Patent ID: 8167217

Claim:
A thermally activated fluid flow controller for controlling the temperature of a mixing of fluids flowing through the flow controller, the flow controller comprising a thermostatic element including, an outer imperforate metal cup having an internal volume which contains a material that expands and contracts according to variations of its temperature, the internal volume including a volumetric zone and at least two separate cavities, each having an opening in open communication with the volumetric zone so that the material passes between the volumetric zone and the at least two separate cavities through the openings when the material expands and contracts, dividing means for dividing the internal volume into the at least two separate cavities, a piston reciprocally movable relative to the outer imperforate metal cup in an axial direction of the outer imperforate metal cup and wherein the piston is coupled to the expandable and contractile material on an opposite side of the volumetric zone from the at least two separate cavities in order to move in opposite directions depending on whether the material expands or contracts, the dividing means having at least one through opening of a size for the material to pass directly between the at least two cavities, such that during retraction of the piston when the material contracts, the material passes through the at least one through opening from one of the at least two cavities to the other of the at least two cavities under the effect of the pressure generated by a force of the piston on the material contained in the volumetric zone.