| 摘要 |
A heat pump system is provided which uses a combination variable orifice valve means and check valve means in place of a separate thermal expansion valve and a separate check valve in parallel fluid flow relationship therewith to control flow between the indoor coil and the outdoor coil. The combination variable orifice metering means and check valve means, which provides controlled fluid flow in one mode of operation and substantially free fluid flow in the other mode of operation, comprises a valve housing having a passage therethrough, a tubular valve body movable in the passage, between a position where fluid can pass freely between the valve body and the valve housing and a position where the fluid passes through the valve body, an orifice in the valve body, and a spring-biased valve plug movable relative to the orifice and cooperating with the orifice to vary the effective area of the orifice to control the flow of fluid through the orifice in the one mode of operation, the fluid passing freely between the valve body and the valve housing in the other mode of operation. The combination variable orifice valve means and check valve means is compact, less expensive, easier to connect and use in a heat pump system, and more reliable than the fixed orifice size devices, such as a capillary tube, and check valve heretofore used in some heat pump systems. It is also more compact and less costly than the separate thermal expansion valve and check valve previously used in some heat pump systems.
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