JPS61502902A - Hollow fibers, their production and their application especially in the field of membrane-type separations - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] Hollow fibers, their production and especially Its application in the field of model separation The present invention provides novel hollow fibers based on fibrous polymeric materials. Regarding fibers.

A considerable number of hollow fibers based on fibrous polymeric materials with asymmetric structure are already known. It is. Such irregular structures generally belong to one of the following groups: (1) A fiber whose major feature is increasing porosity (from the inside to the outside of the fiber) A relatively dense layer, hereinafter referred to as the "epidermis", exists around the internal channels of the fibers, and this internal A group of structures in which a macrovoid exists between the epidermis and the outer periphery of the fibers. Attached drawings of such fibers 1 (a cross-sectional view taken along a plane perpendicular to the longitudinal center line of the fibers). Please refer to such drawings. A shows part of the inner epidermis, B shows the macro void, and C shows the outer periphery of the fiber. The arrow F indicated the increasing porosity from the inside to the outside of the fiber. Such a structure Fibers having the following properties are disclosed in US Pat. No. 491, for example.

(2) As in the above group, the inner skin, the porosity increasing from the inside to the outside of the fiber. A group of structures in which there are but no macro voids. Figure 2 shows the fibers of this group. A indicates the inner epidermis and D indicates the division between such epidermis and the periphery C, of which It can be seen that there are no macro voids inside, arrow F indicates the inside of the fiber. The porosity increases from the outside to the outside. Such fibers are described, for example, in U.S. Pat. No. 51300.

(3) There is an inner epidermis and an outer epidermis, both of which lie on either side of the fibrous section and are multi-layered. There are large amounts of macro voids. Such a fiber is shown in FIG. In this diagram, A is inside E shows the outer epidermis, E shows the outer epidermis, and B shows the macrovoid between them. this kind of The porosity in the fibers also increases, but in both directions of arrows F1 and F2. There is. Fibers of this type are described, for example, in French patent no. 77 34031. Ru.

(4) Contrary to the above groups, it does not have an internal epidermis, but only an external epidermis. A group of structures with Such fibers do not contain any macro voids between the outside and inside of the fiber. do not. Its porosity increases from outside to inside. Figure 4 shows such fibers. vinegar. In the figure, E indicates the outer skin and D indicates the porous layer.The porosity of this group is indicated by the arrow F3. is increasing in the direction of Such fibers are described, for example, in French Patent No. 80 06858. It is described in.

(5) As shown in Figure 3, there is an inner epidermis and an outer epidermis, A group of structures in which a macro void exists between both epidermis. Such fibers are shown in Figure 5. vinegar. A and E represent the inner and outer epidermis, respectively, with macrovoids and Microvoids (B and D) are present in a constant proportion.

The porosity in this case increases in both F4 and F directions.

Such fibers are described, for example, in French Patent No. 79 11 031.

(6) Finally, as shown in Figure 6, there is a group of structures in which no skin force exists. In this case The porous structure between the side circumference G and the outer circumference C consists of macro voids and micro voids, respectively. Contains B. This type of fiber is described, for example, in French Patent No. 73 15427. has been done.

On the other hand, the present invention provides that the relatively thin (less than 1 μm, preferably less than O] μm) at their outer periphery. Due to the presence of a dense layer (skin), hollow fibers with an irregular structure differ from each structure described above. characterized by In a special way: The structure underlying the epidermis is formed by a macroporous layer in direct contact with the dense epidermis. The advantage is the so-called "open" structure, which is open on the inner side of the fiber but not on the outer side. radially homogeneous porous, not open on the sides, regularly spaced with walls and substantially There is a macroporous layer providing cylindrical radial macrovoids in the The voids have a main size greater than 2 tlm, and the proportion of such macro voids is the wall volume. It is characterized by occupying at least 10% of the product.

