JPH0366008B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a channel material that supports the back side of a semipermeable membrane that receives pressure on a stock solution in a liquid separation device, and a method for manufacturing the same. In a liquid separation device using a semipermeable membrane, the semipermeable membrane is generally formed into a long envelope shape (bag shape), and the envelope has a structure that supports the pressure of the stock solution applied from the semipermeable membrane side and allows the permeate to flow through the membrane. A spiral type, in which a channel material that becomes a guiding channel is inserted, and the open end side of the envelope with the channel material inserted is fixed to a hollow shaft and wrapped tightly in a spiral shape, or the above-mentioned multiple sheets. There is a tubular type in which the open end side of a semipermeable membrane envelope is tightly held by a holding plate and stored in a container. In both cases, a high-pressure stock solution is passed from the inside to the outside of a semipermeable membrane envelope supported by a channel material, and the permeated liquid that has passed through the semipermeable membrane is guided by the channel material and taken out. Such liquid separation devices are widely put into practical use as water production devices for pretreatment of boiler water, reuse of wastewater, desalination of seawater, and the like. By the way, the channel material of the above-mentioned liquid separation device is generally a porous fabric such as a woven fabric or a knitted fabric and has fine grooves, but the high pressure of the stock solution acts on this channel material through a semipermeable membrane. Therefore, if the flow resistance is large, the flow rate of permeate decreases, resulting in a problem of decreasing the amount of permeate produced per unit volume. on the other hand,
If an attempt is made to reduce the flow resistance in order to solve this problem, the thickness of the channel material must be increased, which poses a problem that is disadvantageous in making the liquid separation device more compact per unit production amount of permeate. The purpose of the present invention is to reduce the flow resistance without increasing the thickness of the channel material, thereby increasing permeate productivity, and furthermore, to maintain its performance for a long period of time. The object of the present invention is to provide a channel material for a separation device. Still another object of the present invention is to provide a manufacturing method that can efficiently produce the channel material. The channel material for a liquid separator of the present invention that achieves the above object is a channel material for a liquid separator that supports the back side of a semipermeable membrane that receives pressure on an undiluted solution, and the channel material has a fineness of 30 to 50 deniers. A ground texture part knitted from thermoplastic synthetic fiber filament threads and a fineness of 50 to 1.2 times greater than the threads constituting the ground texture part.
The fabric is made of a tricot knitted fabric having ridges woven with 70 denier thermoplastic synthetic fiber filament yarns, and the yarns in the tricot knitted fabric adhere to each other to make the entire knitted fabric rigid. This is a characteristic feature. In addition, the manufacturing method includes knitting a base texture portion from at least two sets of thermoplastic synthetic fiber filament yarns having a fineness of 30 to 50 deniers using a tricot knitting machine having at least three reeds, and needles of the base texture portion.・At least 1 in the loop part
The fineness is greater than that of the yarn constituting the ground weave part of the set.
A tricot knitted fabric is knitted with 50 to 70 denier thermoplastic synthetic fiber filament yarns that are 1.2 times or more larger to form ridges, and the yarns in the tricot knitted fabric are further bonded to each other to create a knitted fabric. It is characterized by making the entire structure rigid. The tricot knitted fabric that is the raw material for the channel material of the present invention is knitted by a tricot knitting machine having at least three or more strands. A three-piece reed knitted fabric, which is an example of the knitted fabric, is shown in FIGS. 1 and 2 A, B, and C. In the three-ply reed knitted fabric shown in Fig. 1, the ground texture part is knitted from relatively fine yarns F and M, and the ridge part is knitted with yarn B, which is thicker than these yarns F and M. It has a detailed structure. Yarns F and M with the above fineness
are supplied to the front reed and middle reed, respectively, and are knitted into a [1/1] double dens knit as shown in Figure 2 A and B.
