CA1050899A - Reverse osmosis kit for producing potable water from seawater - Google Patents
Reverse osmosis kit for producing potable water from seawaterInfo
- Publication number
- CA1050899A CA1050899A CA233,376A CA233376A CA1050899A CA 1050899 A CA1050899 A CA 1050899A CA 233376 A CA233376 A CA 233376A CA 1050899 A CA1050899 A CA 1050899A
- Authority
- CA
- Canada
- Prior art keywords
- potable water
- water
- depths
- pressure relief
- sea
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 239000003651 drinking water Substances 0.000 title claims abstract description 44
- 235000012206 bottled water Nutrition 0.000 title claims abstract description 43
- 239000013535 sea water Substances 0.000 title claims abstract description 17
- 238000001223 reverse osmosis Methods 0.000 title abstract description 18
- 239000012528 membrane Substances 0.000 claims abstract description 23
- 238000011084 recovery Methods 0.000 claims abstract description 10
- 239000012466 permeate Substances 0.000 claims abstract description 7
- 238000003860 storage Methods 0.000 claims description 15
- 238000004519 manufacturing process Methods 0.000 claims description 5
- 229920002284 Cellulose triacetate Polymers 0.000 claims description 2
- 229920002678 cellulose Polymers 0.000 claims description 2
- 239000001913 cellulose Substances 0.000 claims description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 abstract description 24
- 230000004083 survival effect Effects 0.000 abstract description 13
- 238000000034 method Methods 0.000 abstract description 8
- 238000007654 immersion Methods 0.000 description 2
- 238000012423 maintenance Methods 0.000 description 2
- 229910001220 stainless steel Inorganic materials 0.000 description 2
- 239000010935 stainless steel Substances 0.000 description 2
- 238000005303 weighing Methods 0.000 description 2
- 229910000906 Bronze Inorganic materials 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- NNLVGZFZQQXQNW-ADJNRHBOSA-N [(2r,3r,4s,5r,6s)-4,5-diacetyloxy-3-[(2s,3r,4s,5r,6r)-3,4,5-triacetyloxy-6-(acetyloxymethyl)oxan-2-yl]oxy-6-[(2r,3r,4s,5r,6s)-4,5,6-triacetyloxy-2-(acetyloxymethyl)oxan-3-yl]oxyoxan-2-yl]methyl acetate Chemical compound O([C@@H]1O[C@@H]([C@H]([C@H](OC(C)=O)[C@H]1OC(C)=O)O[C@H]1[C@@H]([C@@H](OC(C)=O)[C@H](OC(C)=O)[C@@H](COC(C)=O)O1)OC(C)=O)COC(=O)C)[C@@H]1[C@@H](COC(C)=O)O[C@@H](OC(C)=O)[C@H](OC(C)=O)[C@H]1OC(C)=O NNLVGZFZQQXQNW-ADJNRHBOSA-N 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 239000010974 bronze Substances 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- KUNSUQLRTQLHQQ-UHFFFAOYSA-N copper tin Chemical compound [Cu].[Sn] KUNSUQLRTQLHQQ-UHFFFAOYSA-N 0.000 description 1
- 230000018044 dehydration Effects 0.000 description 1
- 238000006297 dehydration reaction Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- CEJLBZWIKQJOAT-UHFFFAOYSA-N dichloroisocyanuric acid Chemical group ClN1C(=O)NC(=O)N(Cl)C1=O CEJLBZWIKQJOAT-UHFFFAOYSA-N 0.000 description 1
- 235000020188 drinking water Nutrition 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- FUHQFAMVYDIUKL-UHFFFAOYSA-N fox-7 Chemical compound NC(N)=C([N+]([O-])=O)[N+]([O-])=O FUHQFAMVYDIUKL-UHFFFAOYSA-N 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
- 239000008213 purified water Substances 0.000 description 1
- 230000008439 repair process Effects 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
- C02F1/441—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by reverse osmosis
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
- B01D61/02—Reverse osmosis; Hyperfiltration ; Nanofiltration
- B01D61/025—Reverse osmosis; Hyperfiltration
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
- B01D61/02—Reverse osmosis; Hyperfiltration ; Nanofiltration
- B01D61/08—Apparatus therefor
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
- C02F2103/08—Seawater, e.g. for desalination
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A20/00—Water conservation; Efficient water supply; Efficient water use
- Y02A20/124—Water desalination
- Y02A20/131—Reverse-osmosis
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Water Supply & Treatment (AREA)
- Nanotechnology (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Life Sciences & Earth Sciences (AREA)
- Hydrology & Water Resources (AREA)
- Environmental & Geological Engineering (AREA)
- Organic Chemistry (AREA)
- Separation Using Semi-Permeable Membranes (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A method and apparatus for producing potable water from sea water which is particularly suitable for use in survival craft at sea. A reverse osmosis module is lowered from the survival craft to a depth of about 130 fathoms at which depth the external pressure on the module is sufficient to cause substantially pure or at least potable water to permeate through the semi-permeable membrane of the reverse osmosis module into a collecting vessel. A pressure relief valve is provided on the water collecting vessel to prevent excess pressure build-up during recovery and an outlet means is also provided to remove the potable water when the apparatus is received in the survival craft.