According to other features: (1) The external epidermis has a very small thickness of less than 01 μm and less than 1000 μm. permeable to water with substantial absence of pores with large diameter; (2) the proportion of macrovoids accounts for at least 20% of the wall volume; (3) the proportion of macrovoids is substantially The macro-void has a length that can reach more than nine-tenths of the total wall thickness. ; (4) the diameter of the circular cross section of the macro void is generally greater than 5 μm; (5) the present invention hollow fibers are based on fibrous polymers that are soluble in solvents and coagulate in non-solvents. Ru.

Among the examples of polymers that can form fibers according to the invention are vinylidene polyfluoride, polysulfone, polyacrylonitrile, cellulose and cellulose ester poly(vinyl chloride), poly(vinyl acetate), polyamide, poly imide, polycarbonate, poly(phenylene oxide), polystyrene and Furthermore, polyethers, polyetherenobepoly(arylene oxide), polysulfide, polyvinyl polymer, polyallyl polymer, polyazole and Mention may be made of polyimidazole, polyphosphazine, polyhydrazide, or Alternatively, such a fibrous polymer is a copolymer composed of at least one of the above-mentioned polymers. or polymer mixtures.

The above-mentioned fibers can be produced using any known method, especially the spinning method called "dry-blending". Obtainable.

According to this method, a solution of a polymer in a solvent is passed through an extrusion hole by passing gas, vapor or is extruded with a preferably annular spinning nozzle together with the injection of liquid and then the formed medium is The empty fibers are passed through a coagulation bath.

In order to obtain the hollow fibers of the present invention as described above by this method, (1) the polymer solution in the solvent is adding at least one special additive to the liquid; (2) Inject fluid through the extrusion hole Get ready.

Special additives make it possible to obtain macroscopically homogeneous solutions with solvent-polymer combinations, On the one hand, molecules that can be extracted from the fiber when it coagulates or by suitable post-treatments. Choose from. Examples of additive molecules that respond to the above definition include: one hydrophobic unit and at least one hydrophilic unit (ionic or non-ionic) ionic) in the molecule (hydrophobic units are polyoxyethylene ionic or non-ionic surfactants (which can be based on Vinylpyrrolidone, polyvinylpyridine, polyvinyl alcohol, polyethylene More than 500 types including glycols, polyacrylamides, polyacrylic acids Macromolecules with a molecular weight of

The specific fluid for internal injection can be a liquid or a gas, and it at least a sufficient amount of the fibrous polymer to prevent coagulation of the containing solution. Contains one type of solvent.

The scope and interest of the invention will be further apparent from the following description, taken in conjunction with the accompanying drawings. It will be something like that.

Figures 1 to 6, already mentioned, show the different types of known fibers: FIG. 7 is a schematic drawing similar to FIGS. 1 to 6 showing a cross section of a fiber according to the invention. Ru; Figures 8, 9, 10, and 11 show the present invention (which is applicable to fiber electron microscopy). Figure 12 shows the method used to obtain the fibers according to the invention. It is an explanatory process diagram; Figure 13 shows a cartridge using fiber bundles with longitudinal external circulation (CEL). Figure 14 shows a possible embodiment of a fiber bundle with radial external circulation (CER) Another possible embodiment of the cartridge used is shown in Figure 15; A third possible embodiment using fiber bundles having the following structure is shown below.

Referring to these drawings, the outer epidermis indicated by H on the schematic diagram in FIG. Particularly visible from Figures 8 and 9 (axial section); the porous structure is The elongated inward opening can be seen more accurately in the enlarged view Figure 10. Contains macro-voids in the form of open fingers. Such photographic enlargements actually show the fibers. It corresponds to what is seen from the inside. a substantially circular crease distinguishable within it. The data corresponds to the end of such a finger. Macro void J can also be observed in this enlarged view. can. The external epidermis H can be clearly seen in the enlarged photo in Figure 11. There are no visible voids, indicating such epidermal density. Looking at this structure, we can see that there are many fibers. Porosity increases from outside to inside.

