CA1290258C - Membrane assembly for fluid separations - disk - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

A membrane assembly for fluid separations consisting of a compact stack of alternating layers of membrane with layers of fluid conducting materials. The assembly consists of a simplified and improved plate and frame apparatus. The stacked assembly may be placed into a pressure containment device consisting of standard pipe with standard methods of closure. Internal fluid conducting passages are formed from cutouts in the stacked layers thereby greatly simplifying the manufacture and assembly of large diameter fluid separation devices using membranes to effect the fluid separ-ations. The fluid pathways are such that the membrane assembly is particularly efficient in separation.

Description

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1 BACKGROUND OF THE II~VE~TIC~

3 The present invention relates to a fluid separation ap~
4 paratus utilizing a membrane to effect the separation. The fluid 5 separation may be a 1) separation of gaseous mixtures by perm-6 selective gaseous diffusion; 2) separation of dissolved solids 7 from liquids by reverse osmosis; 3) separation or concentration 8 of liquids from mixtures of liquids and dissolved solids by direct 9 osmosis; 4) separation or concentration of liquids and solids bv dialysis; 5) separation of liquids from mixtures of liauids by 11 reverse osmosis or ultrafiltration; 6) the separation of solids 12 from liquids by ultrafiltration; 7) gaseous exchange between ; 13 liquids; and 8) exchanqe between a gas phase and a liquid phase.
14 This invention particularly relates to a stacked assembly of mem-brane and spacer layers in a simplified and commercially advantag-16 eous plate and frame arrangement and to the method of manufacturing 17 such an apparatus.
18 Fluid separations utilizing membranes offer many advan-19 tages over conventional separation techniaues. In the field of water desalination, reverse osmosis membrane processes are now 21 dominating this field, reducing the reliance on ion exchange, 22 distillation and electrodialysis. In gas separation, membrane 23 processes are being accepted as a new method to remove components 24 from a gaseous mixture, such as the removal and recovery of hvdro-gen from process gas streams and the removal of carbon dioxide 26 from natural gas. Ultrafiltration membrane processes are becoming 27 very important in water treatment, pharmaceuticals processing, 28 food processing, wastewater cleanup, and materials recovery from 29 fluids.

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~ L 1, G~ ~ -1 The various types of fluid separations discussed above are 2 ¦not o~ a simple filtra-tion type, but involve the feed fluid being 3 ¦contacted onto one side of the membrane and one or more components 4 ¦of the feed fluid passing through the membrane leaving the feedfluid 51 depleted in those components. ~he feed fluid continually sweeps th~
6 ¦ surface of the membrane, carrying away the nonpermeating components 7 ¦ in the feed fluid. After the feed fluid has contacted the membrane 8 ¦ it becomes the residue or concentrate. The residue fluid maY be th~
9 ¦important component of the system or it ma~v be a waste component.
10 ¦ There are many types of membranes in commercial use 11 ¦and many more in development throuqhout the world. One thing that 12 ¦all membranes share, regardless of their application, is that they 13 ¦must be supported and housed in a suitable package. If a membrane 14 ¦is to effect its intended purpose, -~hat is to separate some com-15 ¦ponent from a mixture, the membrane package apparatus must:
16 1. Support the~membrane against the static and 17 dynamic pressures and forces applied to one side 18 of the membrane.
19 2. Provide a passage to the membrane for the feed fluid.
21 3. Provide for the removal of the fluid that 22 permeated the membrane.
23 4. ~revent the contamination or mixing of the 24 eed fluid and the fluid permeating through the membrane.
26 S. Provide a passage for the residual fluid 27 after it has contacted the membrane.
28 6. Provide a safe housing to contain the _3_ 2~5~3 ,'~ " ~

1 fluids being separated.
2 7. se economical to manufacture.

4 The method of assembling the membrane into the package must be efficient to allow the greatest amount of membrane inside 6 the package as possible. I'he assembled package should also be 7 compact utilizing the least amount of space practical.
8 As membranes were developed, methods to package them were 9 required for the membranes to function. The first membrane pack-ages were of the plate and frame type, borrowed and modified 11 from the filtration industry, U. S. Patent NoO 3,473,668 and 12 3,209,915. These devices consisted of top and bottom vlates with 13 supporting frames and plates in between, U. S. Patent No. 2,597~907.
14 Feed fluid is introduced through the ~op plate and passes down to the feed fluid spacers by way of a manifold on one slde of the 16 pIate and frame assembly. The component of the feed fIuid that 17 permeates the membrane enters a permeate carrier layer and is 18 carried out of this layer to the permeate manifold. Complicated 19 portlng was required to route the feed fluid through the plate and frame stack to achieve the required recovery rates and to 21 remove the permeate fluid from the stac~. The feed fluid depleted 22 in the more permeable component becomes the concentrate or residue 23 and is removed from the assembly via the concentraté manifold.
24 The plate and frame assembly must be constructed of materials that are stron~ enough to contain the feed fluid under pressure. The 26 early plate and frame assemblies were sauare or rectangular in 27 shape.
28 The early attempts to commercialize reverse osmosis and _4_ :
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1 gas separation membranes utilized the plate and frame type of 2 assembly. The process o~ usln~ membrane for these applications 3 was demonstrated but the economics of the svstems were verv poor.
4 This was due, not to poor performance of the membrane but, to the very high cost and low packing density of the plate and frame 6 assemblies. Since it was not economical to utilize membrane for 7 either reverse osmosis or gas separation processes with the plate 8 and frame type of membrane assemblv, other packaging techniques 9 were investigated and developed.
In 1970 the first commercial high pressure membrane 11 system was installed. This reverse osmosis system utilized cellu-12 lose acetate membranes packaged in a spiral wound element con-13 figuration, such as is disclosed in U. S. Patent No. 3,417,870.
14 Flat sheet membranes pa~kaqed into spiral wound elements were then joined on the co~mercial scene by membranes fabricated into hollow 16 fine fiber bundles and into tubular assemblies. Many high pres-17 sure industrial uses of synthetic membranes have been co~nercial-18 ized since 1970 utilizing these three main types of membrane pack-19 ayes.
Plate and frame membrane assemblies have been improved 21 during the past 25 years but the devices as currentlv manufactured 22 are not competitive with membrane packages using hollow fine 23 fibers or spiral wound elements. This is because the plate and 24 frame type oE membrane packages are very complicated and therefore expensive to manufacture. ~he separation devices of Iaconelli U. S.
26 Patent No. 3,695,444 and Olsen U. S. Patent No. 3,623,610 are 27 typical of early plate and frame assemblies. Typical of current 28 art is the separation cell of ICraus U. S. Patent No. 4,340,475.

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,.: . ., :~ , 9~5~3 1 In this device complicated support, se~aratrr, collector and dis-2 ¦tribution plates are required. The memhrane supportina plate for 3 ¦example is formed from many pieces and requires a com~licated 4 Imanufacturing process to produce. The separator plates are like-5 ¦wise complicated. The plates are not only expensive to manufacture 6 ¦they are also thick, on the order of 0.1 to 0.25 inches. Thick 7 ¦plates of this type are unable to compete with the hollow fine 8 ¦fibers or spiral wound elements because of their very Iow membrane g ¦packing densities. In U. S. Patent No. 4,255,263, Galami describes 10 ¦another variation of a stacked separation device. This device also 11 ¦has complicated plates, requiring many parts and materials. In }2 ¦this device the plates are also thick leading to low packing den-13 sity. In U. S. Patent ~!o. ~,310,416 Tanaka describes another 14 plate type membrane device. Again, the plates are very complicated and the assembly complex, with many seals and ports that must be 16 connected between the various plates. This device also has thick 17 plates, again leading to low membrane packing density.
18 In U. S. Patent ~o. 4,243,536 Prolss describes a stacked 19 assembly of disk-shaped elements which are located concentrically around a permeate collection pipe and within a pressure vessel.
21 Membrane layers are placed on both sides of a membrane support 22 and permeate carrier layer. This permeate layer is molded from 23 plastic and contains raised squares and fluid conduction passages.
24 This layer is rather thick being about .25 inches, and conveys the permeate to the centrally located collection pipe. The centrally 26 located pipe contains ports or holes that are precisely located 27 in the center of the permeate collection layer. Located above and 28 below the permeate carrier-membrane assembly is the feed space , .

