Abstract: Disclosed herein is a retainer arrangement for applying a membrane to a physiological sensing unit for the transcutaneous determination of the magnitude of physiological quantitites, particularly for measuring the partial pressure of gases in blood or the like. The arrangement constitutes a preassembly of a membrane, with a clamping ring accommodating the membrane and having an annular recess receiving the rim of the membrane. The clamping ring has a lip in the form of an inwardly protruding annular edge for removably securing the clamping ring together with the membrane to the sensing unit by virtue of the lip resiliently snapping into a peripheral groove of the sensing unit, the lip defining the periphery of the annular recess. In accordance with the invention, an auxiliary retainer element, is provided for temporarily and removably assembling the membrane with the clamping ring prior to assembly with the sensing unit.

Abstract: Disclosed herein are a method and a retainer arrangement for applying a membrane to a physiological sensing unit for the transcutaneous determination of the magnitude of physiological quantities, particularly for measuring the partial pressure of gases in blood or the like. The invention proposes the preparation of a preassembly thus constituting a spare part which will be ready for application to the sensing unit when needed. The preassembly comprises a membrane, a clamping ring for removably assembling the membrane with the sensing unit, and means, including an auxiliary retainer element, for temporarily and removably securing the membrane to the clamping ring prior to assembly with the sensing unit.