GB2137528A - Membrane pack - Google Patents
Membrane pack Download PDFInfo
- Publication number
- GB2137528A GB2137528A GB08412693A GB8412693A GB2137528A GB 2137528 A GB2137528 A GB 2137528A GB 08412693 A GB08412693 A GB 08412693A GB 8412693 A GB8412693 A GB 8412693A GB 2137528 A GB2137528 A GB 2137528A
- Authority
- GB
- United Kingdom
- Prior art keywords
- carrier
- insert
- hole
- membrane
- edge
- 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.)
- Granted
Links
- 239000012528 membrane Substances 0.000 title claims abstract description 66
- 239000012530 fluid Substances 0.000 claims abstract description 21
- 238000003466 welding Methods 0.000 claims abstract description 8
- 238000000034 method Methods 0.000 claims description 5
- 229920001169 thermoplastic Polymers 0.000 claims description 3
- 238000000746 purification Methods 0.000 abstract description 5
- 229920000642 polymer Polymers 0.000 abstract description 2
- 239000012466 permeate Substances 0.000 description 8
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 8
- 239000000853 adhesive Substances 0.000 description 6
- 230000001070 adhesive effect Effects 0.000 description 6
- 239000012141 concentrate Substances 0.000 description 6
- 238000007789 sealing Methods 0.000 description 5
- 239000002351 wastewater Substances 0.000 description 4
- 241000894006 Bacteria Species 0.000 description 2
- 229920001084 poly(chloroprene) Polymers 0.000 description 2
- 239000013464 silicone adhesive Substances 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 239000000706 filtrate Substances 0.000 description 1
- 230000009969 flowable effect Effects 0.000 description 1
- 230000002209 hydrophobic effect Effects 0.000 description 1
- 230000004941 influx Effects 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 229920001296 polysiloxane Polymers 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 239000000565 sealant Substances 0.000 description 1
- 239000002910 solid waste Substances 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D63/00—Apparatus in general for separation processes using semi-permeable membranes
- B01D63/08—Flat membrane modules
- B01D63/082—Flat membrane modules comprising a stack of flat membranes
- B01D63/084—Flat membrane modules comprising a stack of flat membranes at least one flow duct intersecting the membranes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C63/00—Lining or sheathing, i.e. applying preformed layers or sheathings of plastics; Apparatus therefor
- B29C63/0082—Finishing the edges of holes or perforations in the lined product
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C65/00—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor
- B29C65/02—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure
- B29C65/08—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using ultrasonic vibrations
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C66/00—General aspects of processes or apparatus for joining preformed parts
- B29C66/40—General aspects of joining substantially flat articles, e.g. plates, sheets or web-like materials; Making flat seams in tubular or hollow articles; Joining single elements to substantially flat surfaces
- B29C66/41—Joining substantially flat articles ; Making flat seams in tubular or hollow articles
- B29C66/43—Joining a relatively small portion of the surface of said articles
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C66/00—General aspects of processes or apparatus for joining preformed parts
- B29C66/70—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material
- B29C66/73—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material characterised by the intensive physical properties of the material of the parts to be joined, by the optical properties of the material of the parts to be joined, by the extensive physical properties of the parts to be joined, by the state of the material of the parts to be joined or by the material of the parts to be joined being a thermoplastic or a thermoset
- B29C66/739—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material characterised by the intensive physical properties of the material of the parts to be joined, by the optical properties of the material of the parts to be joined, by the extensive physical properties of the parts to be joined, by the state of the material of the parts to be joined or by the material of the parts to be joined being a thermoplastic or a thermoset characterised by the material of the parts to be joined being a thermoplastic or a thermoset
- B29C66/7392—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material characterised by the intensive physical properties of the material of the parts to be joined, by the optical properties of the material of the parts to be joined, by the extensive physical properties of the parts to be joined, by the state of the material of the parts to be joined or by the material of the parts to be joined being a thermoplastic or a thermoset characterised by the material of the parts to be joined being a thermoplastic or a thermoset characterised by the material of at least one of the parts being a thermoplastic
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2313/00—Details relating to membrane modules or apparatus
- B01D2313/04—Specific sealing means
- B01D2313/041—Gaskets or O-rings
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C66/00—General aspects of processes or apparatus for joining preformed parts
- B29C66/01—General aspects dealing with the joint area or with the area to be joined
- B29C66/05—Particular design of joint configurations
- B29C66/10—Particular design of joint configurations particular design of the joint cross-sections
- B29C66/13—Single flanged joints; Fin-type joints; Single hem joints; Edge joints; Interpenetrating fingered joints; Other specific particular designs of joint cross-sections not provided for in groups B29C66/11 - B29C66/12
- B29C66/137—Beaded-edge joints or bead seals
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Manufacturing & Machinery (AREA)
- Separation Using Semi-Permeable Membranes (AREA)
Abstract
A membrane pack (18) for a fluid purification apparatus comprises a porous carrier (74) on the faces of which are located membranes (70,72). The carrier is sealed at the edge of holes (22) formed in the pack by inserting a non-porous polymer ring (76) in a hole (78) in the carrier (74) and ultrasonically welding the membranes (70,72) to the ring (76). <IMAGE>
Description
SPECIFICATION
Membrane pack
This invention relates to a membrane pack and to a method of joining or sealing a membrane to a porous carrier.