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1 whlch is also thick bein~ about 0.2~ inches. mhe feed fluid enters 2 a pipe located next to and o f center ~rom the Dermeate pipe. PortC
3 or holes are located in the feed flui~ pipe that distribute the 4 feed fluid into the feed fluid space. mhe feed fluid spacer layers must be precisely located to match up with the ~orts in the feecl 6 fluid distribution pipe. At the edge of the disk is a cut-out that 7 contains the residual fluid collection pipe. This collection pipe 8 also contains precisely located holes or ports that must match up 9 with the feed fluid space. The assembly is stacked on the centrally located permeate pipe and placed in a pressure vessel. The present 11 invention improves over the art of Prolss in several ways: first 12 there are no internal piPes; ~eed fluidr residual fluid, and per-13 meate fluid are conducted within the stacked assemblv through 14 channels formed by the registration of the notches cut into the layers of material that make up the stacked assembly. Second ! the 16 membrane packing density is much greater than the device of Prolss;
17 the spacer layers are much thinner resulting in much higher packing 18 density. Third, the device is much more economical to manufacture l9 than the device of Prolss; the lavers are made from inexpensive matted, knitted or woven materials rather than the inj-ection molded 21 materials of Prolss. Fourth, the assembly of the present stacked 22 assembly is significantly easier than assembling ~he device of 23 Prolss; there are no internal pipes with precisely drilled holes 24 that the various layers must be aligned to. Fifth, the permeate carrier of the present invention acts as both a membrane support 26 layer and a permeate carrier. This layer can be a paper or paper-27 like material, a woven material or a knitted material. All of 28 ¦these type ~ materials can he made to both support the membrane .

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1 and conduct the permeate to the central permeate collection channel 2 In the stacked assemhly of ~rolss, the membrane suPport and per-3 meate conduction layer are molded from a plastic. The layer has flat, smooth landings that support the membrane and trough-shaped conducting channels molded between the landings. This approach is 6 both uneconomical and inefficient when compared to the present in-7 vention.
8 Conventional fluid separation processes (such as distilla 9 tion, cryogenic fractionation and physical and chemical solvent extraction) have one advantage over the ne~er membrane based pro-11 cesses, this being that large scale projects can benefit from 12 economies of scale. World scale size separation plants can use 13 larger vessels, columns and piping, thereby taking advantage of the 14 economies of scale. Membrane based processes, however, have not lS been able to take advantage of economies of scale because the present membrane packaging techniques are very limited in upward 17 growth in size.
18 The present spiral wound membrane package is limited to 19 about 12 inches in diameter and 60 inches long, containing apPr imately 1300 square feet of membrane. A spiral wound membrane 21 element must be constructed of multiple leaves of membrane, per-22 meate carrier and feed fluid spacer layers. A s~iral wound membrane 23 e~ement with a diameter of 4 inches and a length of 40 inches has 24 3 or 4 leaves, each containing 16 to 25 square feet of active membrane area. The leaf length is limited because the efficiency 26 of the permeate carrier material is poor. A leaf length of more 27 than 40 to 60 inches causes a bac]c pressure in the leaf that is 28 too high to be acceptable. An increase in diameter greatly : .
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1 increases the number of individual membrane leaves requirc~ in 2 each spiral wound element. A 12 inch diameter spiral wound element 3 contains between 24 and 30 individual leaves. Maklng spiral L~ elements with larger diameters, such as l~ lnches results in almost insurmountable manufacturlng problems. There is so much membrane 6 in each element and so many individual membrane leaves to handle 7 that the statistical chance of a defect in each spiral element is 8 very high.
9 One of the major improvements of the instant invention over previous art is that the path the permeate is requlred to 11 travel is greatly reduced. In a membrane package of the instant 12 invention made 60 inches in diameter the permeate has only to 13 travel a maximum of 30 inches to reach the central collection 14 channel.
For hollow fine fiber bun~le elements the same problem 16 exists. The current hollow fiber elements are 8 to l0 inches in 17 diameter. Increasing the diameter to 12 to 16 inches increases 18 the complexity of manufacture and the likelihood of a defect is 19 very high. The hollow fine fiber bundles are limited in length due to the pressure drop of the permeate in the bore of the 21 fiber. Current designs of hollow fiber bundles are limited to 22 about 12 feet in length.
23 Even if it were practical to manufacture spiral wound and 24 hollow fiber elements in 16 inch diameters it is not a significant increase in the economies of scale over existing element sizes.
2~ To be able to compete in world class projects with conventional 27 technologies, membrane packa~es and pressure vessels to contain 28 the packages must be increased to the order of 3G to 60 inch .
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One of the advantages of the present invention is that it provides a method and apparatus to package membranes for these very large systems. It is just as feasible to manu~acture this new membrane package in 36 to 60 inch diameters as it i5 in ~ to 12 inch diameters. A major advantage of the present invention is that each membrane-permeate carrier assembly can be pretested for defec-ts before it is assembled into the pressure vessel or module.
This means that only a few square feet of membrane is lost due to a defect in the membrane or adhesive sealant lines.
Concurrent with the development of the high pressure industrial membrane applications was the development of small and low pressure membrane packages. Examples of these packages are artificial kidneysl home and laboratory reverse osmosis systems, food and beverage processing elements and many special membrane packages. These systems utilized spiral wound elements, hollow fiber bundles and tubular elements but also led to the development of many variations of the original plate and frame package.
~ he present invention is applicable to these very small membrane packages including small medical units. In this regard, the present invention is particularly-adaptable to portable blood oxygenators and ~i.milar devices. The high density of the packing in the present invention makes possible devices which are both eficient and compAct.
In general, the present invention provides a novel membrane device which is simple and less costly to fabricate, - ln -'` ': ' ' : -~2~

