JP3641950B2 - Rotating flat membrane device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a rotary flat membrane device, and more particularly to a rotary flat membrane device that performs filtration of water and wastewater using the rotary flat membrane.
[0002]
[Prior art]
Rotating flat membrane devices are applied to wastewater treatment, pure water devices, separation, purification, concentration, and biotechnology. Like rotating flat membranes, the biggest problem in liquid processing using membranes is that deposits in the liquid to be treated adhere to the membrane surface during operation and form a cake layer of deposits. The performance is degraded.
[0003]
Conventionally, in order to peel off the cake layer formed on the rotating flat membrane, the filtration operation is stopped while the rotating flat membrane is periodically rotated, that is, the suction pump is stopped, so that the membrane is rotated by the centrifugal force of the rotating flat membrane. The surface deposit was peeled off.
[0004]
[Problems to be solved by the invention]
However, when the cake layer of the rotating flat membrane is peeled off by the rotation of the rotating flat membrane as in the prior art, it is necessary to apply a certain level of shearing force due to the turbulent flow to the membrane surface. Must be rotated at high speed. Therefore, it is necessary not only to install a high-power motor that rotates the rotating flat membrane at high speed only for the peeling operation, but also to make the components of the equipment durable, and parts with good machining accuracy and assembly accuracy. Since it must be used, there is a disadvantage that the cost of the apparatus becomes high.
[0005]
Furthermore, when the cake layer is peeled off only by the rotation of the rotating flat membrane, when the cake layer adheres to the membrane at a high density, the peeling efficiency is poor and a long time is required for the peeling operation. For this reason, there is a disadvantage that the processing operation time is greatly reduced.
The present invention has been made in view of such circumstances, and even if a cake layer of deposits is formed at a high density on the rotating flat membrane, the rotating flat membrane is rotated at a low rotational speed to effectively remove the deposits. An object of the present invention is to provide a rotating flat membrane device that can be peeled off.
[0006]
[Means for Solving the Invention]
In order to achieve the above object, the present invention includes a membrane separation tank having a rotating flat membrane, a storage tank for liquid to be processed, and a supply pump for supplying the liquid to be processed from the storage tank to the membrane separation tank. In the rotary flat membrane device having a supply line and a return line for returning the liquid to be treated from the membrane separation tank to the storage tank ,
With turning on the sponge-like member before Kimaku separation tank, put-collecting device is provided for collecting the charged sponge-like member,
The charging / collecting device has a lid member that can be opened and closed at both ends, a container having a screen to which the return line is connected and preventing the sponge-like member from flowing out to the return line, and the lid member. And opening / closing means .
[0007]
According to the present invention, the sponge-like member and the adhering matter attached to the rotary flat membrane by the filtration treatment are introduced by inserting the sponge-like member into the membrane separation tank from the charging / collecting device while the rotary flat membrane is rotated. The cake layer is scraped off by the sponge-like member. Further, when the adhering material is peeled off by the sponge-like member, the sponge-like member is collected in the input / collection device. Therefore, the sponge-like member can be put into the membrane separation tank only when it is desired to peel the cake layer.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of a rotating flat membrane device of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a longitudinal sectional view showing the overall configuration of a rotating flat membrane apparatus, and FIG. 2 is a top view for explaining the structure of a membrane separation tank having a rotating flat membrane.
