Multi-cylinder reverse osmosis apparatus and method
First Claim
1. A reciprocating feed pump for an apparatus for separating a feed fluid into a permeate fluid and concentrate fluid fractions which respectively are permeated and rejected by selective membrane means, the pump having at least three feed cylinders in a cooperating set, each cylinder having a displacer reciprocable within the respective cylinder by a displacer rod, the displacer dividing each cylinder into expansion and pumping chambers having relative displacements which determine approximately recovery ratio of permeate fluid fraction to total feed fluid flow;
- each pumping chamber communicating with valved inlet conduit means to admit feed fluid, and with valved outfeed conduit means to conduct feed fluid to the membranes, each cylinder also having a corresponding expansion chamber valve means which controls flow relative to the corresponding expansion chamber and has a first open position in which a concentrate return conduit means conducts concentrate fluid from the membranes to the expansion chamber, and a second open position to exhaust depressurized concentrate fluid from the expansion chamber, the pump being further characterized by;
(a) each expansion chamber valve means has a closed intermediate position between the two open positions thereof and includes a valve portion associated directly with the respective displacer rod of each cylinder, each valve portion being a portion of an expansion chamber valve means controlling flow relative to a cylinder other than that directly associated with the respective displacer rod,(b) each cylinder having associated dwell means to permit initial travel of the displacer rod of a particular cylinder following a beginning of the respective displacer rod stroke, while the corresponding expansion chamber valve means controlling that particular cylinder is in the closed intermediate position thereof,(c) drive means cooperating with the displacer rods of the cylinders so that the cylinders are phased apart in such a way that when a particular displacer rod of a particular cylinder reaches an end of each stroke thereof, another displacer rod that is associated directly with, and thus actuates, the expansion chamber valve means controlling that particular cylinder is approaching a mid stroke position of said other displacer rod, so that the expansion chamber valve means directly associated with said other displacer rod is entering the closed intermediate position thereof.
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Accused Products
Abstract
Multi-cylinder reverse osmosis pump having at least three cylinders, each feed cylinder having a displacer rod carrying a displacer to divide the cylinder into respective pumping and expansion chambers. Each displacer rod has an expansion chamber valve portion directly associated therewith to control flow of concentrate fluid relative to an expansion chamber of a cylinder other than that directly associated with the respective cylinder rod. Dwell is provided for each cylinder to permit initial travel of the displacer rod at the beginning of each rod stroke while the corresponding valve controlling that cylinder is closed. The displacer rods are phased apart so that when a particular rod of a particular cylinder reaches an end of each stroke, another rod associated directly with the valve controlling that particular cylinder is approaching the mid-stroke position thereof so that the valve directly associated with the other rod is closing.
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Citations
25 Claims
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1. A reciprocating feed pump for an apparatus for separating a feed fluid into a permeate fluid and concentrate fluid fractions which respectively are permeated and rejected by selective membrane means, the pump having at least three feed cylinders in a cooperating set, each cylinder having a displacer reciprocable within the respective cylinder by a displacer rod, the displacer dividing each cylinder into expansion and pumping chambers having relative displacements which determine approximately recovery ratio of permeate fluid fraction to total feed fluid flow;
- each pumping chamber communicating with valved inlet conduit means to admit feed fluid, and with valved outfeed conduit means to conduct feed fluid to the membranes, each cylinder also having a corresponding expansion chamber valve means which controls flow relative to the corresponding expansion chamber and has a first open position in which a concentrate return conduit means conducts concentrate fluid from the membranes to the expansion chamber, and a second open position to exhaust depressurized concentrate fluid from the expansion chamber, the pump being further characterized by;
(a) each expansion chamber valve means has a closed intermediate position between the two open positions thereof and includes a valve portion associated directly with the respective displacer rod of each cylinder, each valve portion being a portion of an expansion chamber valve means controlling flow relative to a cylinder other than that directly associated with the respective displacer rod, (b) each cylinder having associated dwell means to permit initial travel of the displacer rod of a particular cylinder following a beginning of the respective displacer rod stroke, while the corresponding expansion chamber valve means controlling that particular cylinder is in the closed intermediate position thereof, (c) drive means cooperating with the displacer rods of the cylinders so that the cylinders are phased apart in such a way that when a particular displacer rod of a particular cylinder reaches an end of each stroke thereof, another displacer rod that is associated directly with, and thus actuates, the expansion chamber valve means controlling that particular cylinder is approaching a mid stroke position of said other displacer rod, so that the expansion chamber valve means directly associated with said other displacer rod is entering the closed intermediate position thereof. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
- each pumping chamber communicating with valved inlet conduit means to admit feed fluid, and with valved outfeed conduit means to conduct feed fluid to the membranes, each cylinder also having a corresponding expansion chamber valve means which controls flow relative to the corresponding expansion chamber and has a first open position in which a concentrate return conduit means conducts concentrate fluid from the membranes to the expansion chamber, and a second open position to exhaust depressurized concentrate fluid from the expansion chamber, the pump being further characterized by;
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19. A method of membrane separation of a feed fluid into permeate fluid and concentrate fluid fractions which respectively are permeated and rejected by selective membrane means, the membrane means being exposed to pressurized feed fluid supplied by a reciprocating feed pump having at least three feed cylinders in a cooperating set, each cylinder having a displacer means which is reciprocable within the respective feed cylinder, the displacer means dividing the respective cylinder into a pumping chamber in which, during a pumping stroke, feed fluid is pressurized and an expansion chamber in which concentrate fluid is depressurized, each cylinder having a displacer rod for reciprocating the respective displacer means, each cylinder cooperating with valve means in conduit means which communicate with the membrane means, the valve means including an expansion chamber valve means which controls flow relative to the corresponding expansion chamber;
- the method, which occurs in each cylinder, including the steps of;
inducting feed fluid into a particular pumping chamber and simultaneously exhausting concentrate fluid from a corresponding expansion chamber during an induction stroke, followed by pressurizing the feed fluid in the pumping chamber and simultaneously admitting pressurized concentrate fluid into the corresponding expansion chamber to supplement energy supplied to the displacer means during the pumping stroke, the method being further characterized by;(a) actuating directly with each displacer rod a valve portion of an associated expansion chamber valve means of each cylinder so as to control flow relative to an expansion chamber of a cylinder other than that directly associated with the displacer rod, (b) actuating the displacer rods of the cylinders so that actuation of the expansion chamber valve means is phased in such a way that when a particular displacer rod of a particular cylinder reaches an end of each stroke thereof, another displacer rod associated directly with the expansion chamber valve means controlling that particular cylinder is approaching a mid stroke position of said other displacer rod, so that the expansion chamber valve means directly associated with said other displacer rod is entering a closed intermediate position thereof during which no fluid passes therethrough, (c) permitting initial travel of the displacer rod of each cylinder following beginning of each respective displacer rod stroke while the corresponding expansion chamber valve means controlling that particular cylinder is in the closed intermediate position thereof. - View Dependent Claims (20, 21, 22, 23, 24, 25)
- the method, which occurs in each cylinder, including the steps of;
Specification