physically compac-t, and highl.y efficient in operation. According-ly, it is to be expected that our invention will be widely adopted in the art - lOa -"'~;
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325~3 6~2~9~83 SIJU~f~RY OE TffS INVF~TION
Briefly, the present invention p~rtains to a device ~or the separation of two or more different materials comprising:
a pressure vessel adapted to contain ~luids under pressure, an inlet for admitting fluid to be separated to said vessel, a first outlet for removing residue from said vessel, a second outlet for removing permeate ~rom said vessalr and a plurality of separator elements within the pressure vessel between the inlet and the outlets, said separator elements each comprising a pair of separator membranes and a permeate carrier element abutting the opposed faces of the membranes to carry away perm0ate, said separator elements being arranged in superposed relationship within the pressure vessel and themselves being spaced apart to provide distribution zones through which a lateral flow of ~eed fluid to be treated can pass across the active fac~s of the memhranes, the separator eleménts being arranged as a stack, said separator elements with gaps being provided between the edge of each separator element and the inner wall of the vessel at two spaced apart points with the gaps of adjacent separator elements being in registration with one set of registering notches forming a feed ahannel in fluid communication with the inlet for fluid to be separated and the other set of registering gaps forming a residue collection channel in fluid communication with the first outlet, said distribution 20nes being in communication with the feed and residue collection channels at said gaps, and each said separator element also having an internal ~ 2~2.5~3 68~99-83 aperkure in fluid commLInlcation with the permeate carrier element, thP in~ernal apertures of the stacked separator elements, bein~ in registrakion with internal apertures through the distribution elements to define a permeate collection channel in fl.uid communication with said second o~tlet, characterized in that for each separator element the gaps are provided by notches extending inwardly of the peripheral ed~e of the separator element, in that the ~istribution zones are provided by distribution elements provided between, and being shaped similarly to, the successive separator elements of the stac~, there being no direct communication from the interior of the distribution elements to the permeate collection channel, and in that the peripheral edges of the separator and distributor elements are in sealing contact wlth eaah other to form the stac~, said distribution elements being edge sealed against incursion of feed fluid except at said notches.
It is an object of this invention to provide a novel separation means.
More particularly, it is an object of this invention to provide novel separatlon means which is easier and more economical to manufaature.
More specifiaally, it is an important object of our inventlon to provide a novel fluid separation device having a plurality of staaked elements wherein the feed and resiclue ahannels are formed by registered edge notches and the permeate is collected in an internal channel formed by registration of :
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These and other objects and advantages of our invention will be apparent from the more detailed description which follows taken in conjunction with the accompanying drawings.

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~ t ~ EMBRANE
l Membrane ls t:-le term used to identif~ the material that 2 does the separation. lhis membrane may be of a porous nature or ~ it may be of a non-porous nature. Membranes of a ~orous nature 4 can be ultrafiltration membranes. mhese membranes are generall!~
characterized as having pores of a defined and uniform size. An 6 ultrafiltration membrane removes a component or components from 7 the feed fluid on the basis of the size of the components to be 8 removed.
9 Mon porous membranes are characterized as having no pores or having pores much smaller than the component that is to be 11 removed. Reverse osmosis, dialysis and gas diffusion membranes 12 are characterized as being non-porous. Membranes are generally -13 regarded as having an active side or front side that is contacted 14 with the feed fluid and a back side that faces away from the feed fluid. ' 16 Membranes may be fabricated from many materials, from 17 inorganic compounds to the newest polymeric materials. The com-18 position of the membranes does not form a part of this invention 19 which is applicable to porous and non-porous membranes generally.
The structure of membranes are characterized as being uniform 21 throughout or of being anisotropic in cross section. Membranes 22 can be made of one material, mixtures or blends of materials or 24 ¦composites f two or more materials.

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1 B. PE~EATE C~RP~IER ~T~RIAL
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2 Permeate is a term used to identifv that portion of the 3 feed fluid that permeates or crosses through the membrane. Per-4 meate carrier material is a material that receives the ~ermeate from the back side of the membrane and transports the permeate out 6 of the membrane assembly. The permeate carrier material mav do 7 this job ~n its own or it may be joined into some other device or 8 material to complete the removal of the permeate from the membrane 9 assembly. This other material or device may be a permeate tube, a pipe, a port, a channel, a duct, a hose or the like. The permeat~
11 carrier material must also support the membrane against the hvdro-12 static pressure exerted on the feed fluid and hence the membrane.
13 This force will try to crush or flatten the permeate carrier ~
14 material. The permeate carrier material must be selected and en-gineered to withstand these crushing forces to be effective in ~I6 transporting the permeate to its desired location.
17 The permeate carrier material may be of many different 18 types of materials and designs. The simplest would be a layer 19 of paper or fabric directing the permeate to the desired location, and a complicated permeate spacer material would be injection 21 molded from plastic with many intricate passages and ports. A
22 permeate carrier material that can be used advantageously in the 23 instant invention consists of a knitted fabric of a tricot or 24 Simplex desi~n of polyester or nvlon yarns. The fabric is sub-sequently coated with a suitable resin to impart stiffness and 26 resistance to crushing to the fabric.

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~ 3 1 ~ C. FE~D FLUID ~P~CER
2 ~ The ~eed ~lui~ spacer is a la~er that ~rovides fQr the 3 I passage of the feed fluid over the active side of the mem~rane.
4 The feed fluid spacer may serve the function of directing the feed fluid to cover the active side of the membrane in a unifor~
6 manner, reducing stagnant areas as much as possible. The spacer 7 may also impart turbulance to the feed fluid to provide ~ood 8 ¦mixing in the feed fluid as it travels over the active side of the 9 ¦membrane and the more permeable component of the feed fluid is 10 Iremoved. The feed fluid s~acer may be a material that is woven.

11 ¦molded, formed, extruded; knitted, cast or formed in place. The 12 ¦feed spacer laver may consist of no material at all, just a space 13 ¦formed by a separation of the layers of the membrane.

D. PRESSURE V_SSEL AS~EMBLY
16 The term pressure vessel assemblv i5 used to identify the 17 housing -that the membrane assembly is inserted into. The pressure 1~ vessel assembly contains the feed fluid under pressure. The pres-19 sure of the feed fluid may be as high as several thousand psig 2~ and as low as atmospheric. The pressure vessel assembly may also 21 be subjected to a vacuum in some methods of operation. The~pres-22 sure vessel must also safély contain the pressurized feed fluid.
23 The vessel must also contain the feed Eluld from contacting the 24 outside world as many feed fluids processed wlth membranes are toxic or corrosive or flammable.
26 It should be noted that the stacked assembly of the 27 present invention represents a significant advance in the art in 28 ~ that it is e first such device to us the same mate=ials .~ . . .

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~.2~ 58 1 of construction as are used in the spiral Tounc membrane elements.
2 No known art of a plate and frame type of mer~rane assembly has 3 been able to use these ine~pensive and verv e ficient materials of 4 construction. This fact makes it possible for a stac~ed assembl~
of the present invention confi~ured in a 12 inch diameter to have / ¦ the same m m rane pack~ng density as a 12 inch spiral wound lement 10l l3 ; 15 .

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3 One ?referred embodiment of the present invention is 4 shown in Fiqures 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, la, 15, 16, 17, and 18.
6 Figure 1 is a plan view of a membrane-permeate carrier 7 assembly.
8 Figure 2 is an enlargement of a cross-section of the 9 edge of the membrane-permeate carrier assembly taken along the line 2-2 in Figure 1.
11 Figure 3 is a plan view of a feed fluid spacer layer.
12 Figure 4 is an alternative feed fluid spacer layer to 13 the one shown in Figure 3.
14 Figure 5 is a cross section of the edge of the feed;
fluid spacer layer taken along the line 5-5 in Figure 3.

16 Figure 6 is a plan view of the inlet distributor plate.

17 Figure 7 is a plan view of a midsection and residual 18 distributor plate.

19 Figure 8 is a cross section of the edge of the inlet and mldsection and residual distributor plates.
21 Figure 9 is a cross section of the stacked assembly of 22 the membrane, permeate carrier and feed fluid spacer within a 23 pressure housing.
24 Figure 10 is an enlar~ement of the stacked assembly in cross section, showing in detail the arrangement of the various 26 layers of materials at the outside perimeter of the assembly.
27 Figure 11 is an enlargement of the stacked assembly 28 in cross section showing in detail the arranyement of the various .

