摘要 |
<p>A thermoscopic unit such as for use in a thermostat of a fluid mixing valve comprising a hollow body in which a cylindrical convoluted bellows unit is located and sealed to the body to define an expansion chamber in which a thermally responsive material, such as wax, is contained. Temperature changes resulting in a change of volume of the material in the expansion chamber apply an external pressure to change the axial length of the bellows unit, and this may be operably connected to an actuator for a valve assembly. Preferably, there is a reservoir of the material constituted by a tubular coil encircling the hollow body, or a hollow cone extending therefrom. Such reservoir is filled with the material and is in communication with the expansion chamber and provides additional heat transfer surfaces to give fast response to temperature changes.</p> |