More precisely, 1 ctn is equal to 50 μm in the enlarged photographic diagram (Fig. 8), and in the enlarged photographic diagram (Fig. 9). In the figure, 1.5 ttm is equal to 25 ttm, and in the enlarged view Figure 10, 1 crn is 5 μm. In order to obtain the hollow fiber shown in the enlarged view of FIG. - using a spinning method called "mixed method". Such a method is schematically illustrated in FIG.

A polymer solution container 1, advantageously provided with a filter 3a, is fed from a gas bottle 2. under pressure (control of such pressure), for example by introducing an inert gas such as nitrogen. This solution is flowed into the spinning nozzle 6 shown in the enlarged view. Ru.

The polymer solution flowing from vessel 1 contains at least one additive as described above, i.e. ionic or non-ionic (hydrophilic).

(hydrophobic) surfactants or macromolecules with a molecular weight of more than 500, and Contains a solvent for the polymer.

Incidentally, the annular orifice of the spinning nozzle 6 may contain a solvent as described above. Also introduce the fluid that Apparently the fluid flows from the container 4 and its delivery into the spinning nozzle 6. The supply is controlled by a flow meter 5 that controls the flow rate and a valve 8I that is controlled as a function of the desired flow rate. This is how it is done. A fiber 10 downstream of a coagulation vat 7 containing a coagulation solution. The motor 9 that winds up the fiber drawing tension and its storage can be adjusted l.

The coagulation solution can be selected from any suitable non-solvent. Water is preferred for this. Delicious.

By carrying out this method (thus, the irregularities of the hollow fibers according to the invention are eliminated on both sides of the extrudate). obtained by different coagulation at .

The outer surface of the fiber is rapidly solidified by contact with the polymer non-solvent; the unidirectional layer is spun Contact with the solvent contained in the fluid discharged at the central part of the annular orifice of the nozzle 6 Because of the contact, very slow coagulation of the inner surface occurs.

Advantageously, this type of loading is approximately 5 Pascals/sec to 1000 Pascals/sec at the spinning temperature. An extrudable solution that can form a π-form precursor with a viscosity of Obtained using liquid.

Furthermore, the nonsolvent and solvent should preferably be miscible in any proportion. , the additive must of course be a non-solvent for the polymer, and a solvent for the additive must be provided. It can be advantageously removed from the fibers by simple washing with a solvent.

The stronger the nonsolvent for the polymer, the more severe the degree of irregularity, and the more difficult it is to wash and It is clear that the total clotting time before storage is reduced.

In the examples below, the porosity was characterized by observation of negatives obtained by electron scanning microscopy. achieved by. This method is suitable for cases where the epidermis is larger than approximately When ensuring that it does not contain pores of a smaller size, It really can't be detected easily. Testing for the presence of smaller pores is permeable to water. I used superfluous. A method for measuring the permeability to water is the use of several hollow fibers. It consists of forming a loop. Insert the open end of the hollow fiber into the tubesheet. Ru. This loop is then placed into a cylindrical housing. Directs pressurized water into the housing. The water that has passed through the fiber wall is collected from the open end of the loop.

Collected for the pressure difference (expressed in Pascals Pa) applied on both sides of the fiber wall The ratio of the amount of water (expressed as - to area 1/) is used as an indicator of permeability. . Such a ratio, denoted L, is referred to as the "hydraulic permeability coefficient." Its unit is -/i ・s, pa or m/s'pa. All permeabilities were measured at a temperature of 25°C. Set.

Example 1 29% polysulfone (Uael 3500) 22% Torito by weight Toriton x 100 and 49% N.

From a solution consisting of N-dimethylbormamide, water is added as a coagulant by the method described above. , extruding the hollow fibers using N,N-dimethylformamide as the internal injection fluid. did.

Its outer diameter is 580 μm and its inner diameter is 440 μm.

