DE19645537A1 - Coiled membrane module for cross-flow or dead-end filtration processes - Google Patents

Abstract

A coil module has a coil made up of two or more shaped pieces of a membrane material and at lest two shaped pieces of a flat spacing material to form fluid passages between the flat membrane pieces. At least one of the spacing parts is made of a thermoplastic material, and adjoining membrane pieces at at least one end of the assembly are closed by a sealing material between the membrane pieces. The sealing material is made of the thermoplastic material forming the spacing parts between the membrane pieces, and is formed by melting the edges of the material of the spacing parts before the membrane pieces are joined together. Also claimed are: (1) a similarly constructed coil using a membrane formed into a pocket with an internal thermoplastic spacing material, (2) processes for making coil modules of the first and second types, and (3) an arrangement for making a coil module.

Description

The invention relates to winding modules for the filtration of fluids in crossflow and be used in dead-end mode, as well as processes for their manufacture and Devices for performing the method.

The winding modules according to the invention are used for filtration processes in beverage, Food, pharmaceutical, chemical and laboratory areas as well as environmental protection and Biotechnology is required in which it involves the separation of liquid or particulate Components such as B. proteins, microorganisms, cells, etc. and the avoidance of Contamination of the fluids to be filtered arrives.

The winding modules consist of an in one with fluid connections Enclosed wrap, which is made from blanks of flat membranes intermediate spacers is spirally wound, the Spacer fluid channels for the fluid to be filtered, retentate and / or permeate form. Corresponding adjacent flat membranes are used to form the fluid channels connected in a fluid-tight manner in their edge regions. Depending on the arrangement of these connections the winding modules can be operated in crossflow or dead-end mode. Usually the sealing areas of the fluid channels are embedded in Sealants, sealing with adhesives such as epoxy resins and polyurethanes or sealed fluid-tight by welding the flat membranes. So is from DE-OS 35 25 682 A1 a winding module with membrane pockets known that a spacer include, with the flat membranes forming the membrane pockets on their End faces are connected with adhesive seams or corresponding weld seams. EP 0 443 642 A2 discloses a winding module in which two blanks from Flat membranes with a permeate spacer and an outer one  Retentate spacer is spirally wound around a central permeate tube. For Separation of the fluid flows are the edge areas of the end faces of the Retentate spacer is wrapped in a strip-like tape before the wrap is embedded with its end faces for embedding in a sealing compound. The strip-shaped tape is impermeable to the sealant. After curing part of the sealant is cut off together with the tape, creating a Fluid channel for the retentate is exposed. U.S. Patent 4,902,417 describes the Sealing the edges of the membrane pockets by inserting an adhesive tape between the membranes to be joined, the adhesive of the tape forming a fluid-tight connection is to be absorbed by the membranes. Disadvantageous is that the welding is limited to weldable membranes and that can decompose the embedding material and the adhesive seams. The risk of decomposition exists mainly because the winding modules in important areas of application cleaned before and after filtration or between filtration cycles and / or can be sterilized, often by exposure to chemicals and heat is carried out. For winding modules with sealing materials and adhesives that consist of epoxy resins or polyurethanes, for example, as a result of such Operations unwanted substances and decomposition products released that reduce the quality of the filtrate or render the filtrate unusable. By Decomposition of the sealants and adhesives will also reduce the lifespan of the Winding modules reduced. The introduction of sealants and adhesives is also with an additional procedural effort in the manufacture of Connected winding modules and sets an exact dosage and exact mixing of the Individual components ahead.

The invention is therefore based on the object of providing winding modules in which the release of harmful foreign substances is excluded, as well as manufacturing processes such winding modules and devices for performing the method to propose.  

The object is achieved by the in claims 1 and 2, 7 and 8, and 12th claimed features solved. Advantageous developments of the invention described by the features of the subclaims.

According to the invention, the winding modules have a winding consisting of at least two Cutting a flat membrane and at least two cuts more flat There is a spacer for the formation of fluid channels between the flat membranes, wherein at least one spacer consists of thermoplastic material and Adjacent flat membranes at least on one end face by a sealing material are closed between the membrane surfaces. The sealing material is there from the thermoplastic material of the spacer, which is between these Flat membranes located. It is caused by melting the material on the edge Spacers formed before joining the membrane surfaces.

