| 摘要 |
A thermal expansion valve unit comprises a closed vapor system, which includes a temperature sensing chamber in thermal communication with a source such as a two phase refrigerant, and a pressure chamber with a deformable member, the position of which controls the size of an expansion orifice. A line confining a selected vapor, which optionally may be a refrigerant, communicates between the interiors of the temperature sensing chamber and the pressure chamber. A heater, separately controllable, is thermally coupled to the temperature sensing chamber such that the selected refrigerant may be independently heated to change the pressure in the chamber. A thickness of insulating material is disposed between the temperature sensing chamber and the source to limit thermal energy loss to refrigerated elements in the system. The pressure in the temperature sensing chamber changes the force on the deformable diaphragm to adjust the movement of the valve needle to regulate the expansion of refrigerant through the orifice, thus affecting the refrigerated load.
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