Hollow fibers (1) have a skin with no pores of diameter greater than 1000 on its outer surface; (2) The open structures beneath the outer epidermis have a maximum size of approximately 1.5 μm. A microporous layer with a thickness of 30 μm in which pores are present and a length of about 40 μm and a length of about 14 μm. A radially open cylindrical macro-void on its inner surface with a diameter on its inner surface of μm 1 shows a structure according to the invention consisting of a macroporous layer present; macro empty The gap occupies at least 20% of the wall volume.

The presence of pores with a diameter smaller than 1000^ in the epidermis is revealed by the permeability to water. I made it: Lp25℃" 6.9 X 10-" rri/nl-5-PB Example 2 Using N, N'''' dimethylacetamide as the internal injection fluid and water as the coagulant, 28% Vinylidene Polysulfide (PCUK 1000), 18% Tori l-:zxlOOk and 54% N,N-dimethylformamide (wt%) Hollow fibers were spun from the solution. Its outer diameter is 580 μm, and its inner diameter is 4 It is 40 μm.

A hollow fiber has (1) an epidermis on its outer surface that has no pores with a diameter larger than (2) open structures beneath the external epidermis contain pores with a maximum size of approximately 0.5 μm; 4 μm thick microporous layer with a length of about 121 ttm and a diameter of 15 A macro that exhibits a cylindrical macro void that opens and radially arranges on the inner surface with a diameter of μm. A structure according to the invention is provided consisting of a porous layer. Macro voids account for approximately 40% of the wall volume. occupy

The presence of pores with a diameter smaller than 100 OA in the external epidermis depends on the permeability to water. to clarify.

Lp25℃=2.6×10-IO? rIl/m'5-Pa Example 3 Using N,N-dimethylformamide as the injection fluid and water as the coagulant, heavy 18% polysulfone (Udel 3500), 18% polyvinylpyro A solution of lydone (K15) and 64% N,N-dimethylformamide hollow fibers were spun. Its outer diameter is 430 pm, and its inner diameter is 150 μm. Ru.

A hollow fiber exhibiting a structure according to the present invention (1) has a diameter of greater than 100 OA on its outer surface. (2) The open structure underlying the external epidermis is the largest dimension a microporous layer with a thickness of 20μ78 in which there are pores with a diameter of about 1μm, and a length of about 1μm. 20 μm and a diameter of 10 pm on its inner surface and radially open on its inner surface. It consists of a macroporous layer in which cylindrical macropores exist. Macro void is wall volume Approximately 60% of the product is revealed by the transmittance.

Lp25℃=　0.4　x　] W101TVrr? -8-pa addition should not be added. Spinning yarn.

It contains 29% polysulfone (Udel 3500) and 71% N,N-di Obtained in solution in methylformamide.

N,N-dimethylformamide was used as the internal injection fluid. It is the presence of a small amount of macro voids opening towards the outer epidermis and the inner surface. It can be seen that it contains an open lower structure. However, spinning without additives One of the characteristics of Takaru fibers is that their permeability to water is extremely low. This shows that the epidermis has very few pores.

Spinning with water present in the internal injection fluid.

Make the same solution as in Example 1. Such a solution can be used as an internal injection fluid in the following species. Spinning is performed using the above-mentioned method using a similar solution.

90% by weight N,N-dimethylformamide, 10% by weight water.

Hollow fibers are obtained. Its outer diameter is 350 μm and its inner diameter is 110 μm.

The hollow fiber having the structure according to the present invention has (1) a larger diameter than iooo′A on the outer surface; (2) open structures beneath the external epidermis are found with diameters of A macroporous layer 7 μm thick with pores that are legally 1.5 μm, and a length of about 1 A macroporous layer having a diameter of 0.7 μm and containing radially oriented cylindrical macro voids. It will be. Macro voids occupy approximately 40% of the wall volume.

One property of these fibers spun with 10% water in the internal injection fluid is , the macro-voids with a diameter of about 6 μm become narrower in the wall, and therefore they become closer to the inner surface. It has a diameter of only 2 μm when opened.

