摘要 |
A sensor element for a liquid level sensor of the "light prism" type is constructed so as to have a gradually tapering frusto-conical shape and a sensing surface at its lower tip. Such a shape has a tendency to collomate the light transmitted within it and to concentrate all critical reflections in the lower tip of the sensor element, thereby defining a relatively concentrated sensing area. At the same time, the sensor element is shaped and dimensioned in the vicinity of the sensing surface so that the surface tension of the droplet causes the droplet to be lifted upwardly and away from the sensing surface. Any deliterious effect of the droplet on the sensing ability of the sensor is thereby avoided.
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