A method and apparatus for producing potable water from sea water which is particularly suitable for use in survival craft at sea. A reverse osmosis module is lowered from the survival craft to a depth of about 130 fathoms at which depth the external pressure on the module is sufficient to cause substantially pure or at least potable water to permeate through the semi-permeable membrane of the reverse osmosis module into a collecting vessel. A pressure relief valve is provided on the water collecting vessel to prevent excess pressure build-up during recovery and an outlet means is also provided to remove the potable water when the apparatus is received in the survival craft.
Description
10~
This invention relates to a method and apparatus for producing potable water from sea water. More particularly, this invention relates to a method and apparatus for emergency use in lifeboats.
In a survival situation at sea procurement of 1 sufficient drinking water to enable survival for an extended period of time is of paramount importance~ It has been ;
estimated that each person aboard a lifeboat or other survival craft requires a minimum of one ~uart of resh water per day if dehydration i5 to be a~oided. For a . :. i ,. ,
This invention relates to a method and apparatus for producing potable water from sea water. More particularly, this invention relates to a method and apparatus for emergency use in lifeboats.
In a survival situation at sea procurement of 1 sufficient drinking water to enable survival for an extended period of time is of paramount importance~ It has been ;
estimated that each person aboard a lifeboat or other survival craft requires a minimum of one ~uart of resh water per day if dehydration i5 to be a~oided. For a . :. i ,. ,
2~-man boat this means storage of something in excess of 50 pounds of water, occupying about 1 cubic foot of space for .
each day of survival. For any reasonably lengthy survival time, therefore, stored water presents problems I of weight and space utilization in a lifeboat or on an -~
inflatable raft. The initial water supply may be supplemented by catching rain water but of course this is not a predictable `' or certain source and in any case is not available in areas ;l of low or negligible rainfall. Evaporation techniques, based 20 on solar stills are generally of limited effectiveness, the equipment required is bulky, relatively slow, extremely ;~ `
difficult to disassemble in adverse weather conditions, and of course only available for use under favourable weather :, conditions.
` As an alternative to the foregoing, it has been ~' suggested that devices operating upon the principle of xeverse "Z osmosis should be employed, and several devices in which sea ~ water is pumped, under pressures of the order of 1000~1500 psi, ..i, ra j ~: ~ . ., ~os~399 through a semi-permeable membrane have been described in the literature. One such device is described in "Manual Sea Water Demineralizer Development" - Cosmodyne Corporation, June, 1973, a report distributed by the National Technical In~ormation Service of the United States Department of Commerce under AD-775,634. In such devices, manual pumps, with or without energy-recovery cycles, are provided so that survivors can pressurize a reverse osmosis vessel and produce sufficient potable water for survival needs. At the pressures r~quired for reverse osmosis of sea water the pumps are necessarily of a fairly sophisticated nature and hence relatively expensive. Further, increased complexity usually -leads to increased maintenance requirements,and in the survival situation it is unlikely that any maintenance or ~ ;
repairs at all can be carried out.
It is an object of the present invention, therefore, to provide a device for the production of potable water from sea water which avoids the use of manual pumps to provide the : ~ .
pressure necessary to carry out a reverse osmosis process of sea water.
Another object of this invention is to provide a novel method for the production of potable water by reverse ~ osmosis from sea water.
i Thus, by one aspect of this invention there is pro-vided an apparatus for the production of potable water from sea water adapted to be lowered to depths of at least ;. ~
~ ra/ - 2 - ~
, . ' :, ~L~35~899 ;~:
130 fathoms below the surface of the sea and comprising (a) potable water collecting means including: (i) a support member having a semipermeable membrane secured thereto and adapted to permit substantially potable water to permeate therethrough, at pressures corresponding to said dep~hs below the surface, into potable water collecting chamber defined by said support member and said semipermeable membrane; and (ii) outlet means to recover said substantially potable water from said potable water collecting chamber; ;;~ -,;: - ,: .
