| 摘要 |
<p>Reverse osmosis pumping apparatus (12) for pumping under pressure feed fluid (16) to selective membrane means (15) which permeate and reject respectively permeate and concentrate fluid fractions (18, 19). Apparatus has a feed cylinder (25) divided into pumping and expansion chambers (30, 31) by a feed displacer (24) mounted on displacer rod (26) for relative reciprocation. Main valve controls concentrate fluid flow relative to expansion chamber (31) and is mounted for movement relative to and along displacer rod axis and is responsive to force applying reciprocation action to pump such that reversal of force reverses main valve. Recirculating pump (53) can be driven from displacer rod to pump concentrate fluid over membranes to maintain permeate fraction discharge during induction stroke of feed cylinder. Recirculating pump has valve also actuated by reversal of pumping action to direct concentrate flow to membranes, or to the expansion chamber for depressurization to assist in pressuring feed fluid. Because main valve mechanism is actuated by change in reciprocation action, it is not necessary to complete a full displacer stroke before stroke direction reversal. Thus apparatus is particularly suited for power sources which have a non-constant amplitude and frequency, such as manual, wave or wind power sources.</p> |
