Patent ID: 8850869

Claim:
A sensor element for measuring impurities or additives in fluids or for determining a concentration of such impurities or additives in the fluids, the sensor element comprising a first tube-shaped electrically conductive housing with a housing interior which is sealed toward an outside of the tube-shaped electrically conductive housing and through which a fluid to be measured can flow, the sensor element has a housing inlet and a housing outlet for the fluid to be measured, and further comprising a second tube shaped electrode arrangement in the housing interior and forming at least one measuring path between the second tube shaped electrode and a counter-electrode formed by a housing wall of the first tube-shaped electrically conductive housing, wherein the second tube shaped electrode is open at both ends and oriented with an axis parallel to a longitudinal axis (L) of the first tube-shaped electrically conductive housing, wherein the at least one measuring path is a ring-shaped flow channel between an outer surface of the second tube shaped electrode and an inner surface of the first tube-shaped electrically conductive housing, wherein the second tube shaped electrode is held in the housing interior with an electrode holder, which is fastened to the first tube-shaped electrically conductive housing or a housing wall of the first tube-shaped electrically conductive housing so that it is electrically insulated, wherein the first tube-shaped electrically conductive housing has an opening formed by a bushing, wherein the electrode holder leads out of the housing interior through the bushing, wherein the electrode holder extends through an insulating element which fixes the electrode holder in the opening and tightly seals the housing interior at the opening, and wherein the insulating element is made of an electrically insulating material that tightly seals the housing interior and wherein the electrode holder has a cup-shaped form with a cylindrical peripheral wall and a curved bottom wall, the curved bottom wall of the electrode holder is shaped to connect flush with an outer wall of the second tube shaped electrode.