~ (b) potable water storage means including: (i) inlet means for receiving ~
~ ,. -, .":
said potable water from said co]lecting means; (ii) outlet means to recover said potable water; and (iii) pressure relief valve means adapted to relieve ~` ~
air pressure therein and thereby maintain an internal pressure substantially ~ ;
;~ equal to ambient external pressures during recovery of said apparatus from said ~.. - :
~ depths; and (c) pressure relief and check valve means defining a one-way flow ~` ~
, . ~
~!~ path for said potable water from said collecting means to said storage means, :' :
to prevent any backpressure, created during raising of the apparatus from said I depths, from reaching and damaging the semi-permeable membrane.
Ry another aspect of this invention there is provided a method for ~ -~ ,.
producing potable water from sea water comprising lowering a reverse osmosis ~ ;
module to a depth of at least 130 fathoms below the surface of the sea, there-by creating an external pressure on a semipermeable membrane in said module ~`
sufficient to cause substantially potable water to permeate therethrough into ~` a closed storage vessel, raising said module and simultaneously reducing ~1 pressure in said storage vessel to maintain an internal pressure substantially P
equal to ambient external pressure, and removing potable water from said i `
. . - i:- ~: ~
~ storage vessel.
,.,~ :. ::
In order to eliminate the manual pumps of the prior art, an alter~
native reliable source of pressure to drive the reverse osmosis process must `
~, :
be provided. Clearly the one source of pressure which is always available in survival situations is the sea itself, provided only that it is deep enough. However, in shallow seas or on the continental shelf
each day of survival. For any reasonably lengthy survival time, therefore, stored water presents problems I of weight and space utilization in a lifeboat or on an -~
inflatable raft. The initial water supply may be supplemented by catching rain water but of course this is not a predictable `' or certain source and in any case is not available in areas ;l of low or negligible rainfall. Evaporation techniques, based 20 on solar stills are generally of limited effectiveness, the equipment required is bulky, relatively slow, extremely ;~ `
difficult to disassemble in adverse weather conditions, and of course only available for use under favourable weather :, conditions.
` As an alternative to the foregoing, it has been ~' suggested that devices operating upon the principle of xeverse "Z osmosis should be employed, and several devices in which sea ~ water is pumped, under pressures of the order of 1000~1500 psi, ..i, ra j ~: ~ . ., ~os~399 through a semi-permeable membrane have been described in the literature. One such device is described in "Manual Sea Water Demineralizer Development" - Cosmodyne Corporation, June, 1973, a report distributed by the National Technical In~ormation Service of the United States Department of Commerce under AD-775,634. In such devices, manual pumps, with or without energy-recovery cycles, are provided so that survivors can pressurize a reverse osmosis vessel and produce sufficient potable water for survival needs. At the pressures r~quired for reverse osmosis of sea water the pumps are necessarily of a fairly sophisticated nature and hence relatively expensive. Further, increased complexity usually -leads to increased maintenance requirements,and in the survival situation it is unlikely that any maintenance or ~ ;
repairs at all can be carried out.
It is an object of the present invention, therefore, to provide a device for the production of potable water from sea water which avoids the use of manual pumps to provide the : ~ .
pressure necessary to carry out a reverse osmosis process of sea water.
Another object of this invention is to provide a novel method for the production of potable water by reverse ~ osmosis from sea water.
i Thus, by one aspect of this invention there is pro-vided an apparatus for the production of potable water from sea water adapted to be lowered to depths of at least ;. ~
~ ra/ - 2 - ~
, . ' :, ~L~35~899 ;~:
130 fathoms below the surface of the sea and comprising (a) potable water collecting means including: (i) a support member having a semipermeable membrane secured thereto and adapted to permit substantially potable water to permeate therethrough, at pressures corresponding to said dep~hs below the surface, into potable water collecting chamber defined by said support member and said semipermeable membrane; and (ii) outlet means to recover said substantially potable water from said potable water collecting chamber; ;;~ -,;: - ,: .
~ (b) potable water storage means including: (i) inlet means for receiving ~
~ ,. -, .":
said potable water from said co]lecting means; (ii) outlet means to recover said potable water; and (iii) pressure relief valve means adapted to relieve ~` ~
air pressure therein and thereby maintain an internal pressure substantially ~ ;
;~ equal to ambient external pressures during recovery of said apparatus from said ~.. - :
~ depths; and (c) pressure relief and check valve means defining a one-way flow ~` ~
, . ~
~!~ path for said potable water from said collecting means to said storage means, :' :
to prevent any backpressure, created during raising of the apparatus from said I depths, from reaching and damaging the semi-permeable membrane.
