-source 1, a slit 2 for limiting the angle of the light emitted from this light-source, a prism 3 having a bottom surface in contact with the electrolyte 4, and an array of light-receiving elements 5. If the angle of incidence of the light incident upon the bottom surface of the prism 3 at a point β' is just equal to the critical angle between the prism and the sulfuric acid at that time, the light quantity received by the array of light-receiving elements 5 suddenly increases from a point β where the critical angle condition is established. Thus, when the concentration of the sulfuric acid, and hence the index of refraction thereof and said critical angle are changed, the position of the light- receiving element from which the received light quantity suddenly increases is also changed, so that this can be utilized to detect the electrolyte-concentration with high precision.

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