Assembly comprising a seal inserted between two components of different mean thermal expansion coefficient, associated seal, application to sealing of hte electrolyzers and sofc fuel cells

Assembly between two components of different mean thermal expansion coefficients α2, α3 comprising an element forming a seal inserted between the two components, whose mean thermal expansion coefficient αj differs from that α3 of one of the components having the least difference with the coefficient of the seal, the difference αj-α3 having a value of between 0 and 1.10−6 K−1, the seal having a continuous shape comprising three planar surfaces separated from one another and an end portion located outside the portions formed between the surfaces, sealing being provided:

• below the predetermined threshold temperature, by compression of the seal in a direction orthogonal (X) to the components obtained by constant clamping of the components towards each other, which places one of the three planar surfaces bearing upon the component with the coefficient α3 having the least difference with that αj of the seal, the two other planar surfaces upon the component with the coefficient having the greatest difference with that αj of the seal, whilst leaving the end portion free of any contact,
• above the threshold temperature, by orthogonal compression of the seal again obtained by the same constant clamping which maintains the planar surface in fixed bearing upon the component with the coefficient α3 having least difference with that αj of the seal, and by compression of the seal in a direction radial (R) to the components obtained by sliding of the two other planar surfaces on component with the coefficient α2 having the greatest difference with that αj of the seal, until the end portion is placed under radial compression by the same component.