Procedure for the fabrication of a liner serving, as a part of an inline measuring device, to line the interior of a, particularly metallic, support tube, said liner being made from a plastic made from at least four initial components (A, B, C, F), particularly a polyurethane, wherein of the said four initial components (A, B, C, F) at least a first primary component and a second primary component can react with one another, where a prepolymer acts as the primary component and an alcohol, particularly bivalent, serves as the second primary component, wherein a chemical reaction between the first primary component and the second primary component is accelerated by adding at least a secondary component acting as a catalyst, and wherein at least a tertiary component serves as a filler, particularly a coloring filler, wherein said procedure comprises the following steps: - Formation of a first multicomponent system (CF, BCF), particularly also a storable system, serving as an intermediate component, which contains both the secondary component and the tertiary component, at least in part - Formation of a fluid, particularly liquid, second multicomponent system (ABCF), containing the four initial components (A, B, C, F), using the first multicomponent system (CF, BCF), namely in that the first multicomponent system (CF, BCF) is fused with the two primary components (A, B), wherein the second multicomponent system (ABCF) contains the four initial components (A, B, C, F) in a concentration that permits the chemical reaction at least of parts of the two primary components (A, B), - Application of the second multicomponent system (ABCF) on an interior wall of the support tube, - And the production of the liner lining the inside of the support tube from plastic, using the second multicomponent system (ABCF) applied on the interior wall of the support tube, by allowing the primary component contained in the multicomponent system and the second primary component contained in the multicomponent system to react with one another, at least in part, within the support tube. - Formation of a first multicomponent system (CF, BCF), particularly also a storable system, serving as an intermediate component, which contains both the secondary component and the tertiary component, at least in part - Formation of a fluid, particularly liquid, second multicomponent system (ABCF), containing the four initial components (A, B, C, F), using the first multicomponent system (CF, BCF), namely in that the first multicomponent system (CF, BCF) is fused with the two primary components (A, B), wherein the second multicomponent system (ABCF) contains the four initial components (A, B, C, F) in a concentration that permits the chemical reaction at least of parts of the two primary components (A, B), - Application of the second multicomponent system (ABCF) on an interior wall of the support tube, - And the production of the liner lining the inside of the support tube from plastic, using the second multicomponent system (ABCF) applied on the interior wall of the support tube, by allowing the primary component contained in the multicomponent system and the second primary component contained in the multicomponent system to react with one another, at least in part, within the support tube.