Surprisingly, it was found that after cooling the melt a fluid-tight connection between the melt and the associated with it Membrane surfaces are obtained that are not only those in the micro and ultrafiltration range withstands normal pressure differences of up to 10 bar, but also chemical ones Cleaning operations, heat sterilization and pressure surges during backwashing resists. The winding modules according to the invention have an excellent Lifespan by technical measures, as in DE-PS 43 28 407 C1 and 43 28 408 C1 are described, can be further increased. Since the wrap next to it the membranes and spacers do not contain any other substances, they are special suitable for filtration tasks in which it is important to carry in Avoid pollutants and contamination.

Instead of two blanks of the flat membrane, the wrap can consist of at least one Membrane pocket can be formed from at least one blank of a flat membrane consists and an inner spacer made of a thermoplastic material for Includes formation of a fluid channel, wherein the membrane pocket at least one End face through the sealing material of the inner spacer between the Membrane surfaces are closed.

The inventive method for producing a winding module with the winding described above is carried out by

• a) blanks are selected for the spacers, at least of which one has a width that is greater than the width of the blanks of the Flat membranes,
• b) the edge areas of at least one end face of the spacer blanks with the greater width due to the directed supply of energy to at least one end face are melted, the width of the melt being formed Cuts are reduced to at least the width of the flat membranes,
• c) both surfaces of the blanks treated in step b) with congruent surfaces contacted by blanks of the flat membranes under pressure will,
• d) the melt to form a fluid-tight connection to the End faces of the flat membranes is cooled and
• e) the blanks are wound into a spiral wrap.

Winding modules, the windings of which consist of at least one membrane pocket, are produced by prior to the steps c) to e) described above

• a) a cut of a membrane symmetrically around a cut for the inner Spacer is turned over, the membrane cut a smaller Width is twice the width of the blank for the inside Spacer, to a membrane pocket open at one end, such that the inner spacer on the closed end of the membrane pocket rests and protrudes over the membrane surfaces on the open end,
• b) the edge area of the face of the blank for the inner Spacer, which protrudes above the membrane surfaces, is melted by directed energy supply to this end face, whereby by formation of the melt the width of the cut up to at least the width of the membrane pocket is reduced
• c) contacting both surfaces of the blank produced in step b) with the Membrane surfaces under pressure to form the closed Membrane pocket.

In step e), an outer spacer can be used to form a further fluid channel to be wound into the spiral-shaped winding. The procedure  can be carried out continuously if band-shaped blanks as Roll material can be used.

By melting the edge areas of one or both end faces of the inner Spacers and / or the outer spacer can be easily different embodiments for crossflow and dead-end winding modules produce.

It is also possible to use membrane pockets using the method according to the invention to produce inner spacers in order to later of such Roll material required reels that are provided with outer spacers can wrap.

The device for performing the method consists of donors for the required cuts on flat membranes and flat spacers and one Winding device for winding the spiral winding. Before the Winding devices are energy sources for a directed energy supply the edge areas of the end faces of the spacers, which correspond to the neighboring ones Membrane surfaces are to be connected in a fluid-tight manner. The energy supply causes an Melt the material of the spacer in the edge area of the end face onto the it is directed. The energy supply is adjusted so that the material of the Spacer is sufficiently softened when reaching the take-up device, however not drained yet. To avoid dripping, it is beneficial to Guide spacers as vertically as possible. In addition, the energy supply is too dimensioned that the associated with the melting of the material Width reduction of the spacer to at least the width of the Membrane cuts are made because otherwise no or insufficient connection can arise with the adjacent membrane surfaces. In an advantageous Embodiment, the energy sources have an elongated shape and are such arranged that their distance relative to the central axis of the blanks in the direction the take-up device is reduced by an amount which is approximately the Width reduction of the spacers by melting the edge End faces of the spacer material corresponds. To protect the Areas of the spacers to be melted can be above and below it  Areas parallel to the energy sources, for example in the form of Baffles are attached.

The winding takes place with an adjustable winding tension, depending on the material is set.

In an advantageous embodiment, the dispensers consist of rolls ribbon-shaped blanks.

Another advantageous embodiment contains a dispenser that cuts out an open membrane pocket at one end with an inner one inside Spacer contains, which rests on the closed end of the membrane pocket and overhanging the membrane surfaces on the open end. In this case, before Energy source a device for spreading the membrane surfaces on the open Front side of the membrane pocket arranged so that the membrane surfaces during the edge melting of the end faces of the spacer material with the The melt does not come into contact.

The take-up device can additionally be located locally Cooling device must be equipped, which ensures that the melt after the Assemble with the membrane surfaces to form the fluid-tight connection quickly froze.

To implement the energy supply, everyone can be familiar with the expert Energy sources are used, such as infrared radiant heaters electrical resistance heating generated convection heat or Microwave heaters.

The usual shapes such as nonwovens, woven fabrics, knitted fabrics and Lattices of different thread and lattice thickness are used, whereby Latticework is preferred. As a thermoplastic material for the spacers all materials from the group of polyalkanes, polysulfones, Polyether sulfones and polyamides, with polyalkanes and in particular polyethylene thereof and polypropylene are preferred. The melting point of the spacer materials should be are below the softening or decomposition point of the membranes.

All porous inorganic and organic flat membranes can be used as membranes be used that have sufficient flexibility to form a have a spiral winding. A particularly good connection is with coarse-pored  Ultrafiltration membranes <100,000 Dalton and with microfiltration membranes with Pore sizes <0.01 µm achieved. The membranes can be unreinforced or with a porous fabrics can be reinforced, which is advantageously made of thermoplastic Polymer fibers exist. It has been found that hydrophilic, porous membranes are made of organic polymers, such as polyether sulfones, polysulfones and polyamides, which are connected to porous sheets made of thermoplastic polymer fibers, have no edge hydrophobicity adjacent to the edge region of the fusion joint. Winding modules made from such membranes are by means of compressed gases Diffusion, pressure maintenance and bupple point tests can be checked for integrity.

The invention is explained in more detail with reference to the following figures .

Show it:

Fig. 1 shows schematically an axial section through the winding of a crossflow winding module of the invention,

Fig. 2 shows schematically an axial section through the winding of a dead-end winding module of the invention,

Fig. 3 shows schematically an axial section through the winding of a crossflow winding module of the invention with a membrane bag,

Fig. 4 shows schematically an inventive device for producing the winding modules according to the invention and

Fig. 5 shows schematically the arrangement of the power sources in an embodiment of the device according to Fig. 4.

The winding module 1 shown in Fig. 1 comprises a winding 2, the scale of two blanks of a flat membrane 3, 4 and two blanks spacers 5, 6 is formed to form fluid channels between the flat membranes and a porous core tube 7. The spacer 5 serves as a retentate channel and the spacer 6 serves as a spiral permeate channel. The spacer 6 consists of a thermoplastic material. The flat membranes adjacent to the spacer 6 are closed on both end faces 8 , 9 by a sealing material 10 between the membrane surfaces. The sealing material 10 consists of the thermoplastic material of the spacer 6 and was formed by melting the edge of the material of the spacer 6 before joining the membrane surfaces. The housing of the winding module, which is provided with fluid connections, is only shown in fragmentary form for better clarity by a housing wall 11 , against which the winding 2 is known, e.g. B. is sealed by sealing rings 12 . In crossflow operation, the fluid to be filtered flows over the flat membranes 3 , 4 along the retentate channel, which is formed by the spacer 5 , as indicated by the arrows. The part of the fluid that passes through the membranes is passed as permeate into the porous core tube 7 via the spiral permeate channel, which is formed by the spacer 6 , and is discharged from the module.

