Patent ID: 6177874
Filing Date: 2001-01-23
Classification: G01F,Y10S

Abstract:
A liquid supplying device chemical solution, comprising:a liquid;a liquid container for storing the liquid;a fiber photoelectric sensor entirely made of an optical fiber that fits into the liquid container, wherein the fiber photoelectric sensor is used for detecting the liquid level of the liquid inside the liquid container by making contact with the liquid, and then generating a detected signal when the liquid level has dropped to a predetermined residual level that exposes a tip of the optical fiber;a capillary tube that also fits into the liquid container for conducting the liquid, wherein the tube enables the outflow of the liquid from the liquid container; anda sheath for protecting the fiber photoelectric sensor against chemical erosion, wherein the fiber photoelectric sensor is enclosed by the sheath except that the tip is exposed to the liquid when the liquid level is higher than the tip, or an air inside the liquid container when the liquid level is dropped lower than the tip.