| 摘要 |
Reverse osmosis pump using a fluid volume exchange structure interconnecting pumping and expansion chambers of feed cylinder externally of feed cylinder. This structure permits exchange of volume between pumping and expansion chambers following initiation of induction or pumping stroke. Volume exchange provides a dwell interval to shift main directional valve across closed center position thereof, thus increasing tolerance to valve actuation, and also tends to equalize pressure differences across ports of the valve prior to opening of such ports, thus reducing erosion and valve gear wear. Also tends to reduce pressure differences across feed displacer, thus reducing sealing problems. Volume exchange structure can be a resilient diaphragm with no intermixing of fluid, mechanically timed valve permitting intermixing of fluid, or cross-over relief valves which are pressure responsive to permit intermixing of fluid.
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