is fed to the back osa and knitted into a [1/0] chain stitch as shown in Figure 2C. With this type of knitting, the sinker loop part of the stitches formed by the front recess and middle recess becomes the ground weave part, and the chain stitch formed by the needle loop part and back recess becomes the ridge part. . That is, the tricot knitted fabric of the channel material material of the present invention comprises at least three sets of at least one set of thick thermoplastic synthetic fiber filament yarns and at least two sets of fine fineness thermoplastic synthetic fiber filament yarns. It can be knitted using a warped thermoplastic synthetic fiber filament yarn using a tricot knitting machine with at least three reeds, and the ground texture part is knitted with the two sets of yarns on the fineness side, This 2
Another needle loop is formed by the threads of the set.
The ridge portions are formed by knitting a set of thick yarns, thereby forming a tricot knitted fabric having a ground weave portion and a ridge portion. In this way, the ground weave portion is knitted with at least two threads of fineness, and the ridge portion is further knitted with at least one thread of thicker fineness than the threads forming this ground weave portion. As a result, a structure is formed that is thinner in the ground tissue and thicker in the ridges. Therefore, a space for a flow path with a U-shaped cross section connected by a thin ground structure is formed between two adjacent ridges. In order to make the thickness relationship between the ridges and the ground texture more noticeable, the fineness of the thick yarns that make up the ridges should be 1.2% higher than that of the fine yarns that make up the ground texture. It is necessary to make it more than twice as large. Further, the fineness of the ridge portion must be selected within the range of 50 to 70 deniers and the ground texture portion within the range of 30 to 50 deniers. The tricot knitted fabric knitted as described above needs to be further stiffened by bonding the yarns to each other so that it will not be easily crushed by a high-pressure stock solution. Such adhesion treatment may include resin processing to adhere melamine resin, or thermoplastic synthetic fiber filament yarns constituting the tricot knitted fabric may be made into a composite structure consisting of a low melting point component and a high melting point component, It can also be carried out by melting only the low melting point component by heat treatment and fusing the yarns together. In particular, the latter method of fusing low-melting components is advantageous in applications where it is necessary to produce highly purified permeated water, since there is no eluate in the permeated water compared to the case of resin processing. The thermoplastic synthetic fiber filament yarn consisting of a low melting point component and a high melting point component may be in the form of a composite yarn, a mixed fiber yarn, or the like. In the case of composite yarns, both core-sheath type composite yarns, in which a low melting point component is placed on the sheath side and a high melting point component on the core side, and bimetallic type composite yarns, in which both components are laminated from both the left and right sides, can be used. It is. The mixed fiber yarn is a mixture of a filament having a low melting point component and a filament having a high melting point component. As for the ratio of the two different components, it is preferable that the low melting point component that becomes the adhesive does not exceed 50%, but this is not the case as long as the high melting point component that becomes the skeleton after melting functions sufficiently in terms of strength. Further, it is sufficient that the difference in melting point between the two components is at least 10°C, preferably 20°C or more. Typical combinations of high melting point components and low melting point components are high melting point polyester and low melting point polyester,
There are high melting point polyamides and low melting point polyamides, high melting point polyolefins and low melting point polyolefins, and among these, a combination of high melting point polyesters and high melting point polyesters is preferred from the viewpoint of rigidity after fusion processing. Generally, low melting point components can be easily obtained by making them into polymer copolymers.
The melting point difference can be changed by changing the copolymerization ratio, adding a copolymerization component, changing the copolymerization component, changing stereoregularity or degree of polymerization, etc. Also,
Apart from this, it may also be combined with different types of polymers having different melting points. The thermoplastic synthetic fiber filament yarn consisting of a combination of both of the above-mentioned components must be used in the yarn of the base structure part and the ridge part, and the low melting point component used in both parts must have the same melting point. is desirable. FIGS. 3 and 4 illustrate a spiral type fluid separation device using the above-mentioned channel material. 1 is a fluid separation element, and 2 is a cylindrical container housing this fluid separation element 1. The fluid separation element 1 is sealed at one end with a sealing material 3 within a cylindrical container 2, and has a permeate discharge pipe 4 at the other end protruding to the outside of the cylindrical container 2. The cylindrical container 2 is provided with a stock solution supply pipe 5 on the peripheral wall and a stock solution discharge pipe 6 on the side wall. As shown in FIG. 4, the fluid separation element 1 has a permeate discharge pipe 4 made of a hollow pipe with a small hole 7 in the center, and an envelope-shaped semipermeable membrane 9 is spirally wound around the outside of the permeate discharge pipe 4. ing. The envelope-shaped semipermeable membrane 9 has a permeate channel material 10 according to the present invention inserted therein, and the permeate discharge pipe 4 is opened with its open end facing the small hole 7.