The presence of pores in the external epidermis with a diameter smaller than 1 oao reveal.

Lp25℃=0.4 6 x 1 0-10tri/+/-s-pa In the present invention Hollow fibers obtained from is an excess or It can be used directly in microfiltration or as a liquid film carrier.

The presence of an external skin in the structure of the fibers according to the invention allows the fluid to be treated to flow through the fibers. Can be used for super offshore or mithal offshore in devices that circulate advantageously outside the , thereby making such a device compact as shown in the example below, Improve performance.

Referring to FIG. 13, the cartridges designated C are arranged parallel to each other. A cylinder containing several bundles 12 of hollow fibers] 1. of such fibers The ends are embedded in blocks 13-13a of suitable resin and glued to such blocks. This creates a seal between the liquid that enters orifice A under pressure and is overflowed. ensuring that such liquid is directed substantially parallel to and outward from the fiber centerline (A -D direction). The permeate collected in the internal channels of each fiber is rutted. It flows out of the cartridge at both or one of the fiber ends (arrows B-E').

The cartridge shown in FIG. 14 also has a cylinder 11 and a bundle of hollow fibers 12. The ends of the bundle are embedded in the resin blocks 13 to 13a as described above, and the ends are connected. It is worn. The liquid A to be treated is passed through a tube formed with multiple orifices J5. 14i is thus placed in the center of the fiber bundle, and such tube 14 is aligned with the fiber centerline. and placed in parallel.

It is located at the end remote from the inlet end of liquid A from the removable stopper 161. It's blocked. Due to the presence of the stopper 16, the liquid A is circulated under pressure. Such circulation is carried out substantially at right angles to the fiber centerline due to the presence of the orifice 15. be called. The permeate is collected in the internal channels of the fiber, and it is It flows out of the cartridge by one of them (arrow B-B'). The solution is Any suitable material that provides the desired circulation space between the fiber bundle 12 and the wall of the cylinder 11 17, it flows out at A' according to the arrow f.

On the other hand, referring to FIG. 11 and the ends of the fibers are embedded in blocks 13-13a and treated. Liquid A is pumped under pressure in the direction A-D within the internal channels of the fibers as shown by arrow F. circulates. The permeate is collected on the outside of the fiber bundle and shaped around the cylinder 11. Once completed, B exits the cartridge through one or more orifices and circulates.

Cartridges containing internal hollow fibers of the same volume as the cartridge (in this case The circulation of the medium is carried out using a car made as shown in Figure 15). The purpose is to compare the performance obtained with (occurring within the fiber).

For cartridges (CEL and CER) as shown in Figures 13 and 14. The provided fibers were obtained as described above.

It is 29% polysulfone (Udel 5000), 22% by weight of a solution consisting of Triton x 100 and 49% N,N-dimethylformamide. The internal injection fluid made by spinning is N,N-dimethylformamide, and the hollow Water was used for coagulation of the outer surface of the fibers. These fibers have their structure It has a nonporous epidermis on its outer surface with a diameter of more than 100 OA when viewed from the outside. The open structure beneath the epidermis contains pores whose largest size does not exceed 1.5 μm. Microporous layer and radially oriented cylindrical macro voids open to the inner surface. It consists of a macroporous layer, and these macropores are approximately 15 μm in diameter. It is characterized by being

The fiber fitted in the cartridge CI (Fig. 15) is CompteRendu 1' Aaademie dss 5 sciences Paris, Volume 293, No.■ No., pp. 681-686 (November 9, 1981), “Hollow fi breath of polysulfone, preparation and properties of transfer to ultrafiltr It was obtained by the method described in ation J. They are 18% polysulfone (ud e13300), 18% polyvinylpyrrolidone K 15 (Fluka) and and 64% N,N-dimethylacetamide by spinning. internal Using water as the solidifying fluid.

