JPS5823124B2 - Continuous production method and device for external pressure tubular membrane - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for producing an external pressure type tubular membrane used in a reverse osmosis device and an ultrafiltration device.

In the case where a thin film is formed on the outer surface of a tubular support, it is preferable to hold the support vertically and apply a casting liquid, which is a liquid film raw material, and then pass through a series of steps of aeration and gelation at a constant rate.

As shown in Japanese Patent Publication No. 49-48074, a conventional film forming apparatus suspends a membrane support by a wire,
This is a batch method in which the support is formed into a film one by one, and its conceptual diagram is shown in FIG.

One membrane support 1 is suspended by a thread 2, and the thread 2 is connected to an electric motor 3.
The membrane support 1 is lowered by the operation of the electric motor 3, passes through the die 4, and is coated with the casting liquid.
After passing through the die 4, it is aerated and further gelled in a 50 ice water bath.

The conventional method has a simple device configuration, and because the membrane support can swing freely when passing through the center of a fixed die, the high viscosity casting liquid (which is centered in the die and the film thickness is It has the advantage of being constant.

However, the conventional device has the following practical drawbacks.

In other words, in order to continuously apply casting liquid to a support, it is necessary to suspend an extremely long support connected to each other with a thread, and the device must be extended an unlimited length in the height direction. , which is completely impossible in practice.

If the patch method is still used for production using the conventional method, 1
After completing film formation of the book support, manual work such as attaching threads, changing the thread, and cleaning the die is required, which results in production of only a few books per hour, which is extremely inefficient and at the same time Disadvantages include uncertainty in die cleaning, etc., and variation in membrane performance due to individual differences.

Another method is to fix the support vertically and move the die up or down to apply the casting solution, but it is impossible to perform the series of coating and aeration gelling steps at a constant rate. Yes, it is not practical.

This invention aims to eliminate the above-mentioned drawbacks, and the supports are stored, taken out one by one, connected to each other, passed through a die by roller operation, aerated, and connected to an ice water bath. The present invention provides a method and apparatus for producing an external pressure type tubular membrane in which the membrane is formed on a support, separated one by one, and gelled.

The following embodiment of the present invention will be described based on FIG. 2 to FIG.
9 is a support guide tube, 9 is a roll drive unit, 10 is a die, 11
1 is a casting liquid continuous supply device, 12 is a membrane support separation unit, 1
3 is a membrane support holding part, 14 is an ice water bath, 15 is a conveyor, and 16 is a heat treatment tank.

As shown in FIG. 4, the membrane supports are connected to each other by a convex connector 1T and a concave connector 1B, which are made of synthetic resin and have the same outer diameter as the membrane supports.

These configurations will be explained in detail below. Membrane support holding frame 6
is a membrane support cartridge, in which several dozen membrane supports 1 are vertically attached to the circumferential grooves 19c of two upper and lower disks,
The membrane supports are taken out one by one by a holder at the tip of an arm 20 extending from the rotating membrane support removal mechanism 7 and inserted into the support guide tube 8.

The membrane support has a concave connector attached to its upper end and a convex connector attached to its lower end.

Therefore, in the guide tube, another support is connected to the upper part of the descending support so that the membrane support descends and the upper end of the support reaches into the guide tube. When this happens, the take-out speed of the support take-out section is adjusted so that another membrane support is pierced.

The membrane support is narrowed by four rolls 21, 22, 23, 24 and lowered by their rotation.

The roll drive section 9 is composed of an electric motor and a speed reducer roller.

The speed of descent is regulated by a speed reducer. Although the rate of descent is fundamentally unrelated to this invention, the film forming conditions are an important factor.

In an example, when a casting liquid containing cellulose acetate as the main component was used in membrane formation for reverse osmosis, the rate
Although it is preferable to keep the speed constant within the range of 30 mm/sec, the speed varies depending on the raw material of the casting liquid and the viscosity Q.

The problem with roll drives lies in how to reduce vertical runout and how to reduce the minute vibrations of the drive machine.

The reason for this is that when the membrane support passes vertically through the die, if the eccentricity from the center of the die is too large, the inner periphery of the die will come into contact with the outer periphery of the membrane support, resulting in membrane breakage.

In addition, vibrations cause waveforms on the membrane surface, which also causes cuts in the membrane.

In this invention, for the former, we aim to make the die smaller and lighter, and by installing a cast liquid tank outside, the cast g is hardly stored in the die.
The die is made free in two dimensions in the horizontal direction, and has sufficient followability against the eccentricity of the support.

For the latter, a shock absorber is inserted between the electric motor of the roll drive unit and the roller, and the roll is made of rubber.

The casting liquid supply device 11 is composed of a nitrogen gas cylinder, a pressure regulating valve, and a casting liquid tank, and is configured to supply the casting liquid in the tank to the die by the pressure of the nitrogen gas.

According to the example, the nitrogen gas pressure is 1 to 1.5) cg/c.
77 fG is sufficient.

In this case, the gas is preferably an inert gas such as nitrogen gas to prevent oxidation of the casting liquid.

The membrane support is coated with a casting liquid in a die, and after passing through the die, it is passed through air and aerated.

Next, the aeration time until entering the ice water is an important condition for film formation.

Therefore, although the distance between the lower end of the die and the water surface of the ice water bath varies depending on the raw material and composition of the casting liquid, it is necessary to make the optimum value Q adjustable.

In the example, the cellulose acetate-based casting liquid was 100 m.
+++ is optimal, and depending on the temperature and other atmosphere,
Of course, things will change.