It communicates with the inside of. Moreover, a stock solution channel material 11 is interposed between the outer surfaces of the spirally wound envelope-shaped semipermeable membrane 9, and extends from the stock solution inlet 12 on the surface of the fluid separation element to the stock solution outlet 13 in the center. , this stock solution outlet 13 communicates with the stock solution discharge pipe 6 of the cylindrical container 2. Therefore, in the liquid separation device described above, a portion of the high-pressure stock solution supplied from the stock solution supply pipe 5 passes through the semipermeable membrane 9 while passing through the stock solution channel material 11 from the stock solution inlet 12 of the fluid separation element 1. The permeate passes through and moves to the permeate channel material 10 side, and is guided by the permeate channel material 10 and taken out from the permeate discharge pipe 4. The residual liquid of the stock solution is discharged from the stock solution discharge pipe 6 via the stock solution outlet 13. According to the above-mentioned channel material according to the present invention, the fabric is made of a tricot knitted fabric having a base texture part and a ridge part in which thermoplastic synthetic fiber filaments of a specific fineness are knitted, and the base texture part is thin but the ridge part has a thick fineness. Since it is thicker due to the knitting of the threads, a U-shaped flow path is formed between two adjacent ridges with a relatively large cross-sectional ratio to the total cross-sectional area of the knitted fabric. Therefore, although the overall thickness of the channel material is the same as that of conventional channel materials, the flow resistance in the liquid separation operation described above is significantly reduced, and the permeate production rate is increased while maintaining a compact equipment capacity. can do. In addition, as will be clear from the examples described later, the ridges of the tricot knitted fabric are made of thick yarns, and the yarns are bonded together to make the entire knitted fabric rigid, making it resistant to high-pressure raw solutions. Since it is made so that it will not be easily crushed, its durability is increased and the good performance of the channel material can be maintained for a long period of time. Example 1 Three types G made of polyethylene terephthalate with the following deniers and filament numbers:
Filament yarns H and I were prepared. G: 37.5 denier, 18 filaments H: 25 denier, 12 filaments I: 15 denier, 12 filaments There are also three types consisting of the following denier and number of filaments, which are made of a polymer made by copolymerizing polyethylene terephthalate with 10 mol% isophthalic acid. Filament yarns g, h, and i were prepared. g: 37.5 denier, 18 filament h: 25 denier, 12 filament i: 15 denier, 12 filament Furthermore, the above filament threads are connected to G, g to g,
Mixed yarns J, K, and L of 75 denier, 50 denier, and 30 denier were prepared by mixing H, h with each other, I with each other, and i with each other at a ratio of 1:1. Next, using the knitting structure shown in FIGS. 1 and 2, the mixed fiber yarn L is applied to the front woven fabric and the middle woven fabric.
The above-mentioned mixed yarn K was supplied to the back tread, and a 32 gauge, 3-ply tricot knitted fabric was knitted. After refining this knitted fabric, the well and course densities after heat treatment are 47/25mm, 60/25mm and 48/25, respectively.
mm, set the tenter conditions so that it is 73/25 mm.
Heat fusion processing was performed at 250° C. for 1 minute to create two types of channel materials P and Q (corresponding to the above-mentioned well and course density, respectively) corresponding to the present invention. On the other hand, using the above mixed fiber yarn J as a comparative product, 32
A double denbi knitted fabric was knitted with a gauge and 2 sheets of Osa and Torikotsu. After refining this knitted fabric, the well and course densities after heat treatment are 40/25 respectively.
mm, determine the tenter conditions so that it is 54/25 mm.
A channel material R was created by thermal fusion processing at 250°C for 1 minute. For these channel materials P, Q, and R, the flow resistance coefficient H and the thickness of the channel materials measured using a pressure drop measuring device shown in FIG. 5, which will be described later, were compared, and the results shown in Table 1 were obtained. The size of the channel material in the test was 0.024 m ² (width 0.08 m x length 0.3 m) within the seal, high pressure water pressure 30 Kg/cm ² , differential pressure Δp 2 Kg/cm ² , and water temperature. The temperature was 25℃.