[0009]
As shown in FIG. 1, the rotary flat membrane device 10 of the present invention includes a membrane separation tank 12 having a rotary flat membrane 16, a storage tank 11 for liquid to be processed, and a liquid to be processed from the storage tank 11 to the membrane separation tank. composed of a supply line 13 provided with a supply pump 19 for supplying, and the return line 17 returns the liquid to be treated from the membrane separation tank 12 to the storage tank 11. In the membrane separation tank 12 to which the liquid to be treated is supplied, as shown in FIG. 2, two hollow rotary shafts 14 and 14 parallel to the left and right are rotatably arranged in parallel. Each of the hollow rotating shafts 14 supports a plurality of rotating flat membranes 16, 16... Having a disk shape so as to face a communication port (not shown) drilled at a predetermined interval in the axial direction. The rotating flat membrane 16 is constituted by coating a microfiltration membrane or an ultrafiltration membrane on a water-permeable spacer such as a nonwoven fabric or a net on a membrane support, and the material of the membrane is polystyrene or polypropylene. A polymer resin film such as polyethylene or polyolefin can be used. The rotating flat membranes 16 supported by the two hollow rotating shafts 14 arranged side by side are configured such that parts of the adjacent rotating flat membranes 16 overlap each other. Both ends of the hollow rotary shaft 14 are extended outside the membrane separation tank 12, and the membrane separation tank 12 and the hollow rotary shaft 14 are secured to the water tightness by the shaft sealing means 18. The one closed end of the hollow rotary shaft 14 is connected to the motors 20 and 20, respectively, and the other open end is connected to the filtrate pipes 22 and 22, respectively. The hollow rotary shaft 14 and the rotary flat membrane 16 rotate integrally. Is done. The filtrate pipe 22 is composed of branch pipes 24 and 24 respectively connected to the two hollow rotary shafts 14 and a trunk pipe 26 where the branch pipes 24 are joined. A suction pump 28 is provided in the trunk pipe 26. Further, the connection between the hollow rotary shaft 14 and the branch pipe 24 is connected via connecting devices 30 and 30 for preventing the rotation of the hollow rotary shaft 14. The rotating flat film 16 supported by the two hollow rotating shafts 14 is rotated in the same direction. In this case, it is preferable to change the number of rotations according to the size of the diameter of the rotating flat membrane 16. Due to the rotation in the same direction, in the overlapping portion of the rotating flat membranes 16, the rotation direction is opposite and turbulence is generated.
[0010]
The filtration operation of the liquid to be processed by the rotary flat membrane device 10 configured as described above is performed by operating the suction pump 28 while rotating the rotary flat membrane 16 by the motor 20. That is, by the operation of the suction pump 28, the inside of the rotary flat membrane 16 becomes negative pressure through the filtrate pipe 22 and the hollow rotary shaft 14, and the liquid to be treated in the membrane separation tank 12 is suction filtered into the rotary flat membrane 16. Then, the deposits in the liquid to be treated are removed, and a cake layer is formed on the surface of the rotating flat film. The filtered water that has passed through the rotating flat membrane 16 is drawn out of the apparatus 10 through the hollow rotating shaft 14 and the filtrate pipe 22.
[0011]
As shown in FIG. 1, an upper portion of the membrane separation tank 12 is provided with a loading / recovering device 34 for loading the sponge-like member 32 into the membrane separation tank 12 and collecting the loaded sponge-like member 32. It is done. As shown in FIG. 3, the charging / recovering device 34 has lid members 36, 36 that can be opened and closed at both ends, and a container 40 having a screen 37 that prevents the sponge-like member 32 from flowing out to the return line 17, It comprises motors 42, 42 that can rotate forward and backward to open and close the lid member 36 of the container 40, and the motor 42 is connected to the controller 48 through signal rotation. Thus, the controller 48 rotates the motor 42 forward and backward to rotate the rotation shafts 44 and 44 that rotatably support the lid member 36 on the container 40 main body, thereby opening the openings 46 at both ends of the container 40. 46 is opened and closed.
[0012]
As shown in FIG. 1, the membrane separation tank 12 side of the return line 17 is branched into two, the first branch line 17A is directly connected to the membrane separation tank 12, and the second branch line 17B is input / recovery. It is connected to the device 34. The first branch line 17A and the second branch line 17A are provided with automatic opening / closing valves 50 and 52, respectively, and connected to the controller 48 via a signal cable. The filtrate line 26 is provided with a filtration pressure detector 49 for detecting the filtration pressure, and the detected pressure value is sequentially transmitted to the controller 48 via a signal cable.
[0013]
Next, the sponge-like member 32 that is put into the membrane separation tank 12 and peels the cake layer 15 formed on the rotating flat membrane 16 will be described.
