Patent ID: 8714461

Claim:
An apparatus, comprising: a first gas compartment comprising a first substrate and a second substrate; a second gas compartment comprising the second substrate and a third substrate; the first substrate having a face in contact with at least one hot medium and having an other face in contact with a main gas and having fixed supports; the second substrate having a face in contact with the secondary gas and having an other face in contact with a main gas; the third substrate having a face in contact with the secondary gas and having an other face in contact with at least one cold medium; a first at least one flexible seal attached to one end of the second substrate and to the opposing end of the first substrate to form at least one closed enclosure comprising the main gas so that the second substrate moves when the main gas undergoes volumetric thermal expansion; a second at least one flexible seal attached to other end of the second substrate and to the opposing end of the third substrate to form at least one closed enclosure comprising the secondary gas so that this enclosure contracts when the main gas undergoes volumetric thermal expansion; and the second gas compartment is vented such that the secondary gas pressure remains constant and allows a maximum volumetric thermal expansion of the main gas.