Patent US4243523A successfully refreshed from Google Patents.
US4243523A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Water purification process and system
Assignee: Allied Water Corp
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Filing: 1978-08-07
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Granted: 1981-01-06
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Expires: 1998-08-07
Abstract
Abstract Apparatus is described for purifying or desalinating relatively small quantities of water using one or a few membrane units with relatively modest power requirements. The apparatus uses a pump, an eductor or a combination of both in recirculating a portion of the feed water through a reverse osmosis membrane assembly. The method includes recirculating a portion of the feed water through the membrane assembly and discharging a portion of the recirculated feed water from the system.
Inventors
- 👤 John P. Pelmulder
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 23:17
CPC Classifications
B; B01; B01D; B01D61/00; B01D61/02; B01D61/08; B01D2313/00; B01D2313/24; B01D2313/243; Y; Y02; Y02A; Y02A20/00; Y02A20/124; Y02A20/131
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
292 words
A method for the desalination of sea water and the like to produce potable water, comprising, providing a membrane element with an inlet and an outlet and having a flow cross-section with a width to height ratio of greater than fifty, establishing a feed flow at a pressure in excess of the osmotic pressure to one side of the membrane element, which feed flow is at a rate less than sufficient to maintain the design minimum flow velocity in the flow cross-section of the membrane, recirculating a portion of the concentrate from the outlet to the inlet of the membrane element at a pressure in excess of the osmotic pressure and in excess of the feed flow pressure at a rate sufficient to cause the flow velocity at the surface of the membrane to exceed the design minimum flow velocity, said concentrate being recirculated at a rate which itself is less than the design minimum flow velocity in the flow cross-section of the membrane, recovering permeate product passing through said membrane while maintaining said feed flow at a rate which is sufficient to maintain salinity in said permeate product at or below a maximum acceptable level, and continuously discharging an amount of said concentrate at a rate substantially equal to the difference between the feed flow rate and the recovery permeate product flow rate, said concentrate discharge rate being less than the design minimum flow velocity in the flow cross-section of the membrane and being greater than ##EQU9## where P is the product flow rate and R is the theoretical recovery rate of product in a system not employing recirculation wherein the theoretical feed flow rate is equivalent to the sum of the actual feed flow rate and the actual recirculation rate.
Claim 2
Independent Claim
292 words
A method for the desalination of sea water and the like to produce potable water, comprising, providing a membrane element with an inlet and an outlet and having a flow cross-section with a width to height ratio of greater than fifty, establishing a feed flow at a pressure in excess of the osmotic pressure to one side of the membrane element, which feed flow is at a rate less than sufficient to maintain the design minimum flow velocity in the flow cross-section of the membrane, recirculating a portion of the concentrate from the outlet to the inlet of the membrane element at a pressure in excess of the osmotic pressure and in excess of the feed flow pressure at a rate sufficient to cause the flow velocity at the surface of the membrane to exceed the design minimum flow velocity, said concentrate being recirculated at a rate which itself is less than the design minimum flow velocity in the flow cross-section of the membrane, recovering permeate product passing through said membrane while maintaining said feed flow at a rate which is sufficient to maintain salinity in said permeate product at or below a maximum acceptable level, and continuously discharging an amount of said concentrate at a rate substantially equal to the difference between the feed flow rate and the recovery permeate product flow rate, said concentrate discharge rate being less than the design minimum flow velocity in the flow cross-section of the membrane and being greater than ##EQU9## where P is the product flow rate and R is the theoretical recovery rate of product in a system not employing recirculation wherein the theoretical feed flow rate is equivalent to the sum of the actual feed flow rate and the actual recirculation rate.
Claim 3
Dependent Claim
54 words
The method of claim 1 wherein the feed flow rate is between 100 gallons per day and 25 gallons per minute, wherein the recirculation rate is between 0.5 gallons per minute and 5 gallons per minute, and wherein the concentrate discharge flow rate is between 90 gallons per day and 22 gallons per minute.