4 to 9 show sponge-shaped members 32 of various shapes, FIG. 4 is a sponge ball shape, FIG. 5 is a cube shape, FIG. 6 is a string shape, and FIG. FIG. 8 shows a threadball shape. Moreover, the sponge piece made into indefinite shape like FIG. 9 can also be used. As for the size of the sponge-like member 32, it is appropriate to use a member having a minimum dimension of about 1 to 15 mm. The reason for this is that when the amount of sponge-like member 32 introduced into the membrane separation tank 12 is constant, the smaller the sponge-like member 32, the larger the total surface area. However, if the sponge-like member 32 is too small, the grinding force for scraping the cake layer 15 becomes weak.
[0014]
Since the relationship between the size of the sponge-like member 32 and the peelability is also affected by the number of rotations of the rotating flat membrane 16, it is possible to change the size of the sponge-like member 32 according to the number of revolutions of the rotating flat membrane 16. It is a factor to improve. The specific gravity of the sponge-like member 32 needs to be substantially equal to the specific gravity of the liquid to be treated so that it can be easily dispersed in the liquid to be treated when the rotating flat membrane 16 is stirred. However, it is not necessary to make all the specific gravity of the many sponge-like members 32 to be supplied the same, but it is preferable to change the specific gravity. This is because when the rotating flat film 16 is rotated, the flow of the liquid to be processed near the periphery of the rotating flat film 16 is fast, and the liquid to be processed near the center of the rotating flat film 16 has a slow flow. This is because mixing the sponge-like member 32 makes it easy to uniformly disperse the sponge-like member 32 over the entire surface of the rotating flat film 16. The material of the sponge-like member 32 may be any material that does not damage the rotating flat membrane 16 such as porous urethane foam, sponge, etc., and can exhibit a grinding force.
[0015]
Next, a method of using the charging / recovering device 34 for peeling the cake layer 15 attached to the surface of the rotating flat film 16 with the sponge-like member 32 will be described.
When the liquid to be treated is filtered, the controller 48 opens the automatic opening / closing valve 50 of the first branch line 17A, closes the automatic opening / closing valve 52 of the second branch line 17B, and closes the lid member 36 of the container 40. Are closed so that the sponge-like member 32 does not flow into the membrane separation tank 12. As a result, the liquid to be treated supplied from the storage tank 11 to the membrane separation tank 12 by the supply pump 19 is circulated back to the storage tank 11 by the return line 17 flowing through the first branch line 17A. Thereby, the deposit in the liquid to be treated is filtered by the rotating flat membrane 16.
[0016]
Then, when the pressure value of the filtration pressure detector 49 becomes equal to or higher than the predetermined value, the controller 48 keeps the automatic opening / closing valve 52 of the second branch line 17B closed and opens the both end openings 46 of the container 40 so as to open. The member 36 is swung. As a result, the sponge-like member 32 in the container 40 exits from the container 40 into the membrane separation tank 12 along the swirling flow of the liquid to be treated by the rotation of the rotating flat membrane 16. The sponge-like member 32 coming out of the container 40 is dispersed throughout the membrane separation tank 12 by the rotation of the rotating flat membrane 16 and moves around on the swirling flow generated by the rotation of the rotating flat membrane 16. Therefore, the sponge-like member 32 and the cake layer 15 come into contact with each other, and the cake layer 15 is scraped off by the sponge-like member 32.
[0017]
When the peeling of the cake layer 15 by the sponge-like member 32 is completed, the controller 48 closes the automatic opening / closing valve 50 of the first branch line 17A and opens the automatic opening / closing valve 52 of the second branch line 17B, and two lid members Close one of the 36. As a result, a water flow from the inside of the membrane separation tank 12 toward the second branch line 17B is generated, so that the sponge-like member 32 introduced into the membrane separation tank 12 enters the container 40 from the opened opening 46 side of the container 40. Collected. In this case, when the rotating flat membrane 16 is rotated counterclockwise as shown in FIG. 1, a swirling flow in the direction of the arrow is generated. Therefore, the right lid member 36 in FIG. It becomes easier to collect when closed.
