JPH11114561A - Membrane filtration device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a filtration column for which the installation space is small by connecting a lower water collecting section in the lower end part of the membrane element to a permeated water take-in port at the upper end part with a water collecting pipe provided outside of the membrane element to facilitate the production of a membrane element and to make the membrane element small sized without decreasing the membrane surface area. SOLUTION: A pressurized raw water supplied from a supply pipe 5 to a lower part raw water section 4 enters inside of an external cylinder 22 of the upper and lower membrane elements from a water passing port 23 of the external cylinder 22 to be in contact with many hollow yarn membranes and the permeated water enters in the hollow part of the hollow yarn membrane. Thus, a part of the permeated water descends to be collected to the lower water collecting section 17. And the remaining flows upward in the hollow part, a part of which descends to be collected in an intermediate water collecting section 15 and the remaining of which flows upward in the hollow part to be collected to a permeated water take-out port 11. The permeated water collected in the lower water collecting section 17 ascends upward in the lower water collecting pipe 19, is joined with the permeated water collected in the intermediate water collecting section 15, flows into an upper treating section 3 on a can plate and is taken out outside of the system through a water sampling pipe 6. The installation space is decreased.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a can plate for partitioning the inside of a filtration tower into an upper treatment chamber and a lower raw water chamber, a permeated water at an upper end portion of a membrane element comprising a hollow fiber membrane, a cartridge type microfilter and the like. The present invention relates to a membrane filtration device in which an outlet is attached to communicate with an upper processing chamber, the membrane element is suspended from a can plate into a lower raw water chamber, and a lower water collecting chamber is provided at a lower end of the membrane element.

[0002]

2. Description of the Related Art External pressure type membrane filtration devices as described above are known. In a known external pressure type membrane filtration device, two membrane elements composed of hollow fiber membranes are connected in series in the up-down direction, and the permeate outlet at the upper end of the upper membrane element is connected to the upper treatment chamber of the filtration tower. The two membrane elements attached to the can plate are suspended from the can plate into the lower raw water chamber, and an intermediate water collecting chamber is provided between the lower end of the upper membrane element and the upper end of the lower membrane element.
A lower collecting chamber is provided at the lower end of the lower membrane element.
Therefore, a part of the permeated water permeating through the hollow fiber membrane of the lower membrane element and entering the hollow portion flows upward in the hollow portion and collects in the intermediate water collecting chamber, and the remaining permeated water remains in the hollow portion. The water flows downward and collects in the lower collecting chamber at the lower end. Since the lower membrane element is mixed with the intake pipe communicating with the intermediate water collection chamber and the lower water collection chamber as in the case of the hollow fiber membrane, the permeated water collected in the lower water collection chamber is collected in the above-mentioned intake pipe. Flows upward into the intermediate water collecting chamber, and flows upward in the hollow portion of the hollow fiber to be combined with the permeated water entering the intermediate water collecting chamber. Also, a part of the permeated water that has passed through the hollow fiber membrane of the upper membrane element and entered the hollow portion flows upward in the hollow portion and flows from the permeated water outlet into the upper treatment chamber on the can plate. The remainder of the permeated water flows downward in the hollow part and enters the intermediate collecting chamber.

[0003]

That is, all the permeated water permeating through the hollow fiber membrane of the lower membrane element and the permeated water through the hollow fiber membrane of the upper membrane element are formed in the intermediate water collecting chamber. And the permeated water flowing downwards is collected and becomes large. Then, a large amount of permeated water collected in the intermediate water collecting chamber flows upward in the water intake pipe mixed in the upper membrane element so as to communicate with the permeated water outlet and the intermediate water collecting chamber like the hollow fiber membrane. Must flow through the upper permeate outlet to the upper processing chamber on the can plate. Therefore, the intake pipe in the lower membrane element
Permeate the hollow fiber membrane of the lower membrane element and enter the hollow part,
The cross-sectional area should be large enough to allow the permeated water collected in the lower collecting chamber to flow downward through the hollow part and to flow upward to the intermediate collecting chamber, whereas the intake pipe in the upper membrane element is The total amount of permeated water that has passed through the hollow fiber membrane of the membrane element of the above and the permeated water that has passed through the hollow fiber membrane of the upper membrane element and has flowed downward in the hollow portion is increased upward. Either a large cross-sectional area required for flowing is required, or the number of intake pipes used needs to be increased. In this case, if the intake pipe of the upper membrane element and the intake pipe of the lower membrane element have the same sectional area or the same number of used pipes, the permeated water flowing upward in the intake pipe of the upper membrane element Therefore, the number of stages of the membrane elements connected in series in the vertical direction cannot be increased to a certain level or more.

