Sensor device for water softener system

Claim 1

In a water treatment system for softening water a sensor device in a water treatment tank containing an ion exchange material, and a sensor element responsive to calcium/sodium conditions operatively associated with the sensor device, said sensor element being in direct contact with said ion exchange material and expansible and contractible according to said calcium/sodium condition, said sensor element being in the form of a tube, the exterior diameter of such tube being in direct contact with the water and the ion exchange material in the tank, and the water in the tank flows through the interior of the tube in direct contact therewith, said tube mounted in end pieces at respectively opposite ends of the tube, each said end piece having an opening to the interior of the tube, said end pieces each have a metallic interior surface, an electrical circuit operatively connected with said surfaces, and a circuit completing member in said tube normally out of contact with said surfaces brought into direct contact therewith by contraction of said tube in response to a calcium state in said treatment tank, and said circuit completing member comprising a metal spring having end contact with said surfaces to complete the electrical circuit and compressible after circuit completing contact is made upon further contraction of said tube.