Ry another aspect of this invention there is provided a method for ~ -~ ,.
producing potable water from sea water comprising lowering a reverse osmosis ~ ;
module to a depth of at least 130 fathoms below the surface of the sea, there-by creating an external pressure on a semipermeable membrane in said module ~`
sufficient to cause substantially potable water to permeate therethrough into ~` a closed storage vessel, raising said module and simultaneously reducing ~1 pressure in said storage vessel to maintain an internal pressure substantially P
equal to ambient external pressure, and removing potable water from said i `
. . - i:- ~: ~
~ storage vessel.
,.,~ :. ::
In order to eliminate the manual pumps of the prior art, an alter~
native reliable source of pressure to drive the reverse osmosis process must `
~, :
be provided. Clearly the one source of pressure which is always available in survival situations is the sea itself, provided only that it is deep enough. However, in shallow seas or on the continental shelf
- 3 -~5~39~ ::
extended surviv~ pexiods before rescue are most unlikely, Thus, if a reverse osmosis unit is lowered into the ocean depths, a sufficient pressure differential between one side of a semi-permeable membrane and the other may be developed so that reverse osmosis can be made to occur. Potable water passes through the membrane and is collected within. The osmosis unit can then he retrieved and the potable water collected. Calculations show that at pressures of approx-imately 24 atmospheres or 350 psi reverse osmosis o sea ;.
water can be effected. 24 atmospheres corresponds to a depth of approximately 130 fathoms (780 ft). ~
The invention will now be described in more detai~ -with reference to the following examples and the drawings in `
which: ~
Fig. 1 is a front elevation o~ a first embodiment `
. ~, ,, . ~ .
of the invention;
Fig. 2 is a sectional view of part of the first embodiment of the apparatus of the invention;
Fig. 3 is a sectional view of a second embodiment 20 of the apparatus of the in~ention; and .:. .
Fig. 4 is a graph relating salinity with immersion at selected depths for different periods o~ time.
Referring firstly to Figs. ~ and 2, there is shown ;~ a cylindrical reverse osmosis module 10, having an outer casing 1, a sea water inlet 2 at one end thereof, a sea water outlet 2A at the other end thereof and a 1/3 psi NUPRO~
stainless steel pressure relief and che k valve 3 at the other end thereof. Pxeferably, but not essentially, the module 10 ra/
,x,, . ~ . ",, ",, ~",~
. : i; : ; , : ; ~ , . ~ . ; . .
~05~899 is of the Enro UIIP 98 type, which is approximately 22" long and 4" diameter, and provided with a spiral wrapped reverse osmosis membrane 4 on a grid support 5, thus forming an outer chamber 6 and an inner chamber 7 sealed therefrom. It will, of course, be appreciated that any suitable reverse osmosis membrane system may be employed. A 1000 cc stainless ste~
Whitney~ cylindrical storage vessel 8 is mounted on the ;~
top of the reverse osmosis modulel~ with any convenient -~
external mounting framework 9, and in fluid communication with ~ `
I0 the interior chamber 7 of the module 10via valve 3. A ~0 psi air pressure relief valve 11 is provided at the top of ;~
vessel 8 and an outlet valve 12 for desalinated water at the -~
I bottom thereof. A lifting ring 13 is provided at the top of ;~ the framework 9 for attachment of a cable 14.
In operation, the entire apparatus, containing air at atmospheric pressure and weighing about 70 lbs., is lowered ;
~ on cable l4, from a boat, to the desired depth, usually of `
`j~ thé order of 130-150 fathoms and held at that depth for a `~
! ' ';, ~ `
period of time of the order of 3-7 minutes and then retxieved.
` ~Lowering and raising takes about 4 minutes. When the apparatus reaches the desired depth the external pressure in chamber 6 ~ on the membrane 4 is sufficient to cause reverse osmosis '! ~ therethrough and substantially pure water is orced to ,., ; ~ :.
permeate th~ough the membrane into the inner chamber 7. As potable water is produced, concentrated sea water escapes through~outlet 2A in~order to avoid excessive salt concen-,~ tration build-up in the outer chamber 6. Check valve 3 opens ',! :~ ~ and the water passes into storage vessel~8, compressing the -. . :
'3 ' ra/ _ 5 _ .
;~1': : .
5~)89'3 ~ ~
air contained therein. Upon raising the apparatus, check valve 3 closes thereby preventin~ the purified water from returning to the module lO,and the pressure relief valve 11 opens to release sufficient air to maintain the pressure in the storage tank at a desired level above that of the ~`
surroundings. Also, check valve 3 prevents pressurized air in storage vessel 8 from applying back pressure on the membrane 4, and osmosis taking place cluring recovery. Upon recovery into the boat the desalinated water can be removed by opening outlet valve 12 and the apparatus prepared for another purification cycle. -, I Example 1 ~.. . ..