For this reason, if the outer diameter of the upper membrane element is made equal to the outer diameter of the lower membrane element, and the cross-sectional area or the number of used intake pipes of the upper membrane element is made larger than that of the lower membrane element. The effective membrane area of the upper membrane element by the hollow fiber membrane is smaller than the membrane area of the lower membrane element, and the membrane filtration efficiency is reduced. In addition, when manufacturing a membrane element, it is necessary to manufacture a plurality of types of membrane elements having different cross-sectional areas or the number of used water intake pipes having the same outer diameter, but having different sizes, which is very complicated.

[0005]

DISCLOSURE OF THE INVENTION The present invention has been developed to solve the above-mentioned problems, and a membrane element is provided on a can plate which partitions the inside of a filtration tower into an upper treatment chamber and a lower raw water chamber. A membrane in which the permeate outlet at the upper end is attached to communicate with the upper treatment chamber, the membrane element is suspended from the can plate into the lower raw water chamber, and a lower water collecting chamber is provided at the lower end of the membrane element. In the filtration device, a lower water collecting chamber at a lower end of the membrane element and a permeate outlet at an upper end are connected by a water collecting pipe provided outside the membrane element.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In each of the illustrated embodiments, reference numeral 1 denotes an external pressure type filtration tower;
The raw water is pressurized and supplied to the lower raw water chamber 4 by a supply pipe 5. The periphery of the can plate 2 is sandwiched between a flange on an upper peripheral edge of a can body forming the lower raw water chamber 4 and a flange on a lower peripheral edge of a can lid forming the upper processing chamber 3, and flange-joined with bolts and nuts. I have.

Reference numerals 8 and 9 denote upper and lower membrane elements connected in series in the vertical direction. The permeated water is attached to the upper end of the upper membrane element 8 by sealing with an O-ring or a sealing material 10 such as a packing and facing upward. The outlet 11 penetrates through an opening 2 ′ formed in the can plate 2 from below to above. The permeated water outlet 11 has a contact portion 11 'formed of an enlarged portion or a flange that contacts the lower surface of the can plate, and an O-ring or packing is provided between the contact portion 11' and the lower surface of the can plate. Is fixed to the can plate with a fixing screw 13 such as a nut which is screwed into the permeated water outlet 11 from the outer periphery of the upper end and fastened to the upper surface of the can plate with the sealing material 12 interposed therebetween. While communicating with the upper processing chamber 3 on the plate, the upper and lower membrane elements 8,
Numeral 9 is suspended from the opening 2 'of the can plate into the lower raw water chamber 4.

An intermediate water collecting chamber 15 is provided between the lower end of the upper membrane element 8 and the upper end of the lower membrane element 9 by sealing with a sealing material 14 such as an O-ring or packing. A lower water collecting chamber 17 is provided at the lower end of the lower membrane element 9 by sealing with a sealing material 16 such as an O-ring or packing.

Then, the permeated water outlet 11 and the intermediate water collecting chamber 1
5 is connected by an upper collecting pipe 18, and the intermediate collecting chamber 15 and the lower collecting chamber 17 are connected by a lower collecting pipe 19. For this reason, for example, as shown in the figure, a T-shaped fitting 20 is attached to one side of the intermediate water collecting chamber 15, an elbow 21 is attached to one side of the permeated water outlet 11 downward, and a downward end of the elbow is attached. And the upward end of the T-shaped pipe joint 20 are connected by an upper water collecting pipe 18, and an elbow 21 is mounted upward on one side of the lower water collecting pipe 19. The parts may be connected by a lower collecting pipe 19.

