JPH05317658A - Separating pipe - Google Patents

Abstract

PURPOSE:To separating pipe which allows efficiently back washing and easily liquidtightly shut off a raw liquid side and permeated liquid side from each other at both ends of a tubular member by inserting a tubular membrane into a sheath pipe consisting of a woven fabric or porous sheet. CONSTITUTION:A core bar 3 having a spherical part 31 at its front end is inserted into the tubular semipermeable membrane 1 in order to insert the tubular semipermeable membrane 1 into the sheath pipe 2 if the gap between the sheath pipe 2 and the tubular semipermeable membrane 1 is small. The method of inserting the sheath pipe 2 consisting of the woven fabric or the porous sheet onto the core bar 3 from its spherical part 31 side and removing the core bar 3 after the end of the insertion of this sheath pipe 2 is used. Plural pieces of the tubular membranes inserted into the sheath pipes (separating pipes) A are housed into a cylindrical case 4 and a resin is injected to both ends of the tubular membranes inserted into the sheath pipes to form partition walls 5, 5. A filtrate outlet 40 is provided in the case 4. One end 41 side of the case 4 is used as a raw liquid inlet and the other end 42 side of the case 4 as a concd. liquid outlet. As a result, the sheath pipes 2 reinforce the tubular membranes against the internal pressure and, therefore, the back washing liquid is brought into well contact with the outside surfaces of the membranes.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a separation tube used when purifying, purifying or concentrating a liquid by ultrafiltration or reverse osmosis separation.

[0002]

^2. Description of the Related Art An ultrafiltration membrane or a reverse osmosis membrane may be used for purification and concentration of a stock solution. In the ultrafiltration membrane, a molecular weight of 1000 to 300 is usually applied at an operating pressure of 10 kgf / cm ² or less. 2,000 high molecular weight substances can be separated, and water, ions, and low molecular weight substances can be permeated. In reverse osmosis separation membranes, usually several kgf / cm ²
With the above operating pressure, it is possible to concentrate and separate low molecular weight ions and organic compounds of 50 Å or less.

In the above ultrafiltration membrane and reverse osmosis separation membrane, they are used in a tubular, hollow fiber, flat membrane or spiral form. Therefore, in order to treat the stock solution by ultrafiltration or reverse osmosis separation, it is necessary to apply the above-mentioned predetermined operating pressure to the stock solution, and the membrane is exposed to this pressure. Mechanical reinforcement is required.

Among the above-mentioned membrane forms, in the tubular membrane,
Since the hoop stress acts on the membrane under the pressure in the tube, it is necessary to reinforce the tubular membrane so as to keep the hoop stress below the allowable tensile force of the membrane.

For the purpose of such reinforcement, it has been conventionally known to insert a tubular membrane into a highly rigid perforated tube such as a perforated metal tube, a perforated FRP tube or a porous FRP tube in a close contact state.

In this case, as a structure of the membrane separation module, a plurality of tubular membranes (separation tubes) inserted in a high-rigidity perforated tube are arranged in parallel, and headers are provided at both ends of these separation tube groups.
Permeability in the undiluted solution is obtained by attaching the undiluted solution to the separation tube group in series (to form a zigzag passage) or in parallel and allowing the undiluted solution to circulate in the separation tube under the above operating pressure. The component (solvent) is permeated to the outside of the separation tube through the tubular membrane and the hole of the high-rigidity perforated tube, the solute of the undiluted solution becomes high in concentration, and this concentrated solution is flown out from the undiluted solution outlet.

[0007]

In the membrane separation, not only suspended substances and colloids in the stock solution but also the formation of a gel layer by the adhesion of slime on the membrane surface accompanying the growth of microorganisms and the membrane, and further, the permeation side support Since the separation performance will gradually decrease due to the clogging of the membrane, it is necessary to periodically wash not only the front surface of the membrane but also the back surface side to recover the separation performance. As a known method, a reverse-side cleaning method is known in which a sterilizing cleaning liquid is sprayed from the permeate side within a pressure range in which the film form is not deformed.

However, in the above-mentioned tubular membrane inserted in the high-rigidity perforated tube, unless the force of the reverse-side cleaning liquid is increased, pressure is not applied through the high-rigidity perforated tube, and it is difficult to carry out effective reverse-side cleaning. On the other hand, if pressure is applied to the permeate side,
There is a risk that the membrane will be deformed inward by the back pressure and damage will occur.