A device as described hereinabove with reference to Figures 1 and 2 was prepared and tested at various depths in Haro Strait off Vancouver Island, B. C., Canada, for periods of time varying between 1.5 and 7 minutes at depth. The ~, natural salinity in thls area is about 2.7-3.0%. The depth ~
'~ of water was measured by means of a type 8 depth gauge ~;;
;l~ manufactured by Tsurami Saki Kosakusho Co. Ltd. and corrected ~!
`~` 20 for slope of cable. As seen from Fig. 4, which summarizes the results, the relationship between salinity of water produced and maximum depth of immersion appears to be linear when the device was maintaine~ at maximum depth for 3 minutes and raised and lowered at constant speed (approximately 4 minutes).
It was also found that by leaving the device at maximum depth fox 7 minutes an improved, lower salinity, product was . . , ~ .
~ obtained.
, It will, of course, be appreciated that many modifi-cations to the apparatus described hereinabove are possible ... . . ~ .
-' ra/
105~8~9 and within the scope and purview of the present invention.
; For example, as the purity of the water produced improved with depth the apparatus should be sixed so that as much water as possible is collected at maximum depth, and as little as possible during raising and lowering. For the same reason, sea water inlet 2 and outlet 2A may be provided with a pressure operated valve to accurately regulate water intake to the desired pressure levels only. ;~
A simplified version of the device of Figures 1 and 2 is shown in Figure 3 and represents an inexpensive embodiment ;~
particularly suitable for use on small survival craft where space is very limited and the amount of water required is smaller. In Fig. 3, the reverse osmosis module and the water :, , i storage vessel are combined in the form of a cylindrical sintered porous vessel 20 with solid non-porous ends 21 and 22 and weighing only 4-6 lbs. in air and 2-4 lbs. in water ; when empty. Preferably, the vessel 20 is a sintered bronze or stainless steel material and is conveniently 3" in diameter .. - ~.
~ and 8" long. The porous walls of vessel 20 are covered with ~
.
a semipermeable membrane 23, preferably cellulose diacetate- ;~
cellulose triacetate which is either cast or attached to the outer surface, thereby forming a reverse osmosis module similar to that of Figure 1 but without the casing 1. Non-porous end 22 is provided with a 1/3 psi pressure relie i valve 24~ an outlet valve 25, and a lifting ring 26. The principle of operation is as beore in that as the unit is lowered into the sea, the external pressure rises until, at a pressure of about 24 atmospheres (130 fathoms depth) reverse ' ra/ _ 7 _ . ,~.. ,, . ,, ., .. . . j , ., . ~ ~ ., :,. ~. : : :,, , . , .
.: : : . - , , :
:- ' : . . ' g9 osmosis takes place and desalinated water permeates through the membrane 23 and porous walls 20 into the vessel. When three-quarters full of water, the unit only weighs 6-8 lbs.
in air and 4-6 lbs. in water so ~hat raising and lowering upon a thin steel wire, such as that used by sportsfishermen presents little difficulty. Upon recovery, as the unit is raised, the excess trapped air pressure in the vessel escapes through relief valve 24 thereby preventing the internal pressure from rising significantly above the surrounding - 10 external pressure and forcing the membrane 23 off the surface of the vessel 20. Upon recovery at the survival craft, the potable water is removed via valve 25 and the unit is then ready for return to the sea for further recovery.
:: ~
, :
' ' ' "' , xa/
~... . . . . ..
: . . . ...... . . . . . .
, . . . . .. .
:, , . :
` : , ~ 1' ':
extended surviv~ pexiods before rescue are most unlikely, Thus, if a reverse osmosis unit is lowered into the ocean depths, a sufficient pressure differential between one side of a semi-permeable membrane and the other may be developed so that reverse osmosis can be made to occur. Potable water passes through the membrane and is collected within. The osmosis unit can then he retrieved and the potable water collected. Calculations show that at pressures of approx-imately 24 atmospheres or 350 psi reverse osmosis o sea ;.
water can be effected. 24 atmospheres corresponds to a depth of approximately 130 fathoms (780 ft). ~
The invention will now be described in more detai~ -with reference to the following examples and the drawings in `
which: ~
Fig. 1 is a front elevation o~ a first embodiment `
. ~, ,, . ~ .
of the invention;
Fig. 2 is a sectional view of part of the first embodiment of the apparatus of the invention;
Fig. 3 is a sectional view of a second embodiment 20 of the apparatus of the in~ention; and .:. .
Fig. 4 is a graph relating salinity with immersion at selected depths for different periods o~ time.
