Fluid treatment system

• US 4,650,586 A
• Filed: 02/19/1985
• Issued: 03/17/1987
• Est. Priority Date: 09/26/1983
• Status: Expired due to Term

• Current Assignee: Kinetico, Inc. (BJA Croonen BV)
• Original Assignee: Kinetico, Inc. (BJA Croonen BV)
• Inventors: Ellis, George S. III
• Primary Examiner(s): SPEAR JR, FRANK
• Application Number:
  US06/703,126
• Time in Patent Office: 756 Days
• Field of Search: 210/257.2, 210/321.1, 210/321.2, 210/636, 210/409
• US Class Current: 210/636
• CPC Class Codes: B01D 2321/12 Use of permeate
• CPC Class Codes: B01D 61/08 Apparatus therefor
• CPC Class Codes: B01D 61/12 Controlling or regulating
• CPC Class Codes: B01D 65/02 Membrane cleaning or sterilisation ; Membrane regeneration

Abstract

Apparatus and method for purifying a solvent such as water, using a reverse osmosis process. The apparatus includes a reverse osmosis (R.O.) unit, a storage tank for storing permeate produced by the reverse osmosis unit, and a flushing arrangement for cleansing the concentrate side of a reverse osmosis membrane at the conclusion of a purifying cycle. A flow regulating arrangement 34, 40, 42 maintains one of two pressures at the concentrate output. A system controller controls the communication of feed water to the R.O. unit and the concentrate pressure. A flushing accumulator receives permeate during a purifying cycle. When the cycle is terminated, the permeate stored in the accumulator is transferred to the input side of the R.O. unit and flushes the membrane. The permeate is driven from the accumulator by a feed water generated force exerted on the permeate by an isolated pressurization chamber forming part of the accumulator. According to a feature of this embodiment, the R.O. unit, the flushing accumulator and the system controller are integrated in a unitary package which is relatively maintenance free.

Claims

1. A system for purifying water utilizing a reverse osmosis process, comprising:

(a) a reverse osmosis unit having an input for feed water to be treated and outputs from which concentrate and permeate are separately discharged;

(b) pressure controlling means for maintaining predetermined fluid pressures at the concentrate output of the reverse osmosis unit;

(c) pressurized storage means for storing permeate produced by said reverse osmosis unit;

(d) system control means responsive to the quantity of permeate in said storage means and operative to terminate a purifying cycle by terminating the communication of feed water to the reverse osmosis unit when a predetermined quantity of permeate is stored in said storage means;

(e) a flushing means for flushing said reverse osmosis unit with permeate when said purifying cycle is terminated, said flushing means including a flush accumulator for storing a predetermined quantity of permeate; and

,

(f) a flush control means including a means for pressurizing said accumulator with a fluid pressure when said purifying cycle is terminated whereby said stored permeate is expelled from said accumulator.

2. The apparatus of claim 1 wherein said flush control means includes a shiftable spool valve having first and second end faces each defining an effective pressure area, said first end face being smaller in area than the second end face and communicating with feed water pressure, said second end face communicating with pressure in the reverse osmosis unit such that during a purifying cycle, said reverse osmosis pressure generates a force on said spool valve sufficient to overcome the force generated by the feed water pressure.

3. In a system for purifying water utilizing a reverse osmosis process, a membrane flushing apparatus, comprising:

(a) a flushing accumulator including a storage chamber for storing a predetermined quantity of permeate;

(b) conduit means for communicating said storage chamber with an input to said reverse osmosis unit;

(c) pressure control means for pressurizing the permeate in said flush accumulator to effect discharge of said permeate from said accumulator, said pressure control means including a valve member responsive to the pressure in said reverse osmosis unit and operative upon sensing a reduction in pressure in said reverse osmosis unit below a predetermined level to pressurize said permeate to a pressure sufficient to drive said permeate from said accumulator when said reverse osmosis unit is not operating in a purifying cycle.

4. An apparatus for purifying solvent such as water by reverse osmosis, comprising:

(a) a housing defining an inlet for feed water to be treated, an outlet for permeate and an outlet for discharging waste;

(b) a reverse osmosis membrane located in a compartment disposed within said housing including an input for receiving feed water to be treated, an output for permeate and an output for discharging concentrate;

(c) an expansible chamber formed by an elastomeric member surrounding said membrane compartment including means for receiving permeate from said reverse osmosis compartment;

(d) means for exerting a force on said elastomeric member tending to contract said expansible chamber, said means including a control valve mounted in said housing, responsive to pressure in said reverse osmosis compartment and operative, upon sensing a decrease in pressure below a predetermined level in said compartment, to communicate feed water under pressure from said inlet to a region on said elastomeric member, isolated from said expansible chamber, to produce a driving force to urge permeate from said expansible chamber.