The upper and lower membrane elements 8, 9 of the embodiment of FIG.
Are provided with adhesive podding layers 24, 24 at the inner upper and lower ends of an outer cylinder 22 having a plurality of water passage holes 23, and a large number of hollow fiber membranes 25 are provided on the upper surface of the upper podding layer and the lower pond. It is opened on the lower surface of the padding layer and fixed between the upper and lower podging layers 24, 24, and no intake pipe is used.

Therefore, the pressurized raw water supplied from the supply pipe 5 into the lower raw water chamber 4 enters the inside of the outer cylinder 22 of the upper and lower membrane elements through the water passage hole 23 of the outer cylinder 22 and a large number of hollow fiber membranes. The permeated water that has passed through the hollow fiber membranes contacting each one into the hollow fiber membrane enters the hollow portion of the hollow fiber membrane. In this way, a part of the permeated water entering the hollow portion of the hollow fiber membrane 25 of the lower membrane element 9 descends and collects in the lower water collecting chamber 17, and the remaining permeated water flows upward in the hollow portion and becomes intermediate. It gathers in the water collecting room 15. Part of the permeated water that has entered the hollow portion of the hollow fiber membrane 25 of the upper membrane element 8 descends and collects in the intermediate water collecting chamber 15, and the remaining permeated water flows upward through the hollow portion to form the permeated water. Gather at the outlet 11.

The permeated water collected in the lower water collecting chamber 17 flows upward in the lower water collecting pipe 19, and further joins with the permeated water collected in the intermediate water collecting chamber 15 to flow upward in the upper water collecting pipe 18. The permeated water is collected at the permeated water outlet 11, merges with the permeated water flowing upward to the permeated water outlet 11, flows into the upper treatment chamber 3 on the can plate, and is taken out of the system by the water sampling pipe 6 from here. . Although the whole amount may be transmitted through the membrane as described above, the raw water supplied to the lower raw water chamber 4 and not permeating the hollow fiber membrane may be discharged from the drain pipe 7 as concentrated water.

A conventional membrane element having an outer cylinder having an outer diameter of 110 mm was manufactured using 10360 hollow fiber membranes having an outer diameter of 0.41 mm, an inner diameter of 0.27 mm, an effective length of 1 m, and an intake pipe. The intake pipe was selected so that the maximum linear velocity of the permeated water flowing upward in the pipe did not exceed 2 m / sec, and the nominal diameter was 40A. Two membrane elements were connected in series one above the other (hereinafter referred to as one train), and a filter capable of processing 350 m ³ per hour by this train was designed. The number of trains used was 53 ( The number of membrane elements is 106), the diameter of the can plate is 1150 mm, the area of the membrane elements is 13.33 m ² , and the throughput of one train is 6.
67 m ³ / hour. In addition, the throughput of one train is 6.6.
7m ³ / hour x number of trains used 53 = 353.50
m ³ / hour.

The same hollow fiber membrane is used, and as shown in FIG. 1, the membrane element does not have a water intake pipe.
A 10 mm membrane element was produced. Since there is no intake pipe, the number of hollow fiber membranes used has increased to 12,800, and the area of the membrane element has increased to 16.46 m ² . When two of these membrane elements were connected in series one above the other to form one train, and a filter of 350 m ³ / hour was designed with this train, the number of trains used was reduced to 43 and the throughput of one train was reduced. Improved 8.23 m ³ / hour. Incidentally, 1 train throughput 8.23M ³ / hour × train using number 43 present = 353.890M is ³ / h. The upper and lower collecting pipes having a nominal diameter of 40A were arranged outside the upper and lower membrane elements constituting each train as shown in FIG. 1, but as a result of the number of trains being reduced from 53 to 43, the number of The diameter is reduced from 1150 mm to 1050 mm, and the installation area can be reduced by reducing the diameter of the filtration tower. The upper and lower collecting pipes can be accommodated in a gap between the trains.

The upper and lower membrane elements 8, 9 of the embodiment of FIG.
Consists of a cartridge-type microfilter having a flat membrane folded in a bellows shape and having a large number of annular folds 26 continuously folded inward on the outer periphery in the vertical direction, and a large number of continuous annular folds 26 in the vertical direction. And a central water channel 27 penetrating in the up-down direction surrounded by an inner periphery of the water passage.

Also in this embodiment, the pressurized raw water supplied from the supply pipe 5 into the lower raw water chamber 4 comes into contact with the annular folds 26 of the upper and lower membrane elements, and the permeated water passing through the folds is inside the membrane element. to go into. Thus, a part of the permeated water entering the lower membrane element 9 descends through the central water channel 27 and collects in the lower water collecting chamber 17, and the remaining permeated water flows upward through the central water channel to intermediate water collection. Gather in room 15. Part of the permeated water entering the upper membrane element 8 descends through the central water channel 27 and collects in the intermediate water collecting chamber 15, and the remaining permeated water flows upward in the central water channel to take out the permeated water outlet. Gather at 11.

The permeated water collected in the lower water collecting chamber 17 flows upward in the lower water collecting pipe 19, and further joins with the permeated water collected in the intermediate water collecting chamber 15 to flow upward in the upper water collecting pipe 18. The permeated water is collected at the permeated water outlet 11, merges with the permeated water flowing upward to the permeated water outlet 11, flows into the upper treatment chamber 3 on the can plate, and is taken out of the system by the water sampling pipe 6 from here. . Although the whole amount may be filtered by the membrane as described above, the raw water supplied to the lower raw water chamber 4 and not permeating the hollow fiber membrane may be discharged from the drain pipe 7 as concentrated water.

In this embodiment, the permeated water can be caused to flow upward to the permeated water outlet at the upper end of the membrane element by the water collecting pipe outside the membrane element and flow into the upper treatment chamber on the can plate. Since the cross-sectional area of the water channel 27 can be reduced and the diameter of the annular fold 26 turned inward on the outer periphery of the membrane element can be reduced, the size can be reduced without reducing the membrane area of the membrane element, and the membrane element can be connected in series in the vertical direction. The number of stages of membrane elements to be connected can be increased.

[0019]

As is apparent from the above, according to the present invention, the permeated water descending to the lower water collecting chamber provided at the lower end of the membrane element is transferred to the upper end of the membrane element by the water collecting pipe provided outside the membrane element. It is designed to flow upward to the permeated water outlet of the section. Therefore, it is possible to omit a water intake pipe that allows the permeated water that has descended to the lower water collecting chamber to flow upward to the permeated water outlet inside the membrane element.
Even if an intake pipe is provided inside the membrane element, reduce the cross-sectional area or the number of pipes used, and reduce the size of the membrane element without decreasing the membrane area, or increase the number of membrane elements connected in series vertically. Accordingly, it is possible to provide a filtration tower having a reduced installation area with a reduced diameter of the filtration tower.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a main part of an embodiment of a membrane filtration device of the present invention.

FIG. 2 is a sectional view showing a main part of another embodiment of the membrane filtration device of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Filtration tower 2 Filtration tower can plate 3 Upper treatment chamber 4 Lower raw water chamber 5 Pressurized raw water supply pipe 6 Permeated water sampling pipe 7 Concentrated water drain pipe 8 Upper membrane element 9 Lower membrane element 11 Permeated water Outlet 13 Fixing screw 15 Intermediate water collecting chamber 17 Lower water collecting chamber 18 Upper water collecting pipe 19 Lower water collecting pipe 20 T-shaped fitting 21 Elbow

Claims (1)

[Claims] 1. A membrane plate, wherein the inside of a filtration tower is divided into an upper treatment chamber and a lower raw water chamber, and a permeate outlet at the upper end of the membrane element is attached to communicate with the upper treatment chamber. In a membrane filtration device having a lower collecting chamber at the lower end of the membrane element and a lower collecting chamber at the lower end of the membrane element, A membrane filtration device, wherein the outlet is connected to a water collection pipe provided outside the membrane element.