In the separation device having the above structure, it is necessary to separate the raw liquid side and the permeated liquid side at both ends of the separation tube in a liquid-tight manner by partition walls. In this case, the high rigidity perforated tube and the tubular membrane are separated from each other. Since it belongs to the permeate side and the inside of the tubular membrane belongs to the raw solution side,
Between the tubular membrane and the high-rigidity perforated tube at the end of the separation tube, for example,
It is necessary to seal with the injected resin, but since the gap between them is very small, it is difficult to seal with the injected resin.

An object of the present invention is to efficiently wash the reverse side when the tubular membrane is reinforced against the internal pressure by inserting it into the tubular reinforcing body, and, moreover, between the raw solution side and the permeate side at both ends of the tubular membrane. It is an object of the present invention to provide a separation tube that can easily perform liquid tight isolation.

[0011]

The separation tube of the present invention is characterized in that a tubular membrane is inserted into a sheath tube made of a woven cloth or a porous sheet.

[0012]

The tubular membrane can be reinforced against the internal pressure because the woven cloth or porous sheet used for the sheath tube has a considerable tensile strength. Further, the woven cloth or the porous sheet allows the reverse side cleaning solution to pass through well, and the sheath tube is flexible so that the separation side tube can be vibrated by spraying the reverse side cleaning solution. Since this can be promoted, efficient cleaning and recovery can be achieved.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. 1A is a plan view showing an embodiment of the present invention, and FIG.
(B) is a cross-sectional view taken along line (a) of FIG.
In (a) and (b) of FIG. 1, 1 is a tubular semipermeable membrane, and an ultrafiltration membrane or a reverse osmosis separation membrane is used as the membrane. 2 is a sheath tube made of woven cloth or porous sheet,
The tubular semipermeable membrane 1 is inserted. The sheath tube 2 may be made of two woven cloths or porous sheets, and both ends thereof are sewn with a sewing machine.

In the above, the inner diameter of the sheath tube 2 is set to be larger than the outer diameter of the tubular semipermeable membrane 1. Therefore, in the tubular semipermeable membrane 1, the inner pressure is expanded to the inner diameter of the sheath tube 2,
Further expansion is kept extremely small due to the reinforcing effect of the sheath tube 2.

The inner diameter of the tubular semipermeable membrane 1 is R ₁ , the thickness is t ₁ , the Young's modulus is E ₁ , and the inner diameter of the sheath tube 2 is R ₂ (R ₂ >).
R ₁ ), the thickness is t ₂ , the Young's modulus is E ₂ , and the internal pressure is P, the tensile strain of the semipermeable membrane when the tubular semipermeable membrane 1 is expanded to the inner diameter of the sheath tube by the internal pressure is (R _2- R ₁ ) / R ₁
And the increase Δε in tensile strain of the semipermeable membrane due to further expansion is Δε = PR ₂ / (t ₁ E ₁ + t ₂ E ₂ ) (1), and the tensile strain due to internal pressure expansion of the tubular semipermeable membrane is The strain ε is ε = R ₂ [1 / R ₁ + P / (t ₁ E ₁ + t ₂ E ₂ )]-1 (2).

Thus, the stock solution pressure P (usually 10 to 50 k
g / cm ² ), the inner diameter of the tubular semipermeable membrane 1 (usually 3 to 30 m
m), thickness t ₁ (usually 1.0 to 2.0 mm), etc. are set to predetermined values, and under such conditions, the tensile strain ε of the film expressed by the above-mentioned second equation is set as an allowable strain, and the sheath The inner diameter R ₂ , the thickness t ₂ , the Young's modulus E _2, etc. of the tube 2 are adjusted. In the case of a cellulose acetate tubular reverse osmosis separation membrane, the tensile strain ε is set to 5.0% or less.

In the above second equation, when the internal pressure P is low,
[1 / R ₁ + P / (t ₁ E ₁ + t ₂ E ₂ )] is small, so that the inner diameter R _{2 of the} sheath tube can be increased by that much under the same membrane tensile strain, and the ultrafiltration membrane In, the gap between the tubular membrane and the sheath tube can be made larger than that of the reverse osmosis separation membrane.