They have a nonporous epidermis with a diameter greater than 100 OA in the internal phase and an open skin on the external surface. It is characterized by the presence of a microporous layer containing free macropores. Ru.

Table 1 summarizes the characteristics of IJ Tsuji shown in the examples below.

5 K)/l NaCl aqueous solution at 25°C using cartridge CL (Fig. 13). Ultra-filter. Kerr) The circulation flow velocity at the inlet of IJ Tsuji is 4.6 x 10-’d / It is S. The pressure at the inlet is 5 kPa, and the pressure from the cartridge is At the outlet, the feed pressure loss is 1'OQ kPa, ie 15 kPa.

Measure the conductivity of the treatment solution and permeate and know that they are the same, this demonstrated that the fibers freely pass saline solutions.

Then, using cartridge CEL (Figure 13), the average molecular weight Mv = 400 00 Dextran T70 109// solution is ultrafiltered. Concentration of treated solution is kept constant by circulating the ultrafiltrate. Ultrafiltrate and processing solution in differential refractometer Analysis showed that the ultrafiltrate did not contain dextran T70 and therefore the fibers were This shows that it retains all the macromolecules.

The circulation flow rate (outside the fiber) at the inlet to the cartridge is 4.6 x 10-'tr? /S in be. The inlet pressure is 118 kPa and the outlet pressure is 100 kPa, immediately This is a charging pressure loss of 18 kPa.

The ultrafiltrate flow rate is 2.3 x 10-'yr+'/S.

Comparison with similar cartridge CI (Figure 15) Same solution as above used for ultrafiltration When 4. Circulating flow rate of 6 x 10”φ′S, holding all Dextran T70, inlet pressure The force is 125 kPa and the outlet pressure is l Q Q kPa, i.e. the charging pressure The force loss is 25 kPa.

The ultrafiltrate flow rate is 0.51 x 10-'-.

car) The power required to circulate the fluid in the IJ is determined by the circulation flow rate and the charging pressure drop. equal to the product of losses, i.e. 083 Watts for cartridge CEL It is 1.2 watts for I.

The energy consumed per unit volume of ultrafiltrate is calculated by the circulation divided by the ultrafiltrate flow rate. equal to the power required, i.e. 0.10 KWh/d (3 x6xlOdule/7d) 0.65xwh for cartridge CI, zQ2 3x5xlO joules/-).

Regarding cartridge CFtL than cartridge CI, the permeate unit capacity is It is known that the ultra-filtrate flow rate is high and the energy consumption is low.

As in Example 6, the fibers of the cartridge CER used here (Fig. 2) were It is demonstrated that 59/l aqueous NaCl solution passes freely.

109 of polyvinylpyrrolidone (pvp) K2O with average molecular weight Mm=36000 /l solution is ultrafiltered on a cartridge CER at 25°C. Example 11 The concentration of the treated solution is kept constant and the fiber retains all pvp y, 90. It proves that. The circulation flow rate (outside the fiber) at the inlet of the cartridge is 4.6 X1. It is O-'d. Inlet pressure is 123kPa, outlet pressure is 100kP a, that is, the charging pressure loss is 23 kPa.

The ultrafiltrate flow rate is 0.86 x 10-'y++''.

Comparison with similar cartridge CI Cartridge CI uses the same solution as described above for ultrafiltration. It contains 90% polyvinylpyrrolidone fibers. cartridge The circulation flow rate (within the fiber) at the inlet to is 4.6 x 10-'ty+'/S.

The inlet pressure is 175 kPa and the outlet pressure is 100 kPa, i.e. The pressure loss is 75 kPa.

The ultrafiltrate flow rate is 0.66 x 10-'td/S.

The power required for circulation of the treated solution in the cartridge and the The energy dissipated by the capacity is calculated as in Example 1.

electric crab Cartridge CERl stuck 1. About IW cartridge cr 3,4W energy: About cartridge CEH 0.36 kW heating (128 mowing 06 joules/-) About Cartridge CI 1.43 kwh/d (5,15xl G/I) ) Higher ultrafiltrate flow rate for cartridge CEH than for cartridge CI. and the energy consumption for smaller overflow unit volumes are found.

Example 8 A 6971 solution of lactoserum protein was added at a temperature of 25°C. Kerr) IJ Tsuji CER (Fig. 2) I is thus ultrafiltered.

Analysis of the ultrafiltrate shows that all of the protein is retained in the fibers.

This solution of 6 g/l is concentrated to 309 g/l, which gives an initial volume of 11 to a final volume of 0.2I. Circulating flow rate into the cartridge (outside the fibers) ) is 3×10-'1. The inlet pressure is 108 kPa, and the outlet pressure is 100 kPa, and the charging pressure loss is 8 kPa.

The super-filtrate flow rate ranged from 1.06 x 10-'i/S at the beginning to 0. 33 x 10”’i/S. This is the average of 0.53 x 10”i/S. Give the average offshore liquid flow velocity. Regarding the power required for circulation and the unit capacity of ultra-overflow liquid, Calculate the energy expended as in Example 1.

Q, l, 3 kWh/h (0.45 x 106 joule/l) according to the method in Table 2. After cleaning the cartridge, the initial hydraulic permeability of the cartridge is recreated.

Example 9 Super-filtering the skimmed milk by cartridge CEiRl at a temperature of 50°C Ru.

Analysis of superfiltrate shows that the protein was all retained by the fibers.

This milk is concentrated three times, thereby reducing the initial volume of 0.31 to a maximum of 0.31. Pass to final volume. The circulation flow rate (outside the fiber) at the inlet of the cartridge is 2×1 0-’d/S, the inlet pressure is 110 kPa, and the outlet pressure is l Q Q kPa. That is, the charging pressure loss is 10 kPa.

The super-offshore liquid flow rate changes from 1.5 x 10”y&/S at the beginning of concentration to of 0.12 x 10”d/S, that is, the average super-offshore liquid velocity is 0.31. x 10-'silence/S.

The power required for circulation and the energy consumed for the unit capacity of super offshore liquid are Example 6 (Calculate like this.

Electric crab 0.2W Energy: 0.18 kWh/enemy (0.64 x 10' Joule/-).

After cleaning the cartridge from Method F in Table 2, the initial hydraulic permeability of the cartridge is reproduced.

Table 2. Washing process for milk products after washing (A) = room temperature The invention has been described purely by way of illustration and not by way of limitation, and it is understood that useful modifications may be made. It is to be understood that what may be done without departing from the scope of the invention.

FIG, I FIG, 2 FIG, 3 FIG, 4 F old, 5 FIG, 6 Fig.12 Procedural amendment (method N) 3. person who makes corrections Special relation to the incident? f　RIL The length of Jin [Co., Ltd.]'s tokuken payday Ming Dynasty, Hosogoku, 1st Edition, Meizuki Kiyome no Kettle, 3) Ming Dynasty, Zo'te Yu, N Bo 1 Ran 1 ．． C O stone forgotten f　) Thick 4) Words five inches (゛) Bashirito D4 Martyr 4 #eL (Ritsichi Shishi) Jino)? J-l---＾#k　PCT/FR85100147ANNEX　T o TF, E 1NTER, NAτl0i4AL 5EARCHREPORτO N

Claims (17)