The purification of waste water or other fluids can be accomplished by the use of membrane packs which include membranes lying on the outside of a highly porous carrier. Feed fluid such as waste water can be applied under pressure to the outside of the membrane pack, so that permeate such as pure water can pass through the membrane into the porous carrier and travel along the carrier to a permeate outlet. U.S. Patent 4, 025,425 by Croopnick et al, describes an apparatus of this type wherein the feed fluid (e.g. waste water) passes between membrane packs, permeate (e.g. pure water) passes through the membranes into the carrier and is expelled from the extreme periphery of the carrier, and the concentrate (left after much of the permeate has been removed) passes through several large exit holes in the pack to reach a collecting location.At any location where an edge of the membrane pack comes in contact with impure fluids such as the feed fluid or concentrate, as occurs in the exit holes of the device in the above-mentioned patent, there is danger of contamination of the permeate. It is necessary to construct such edges to securely seal the pores of the carrier against the influx of impure fluid, and to seal the carrier to the membranes to prevent leakage of impure fluid between them. A very secure seal is required in many applications, such as where the feed fluid and concentrate contain bacteria that could contaminate a pure water filtrate.
The sealing of a membrane structure to a carrier is complicated by the fact that many of the most useful membrane structures must be kept continuously wet, and are irreparably damaged if allowed to dry for even a short period of time. One technique for sealing a carrierto such membrane structures isto utilize a hydrophobic adhesive such as a silicone adhesive to join them, since water will not wet the silicone and it therefore can join to the surface of a membrane structure. However, silicone adhesives cannot be utilized in the presence of certain chemicals with a high pH such as 10 to 12 or more, as are encountered in the pulp processing industry. Other adhesives such as neoprene can provide a strong joint that is useful in the presence of such chemicals, but neoprene is wetted by water and will not stick to a wet membrane structure.
According to the present invention there is provided a membrane pack with a sealed edge comprising:
a sheet-like carrier which is permeable to the lateral flow of fluid therein, said carrier having an edge;
an insert of substantially nonporous thermoplastic polymer lying in the same plane as the carrier and having a first edge lying against said edge of said carrier but free of interlocking connection therewith, and an opposite second edge forming an edge of the membrane pack; and
a membrane structure lying over a face of said
carrier and extending beyond said carrier edge to lie
over said insert, said insert being heat welded to the
portion of said membrane structure which lies
beyond said carrier edge, whereby to seal the carrier
against the inflow of fluid therein which passes
across said second edge of the insert.
Also according to the present invention there is
provided a method for forming a membrane pack
having a fluidsealed edge, comprising:
laying a nonporous insert that has a hole, in a hole
of a carrier to fit closely within the carrier hole, but with the insert and carrier being free of interlocking connection;
laying a membrane structure having a hole that is smaller than said carrier hole, over said carrier and
insert and with the membrane structure hole substantially aligned with the insert hole; and
ultrasonically welding said membrane facewise to said insert.
The invention will be best understood from the following description of a preferred embodiment thereof, given by way of example only, reference being had to the accompanying drawing, wherein:
Figure 1 is a partial perspective and sectional view of a purification apparatus;
Figure 2 is a partial sectional view of the purification apparatus shown in Figure 1;
Figure 3 is an enlarged sectional view of a portion of a membrane pack of the apparatus of Figure 2, with the vertical dimensions exaggerated; and
Figure 4 is a plan view, partly broken away of the membrane pack of Figure 3.
Figures 1 and 2 illustrate portions of a purification apparatus 10 which can receive a feed fluid such as waste water, and separate out a selected portion such as pure water, from the rest of the feed fluid which may contain solid waste particles including bacteria. In the particular apparatus 10, feed fluid is pumped along a central passageway 12, while the apparatus is rapidly rotated about its axis 14. The feed fluid passes through spaces 16 between membrane packs 18 of the apparatus to flow rapidly outwardly. During such flow, a component (e.g. pure water) of the feed fluid which can pass through membranes of the membrane packs 18, passes into the inside of the membrane packs. Such fluid, which may be referred to as permeate, moves radially within the membrane packs until it reaches the extreme peripheries of the packs and flies out against a wall 20 where it is collected.The portion of the feed fluid left after permeate has passed out of it, and which may be referred to as a concentrate, passes upwardly through aligned holes 22 in the membrane packs, for removal from the apparatus.
The membrane packs must be securely sealed in the regions immediately around the holes 22, to assure that concentrate moving through the holes does not enter any of the membrane packs 18 to mix with the permeate moving therethrough.