The winding module 1 shown in FIG. 2 consists of a winding 2 , which is formed from two blanks of a flat membrane 3 , 4 and two blanks of flat spacers 5 , 6 for forming fluid channels between the flat membranes and a dense winding core 13 . The spacer 5 serves as a spiral fluid channel for the fluid to be filtered and the spacer 6 serves as a spiral permeate channel. Both spacers are made of thermoplastic materials. The flat membranes adjacent to the spacers are each sealed on one of the end faces 8 , 9 by a sealing material 10 , 10 'between the membrane surfaces. While the sealing material 10 consists of the thermoplastic material of the spacer 6 and was formed by melting the material of the spacer 6 on one end face before the membrane surfaces are lying together, the sealing material 10 'consists of the thermoplastic material of the spacer 5 and was made by melting the edge Material of the spacer 5 is formed on the opposite end face before joining the membrane surfaces. The housing of the winding module, which is provided with fluid connections, is only shown in fragmentary form for better clarity by a housing wall 11 , against which the winding 2 is known, e.g. B. is sealed by sealing rings 12 . In dead-end operation, the fluid to be filtered flows into the spiral fluid channel, which is formed by the spacer 5 , as indicated by the arrows, and selectively penetrates the adjacent flat membranes 3 , 4 . The part of the fluid that passes through the membranes is discharged from the module as permeate via the spiral permeate channel, which is formed by the spacer 6 .

The winding module 1 shown in FIG. 3 consists of a winding 2 , which is formed from a membrane pocket 14 from a blank of a flat membrane 3 and two blanks of spacers 5 , 6 for forming fluid channels and a porous core tube 7 . The spacer 5 serves as a retentate channel and the inner spacer 6 as a spiral permeate channel. The inner spacer 6 is made of a thermoplastic material. The membrane pocket is formed by symmetrically turning the blank of the flat membrane around the inner spacer, so that one end face of the membrane pocket is closed by the folded membrane itself and the opposite end face 8 by a sealing material 10 between the membrane surfaces. The sealing material 10 consists of the thermoplastic material of the spacer 6 and was formed by melting the material of the spacer 6 on one of the end faces before the membrane surfaces were joined together. The housing of the winding module, which is provided with fluid connections, is only shown in fragmentary form for better clarity by a housing wall 11 , against which the winding 2 is known, e.g. B. is sealed by sealing rings 12 . In crossflow operation, the fluid to be filtered flows over the flat membrane 3 of the membrane pocket along the retentate channel, which is formed by the spacer 5 , as indicated by the arrows. The part of the fluid that passes through the membranes is passed as permeate into the porous core tube 7 via the spiral permeate channel, which is formed by the spacer 6 , and is discharged from the module.

The device shown in Fig. 4 consists of the dispensers 15 to 18 , which are arranged so that the blanks of the roll 2 are wound in the manner characteristic of the corresponding module structure by the winding device 19 . The dispensers are rolls with band-shaped cuts for the spacer 6 (dispenser 15 ), for the flat membrane 4 (dispenser 16 ), for the spacer 5 (dispenser 17 ) and for the flat membrane 3 (dispenser 18 ). The blanks are fed to the winding core 13 of the winding device 19 in the order shown in FIG. 2. In front of the winding device, energy sources 20 , 21 are arranged adjacent to one of the end faces 8 , 9 of the blanks for the spacers 5 , 6 . A directed energy supply is directed from the energy source 20 to the edge region of the end face 9 of the spacer 6 and from the energy source 21 to the edge region of the end face 8 of the spacer 5 , whereby the thermoplastic material melts in the respective region and the width of the corresponding spacer is reduced . When the blanks are joined together on the winding device under appropriate pretensioning (not shown) and cooling (not shown), a winding is formed according to FIG .

FIG. 5 shows a schematic top view of the arrangement of the energy sources in one of the embodiments of the device according to FIG. 4. The energy sources 20 , 20 'have an elongated shape and are located at a distance from the center axis A of the blanks 3 , 4 , 6 (dispensers 15 , 16 , 18 ), which decreases in the direction of the winding device 19 by an amount which is approximately corresponds to the reduction in the width of the blank of the spacer 6 by melting its respective end face 8 , 9 at the edge.

In FIG. 5, the dispenser 16 has only been shown angled to make the cut of the spacer 6 running underneath it visible.