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2 ~3 layers of materials at the center of the assembly.
Figure 12 is a plan view of the back or porous side of a cellulose membrane layer.
Figure 13 is a cross-section of the central aperture similar to the view in Figure 11.
Figure 14 is a cross section of the stacked assembly showing the path of feed, permeate and residue fluids through the assembly.
Figure 15 is a cross section of the stacked assembly utilizing a drawbar arrangement.
Figure 16 is a cross section of the stacked assembly utilizing standard pipe and weld on flanges for the containment vessel.
Figure 17 is an alternate configuration of introducing the feed fluid into the vessel and removing the residual fluid from the vessel.
Figure 18 is another configuration for introducing the feed and removing the residual.
Figure 19 is a plan view of the membrane-carrier assembly of the second specific embodiment of the invention.
Figure 20 is a plan view of the fluid feed spacer layer of the second speclfic embodiment.
Figure 21 is a plan view of an alternate form Qf the fluid feed spacer layer of the second specific embodiment.
Figure 22 is a plan view of the membrane-carrier assembly of Figure 19 in registration with the fluid feed spacer layer of Figure 20.

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'' 5~3 Figure 23 shows the feed fluid inlet distribution plate of the second specific embodiment.
Figure 2~ is as shown in Figure 22 with the general direc-tion of fluid flow being indicated.
Figure 25 depicts the operation of the second specific embodiment.
Figure 26 is a plan view of the membrane-carrier assembly o.f the third specific embodiment of the invention.
Figure 27 is a plan view of the fluid feed spacer layer of the third specific embodiment.
Figure 28 is a plan view of the feed fluid distribution ..
plate of the third specific embodiment.
Figure 29 is a plan view of the midsection and residual fluid distribution plates of the th.ird specific embodiment of the invention.
Figure 30 shows the membrane-permeate carrier assembly of the fourth specific embodiment of the invention.
Figure 31 shows the feed fluid spacer layer of the fourth specific embodiment of the invention.
Figure 32 shows a view of the stacked assembly of the fifth specific embodiment of the invention.
Figure 33 shows an assembly of several modules of the fifth speci:Eic embodiment of the invention.

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~ 2~0;2 5 1 DESCRIPTIo~l or TH~ PP~EFE~P~ED ~rlBODIME~T~
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4 Referring to Figure 1, a membrane-permeate carrier assembly is shown in plan section. The assembly is of a cir-6 cular shape of a gi~en diameter. ~he assemblv consists of a 7 permeate carrier material 10 cut into a circular shape with 8 a central aperture 12 and with two opposed notches 14 and 16 9 cut out of the perimeter of a given slze and shape. Two layers 18 and 20 of membrane are i~entical in shape to the permeate lI carrier material 10. The membrane layers 18 and 20 are placed 12 in contact with the permeate carrier material 10 with the active 13 sides 22 and 24 of the membranes 1~ and 20 facing awav from the I4 permeate carrier material 10. The notches in the three layels, viz, the two membrane and the permeate carrier layer are in 16 registration. Adhesive line 26 is placed between the membrane 17 layers 18 and 20 and the permeate carrier material 10 around the 18 perimeter of the assembly. Adhesive lS absent from the perimeter l9 of the central aperture 12 in area 28 leaving the permeate carrier material able to communicate with the central aperture 12.
21 Fi~ure 2 shows in cross-section the edye or periphery of 22 the membrane-permeate carrier assembly. Adhesive line 26 saturates 23 the permeate carrier material lOand m~mbranes 18 and 20 forming a peripher .
24 al seal bet~een these three layers. Me~brane active sides 22 and 24 are shown.
Figure 3 is a plan view of a feed fluid spacer laYer 26 assembly. This assembly is identical in shape to the membrane-27 permeate carrier assembly shown in Figures 1 and 2. The feed 28 spacer 32 has two opposed notches 34 and 36 and a central aperture ~: . .
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7 . ~ ~i 1 38. Around the perlmeter is placed a sealing bead or ring 40, 2 this sealing ring being absent from the e~ges of the notches 34 3 and 36 in area 42 and 4~, respecti~ely. ~ sealina ring or boss 46 is formed around central aperture 3~. Peed flui~ distri~ution lines 48 are formed in the feed spacer material to direct the feed 6 fluid across the feed fluid spacer layer in such a manner as to 7 minimize stagnant area.s. Feed fluid enters the layer at notch 34 at 8 point 42 and passes through the spaces 50 formed between the feed 9 fluid distribution lines 48 and exits the laver at point 44 in notch 36. It must be note~ that many different configurations 11 of feed fluid distribution lines may be employed. It is desirable 12 to adapt the feed fluid distribution patterr. to the feed fluid beinc 13 utilized. Such modification takes into effect feed fluid composi-14 tion, viscosity, velocity, temperature and any other factors that are important.
16 Figure 4 is a plan view of an alternate to the feed fluid 17 spacer layer shown in Figure 3. This alternate is suitable for 18 fluid separations where accurate feed fluid direction and mixing 19 are not required, as in the separation of gases. This alternate form of the feed fluid spacer layer contains no feed fluid distri-21 bution lines, and ma~ in fact consist of a space between the two 22 adjacel1t layers of membrane. Feed fluid enters notch 52 and flows 23 pastthe surface o the membrane, around sealiny boss 54 at central a~erture 56 24 and exits the layer at 58. Aro ~d the ~erimeter is ~laced sealing bead or ring 57 F~gure 5 is a cross-section of the feed fluid spacer 26 assembly of Figure 3 showing the feed fluid spacer material 32, the 27 perimeter sealing ring 40, the feed fluid distribution lines 48 and 28 the feed fluid space 50. In operation feed fluid enters notch 34Of , ~ ' ' ~ ~ , . ' ' ' .

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1 Figure 3 and travels througll the feed fluid spacer material being 2 I directed by distribution lines 50 to notch 36. The feed fluid is dire~ted 3 ¦ around central aperture 38. Feed fluid is pre~ented Crom b~passing feed 4 ¦ fluid s acer ~y perimeter sealing bead or ring 40.
5 I Figure 6 is a plan view of the Eeed fluid inlet distribu-6 ¦ tion plate 60 showing an inlet port 62 and a perimeter seal 64.
7 ¦The shape of the plate is circular and the same diameter as the 8 ¦membrane-permeate assembly.
9 ¦ Figure 7 is a plan view of a midsection and residue dis-10 ¦tribution plate 66 showing port 68 and central aperture 70. The 11 ¦shape is circular and the diameter is identical to the membrane-12 ¦permeate carrier assembly. The central ape~ture is the same diameter 13 ¦as the central aperture in the membrane-permeate carrier assemblv.
14 1 Figure 8 is an enlargement of the plates 60 and 66 shown 15 ¦in Figures 6 and 7 identifying the plate 60 (or 66) and perimeter 16 ¦ seal 72 in groove 74. It must be noted that plate 60 may be of 17 ¦almost any thickness and that alternate means may be employed to 18 ¦affect a seal at the perimeter.
19 ¦ Referring to Figures 9, 10 and 11, the stacked assembly 20 ¦is described as follows: feed port 76 consists of piPe 78 which 21 ¦is attached to and communicates through port 80 in bulkhead 82 22 ¦whlch contains the feed fluid pressure within vessel 84. Bulkhead 23 ¦82 is held in place by segmented ring 86 which is placed in groove 24 ¦88 of pressure vessel wall 84. ~he segmented rinq 86 is held in 25 ¦place by a snap ring or retaining ring 90 located ln groove 92 26 ¦in segmented ring 86. Feed fluid is prevented from leaking passed 27 ¦bulkhead 82 by means of seal 94 in groove 96 around the perimeter of 28 ¦bulkhead 82. Feed fluid holding cavity 98 slows down the velocity ~of the feed fluid. Feed fluld is directed by feed fluid distribu-'' .' ~'~