[Table] As is clear from Table 1, the channel materials P and Q according to the present invention have a small thickness and a small flow resistance coefficient H, and are superior to the comparative channel material R in both aspects. . Next, we increased the pressure of high-pressure water to 70Kg/cm ² and further raised the water temperature to 40℃, and after continuing the test for 200 hours, we measured the flow resistance coefficient H and thickness and investigated the changes. The results shown in Table 2 were obtained.

[Table] As is clear from Table 2, the channel materials P and Q according to the present invention have a higher flow resistance coefficient H than the comparative product R.
It can be seen that the rate of increase in is small and the performance is stable over a long period of time. Example 2 Channel materials S, which were made thinner by further calendering the two types of three-ply tricot knitted fabrics knitted as materials for channel materials P and Q in Example 1,
I created T. When these were measured in the same manner as in Example 1, the results shown in Table 3 were obtained when the water temperature was 25.degree. C., and the results shown in Table 4 were obtained when the water temperature was 40.degree. C. for 200 hours.

【table】

[Table] As is clear from Tables 3 and 4 above, the flow resistance coefficient H increases slightly due to thinning through calendering, but the thickness decreases further, which is advantageous for making the device more compact. There is. Also, compared to the measured value at a water temperature of 25℃,
℃, the rate of change in measured values after 200 hours is small;
It can be seen that the performance is stable over a long period of time. (Description of Pressure Loss Measuring Instrument) As shown in FIG. 5, a channel material 50 to be measured and a semipermeable membrane 51 are stacked and sandwiched between upper and lower support frames 52 and 53. High-pressure water is supplied from a high-pressure water supply pipe 55 to a flow path 54 formed on the semipermeable membrane 51 side and discharged from a discharge pipe 56, and low-pressure water is supplied to a flow path 57 on the flow path material 50 side. Low pressure water is supplied from the pipe 58 and discharged from the discharge pipe 59. A meter 60 is provided at the end of the discharge pipe 59 to measure the amount of liquid flowing out. Now, when high-pressure water corresponding to the stock solution is supplied from the high-pressure water supply pipe 55, and low-pressure water corresponding to the permeate is supplied from the low-pressure water supply pipe 58 while maintaining this state, the pressure of the high-pressure water is As the height increases, the channel material 50 is deformed under pressure, and the flow rate of low-pressure water decreases. From this, the degree of deformation of the channel material 50 can be expressed as the flow resistance coefficient H by measuring the pressure drop (differential pressure) Δp and flow rate q of this low-pressure water. That is, the flow rate q is generally given by the following formula. q=(1/H)(dΔp/Δl)w (where l is the length of the flow path, w is the width of the flow path) By solving this, the flow resistance coefficient H is obtained as shown in the following equation. . H=K(Δp/q)(atm/ton/day) (where K is a constant determined by the device) Therefore, by measuring Δp and q, the flow resistance coefficient H can be determined.

[Brief explanation of drawings]

Fig. 1 is an enlarged plan view of the main part of the tricot knitted fabric (three-layered rectangular knitted fabric) which is the material of the channel material of the present invention;
Figures A, B, and C are organization charts for each reed of the same tricot knitted fabric, Figure 3 is a vertical cross-sectional view showing an example of a liquid separation device using the same channel material, and Figure 4 is the - of Figure 3. 5 is a schematic diagram of a pressure loss measuring device. F...Front reed yarn, M...Middle...
Thread of Osa, B...Thread of Back Osa, 1...
Fluid separation element, 9... Envelope-shaped semipermeable membrane, 10...
Channel material.

Claims (1)

[Scope of Claims] 1. A channel material for a liquid separator that supports the back side of a semipermeable membrane that receives pressure on an undiluted solution, the channel material having a fineness of 30
A base fabric part knitted from ~50 denier thermoplastic synthetic fiber filament yarns and a 50-70 denier thermoplastic synthetic fiber filament yarns having a fineness of 1.2 times or more greater than the yarns constituting the base fabric part. 1. A channel material for a liquid separator, characterized in that the fabric is made of a tricot knitted fabric having ridged portions, and the yarns in the tricot knitted fabric adhere to each other to make the entire knitted fabric in a rigid state. 2. The liquid separation according to claim 1, wherein the thermoplastic synthetic fiber filament thread is formed from a low melting point component and a high melting point component, and the low melting point component melts and solidifies to bond the threads together. Channel material for equipment. 3. Using a tricot knitting machine having at least three reeds, the ground structure is knitted from at least two sets of thermoplastic synthetic fiber filament yarns with a fineness of 30 to 50 deniers, and the needles and
The loop portion has a fineness of 50 to 1.2 times greater than that of the yarns constituting at least one set of the ground texture portions.
A tricot knitted fabric is knitted with 70 denier thermoplastic synthetic fiber filament threads to form ridges, and the yarns in the tricot knitted fabric are further bonded to each other to make the entire knitted fabric rigid. A method for manufacturing a channel material for a liquid separation device, characterized by: 4. A thermoplastic synthetic fiber filament yarn is formed from a low melting point component and a high melting point component, and a tricot knitted fabric knitted from the thermoplastic synthetic fiber filament yarn is heat treated to melt only the low melting point component,
The method for manufacturing a channel material for a liquid separation device according to claim 3, wherein the molten low melting point portion adheres the threads to each other.