Referring firstly to Figs. ~ and 2, there is shown ;~ a cylindrical reverse osmosis module 10, having an outer casing 1, a sea water inlet 2 at one end thereof, a sea water outlet 2A at the other end thereof and a 1/3 psi NUPRO~
stainless steel pressure relief and che k valve 3 at the other end thereof. Pxeferably, but not essentially, the module 10 ra/
,x,, . ~ . ",, ",, ~",~
. : i; : ; , : ; ~ , . ~ . ; . .
~05~899 is of the Enro UIIP 98 type, which is approximately 22" long and 4" diameter, and provided with a spiral wrapped reverse osmosis membrane 4 on a grid support 5, thus forming an outer chamber 6 and an inner chamber 7 sealed therefrom. It will, of course, be appreciated that any suitable reverse osmosis membrane system may be employed. A 1000 cc stainless ste~
Whitney~ cylindrical storage vessel 8 is mounted on the ;~
top of the reverse osmosis modulel~ with any convenient -~
external mounting framework 9, and in fluid communication with ~ `
I0 the interior chamber 7 of the module 10via valve 3. A ~0 psi air pressure relief valve 11 is provided at the top of ;~
vessel 8 and an outlet valve 12 for desalinated water at the -~
I bottom thereof. A lifting ring 13 is provided at the top of ;~ the framework 9 for attachment of a cable 14.
In operation, the entire apparatus, containing air at atmospheric pressure and weighing about 70 lbs., is lowered ;
~ on cable l4, from a boat, to the desired depth, usually of `
`j~ thé order of 130-150 fathoms and held at that depth for a `~
! ' ';, ~ `
period of time of the order of 3-7 minutes and then retxieved.
` ~Lowering and raising takes about 4 minutes. When the apparatus reaches the desired depth the external pressure in chamber 6 ~ on the membrane 4 is sufficient to cause reverse osmosis '! ~ therethrough and substantially pure water is orced to ,., ; ~ :.
permeate th~ough the membrane into the inner chamber 7. As potable water is produced, concentrated sea water escapes through~outlet 2A in~order to avoid excessive salt concen-,~ tration build-up in the outer chamber 6. Check valve 3 opens ',! :~ ~ and the water passes into storage vessel~8, compressing the -. . :
'3 ' ra/ _ 5 _ .
;~1': : .
5~)89'3 ~ ~
air contained therein. Upon raising the apparatus, check valve 3 closes thereby preventin~ the purified water from returning to the module lO,and the pressure relief valve 11 opens to release sufficient air to maintain the pressure in the storage tank at a desired level above that of the ~`
surroundings. Also, check valve 3 prevents pressurized air in storage vessel 8 from applying back pressure on the membrane 4, and osmosis taking place cluring recovery. Upon recovery into the boat the desalinated water can be removed by opening outlet valve 12 and the apparatus prepared for another purification cycle. -, I Example 1 ~.. . ..
A device as described hereinabove with reference to Figures 1 and 2 was prepared and tested at various depths in Haro Strait off Vancouver Island, B. C., Canada, for periods of time varying between 1.5 and 7 minutes at depth. The ~, natural salinity in thls area is about 2.7-3.0%. The depth ~
'~ of water was measured by means of a type 8 depth gauge ~;;
;l~ manufactured by Tsurami Saki Kosakusho Co. Ltd. and corrected ~!
`~` 20 for slope of cable. As seen from Fig. 4, which summarizes the results, the relationship between salinity of water produced and maximum depth of immersion appears to be linear when the device was maintaine~ at maximum depth for 3 minutes and raised and lowered at constant speed (approximately 4 minutes).
It was also found that by leaving the device at maximum depth fox 7 minutes an improved, lower salinity, product was . . , ~ .
~ obtained.
, It will, of course, be appreciated that many modifi-cations to the apparatus described hereinabove are possible ... . . ~ .
-' ra/
105~8~9 and within the scope and purview of the present invention.
; For example, as the purity of the water produced improved with depth the apparatus should be sixed so that as much water as possible is collected at maximum depth, and as little as possible during raising and lowering. For the same reason, sea water inlet 2 and outlet 2A may be provided with a pressure operated valve to accurately regulate water intake to the desired pressure levels only. ;~
A simplified version of the device of Figures 1 and 2 is shown in Figure 3 and represents an inexpensive embodiment ;~
particularly suitable for use on small survival craft where space is very limited and the amount of water required is smaller. In Fig. 3, the reverse osmosis module and the water :, , i storage vessel are combined in the form of a cylindrical sintered porous vessel 20 with solid non-porous ends 21 and 22 and weighing only 4-6 lbs. in air and 2-4 lbs. in water ; when empty. Preferably, the vessel 20 is a sintered bronze or stainless steel material and is conveniently 3" in diameter .. - ~.