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tion plate 100 through port 102. Distribution plate 100 is sealed to the inside surface of the pressure vessel 84 by mea~s of seal 104 in groove 106 around the perime-ter of distribution plate 100.
Feed fluid is directed in-to the feed fluid distribution channel 108, formed by the registration of feed fluid spacer layers and membrane-permeate carrier assemblies of the stacked subassembly 110. Within stacked subassembly 110, feed fluid spacer layers 112 are alternated with membrane-permeate carrier assemblies 114. The membrane-permeate carrier assemblies 114 consist of two outward facing layers of membrane 116 sealed to the permeate carrier material 118 with peripheral adhesive line 120.
The feed fluid spacer layer 112 has a central aperture around which is formed a seal 122 with the active faces of the two layers of membrane 116 of the membrane-permeate carrier assembly 114. Registration of the layers forms the permeate collection and distribution channel 124 down the center of the stacked assembly.
On the opposite side of feed fluid distribution channel 108 i.s the residual collection and distribution channel 126 also formed by the cut out notches and the registration of the layers in the stacked assembly. Midsection distribution plate 128 distributes the residual fluid from the first stacked subassembly 110 through port 130 into the feed fluid distribution channel 132 of the second ~tacked ~ubassembly 134. A perimeter seal 136 in groove 138 prevents the residual fluid from leaking past the plate 128.
In second stacked subassembly 134 feed distribution channel 132, permeate collection channel 124 and residual channel .

~.290~5~3 140 are formed as described above. In third s-tacked subasse~bly 142 residual channel 144, permeate collection channel 124 and feed distributlon channel 146 are formed as described above. Residual fluid leaving - 22a -~ X

02~5~3 . .

1 ~ the third stacked subasse~bl~ 142 is directed by distribution 2 plate 1.48 through port 150 into the residual fluid cavit~. 152.
3 Permeate is carried down channel 124 through port 154 in distribu-4 tion plate 148. A suitable seal is formed at 156 between the feed fluid spacer layer and distribution Plate 148 around port 150 to 6 prevent the contamination or mixing of the feed fluid or residual 7 fluid with the permeate fluid. Permeate channel 124 extends 8 through the residual cavity 152 by means of pipe 158 sealed to dis-9 tribution plate 148 and bulkhead 160 at points 162. Permeate .
exits the stacked assembly via port 164 in bulkhead 160 and pipe 11 166 which i.s sealed to bulkhead 160 at point 168. Residual exits 12 the stacked assembly via port 150 in distribution plate 148 and 13 flows into residual cavity 152 and then out of the pressure housing 14 via port 170 through bulkhead 160 and via pipe 172 to bulkhead 160 at 17~.: Bulkhead 160 is held in place and sealed in a manner :
16 identical to that described for bul~head 82.
17 Another midsection distribution plate 176 separates second 18 stacked assembly 134 from third stacked assembly 142. The residual 19 fluid from the second stacked subassembly 134 passes downwardly through port 178 into feed fluid distribution channel I46.
21 As can be seen in Figure 10, each of the feed fluid 22 spacer layers 112 in each subassembly has a per.~.eter sealing ring 23 180 which is present around the edge of the feed fluid layer 24 except at the notches, as is explained above in regard to Figures 3 to 5.
26 For the present invention to function it is essential 27 that a leak free seal be formed between the face or active side of 2~ the membranes 116 and the feed spacer layer 112 around the central ~: . . . . . . . .

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~.~90~S8 ~8299-83 collection channel 124 at point 117 in Figure 11. On the feed fluid side of this seal ~he pressures can be quite high while on the permeate side of this seal the pressures are usually much Iower. This condition would force feed fluid into the permeate cavity if the seal is not complete and intact and strong enough to withstand this pressure differential. With some types of mem-branes which can be used in the practice of the present invention this problem is exacerbated by the fact that the membranes in service are brittle. An example being dried cellulose acetate membrane for gas separation. When sealant or adhesive is placed ; on the active side of the membrane a good bond can be made. How-ever, in service the outer perimeter of this adhesive or sealant line is stressed. The active surface of the membrane is very thin and since the adhesive or sealant does not penetrate the membrane but bonds to the active surface, cracks can develop causing leaks at this adhesive line. To remedy this problem the membrane must be reinforced at this sealant line.
Referring to Figure 12 a plan view of the back or porous side of a celLulose me~brane layer 116. A low viscosity epoxy, urethane or other suitable resin is placed around the perlmeter of the central collection channel 124. The resin is selected so that it penetrates into the porous substructure of -the membrane and ills the membrane. The resin is compressed cluring curing so that after the resin is cured the impregnated area is not thicker than the surrounding non-impregnated area. This impregnation step with a suitable resin is completed after the membrane layer has - 2~ -' ' .

:, . . .

0~5~3 been cut into the proper shape but before the membrane layer has been assembled into the membrane-permeate carrier assembly. In Figure 12, element 182 identifies the annular ring of impregnating - 24a -,;

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~.X9~5~3 1 ~ 9 ~) 1 ~ resin placed around central collection channel 124. Item 122 2 ¦ identifies the annular ring of sealant or adhesi~e tnat is ~,laced 3 ¦on the ac~ive side or face of the membrane. It snould be noted 4 ~that the im2regnating resin is ~iider than the bon~ing or sealant 5 ¦ring.
6 ¦ rigure 13 is a cross section of the central collection 7 ¦channel 124 similar to the view in Figure 11. In ~igure 13, layer 8 ¦112 is the feed fluid spacer, 116 is the membrane, 118 is the per-9 ¦meate carrier rnaterial and 186 is the membrane-permeate carrier 10 ¦assemblv. Item 122 is the sealant or adhesive bond formed or 11 ¦placed between the active or face side of the membrane 116 and the 12 ¦feed fluid spacer laver 112. Item 1~2 is the area of thc resin ïm-13 ¦pregnated membrane that reinforces the sealant line 122 at the in-14 ¦terface with membrane 116. ~oin~ 188 is the area where the ~er~eate carrier15 ¦materialll~ has Eluid oommunication with the central collection channel 124.
16 Referring to Figure 14 a cross section of the stacked 17 assembly showing the path of the feed fluid, the residual fluid 18 and the permeate fluid through the assembly. In operation, the 19 feed fluid enters feed fluid port 7G passes through bulkhead 82 and passes into feed fluid holding cavity 9~. The feed fluid passes 21 through port 102 in the feed fluid distribution plate 100 into 22 the first stacked subassembl~ 110. The feed fluid spacer layers 23 and the membrane-permeate carrier assemblies are assembled together 24 in a manner so that the notches in each la~er are in register or alignment. The alignment or registration of said la~ers forms 26 two channels 108 and 126 down the sicles and a channel 124 down the 27 center of the stacked assembly. Distribution plate 100 is so posi-28 tioned to place the feed fluid distribution port 102 over channel , .