[Claims] 1. There is a relatively dense layer (epidermis) with a very small thickness (less than 1 μm) around the outer periphery. , it combines an open structure with increasing porosity in the direction of the inner surface and below the epidermis above. The open structure is an irregular structure consisting of a macroporous layer in direct contact with the epidermis. A hollow fiber based on a polymeric fibrous material having a structure of pores with dimensions smaller than 2 μm are present in a substantially cylindrical radially oriented and regular A macroporous layer exists within which macro voids are spaced apart, and the fiber Such a matrix has a radially homogeneous porous wall that is open on the inner side and not open on the outer side. Macro-voids have major dimensions greater than 2 μm, and the proportion of such macro-voids is equal to the wall volume. Hollow fibers, characterized in that they account for at least 10%. 2. The outer skin has a thickness of less than 0.1 μm and a direct thickness of more than 1000 Å. The hollow fiber according to claim 1, which has no pores of any size and is permeable to water. 3. Claims 1 or 2, wherein the proportion of macro voids is at least 20% of the wall volume. or the hollow fiber according to item 2. 4. Substantially cylindrical macrovoids extend over nine-tenths of the total fiber wall thickness The hollow fiber according to any one of claims 1 to 3, which can have a length Wisdom. 5. Claim 1, wherein the diameter of the circular cross-section of the macrovoid is generally greater than 5 μm. - The hollow fiber according to any one of Item 4. 6. Hollow fibers are based on fibrous polymers that dissolve in solvents and coagulate in non-solvents. The hollow fiber according to any one of claims 1 to 5. 7. The fibrous polymer is made of vinylidene polyfluoride, polysulfone, polyacrylic Lonitrile, cellulose and cellulose esters, poly(vinyl chloride) , poly(vinyl acetate), polyamide, polyimide, polycarbonate, polycarbonate poly(phenylene oxide), polystyrene and more generally polyether, Polyester, poly(arylene oxide), polysulfide, polyvinyl Polymers, polyallyl polymers, polyazole and polyimidazole, polyphosph selected from azine, polyhydrazide; such fibrous polymer is selected from the polymers mentioned above; Selectable from copolymers or mixtures of copolymers composed of at least one of The hollow fiber according to claim 6. 8. Dissolve the fibrous polymer in a solvent at a concentration suitable for spinning, with a Among macromolecules of molecular weight or among ionic or nonionic surfactants. containing a polymer, a solvent and an additive, with the addition of at least one selected additive; passing the solution through a spinning nozzle, advantageously of annular type, and simultaneously injecting the fluid into an extrusion hole; The fluid is a liquid or a gas and solidifies the solution containing the fibrous polymer. At least one solvent for the fibrous polymer to prevent such fluids. a filament composed of the above solution containing a sufficient amount of the above fluid and surrounding the above fluid; to a fibrous polymer selected to rapidly settle the outer surface of the filament. Claims characterized in that passing through a coagulation bath containing at least one non-solvent A method for producing a hollow fiber according to any one of Items 1 to 7. 9. Macromolecules with a molecular weight greater than 500 include polyvinylpyrrolidone, polyvinylpyrrolidone, Pyridine, polyethylene glycol, polyacrylamide, polyacrylic acid, polymer The method according to claim 8, which belongs to the group of ribinyl alcohols. 10. Surfactants with hydrophobic units containing polyoxyethylene chains 9. The method according to claim 8, wherein the method is selected from: 11. The fluid injected into the extrusion hole is the solvent used to dissolve the fibrous polymer. 11. A method as claimed in any one of claims 8 to 10. 12. Claim No. 1, wherein the additive added to the solution of the fibrous polymer is soluble in the coagulation bath. The method according to any one of Items 8 to 11. 13. In any one of claims 1 to 7 in the field of membrane separation method Application of hollow fibers. 14. Made from hollow fibers, the circulation of the liquid to be treated is carried out under pressure on the outside of the fibers. A cartridge that circulates the filtrate that has passed through the fiber walls within the fiber's central channel. Application of claim 13 to the field of ultrafiltration or microfiltration using Azalea . 15. The hollow fibers constituting the cartridge have an outer diameter of at least equal to 0.1 mm. 15. The application according to claim 14. 16. Claims in which the cartridge has a capacity of at least 1000 m2/m3 Application as described in Section 1. 17. The pressure difference maintained on both sides of the wall of the hollow fiber is less than 106Pa, 104P The application according to claim 16, wherein the application is greater than a.