~ and 8" long. The porous walls of vessel 20 are covered with ~
.
a semipermeable membrane 23, preferably cellulose diacetate- ;~
cellulose triacetate which is either cast or attached to the outer surface, thereby forming a reverse osmosis module similar to that of Figure 1 but without the casing 1. Non-porous end 22 is provided with a 1/3 psi pressure relie i valve 24~ an outlet valve 25, and a lifting ring 26. The principle of operation is as beore in that as the unit is lowered into the sea, the external pressure rises until, at a pressure of about 24 atmospheres (130 fathoms depth) reverse ' ra/ _ 7 _ . ,~.. ,, . ,, ., .. . . j , ., . ~ ~ ., :,. ~. : : :,, , . , .
.: : : . - , , :
:- ' : . . ' g9 osmosis takes place and desalinated water permeates through the membrane 23 and porous walls 20 into the vessel. When three-quarters full of water, the unit only weighs 6-8 lbs.
in air and 4-6 lbs. in water so ~hat raising and lowering upon a thin steel wire, such as that used by sportsfishermen presents little difficulty. Upon recovery, as the unit is raised, the excess trapped air pressure in the vessel escapes through relief valve 24 thereby preventing the internal pressure from rising significantly above the surrounding - 10 external pressure and forcing the membrane 23 off the surface of the vessel 20. Upon recovery at the survival craft, the potable water is removed via valve 25 and the unit is then ready for return to the sea for further recovery.
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, . . . . .. .
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Claims (7)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. An apparatus for the production of potable water from sea water adapted to be lowered to depths of at least 130 fathoms below the surface of the sea and comprising:
(a) potable water collecting means including: (i) a support member having a semipermeable membrane secured thereto and adapted to permit substantially potable water to permeate therethrough, at pressures corresponding to said depths below the surface, into potable water collecting chamber defined by said support member and said semipermeable membrane; and (ii) outlet means to recover said substantially potable water from said potable water collec-ting chamber;
(b) potable water storage means including: (i) inlet means for receiving said potable water from said collecting means; (ii) outlet means to recover said potable water; and (iii) pressure relief valve means adapted to relieve air pressure therein and thereby maintain an internal pressure substantially equal to ambient external pressures during recovery of said apparatus from said depths; and (c) pressure relief and check valve means defining a one-way flow path for said potable water from said collecting means to said storage means, to prevent any backpressure, created during raising of the apparatus from said depths, from reaching and damaging the semi-permeable membrane.
(a) potable water collecting means including: (i) a support member having a semipermeable membrane secured thereto and adapted to permit substantially potable water to permeate therethrough, at pressures corresponding to said depths below the surface, into potable water collecting chamber defined by said support member and said semipermeable membrane; and (ii) outlet means to recover said substantially potable water from said potable water collec-ting chamber;
(b) potable water storage means including: (i) inlet means for receiving said potable water from said collecting means; (ii) outlet means to recover said potable water; and (iii) pressure relief valve means adapted to relieve air pressure therein and thereby maintain an internal pressure substantially equal to ambient external pressures during recovery of said apparatus from said depths; and (c) pressure relief and check valve means defining a one-way flow path for said potable water from said collecting means to said storage means, to prevent any backpressure, created during raising of the apparatus from said depths, from reaching and damaging the semi-permeable membrane.
2. An apparatus for the production of potable water from sea water adapted to be lowered to depths of at least 130 fathoms below the surface of the sea and comprising:
(a)a potable water collecting means including: (i) an outer casing; (ii) porous support member secured within said outer casing thereby defining an inner and outer chamber; (iii) a sea water inlet and outlet in said outer chamber; and (iv) a semipermeable membrane mounted on said support member and adapted to allow substantially potable water to permeate therethrough into said inner chamber at pressures corresponding to said depths; (v) outlet means to recover said substantially potable water from said inner chamber;
(b) a potable water storage means including (i) inlet means for receiving said potable water from said collecting means; (ii) outlet means to recover said potable water; and (iii) pressure relief valve means adapted to relieve air pressure therein and thereby maintain an internal pressure substantially equal to ambient external pressures during recovery of said apparatus from said depths; and (c) pressure relief and check valve means defining a one-way flow path for said potable water from said inner chamber to said storage means, to prevent any back-pressure, created during raising of the apparatus from said depths, from reaching and damaging the semi-permeable membrane.