~.Z~2~8 6829g-83 108. It must be noted that the notches cu-t into each layer of material may be of various shapes and sizes. The size would most logically be de-termined to be as small as possible while maintain-ing acceptable fluid velocity rates. The size, shape and position of the notches cut into each layer would generally be identical to all other layers within a subassembly. The location of the notches may also be positioned at points other than opposed to each other. They could be positioned next to each other with only a thin wall of material separating them. In effect the separation of the notches could be as little as one radial degree and as much as 180 radial degrees. Feed fluid enters this channel 108 and is prevented from traveling downward in channel 140 by midsection distribution plate 128. Feed fluid is forced to flow into the first stacked subassembly lI0 and into the feed fluid spacer layers in parallel toward channel 126 formed on the opposite side of the stacked assembly by the registration of the notches. This channel 126 becomes the residual fluid collection channel. The residual fluid from stacked subassembly 110 leaves the residual fluid collection channel 126 through port 130 in midsection distribution plate 128. This residual fluid after passing through distribution plate 128 becomes the feed fluid for the next sub-assembly 134 and is distributed down the feed fluid distribution channel 132 into the feed fluid spacer layers of this subassembly.
As the feed fluid passes throuyh the feed fluid spacer layers the more permeable component of the feed fluid passes through the membrane and into the permeate carrier material. The permeate ;

' : , ,,, . , ~ Z~9~;~.5~3 ~8299-~3 -flows toward the area of less pressure which i8 the central area of the membrane--permea-te carrier assembly. The permeate enters this permeate collection channel 124 and is joined by permeate - 26a -~ '.

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2 from other layers and subassemblies. The permeate flo-~s dot.~n _entral channel 12~ formed by the registration of the cer.tral 3 ~oles in the membrane-permate carrier assemblies and the central 4 loles in the feed fluid spacer layers and out of the assembly 5 through the permeate outlet port 166.
6 The feed fluid that entered subassembly 134 through the 7 feed fluid distribution channel 132 flows through the feed fluid 8 spacer layers to channel 140 on the other side of the assembly. Th 9 fluid then becomes the residual fluid for this subassembly, 13a, and leaves this subassembly via channel 1~0 and port 17~ in midsec-11 tion distribution plate 176. The fluid entering subassembly 142 12 becomes the feed fluid for this subassembly. The feed fluid 13 passes down feed fluid distribution channel 146 and flows ln 14 parallel through the feed fluid spacer layers of this subassembly.
The fluid collects in channel 1~4 where it becomes the residual ~6 fluid from this subassembly. The residual leaves subassembly 142 17 via port 150 in the residual distribution plate 148. The so direc-18 ted residual fluid enters the residual cavity 152 and out of the 19 stacked assembly via residual fluid exit port 170 in bulkhead 160.
It is understood that there may be many subassemblies 21 formed within one stacked assembly. The number of subassemblies 22 is determined by the amount of the more ~ermeable component of 23 the feed fluid that is to be removed by the membrane. In effect, 24 the more subassemblies are built into the stackecl assembly the longer the path length the feecl fluid remains in contact with the 26 membrane and the higher the recovery or removal of the more 27 permeable component of the feed fluid mixture. The number of feed 28 fluid spacer layers and the number of membrane-permeate carrier ,,: ' ,: . .
'~ ' ' ` ' ;. ~

5~3 1 assemblies contained in each subassembl~ is de-termined b~ t.~e o~ti-2 mum feed fluid velocit~7 through the feed flui~ s~acer la~ers. For 3 a given feed fluid volume entering the feed fluid distribution L~ channel the feed fluid velocity through a sin~le feed fluid spacer layer is determined bv the number of feed fluid spacer layers 6 present in the subassembly. ~he greater the number of feed fluid 7 spacer layers configured in parallel the lower the feed fluid 8 velocity through a single layer. ~n advantage of the instant inven-9 tion over existing art is that it is possible to configure a single pressure vessel to give virtually any recovery level desired.
11 This is not possible to do in membrane assemblies using hollow fine 12 fibers or spiral wound elements.
13 Referring again to Figure l4, there is a differential 14 pressure formed across the stac~ed assembly between the feed fluid holding cavity 98 and the residual cavity 152. ~his pressure dif-16 ferential is so formed because of the friction and consequent 17 pressure drop of the fluid flowing through the feed spacer layers.
18 The embodiment of the present invention described above utilizes 19 this pressure differential between cavity 98 and cavity 152 to compress the stacked assembly. Residual distribution plate 148 is 21 fixed in plac~ and cannot move. Feed distribution plate lO0 and 22 all midsection distribution plates are free floating and can move 23 downward toward the residual distrlbution plate putting com~ressive 24 force on the layers of the stacked assernbly. This is helpful in ~orming leak ~ree seals between the outward facing surface o~ the 26 ~embrane and the feed fluid spacer layers around the central aper-27 ture. In fact, it is pc,ssible with some membrane and feed fluid 28 spacer cornbinations to form a d~namic seal at this point.

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5~3 Figure 15 is a cross sectional drawin~ of an alternate em~odiment of the instant invention. In t'his Figure the pressure vessel and stacked assembly inside the vessel are identical with that shown in Figure 9 except for the presence of a drawbar 190 down the center channel and drawbar tightening apparatus. Drawbar 190 exits the vessel assembly throu~h permeate outlet port 166 and passes through seal gland 192 and seal 194 to tightening nut 196.
Drawbar 190 is threaded on the end so that when nut 196 is tightened drawbar 190 is pulled out of t'he vessel. The other end of drawbar 190 is screwed into feed distribution plate 100 at 198.When the drawbar is pulled out of the vessel assembly the effect is to put compressive force on the stacked assembly. This compressive force may be needed to prevent the feed fluid from leaking past the feed fluid seal formed around the central aper-ture in the membrane-permeate carrier assembly. The compressive force exerted on the stacked assembly by the drawbar being pulled out of the vessel assembly is in addition to the compressive force exerted by the pressure differential between cavities 98 and 152.
Permeate fluid exits the stacked assembly via a tee connection 200.
It is understood that there are many me-thods to form a seal around drawbar 190 and to pull drawbar 190 out of the pressure vessel assembly and t'ha-t those methods would become apparent to those skilled in the art. Such me-thods are intended to fall with-in t'he ~cope of the appended claims.

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, ,. ,; , ,~: , ~ 29~)2S~3 6829~-83 Figures 16, 17 and 18 are modifications of the instant invention. In Figure 16 the pressure vessel is closed by pipe flan~es. Standard weld-on flanges 218 are welded to the pipe of the pressure vessel and the internal welds are ground smooth at 202. A blind - 29a -, ~.29~25~3 G, 1 flange 20~ is ported at 206 on the feed inle~ end and at 208 and 2 210 on the residual end. Flange 20~ is ileld b~ the nut 21~ and 3 bolt 214 assembly. Gasket ~16 is Dositioned between blind flange 4 204 and weld on flange 21~. All other ~arts of -the stac~ed assem-bly are as described in Eigures 9, 14 and 15.
6 Flgure 17 is a cross section of a modification of the 7 pressure vessel shown in ~igure 16. In ~iaure 17 the feed inlet 8 port 220 is through the side of the vessel. The residual port 222 9 could also be similarly placed. Permeate out port 224 is as depicted in ~igure 16. Stacked assembly is item 228.
11 Eigure 18 is a modification of the vessel arrangement 12 shown in Figure 17 where the feed fluid enters the pressure ~essel 13 assembly in the center of the vessel and the residual and permeate 14 fluids are taken out of each end of the vessel.
It is understood that there are many methods to close the 16 pressure vessel of the present invention and would become apparent 17 to those skilled in the art. Such methods are intended -to fall 18 within the scope of the appended claims.