Figures 3 and 4 show a portion of a membrane pack 18, in the region which includes a hole 22 through which concentrate passes. The pack includes a highly porous carrier 74, and membrane structures 70, 72 lying over either face of the carrier.
A ring-shaped insert 76 of thermoplastic polymer lies closely within an enlarged hole 78 formed in the carrier. Although the carrier 74 is porous, the insert 76 is nonporous. The holes 22 in the membrane structures and the hole 82 in the insert are of substantially the same diameter. The faces of the insert 76 are sealed to the membrane structures by ultrasonic welding. Where the membrane structures are unbacked, they can be directly sealed to the insert without the use of any impregnating.
As described in our patent application 8204128 (G.B. 2092914), from which this application is divided out, the use of ultrasonic welding enables a wet membrane to be welded to an underlying polymer layer without first drying the membrane.
The insert 76 is initially thicker than the carrier 74, and is reduced in thickness in the course of ultrasonic welding. A membrane pack of the type shown in
Figures 3 and 4 has been constructed using an insert 76 of Veristrate, a double sided sealant tape manufactured by the 3M Company. An adhesive was utilized, not because of its adhesive characteristics, but because it has a low melting temperature, to avoid damage to the membrane. The adhesive will not stick to a wet membrane. The ultrasonic welding displaces the water on the membrane structures, and heats the adhesive so it is more flowable and active. The carrier 74 was about 50 mil (1.27 mm) thick, while the insert 76 was initially about 10 (0.254 mm) to 30 mil (0.162 mm) thicker. A stop was utilized on the welding horn to limit compression of the insert. The insert had an inside hole diameter of about 2 inches (50.8 mm) and an outside diameter of about 2-1/4 inches (57.15 mm).
The preferred embodiment of the invention provides a pack and method for constructing it, which enables the secure sealing of an edge of the carrier and secure sealing of the membrane structures lying against one or both surfaces of the carrier, and which is useful in joining a wet membrane structure.
Claims (4)
1. A membrane pack with a sealed edge comprising:
a sheet-like carrier which is permeable to the lateral flow of fluid therein, said carrier having an edge;
an insert of substantially nonporous thermoplastic polymer lying in the same plane as the carrier and having a first edge lying against said edge of said carrier but free of interlocking connection therewith, and an opposite second edge forming an edge of the membrane pack: and
a membrane structure lying over a face of said carrier and extending beyond said carrier edge to lie over said insert, said insert being heat welded to the portion of said membrane structure which lies beyond said carrier edge, whereby to seal the carrier against the inflow of fluid therein which passes across said second edge of the insert.
2. The membrane pack described in claim 1, wherein:
said carrier has a hole with walls forming said carrier edge, said insert is of annular shape and lies closely within said hole, and said membrane has a hole of about the same diameter as the inside diameter of said annular insert and is aligned therewith.
3. A membrane pack comprising:
a porous sheet-like carrier having a hole;
a substantially ring-shaped nonporous insert lying closely within said carrier hole, but with said insert being free of undercut surfaces interlocking with said carrier, to permit simple placement of the insert in the hole; and
a membrane structure lying over said carrier and having a hole of about the same diameter as the hole in said ring-shaped insert;
the holes in said membrane structure and insert being aligned, and said membrane structure and insert being aligned, and said membrane structure being joined facewise to said insert.
4. A method for forming a membrane pack having a fluid sealed edge, comprising:
laying a nonporous insert that has a hole, in a hole of a carrier to fit closely within the carrier hole, but with the insert and carrier being free of interlocking connection.
laying a membrane structure having a hole that is smaller than said carrier hole, over said carrier and insert and with the membrane structure hole substantially aligned with the insert hole; and
ultrasonically welding said membrane facewise to said insert.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB08412693A GB2137528B (en) | 1981-02-13 | 1984-05-18 | Membrane pack |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US06/234,394 US4576715A (en) | 1981-02-13 | 1981-02-13 | Membrane pack and method of making |
GB08412693A GB2137528B (en) | 1981-02-13 | 1984-05-18 | Membrane pack |
Publications (3)
Publication Number | Publication Date |
---|---|
GB8412693D0 GB8412693D0 (en) | 1984-06-27 |
GB2137528A true GB2137528A (en) | 1984-10-10 |
GB2137528B GB2137528B (en) | 1985-06-26 |
Family
ID=26287759
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB08412693A Expired GB2137528B (en) | 1981-02-13 | 1984-05-18 | Membrane pack |
Country Status (1)
Country | Link |
---|---|
GB (1) | GB2137528B (en) |
-
1984
- 1984-05-18 GB GB08412693A patent/GB2137528B/en not_active Expired
Also Published As
Publication number | Publication date |
---|---|
GB2137528B (en) | 1985-06-26 |
GB8412693D0 (en) | 1984-06-27 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 19930212 |