Claim 4
Dependent Claim
24 words
The method of claim 1 wherein the recovery flow rate of product with respect to feed flow rate is between about 10% and 20%.
Claim 5
Dependent Claim
301 words
Apparatus for desalinating sea water and the like to produce potable water, comprising, a membrane element having an inlet and outlet and having a flow cross-section with a width to height ratio of greater than fifty, means for establishing a feed flow at a pressure in excess of the osmotic pressure to the inlet of the membrane element and at a rate less than sufficient to maintain the design minimum flow velocity at the surface of said membrane element, means for recirculating a portion of the concentrate from said outlet of said membrane element to said inlet of said membrane element at a pressure in excess of the osmotic pressure and in excess of the feed flow pressure and at a rate sufficient to provide a flow velocity at the surface of said membrane which is in excess of the design minimum flow velocity, said concentrate being recirculated at a rate which itself is less than the design minimum flow velocity in the flow cross-section of the membrane, means for recovering said permeate product passing through said membrane, means for maintaining said feed flow at a rate which is sufficient to maintain salinity in said permeate product at or below a maximum acceptable level, and means for continuously discharging an amount of said concentrate at a rate substantially equal to the difference between the feed flow rate and the permeate product flow rate, said concentrate discharge rate being less than the design minimum flow velocity in the flow cross-section of the membrane and being greater than ##EQU10## where P is the product flow rate and R is the theoretical recovery rate of product in a system not employing recirculation wherein the theoretical feed flow rate is equivalent to the sum of the actual feed flow rate and the actual recirculation rate.
Claim 6
Dependent Claim
301 words
Apparatus for desalinating sea water and the like to produce potable water, comprising, a membrane element having an inlet and outlet and having a flow cross-section with a width to height ratio of greater than fifty, means for establishing a feed flow at a pressure in excess of the osmotic pressure to the inlet of the membrane element and at a rate less than sufficient to maintain the design minimum flow velocity at the surface of said membrane element, means for recirculating a portion of the concentrate from said outlet of said membrane element to said inlet of said membrane element at a pressure in excess of the osmotic pressure and in excess of the feed flow pressure and at a rate sufficient to provide a flow velocity at the surface of said membrane which is in excess of the design minimum flow velocity, said concentrate being recirculated at a rate which itself is less than the design minimum flow velocity in the flow cross-section of the membrane, means for recovering said permeate product passing through said membrane, means for maintaining said feed flow at a rate which is sufficient to maintain salinity in said permeate product at or below a maximum acceptable level, and means for continuously discharging an amount of said concentrate at a rate substantially equal to the difference between the feed flow rate and the permeate product flow rate, said concentrate discharge rate being less than the design minimum flow velocity in the flow cross-section of the membrane and being greater than ##EQU10## where P is the product flow rate and R is the theoretical recovery rate of product in a system not employing recirculation wherein the theoretical feed flow rate is equivalent to the sum of the actual feed flow rate and the actual recirculation rate.
Claim 7
Dependent Claim
25 words
The apparatus of claim 4 wherein said feed flow establishing means are a pump, and wherein said means recirculating said concentrate water include a pump.
Claim 8
Dependent Claim
25 words
The apparatus of claim 4 wherein said feed flow establishing means are a pump, and wherein said means recirculating said concentrate water include an eductor.
Claim 9
Dependent Claim
14 words
The apparatus of claim 6 wherein said eductor is located within said membrane assembly.
Claim 10
Dependent Claim
15 words
The apparatus of claim 6 wherein said recirculating means are located within said membrane assembly.
Claim 11
Dependent Claim
15 words
The apparatus of claim 4 wherein said membrane assembly contains only a single membrane element.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-01-06 | 1984-07-07 | 1985-01-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-01-06 | 1988-07-07 | 1989-01-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-01-06 | 1992-07-07 | 1993-01-06 | $7700.00 | Window Closed / Lapsed |