DESCRIPTION OF A SECO~D EMBODIMENT

22 In the embodiment described in Fi~ures 1 through 18 the 23 membrane and associated materials are of a circular shape. A
24 Isecond embodiment uses membrane and associated materials in a Isemicircular shape. Fi~ure 19 is a plan view of the membrane-26 carrier assembly 300 showing the semicircular shape. Perimeter ad-27 hesive line 302 is continuous around the perimeter of the assembly 28 300. As noted a dashed line is drawn through the center line of the ,. :

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~29~)2.~3 1 central per~eate collection channel 30~ parallel to the line of the cut 2 through the assemblv 300. The distance of the space from the 3 center line to the edge of the assemblv is aiven as ~istance 306.
4 A tab 308 protrudes from the side of the assembly 300 to form and enclose the permeate collection channel 304. Perimeter adhesive 6 is placed as shown by item 310 of Figure 19. The perimeter adhesive 7 line is absent from area 312 thus providing a communication channel 8 Prom the main area of the assembly 300 to the central permeate col-9 lection channel 304. Two areas 314 and 316 are shown. The pur~ose of these areas is discussed hereinbelow.
11 Figure 20 is a plan view of the feed fluid spacer layer 12 318 for this second embodiment. Item 320 of this Figure is the 13 perimeter seal ring around the perimeter of the feed fluid spacer 14 layer 318 except in areas 322 and 324 where the perimeter sealing ring is absent. The seal is present in area 326 around the peri-16 meter of the central permeate collection channel 304. The shape 17 and area of the feed fluid spacer layer is the same as the membrane .
18 carrier assembly 300. ~his configuration of the feed fluid spacer 19 layer 318 has no feed fluid distribution lines.
Figure 21 is a plan view of an alternate form of the feed 21 ~luid spacer layer for this embodiment showing fee~ fluid distri-22 bution lines 327. Perimeter sealing ring 320 i9 absent from areas 23 328 and 330 but present at area 326. In operation feed fluid 24 enters the feed fluid spacer layer at point 328 and travels to exit from the feed fluid spacer at point 330, the feed fluid could 26 also enter at point 33'0 and travel to and exit from point 328.
27 In both cases being directed by feed fluid distribution lines 327.
28 ¦It must be noted that many different configurations of feed fluid ~ I -31-.... , ~ . ,-::' ~ ' - -', ' ': ' :

~ 2~5~3 dis-tribution lines may be employed. It is desirable to arrange the feed fluid distribution pattern to the feed fluid being processed. Such configurations would -ta~e into effect feed fluid composition, viscosity, velocity, temperature and any other factors that are important.
Figure 22 is a plan view of a membrane-carrier assembly 300 placed in registration with a feed fluid spacer layer 318.
When the two layers are placed in such a registration it can be seen t'hat two c'hannels are formed 314 and 316. A central permeate collection channel 304 is also formed~ ~rea 332 is the active area of the membrane portion of the membrane-carrier assembly 300 and item 334 is the area of the feed fluid spacer layer 318.
Figure 23 is a plan view of the feed fluid inlet distri-' bution plate which is generally similar to Figure 6.
Figure 24 is a plan view of the membrane-permeate carrier assemblies 300 in registration with feed fluid spacer layers 318. Feed fluid is shown entering feed fluid distribution channel 314 and being distributed through the feed fluid spacer layers 31~ -to residual distribution channel 316. Permeate enter-ing the permeate carrier material travels to the central permeatecollection channel 304 which is formed by the registration of a plurality of the feed fluid spacer layers 318 and membrane-carrier assemblies 300. Figure 24 diEers Erom Figure 22 in showing the general direction of the fluid flow. rrhe operation of the device is further shown by Figure 25 to which we now turn.
E'i~ure 25 depicts the operation of t'he .se~licircular embodiment of the present invention. In many respects, the struc-ture of Figure 25 parallels that of E'igures 9 and 14. Feed fluid , ' ' ' ' ' ~ ~9C325~

1 ~enters the vessel at point 336 into feed cavity 338 and ~asses 2 ¦through feed fluid distribution port 1~2 in distribution plate 3 ¦160. The feed fluid enters subassemblv 340 and into the feed ¦fluid distribution channel 314 and travels through the feed fluid 5 ¦spacer layers 318 to channel 316. This is the residual collection 6 ~channel for this subassembly 3ao. The fluid flows throu~h port 7 1342 in distribution plate 344. The component of the feed fluid 8 ¦that permeates the membrane travels across the surface of the 9 ¦membrane into the permeate carrier material and into the permeate 10 ¦collection channel 304. Pe~imeter sealing bead or ring 320 on feed 11 ¦fluid spacer layers 318 forms a seal to the inside wall of the ves~
12 ¦sel to prevent feed fluid from bypassing subassemblies 340 and 346.
13 ¦The feed fluid entering second subassembly 34G is distributed 14 ¦through the feed fluid spacer layers in parallel toward the residual collection channel 316. The residual fluid collects in channel 316 16 and passes out of this second subassembly via port 348 in distri-17 bution plate 350. ~he residual fluid then enters the residual 18 fluid cavity 352 and then exits the assembly via port 354. The 19 permeate exits the assembly via port 356. This Fi.gu-e 25 depicts a stacked assembly utilizing ~eed fluid spacer layers as shown 21 in Figure 20. These feed fluid spacer layers are devoid of feed 22 fluid di.stribution lines. If feed f].uid spacer layers of the 23 type clepicted in Figure 21 had been shown, the fluid distribution 2L~ through these layers would have been different.
It will be understood that subassemblies 340 and 346 are 26 each a stack of units of the type depicted in Figures 22 and 24 27 and there may be many such subassemblies per vessel. It is also 28 understood that the pressure vessel hardware has been omitted from this drawing for clarity.

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2 I DESCRIPmI~i\7 OF A THII~D EI~IBODI~lE~T

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5 1 An alternate configuration of the present invention is 6 ¦shown in Figure 26, a plan view of a membrane-permeate carrier as-¦sembl~. The membrane-permeate carrier assemblv is shown as a circu-78 ¦lar shape with the notches 400 and 402 placed on either side of the 9 ¦non-central permeate collection channel 404. In cross section this 10 ¦assembly would be identical with that described in Figure 2. The 11 ¦perimeter adhesive line ~06 is absent in area 408 of Figure 26 to 12 ¦allow for the communication of the permeate carrier material and ¦ the non-central permeate collection channel 404.
¦ Figure 27 is a plan view of a feed fluid spacer laver show-14 ¦l ing a possible ~eed fluid distribution pattern~ Feed enters at410 and exits at 412. The distribution lines are indicated as 414 67 and the spaces between as 416.
When membrane-permeate carrier assemblies are interposed 18 between feed fluid spacer layers and are placed in registration 19 the feed fluid and residual fluid collection and distrlbution 21 channel are formed by the notches 400 and 402. The permeate 22 collection channel 404 is also so formed.
23 Figure 28 is a plan view of the feed fluid distribution 24 plate 418 showing the port 428 and perimeter seal 422.
Figure 29 is a plan view of the midsection and residual 26 fluid distribution plates 424 showin~ the port 426 for feed fluid 27 and residual fluid and port 428 for permeate fluid. ~lement 430 is the perimeter seal. It is to bc undcrstood that notchcs 400 28 and 402 could be located at other points.
'' ` : ' ~ -34-`` : , : ~ ~ . :
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~.Z~ 5~3 Q, 1 In operation the embodiment would operate in a manner as 2 described in ~igures 9 and 1~. The difrerence heing that the 3 permeate is collected in a non-central channel.

DESCRIPTION OE A EO~IRTH E~IB~DIMENT

7 , Figures 30 and 31 show an alternate configuration of the 8 ,present invention. Elere the shape of the various components are Isquare or rectangular instead of circular. Figure 30 sho~s the membrane-permeate carrier assembly. Figure 31 shows the feed fluid 11 ,spacer layer. Generally, the arrangement is the same as described 12 in ~i~ures 1 through 13. In operation the stacked assembly would 13 be inserted into a square or rectangular vessel and operation 14 ,would be identical with that described in Figures 9 and 14.