5. Apparatus for purifying a solvent such as water by reverse osmosis, comprising:

(a) a substantially cylindrical housing having an end cover defining an inlet for water to be treated, and outlet for permeate, and an outlet for waste;

(b) a reverse osmosis module disposed axially within said housing, said module comprising;

(i) an input tube disposed axially with respect to said housing;

(ii) a perforate collector tube surrounding said input tube and defining a permeate collection region between the inside of said collector tube and the outside of said input tube;

(iii) a reverse osmosis membrane disposed around the collector tube and extending into abutting engagement with an inside wall of said module;

(c) an intermediate housing member disposed intermediate said end cover and said reverse osmosis module, said intermediate housing member defining a plurality of fluid passages;

(d) a system controller disposed in said housing for controlling the communication of feed water at said inlet with said input tube;

(e) a flushing accumulator defined by a tubular elastomeric member clamped around said reverse osmosis module, a region on one side of said member defining a permeate receiving chamber and another region defined on another side of said member forming a pressurization chamber;

(f) a pressure control valve for controlling the pressurization of said other region defined by said elastomeric member, said control valve responsive to a decrease in pressure in said reverse osmosis compartment, and operative to communicate feed water pressure to said pressurization chamber to generate a force on said elastomeric member causing it to contract said permeate receiving chamber to cause said permeate to be discharged from said permeate receiving chamber into the input tube of said reverse osmosis compartment.

6. The apparatus of claim 5, wherein said pressure control valve includes a spool valve slidably mounted in a cavity formed in said intermediate housing, said spool shiftable betwen two positions.

7. The apparatus of claim 6, wherein one end of said cavity communicates with fluid pressure in said reverse osmosis membrane compartment and another end of said cavity communicates with said inlet.

8. The apparatus of claim 7, wherein said spool valve defines opposed effective pressure areas on opposite end faces communicating with respective ends of said cavity such that during a purifying cycle, the force generated on the end face communicating with said inlet is less than a force generated on the other end face by the pressure in said reverse osmosis module whereby said spool valve is maintained in a position at which feed water pressure at said inlet is blocked from said pressurization chamber defined by said elastomeric member.

9. A method for purifying water by reverse osmosis, comprising the steps of:

(a) providing a reverse osmosis unit having an input for feed water to be treated and outputs for discharging concentrate and permeate;

(b) communicating said permeate output with a pressurized storage means, during a purifying cycle;

(b) storing a predetermined quantity of permeate in a flushing chamber, the quantity of permeate storable in said flushing chamber being less than the quantity storable in said pressurized storage means;

(d) monitoring the pressure in said reverse osmosis unit;

(e) pressurizing said flushing chamber to drive out said permeate from said chamber upon sensing a drop in operating pressure in said unit;

(f) providing a fluid path from said flushing chamber to an input to said reverse osmosis unit when said permeate is being discharged.

10. The method of claim 9 wherein said step of pressurizing said flushing chamber is achieved by communicating feed water pressure to a pressurization chamber.

11. Apparatus for purifying a solvent such as water utilizing reverse osmosis, comprising:

(a) a reverse osmosis module including an input for receiving feed water to be treated, an output for permeate and an output for concentrate;

(b) system control means for controlling the communication of feed water to said module input;

(c) a flush accumulator incluidng a chamber for storing a predetermined quantity of permeate, and a presurization chamber adapted to receive fluid pressure under predetermined conditions, said pressurization chamber isolated from said permeate receiving chamber;

(d) a flushing control valve operative to communicate fluid pressure to said pressurization chamber upon sensing a predetermined reduction in pressure in said reverse osmosis module whereby said predetermined quantity of permeate stored in said flush accumulator is expelled and conveyed to said module input.

12. The apparatus of claim 11, wherein said control valve includes a spool member defining opposed effective pressure areas, one of said areas being in fluid communication with inlet pressure and the other of said areas being in fluid communication with fluid pressure in said reverse osmosis module.

13. The apparatus of claim 12, wherein said effective pressure areas defined by said spool valve are of a predetermined relative size such that during a purifying cycle, the force generated on the other of said effective pressure areas by the fluid pressure in said reverse osmosis module is greater than a force generated on the one effective pressure area by feed water pressure such that the spool member is maintained in a first position, during a purifying cycle, at which said pressurization chamber defined by said flushing accumulator is communicated with substantially ambient pressure.

14. The apparatus of claim 13, wherein said effective pressure areas are sized such that when the fluid pressure in the reverse osmosis module falls below a predetermined threshold, the feed water pressure becomes effective to overcome the force exerted by said module pressure such that said spool member is driven to a second position at which feed water pressure is communicated to said pressurization chamber whereby permeate stored in said storage chamber is discharged into the reverse osmosis input.

15. The apparatus of claim 14, wherein said reverse osmosis module, flush accumulator and flushing control valve are all located in a canister-like assembly.