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US 6,206,294 B1Granted
Expansion valve
AssigneeFujikoki Corporation
InventorsMitsuya Fujimoto, Kazuhiko Watanabe, Masamichi Yano
Life of this patent
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Abstract
An expansion valve includes a valve body, a valve, a power element, and an aluminum heat sensing shaft. The heat sensing shaft has a hole that makes the heat transfer area of the heat sensing shaft small. Consequently, in a refrigeration system the response of the expansion valve is relatively insensitive to changes in a heat load of an evaporator. Thus, unwanted hunting phenomenon in the refrigeration system is prevented.
Claims6
An expansion valve comprising:
- a valve body having a first path for guiding a liquid-phase refrigerant and a second path for guiding a gas-phase refrigerant between an evaporator and a compressor, wherein the first path includes an orifice;
- a valve that controls the amount of refrigerant passing through said orifice;
- a power element portion formed on said valve body and having a diaphragm that is displaced due to a difference in pressure on the diaphragm,
- wherein said pressure difference is exerted on said diaphragm by upper and lower pressure activating chambers, said lower chamber being connected to said second path;
- and
- a heat sensing shaft for driving said valve, an end of said heat sensing shaft contacting said diaphragm and another end of said heat sensing shaft driving said valve based on displacement of said diaphragm, wherein said heat sensing shaft includes a concave portion formed on a surface of the end of the heat sensing shaft contacting said diaphragm;
- wherein said concave portion is separated from said upper and lower chambers.
4 more elements
Dependencies are inferred from the claim text.