The membrane support separating unit 12 separates the membrane support placed in the ice water bath 14 between the convex connector 17 and the concave connector 18 explained in FIG. Catch the connector while moving at a constant speed,
A holder 26 catches the recessed connector at the upper end.

At the same time, Q-holder 26 descends at a faster speed than holder 25.

By this operation, the convex connector 17 and the concave connector 18 are separated.

After separation, the holder 25 attaches the convex connector.

Next, the holder 27 catches the convex connector, so that the upper and lower parts of the membrane are held by the holders 26 and 27.

The membrane held at both ends is changed in position by the membrane holding section 13G, moved horizontally, and placed on a conveyor.

That is, in the die 10-1, the membrane supports 1 are continuously lowered to form a film, and then the membrane supports 1 are separated one by one, moved horizontally, and sequentially placed on the conveyor 15.
This will happen.

The membrane remains in the ice water bath 14 while moving on the conveyor 15 for one hour, and then is transferred to the conveyor 28 in the heat treatment water bath 16.

The membrane support 1 that has been heat-treated for a certain period of time is made into a product after removing the convex and concave connectors at both ends.

This invention has the above-mentioned structure, and the tubular support is automatically and continuously lowered vertically by the roll drive unit 9, enters the die 10, is coated with a constant thickness of casting liquid, and is aerated. After that, a series of manufacturing steps for gelling the membrane are carried out in the ice bath 14, and then the film is separated from the connection again while changing its position from vertical to horizontal.
The treatment is automatically and continuously carried out sequentially from the heat treatment water tank 16 to the heat treatment water tank 16.

Since the present invention has such a configuration, the introduction of the membrane support 1 into the die 10 is completely continuous, the casting liquid in the die 10 does not come into contact with air, and the casting liquid remains in the die 10. Because there is no liquid, new casting liquid is always applied.

In particular, cellulose acetate-based casting liquid uses acetone solvent, and its evaporation rate is slow even at room temperature.Acetone evaporation due to stagnation causes a change in the composition of the casting liquid, lowering film performance, and causing performance variations. In Although,
In this respect, the present invention is free from such misconceptions.

Furthermore, according to the present invention, automation of film formation has been achieved, and the production volume is approximately 60 films per hour, assuming the length of each film is 1 m, which is expected to be more than 10 times more than the conventional method. This reduces costs.

Furthermore, automation not only makes quality constant and quality control easier, but also eliminates the inspection process, which has a tremendous effect.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing a conventional film forming apparatus, FIG. 2 is a schematic diagram showing a film forming apparatus of the present invention, and FIG. 3 is a schematic diagram showing a side cross section of the ice bath and a heat treatment tank in FIG. 2. FIG. 4 is a sectional view showing the fitted state of the convex connector and the concave connector. DESCRIPTION OF SYMBOLS 1... Membrane support, 6... Support holding frame, 7... Support removal part, 9... Roll 1 rolling part, 10. ...Dai, 211...
Cast liquid continuous supply device, 12... Membrane' support separation section, 13... Membrane support holding section, 14...
...Ice water tank, 16...Heat treatment tank.

Claims (1)

[Scope of Claims] 1. After the membrane support is continuously fed in the longitudinal direction to a roll drive section, the membrane support is passed from the roll drive section Q into a die, and further passed through an aeration space. After immersing the membrane support in an ice-water bath and conveying the membrane support there at a speed higher than the speed of the roll, the membrane support is successively separated from the following membrane supports, and after being kept in the ice-water bath for a certain period of time. A method for continuously producing an external pressure type tubular membrane, characterized in that the membrane is supplied to a subsequent heat treatment section. 2. A membrane support supply section that continuously supplies the membrane support to the roll drive section in the longitudinal direction, a roll drive section that conveys the membrane support vertically while holding it downward Q, and a roll drive section. There is a die for applying the liquid membrane raw material onto the outer surface of the membrane support conveyed from the section, an ice water bath provided below the die through a certain space, and a speed difference O in the liquid in the ice water bath. An external pressure type characterized by having a membrane support separation section for separating the membrane support from subsequent membrane supports one after another, and a membrane support holding section for holding the membrane support in an ice water bath for a certain period of time. Continuous manufacturing equipment for tubular membranes. 3 The membrane support supply section includes a membrane support holding frame that holds a large number of membrane supports on the circumference between rotatable upper and lower discs, and a membrane support holding frame that sequentially takes out the membrane supports with a chuck part and rolls them. 3. The external pressure type continuous production apparatus for tubular membranes according to claim 2, further comprising a membrane support take-out section for supplying the membrane support to the drive section. 4. Claim 2, characterized in that concave and convex connectors are provided at both ends of the membrane support to connect the membrane supports to each other, and the concave and convex connectors are fitted with the connectors of the subsequent membrane supports. The external pressure type continuous manufacturing apparatus for tubular membranes described above. 5. The external pressure type continuous manufacturing apparatus for tubular membranes according to claim 2, wherein the die is provided with a buffer section that allows it to move slightly in the horizontal direction Q. 6. The external pressure type tubular membrane according to claim 2, characterized in that the die O is provided with a liquid membrane raw material supply section that is operated by nitrogen gas pressure in the reservoir that continuously supplies the liquid membrane raw material. Continuous manufacturing equipment. 7. The membrane support separation unit is composed of two conveyors, upper and lower, which are faster than the roll drive unit, and a set of upper and lower holding units ζ trowel holds the membrane support and then separates it from the following membrane support. An external pressure continuous tubular membrane production apparatus according to claim 1, characterized in that: