Thermochemical actuation method and apparatus

Abstract

A pressure vessel (A) is defined by end walls (16) and side walls (18). In the interior, a plurality of fins (12) define an assembly of thin passages (10) that are filled with a material (26) that expands as it changes from a solid to a fluid state. The passages are thin, on the order of 0.01 inches such that heat is transferred relatively quickly into and out of the material. The passages communicate with a manifold area (14) to a piston bore (40) or other structure (B) for converting fluid pressure into mechanical movement. The piston bore holds a low durometer seal (44), a higher durometer seal (46), and a movable piston (42). To generate rotary motion, the piston and vessel assembly are mounted for rotation about an eccentrically placed member (68). As the pressure vessel goes through heating and cooling reservoirs, the pistons expand and contract causing rotation (FIGS. 4-6). In another application, at least two of the assemblies are interconnected by a heat pump (74) such that heat can be moved back and forth between the two. Additional heat pumps are provided for moving heat from the ambient air or other sources of heat to the pressure vessels (FIG. 7). The actuator is also used to control a two position valve (FIG. 9) and a three position valve (FIG. 10). A pair of actuator vessels (160, 162) are connected by a common heat transfer device (164) for causing differential movement between pistons (166, 168), (FIG. 12).