Claims (15)

1. winding module with a winding consisting of at least two blanks of a flat membrane and at least two blanks of flat spacers for the formation of fluid channels between the flat membranes, wherein at least one spacer consists of thermoplastic material and adjacent flat membranes at least on one end face by a sealing material between the membrane surfaces are closed, characterized in that the sealing material consists of the thermoplastic material of the spacer located between these flat membranes, which was formed by melting the edge of the material of this spacer before joining the membrane surfaces. 2. Wrapping module with a wrap at least from a membrane pocket there is at least one cut of a flat membrane and an inner one Spacers made of a thermoplastic material to form a fluid channel includes, the membrane pocket through at least on one end Sealing material is sealed between the membrane surfaces, characterized in that the sealing material from the thermoplastic material of the inner spacer exists by melting the material of this spacer on the edge the joining of the membrane surfaces was formed. 3. winding module according to claims 1 or 2, characterized in that the membranes are connected to a porous fabric. 4. winding module according to claim 3, characterized in that the membranes are hydrophilic, porous polymer membranes.   5. winding module according to claims 1 or 2, characterized in that the thermoplastic material of the spacers is selected from the group of Polyalkanes, polysulfones, polyether sulfones and polyamides. 6. winding module according to claim 5, characterized in that the thermoplastic material has a lower melting point than the membranes. 7. A method for producing a winding module with a winding which consists of at least two blanks of a flat membrane and at least two blanks of flat spacers for the formation of fluid channels between the flat membranes, at least one spacer consisting of thermoplastic material and adjacent flat membranes at least on one end face by a Sealing material between the membrane surfaces are sealed, characterized by the steps

• a) selecting blanks for the spacers, at least one of which has a width which is greater than the width of the blanks of the flat membranes,
• b) melting of the edge area of at least one end face of the spacer blanks with the greater width by directed supply of energy to the at least one end face, the width of these blanks being reduced at least to the width of the flat membranes by forming the melt,
• c) contacting both surfaces of the blanks treated in step b) with congruent surfaces of blanks of the flat membranes under the action of pressure,
• d) cooling the melt to form a fluid-tight connection on the end faces of the flat membranes and
• e) winding the blanks into a spiral wrap.

8. A method for producing a winding module with a winding at least from a membrane pocket, which includes an inner spacer made of a thermoplastic material to form a fluid channel, characterized by the steps

• a) symmetrical turning of a blank of a membrane around a blank for the inner spacer, the membrane blank having a width less than twice the width of the blank for the inner spacer, to a membrane pocket open on one end face, such that the inner spacer on the closed Front of the membrane pocket and protrudes beyond the membrane surfaces on the open front,
• b) melting the edge region of the end face of the blank for the inner spacer, which projects beyond the membrane surfaces, by directional energy supply to this end face, the width of the blank being reduced to at least the width of the membrane pocket by formation of the melt,
• c) contacting both surfaces of the blank produced in step b) with the membrane surfaces under pressure to form the closed membrane pocket,
• d) cooling the melt to form a fluid-tight connection at the end face of the membrane pocket and
• e) winding the membrane bag into a spiral wrap.

9. The method according to claims 7 or 8, characterized in that step d) is carried out simultaneously with step c) and / or step e). 10. The method according to claims 7 to 9, characterized in that the blanks are band-shaped, are pulled off rolls and steps b) to e) be carried out in a continuous process. 11. The method according to claim 8, characterized in that  in step e) at the same time an outer spacer to form another Fluid channel is wound into the spiral winding. 12. Device for carrying out the method according to claims 7 to 11, consisting of dispensers for cutting the components of a wrap and one Winding device for the blanks to form a spiral winding, characterized in that in front of the winding device adjacent to at least one of the end faces of the Spacer cuts energy sources for a directed energy supply to the Edge areas of the end faces of the spacers are arranged. 13. The apparatus according to claim 12, characterized in that the energy sources have an elongated shape and their distance in relation to the Central axis of the blanks in the direction of the winding device by an amount that roughly reduces the width of the spacers by marginal Melting the end faces of the spacer material corresponds. 14. Device according to claims 12 and 13, characterized in that the dispenser rolls are with band-shaped blanks. 15. Device according to claims 12 to 14 with a dispenser, the blanks from a membrane pocket open on one end with an inner one inside Spacer contains, which rests on the closed end of the membrane pocket and overhanging the membrane surfaces on the open end, characterized in that in front of the energy source, a device for spreading the membrane surfaces on the open front of the membrane pocket is arranged so that the membrane surfaces during the melting of the end faces of the spacer material the melt does not come into contact.