[0018]
Thus, in the rotating flat membrane device 10 of the present invention, the input / recovery device 34 is provided in the membrane separation tank 12 so that the input / recovery of the sponge-like member 32 can be automatically performed. 32 can be easily loaded and collected. Further, the sponge-like member 32 can be put into the membrane separation tank 12 only when the cake layer 15 is desired to be peeled off, and the sponge-like member 32 can be recovered when the cake layer 15 is not peeled off. Therefore, wear of the sponge-like member 32 can be minimized, and the sponge-like member 32 does not interfere with the filtration process.
[0019]
As another apparatus for loading and collecting the sponge-like member 32 described in the embodiment of the present invention, a sponge-like member 32 returning from the return pipe 17 with a wire mesh container placed at the outlet of the return pipe 17 is used. When the sponge-like member 32 is put into the membrane separation tank 12, the bottom of the wire mesh container is opened and discharged into the storage tank 11, and the supply pump 19 and the liquid to be treated are put into the membrane separation tank 12 Can also be thrown into. In this case, it is necessary to select the type of pump so that the sponge-like member 32 is not damaged by the supply pump 19.
[0020]
【The invention's effect】
As described above, according to the rotating flat membrane device of the present invention, since the input / recovery device is provided in the membrane separation tank, the operation of inputting / recovering the sponge-like member can be easily performed.
Further, when the sponge-like member is not used, the sponge-like member can be collected, so that the wear of the sponge-like member can be minimized, and the sponge-like member can interfere with the filtration process. Absent.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing the entire structure of a microorganism-supporting rotary flat membrane device of the present invention. FIG. 2 is an upper surface illustrating the structure of a membrane separation tank in the microorganism-supporting rotary flat membrane device of the present invention. FIG. 3 is a perspective view for explaining the structure of the charging / collecting device. FIG. 4 is a perspective view of a sponge-like member having a sponge ball shape. FIG. 5 is a perspective view of a sponge-like member having a cubic shape. FIG. 7 is a perspective view of a spider-like sponge-like member. FIG. 8 is a perspective view of a spongy-like sponge-like member. FIG. 9 is a perspective view of an irregular-shaped sponge-like member. ]
DESCRIPTION OF SYMBOLS 10 ... Rotary flat membrane apparatus 11 ... Storage tank 12 ... Membrane separation tank 13 ... Supply line 14 ... Hollow rotary shaft 15 ... Cake layer 16 ... Rotary flat membrane 17 ... Circulation line 17A ... 1st branch line 17B ... 2nd branch Line 19 ... Supply pump 20 ... Motor 22 ... Filtrate piping 28 ... Suction pump 32 ... Sponge-like member 34 ... Input / recovery device 36 ... Cover member 40 ... Container 42 ... Motor of input / recovery device 44 ... Rotation of the cover member Shaft 46 ... Container opening 48 ... Controller 49 ... Filtration pressure detector 50 ... First branch line automatic opening / closing valve 52 ... Second branch line automatic opening / closing valve

Claims (2)

A membrane separation tank having a rotating flat membrane, a storage tank for the liquid to be processed, a supply line including a supply pump for supplying the liquid to be processed from the storage tank to the membrane separation tank, and the storage tank from the membrane separation tank the rotary flat membrane device having a return line for returning the liquid to be treated,
With turning on the sponge-like member before Kimaku separation tank, put-collecting device is provided for collecting the charged sponge-like member,
The charging / collecting device has a lid member that can be opened and closed at both ends, a container having a screen to which the return line is connected and preventing the sponge-like member from flowing out to the return line, and the lid member. rotary flat membrane apparatus characterized by comprising: a switching means, a to. The rotation detecting a filtration pressure of a flat membrane, the detected value of the rotary flat membrane according to claim 1, characterized in that a control means for controlling the opening and closing of the lid member when it becomes more than a predetermined value.

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