In the above, when the gap between the sheath tube 2 and the tubular semipermeable membrane 1 is small, the tubular semipermeable membrane 1 can be inserted into the sheath tube 2 by inserting (a) to (c) in FIG. ), The core rod 3 having the spherical portion 31 at the tip is inserted into the tubular semipermeable membrane 1 [(a) in FIG. 2], and then the sheath tube 2 is inserted from the spherical portion 31 side of the core rod 3. Then, the method of pulling out the core rod 3 [(c) of FIG. 2] can be used after the insertion of the sheath tube 2 is completed [(b) of FIG. 2].

FIG. 3 is a vertical cross-sectional view of a separation device using the separation tube of the present invention, in which a plurality of tubular membranes (separation tubes) A inserted in a sheath tube are accommodated in a cylindrical case 4 to form a tubular shape. The partition walls 5 and 5 are formed by injecting resin into both ends of the case 4, a permeate outlet 40 is provided in the case 4, and one end 41 side of the case 4 serves as a stock solution inlet. The other end 42 side of the spout 4 serves as a concentrated liquid outlet.

In the above, as the sheath tube, as shown in FIG. 4, a chain sheath tube in which the sheath tube portions 1 and 1 are connected by a strip portion 10 having a constant width is used, and as shown in FIG. -It is preferable to keep the distance between the tubular membranes 1, 1 in the space 4 constant. In the case shown in FIG. 5 (when the number of tubular membranes 1 is 4),
When the distance between the tubular membranes is L and the outer diameter (diameter) of the tubular membranes is D, the width T of the strip portion is set to T = L-Dcos45 ⁰ (3).

The chained sheath tube can be manufactured by stacking two woven fabrics and sewing the belt-shaped portion with a sewing machine. However, if a continuous woven fabric in a plurality of rows in a sheath form is produced by a loom, sewing is not performed. A chain sheath tube can be manufactured. The membrane separation device using the separation tube of the present invention has stable performance, and its test example is as follows.

Test Example The tubular membrane has an inner diameter of 11.5 mm and an outer diameter of 12.8 mm.
Cellulose acetate type tubular reverse osmosis separation membrane is used, the sheath tube is a chained sheath tube, the number of sheath tubes is 4, the circumference of the sheath is 40.8 mm, and the strip is Has a width of 4.25 mm, a wire diameter of 120 μm, an opening of 243 μm,
A polyester woven fabric having a mesh thickness of 182 μm was used. The above cellulose acetate-based tubular reverse osmosis separation membrane was inserted into each sheath tube portion of this chain-like sheath tube, and this was inserted into an inner diameter: 40 mm, outer diameter:
Insert it into a 48 mm stainless steel tube and cut both ends to 27
88mm, using two-part epoxy resin on both ends,
The stainless steel pipes were held vertically, one by one, and cast and cured to shut off the raw liquid side and the permeated side.

Using this membrane separator, 5000 pp
When mNacl water was treated at an operating pressure of 15 kgf / cm ² and a feed water flow rate of 80 l / min, it was possible to perform treatment at a stable salt removal rate.

[0024]

The separation tube of the present invention is constructed as described above, and since the tubular membrane is reinforced against the internal pressure by the woven cloth or the sheath tube made of the porous sheet, the reverse side washing liquid is woven. Alternatively, the outer surface of the membrane can be brought into good contact with the liquid through the porous sheet, and the tubular membrane can be vibrated well by the pressure of the backside washing liquid within a range that does not damage the membrane, so that the backside washing can be efficiently performed.

Since the sheath tube woven fabric or the porous sheet is excellent in resin impregnation property, in the membrane separation apparatus shown in the figure, no gap is left between the resin partition wall and the tubular membrane outer surface, Liquid-tight adhesion is possible, and it is possible to reliably and easily shut off the raw liquid side and the permeated liquid side in the membrane separation device.

[Brief description of drawings]

FIG. 1A is a plan view showing an embodiment of the present invention. FIG. 1B is a sectional view taken along the line A-B of FIG.

FIG. 2 is an explanatory view showing a method for manufacturing a separation tube of the present invention.

FIG. 3 is an explanatory view showing a membrane separation device using the separation tube of the present invention.

FIG. 4 is an explanatory view showing another example of the sheath tube used in the present invention.

FIG. 4 is a cross-sectional view showing a membrane separation device using a separation tube different from the above according to the present invention.

[Explanation of symbols]

 1 tubular membrane 2 sheath tube

Claims (1)

[Claims] 1. A separation tube characterized in that a tubular membrane is inserted into a sheath tube made of woven cloth or porous sheet.