(a)a potable water collecting means including: (i) an outer casing; (ii) porous support member secured within said outer casing thereby defining an inner and outer chamber; (iii) a sea water inlet and outlet in said outer chamber; and (iv) a semipermeable membrane mounted on said support member and adapted to allow substantially potable water to permeate therethrough into said inner chamber at pressures corresponding to said depths; (v) outlet means to recover said substantially potable water from said inner chamber;
(b) a potable water storage means including (i) inlet means for receiving said potable water from said collecting means; (ii) outlet means to recover said potable water; and (iii) pressure relief valve means adapted to relieve air pressure therein and thereby maintain an internal pressure substantially equal to ambient external pressures during recovery of said apparatus from said depths; and (c) pressure relief and check valve means defining a one-way flow path for said potable water from said inner chamber to said storage means, to prevent any back-pressure, created during raising of the apparatus from said depths, from reaching and damaging the semi-permeable membrane.
3. An apparatus as defined in claim 1 or 2, including an external mounting frame adapted for attachment to cable means for raising and lowering said apparatus.
4. An apparatus as defined in claim 1 or 2, wherein said semipermeable membrane is cellulose diacetate-cellulose triacetate.
5. An apparatus as defined in claim 1 or 2, wherein said pressure relief and check valve means is a 1/3 psi pressure relief and check valve.
6. An apparatus as defined in claim 1 or 2, wherein said pressure relief valve means is a 10 psi pressure relief valve.
7. An apparatus as defined in claim 1 or 2, wherein said semipermeable membrane is mounted externally of said support member.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA233,376A CA1050899A (en) | 1975-08-13 | 1975-08-13 | Reverse osmosis kit for producing potable water from seawater |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA233,376A CA1050899A (en) | 1975-08-13 | 1975-08-13 | Reverse osmosis kit for producing potable water from seawater |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1050899A true CA1050899A (en) | 1979-03-20 |
Family
ID=4103820
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA233,376A Expired CA1050899A (en) | 1975-08-13 | 1975-08-13 | Reverse osmosis kit for producing potable water from seawater |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1050899A (en) |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4452696A (en) * | 1981-04-06 | 1984-06-05 | Fernand Lopez | Reverse-osmosis apparatus for producing fresh water from seawater |
| EP0318832A2 (en) * | 1987-11-28 | 1989-06-07 | Joachim Wolf | Filtering device |
| WO2004033373A2 (en) * | 2002-10-08 | 2004-04-22 | Water Standard Company, Llc | Mobile desalination plants and methods for producing desalinated water |
| US7081205B2 (en) | 2002-10-08 | 2006-07-25 | Water Standard Company, Llc | Mobile desalination plants and systems, and methods for producing desalinated water |
| US7416666B2 (en) | 2002-10-08 | 2008-08-26 | Water Standard Company | Mobile desalination plants and systems, and methods for producing desalinated water |
| CN1714048B (en) * | 2002-10-08 | 2010-05-26 | 水质标准股份有限公司 | Mobile desalination plants and systems, and methods for producing desalinated water |
| CN107758776A (en) * | 2017-12-14 | 2018-03-06 | 邵绪贤 | A kind of method and device to be desalinized seawater using high temperature and high pressure environment |
-
1975
- 1975-08-13 CA CA233,376A patent/CA1050899A/en not_active Expired
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4452696A (en) * | 1981-04-06 | 1984-06-05 | Fernand Lopez | Reverse-osmosis apparatus for producing fresh water from seawater |
| EP0318832A2 (en) * | 1987-11-28 | 1989-06-07 | Joachim Wolf | Filtering device |
| EP0318832A3 (en) * | 1987-11-28 | 1989-07-05 | Joachim Wolf | Filtering device |
| WO2004033373A2 (en) * | 2002-10-08 | 2004-04-22 | Water Standard Company, Llc | Mobile desalination plants and methods for producing desalinated water |
| WO2004033373A3 (en) * | 2002-10-08 | 2004-09-23 | Water Standard Co Llc | Mobile desalination plants and methods for producing desalinated water |
| US7081205B2 (en) | 2002-10-08 | 2006-07-25 | Water Standard Company, Llc | Mobile desalination plants and systems, and methods for producing desalinated water |
| US7416666B2 (en) | 2002-10-08 | 2008-08-26 | Water Standard Company | Mobile desalination plants and systems, and methods for producing desalinated water |
| CN1714048B (en) * | 2002-10-08 | 2010-05-26 | 水质标准股份有限公司 | Mobile desalination plants and systems, and methods for producing desalinated water |
| CN107758776A (en) * | 2017-12-14 | 2018-03-06 | 邵绪贤 | A kind of method and device to be desalinized seawater using high temperature and high pressure environment |
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