16 DESCRIPTIO~ OF A FIF~H EMBODIr~E~T

18 Previously described embodiments of the instant invention 19` ~have shown the various layers of the stacked assembly inserted directly into the pressure vessel. Each feed fluid layer forms 21 a seal between itself and the interior of the pressure vessel to 22 prevent the feed fluid from by-passing the membrane la~ers. A
23 urther embodiment of the present invention presents a modular 24 approach to placing the stacked assembly into the pressure vessel.
In this embodiment, the stacked assembly is modular in construction 26 making it possible for the stackecl assembly to be installed and 27 removed from the pressure vessel as a unit or module, rather than 28 as individual layers or groups of layers.

, , ?025~3 1 Figure 32 shows a vie~ of a circular version o~ the 2 stacked assembly (as described in Figur~ 9) in a modular con.~ig~r-3 lation. The permeate tube 500 is ~assed through to~ plate sn2 an~
4 ¦sealed into plate 504 at point 506. Feed fluid ~ort 507 through 5 Itop plate 502 passes feed fluid into holding cavit~ 508. ~he 6 ¦feed fluid passes into the stacked assembly through ~ort 510 in 7 ¦plate 504. The layers of the stacked assembly in area 512 are 8 ¦identical fo those described in Figures 9 and 25. Mid-section dis-9 ¦tribution plates 514 and 516 are shown. A residual distribution 10 ¦plate is shown as item 518.- Residual fluid leaves the residual 11 cavity 520 by means of port 522 in bottom plate 524. Permeate 12 fluid can leave the module by either end of the permeate tuhe at 13 501 or 500~ On each end of the module, the permeate tube has a 14 means of connection with another module or to the perrneate exit l5 pipe. This connection may be by means of a flange and O-ring or 16 gasket arrangement or by means of threaded connections, such as a 17 union. Shown at 530 is a flange arrangement utilizing a gasket 18 and clamp arrangement.
19 When the module is assembled with all of the required layers in registration and the distribution an~ top and bottom 21 plates in place the device is overwrapped with a suitable materiai 22 to provide a fluid barrier and mechanical strength. The outer 23 wrap 534 may be of an elastomer or of fiber reinforced plastic.
24 To force feed fluid to enter the module a seal 536 is installed 25 in a suitable groove in top plate 502. This seal touches the 26 interior wall of the pressure vessel forming a barrier to the feed 27 fluid.
28 ¦ Alternatively, the stacked assem~ly can be enclosed ln a I .
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~ 290~5~

thin-walled vessel or pipe of metal or plastic. The top and bottom plates can be bonded to the vessel or pipe at each end.
It is understood that this modular embodiment of the present inven-tion can utilize the semicircular or the non-central permeate collection embodiments.
Figure 33 shows an assembly of several of the modules of Figure 32 in a pressure vessel. Module 538 is situated inside pressure ve~sel 540 with end flange 542 welded onto vessel 540 and end cap 544 held in place with bolts 546. Feed fluid enters vessel through port 5~8 and enters cavity 550 and passes into the stacked assembly module 518 via port 507. Feed fluid is prevented from by-passing the module by feed seal 552. The residual fluid leaves the first module and enters cavity 554 where it becomes the feed for the next module 556. Modules are connected together and to ~he permeate outlet pipe 558 by connection 532. This permeate is recovered via line 558 and 560. It is understood that the modules of the present invention can be inserted into any suitable pressure containment vessel. The advantage of this embodiment of the present invention is that it is easy to install and replace membrane modules in the pressure vessel in the field.
~ aving fully described the invention, it is intended that it be limited only by the lawful scope of the appended claims.

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Claims (18)

1. A device for the separation of two or more different materials comprising a pressure vessel adapted to contain fluid under pressure, an inlet for admitting fluid to be separated to said vessel, a first outlet for removing residue from said vessel, a second outlet for removing permeate from said vessel, and a plurality of separator elements within the pressure vessel between the inlet and the outlets, said separator elements each comprising a pair of separator membranes and a permeate carrier element abutting the opposed faces of the membranes to carry away permeate, said separator elements being arranged in superposed relationship within the pressure vessel and themselves being spaced apart to provide distribution zones through which a lateral flow of feed fluid to be treated can pass across the active faces of the membranes, the separator elements being arranged as a stack, said separator elements with gaps being provided between the edge of each separator element and the inner wall of the vessel at two spaced apart points with the gaps of adjacent separator elements being in registration with one set of registering notches forming a feed channel in fluid communication with the inlet for fluid to be separated and the other set of registering gaps forming a residue collection channel in fluid communication with the first outlet, said distribution zones being in communication with the feed and residue collection channels at said gaps, and each said separator element also having an internal aperture in fluid communication with the permeate carrier element, the internal apertures of the stacked separator elements, being in registration with internal apertures through the distribution elements to define a permeate collection channel in fluid communication with said second outlet, characterized in that for each separator element the gaps are provided by notches extending inwardly of the peripheral edge of the separator element, in that the distribution zones are provided by distribution elements provided between, and being shaped similarly to, the successive separator elements of the stack, there being no direct communication from the interior of the distribution elements to the permeate collection channel, and in that the peripheral edges of the separator and distributor elements are in sealing contact with each other to form the stack, said distribution elements being edge sealed against incursion of feed fluid except at said notches.

2. A device according to claim 1, wherein the feed fluid inlet is located mid-way along the length of the pressure vessel and residue and permeate outlets are provided at both ends of the vessel, separate stacks being provided in the vessel between the central inlet and the respective ends of the vessel.

3. A device according to claim 1, wherein an array of said stacks is provided with the stacks being disposed end-to-end in said pressure vessel, the residue from one stack providing the feed fluid to the next stack.

4. A device according to claim 1, 2 or 3 wherein said membranes are reinforced adjacent to said internal apertures.

5. A device according to claim 1, 2 or 3 wherein said distribution element is sealed against fluid communication of its interior with the permeate collection channel.

6. A device according to claim 1, 2 or 3 wherein said membranes and permeate carrier elements are sealed around their edges to prevent the incursion of feed material.

7. A device according to claim 1, 2 or 3 wherein said distribution elements contain feed fluid distribution lines.

8. A device according to claim 1, 2 or 3 wherein said permeate carrier element is a woven or knitted material.

9. A device according to claim 8 wherein said permeate carrier element is a woven or knitted material reinforced with a plastics resin.

10. A device according to claim 1, 2 or 3 wherein the separator elements have a flat, disc-like configuration.

11. A device according to claim 1, 2 or 3 wherein the pressure vessel is an elongated rectangular vessel.

12. A device according to claim 1, 2 or 3 wherein the internal apertures are arranged to be in registration centrally of the pressure vessel.

13. A device according to claim 1, 2 or 3 which comprises a pair of said stacks arranged side-by-side, the separator elements of each stack being configured to form said notches between the stacks, the two stacks being in common registry at said internal apertures.

14. A device according to claim 1, 2 or 3 wherein the stacks are provided with end plates adapted to seal against the internal wall of the pressure vessel, said end plates being provided with apertures therethrough as required for communication with the feed inlet and the residue and permeate outlet channels.

15. A device according to claim 1, 2 or 3 which comprises a plurality of modular units sealingly inserted into the pressure vessel, each said modular unit comprising one or more of said stacks with permeate connection tubes being provided at opposite ends of each module for sealing communication with the permeate tube of an adjacent module.

16. A device according to claim 1, 2 or 3 wherein said membrane is an ultra-filtration membrane.

17. a device according to claim 1, 2 or 3 wherein said membrane is a reverse osmosis membrane.

18. A device according to claim 1, 2 or 3 wherein said membrane is a gas separation membrane.