JPH0618575Y2 - Rotary filtration device - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to a rotary filtration device for separating and concentrating bacteria and the like using a microfiltration membrane or an ultrafiltration membrane. The present invention relates to an improved rotary filtration device capable of efficiently cleaning and removing an adhesion layer formed on the surface of an element with a simple structure.

[Prior Art] In a filtration method of pressurizing or vacuum-filtering a stock solution containing suspended cells and the like using a microfiltration membrane or an ultrafiltration membrane, the stock solution is included in the stock solution as the filtration progresses. The fine particles, gelatinous substance, etc. are captured on the surface of the filtration membrane, and an adhesion layer is formed on the filtration surface.

Since the adhesion layer composed of these fine particles and a high-viscosity substance such as gelatin has a high filter compressibility, the filter surface is rapidly clogged with the progress of the filter to increase the filter resistance.

A rotating filtration device, that is, a plurality of filtration devices equipped with hollow small chambers inside, is a typical device that suppresses the formation of an adhering layer on the filtration surface to prevent a decrease in filtration efficiency and continuously filters. They are provided on the shaft in a concentric manner with a gap in series, and they are integrally rotated to give a centrifugal force to the fine particles and the like captured on the surface of these filtration elements to eliminate them in the outer peripheral direction, while There is a filtering device that suppresses the formation of an adhered layer by generating a turbulent flow or a vortex in the stock solution due to a relative speed difference with the filtering element.

However, in these rotary filtration devices, simply rotating the plurality of filtration elements integrally causes a so-called co-rotation phenomenon in which the undiluted solution between these filtration elements flows together in the same direction as the filtration elements, resulting in a filtration surface. Since the intended purpose of suppressing the formation of the adhesion layer cannot be achieved, various measures have been added to the structure for preventing the occurrence of this accompanying flow, and many proposals have been made.

As these conventional rotary filtration devices, for example, a fixed filtration element is arranged between a plurality of rotary filtration elements mounted on a hollow rotary shaft (Japanese Patent Laid-Open No. 47-23949), and the outer peripheral portion is brought into contact with the filtration tank wall. An annular filter element equipped with a rotating back-feeding blade and provided with a flow section near the hollow rotary shaft, and a filter element having a flow gap in the outer peripheral portion are alternately attached to the rotary shaft, while scratching between these filter elements. Rotatable blades (JP-A-48)
-87473), between one or more filter elements attached to the hollow rotating shaft and in the hollow part provided inside these filter elements, one or more extending in a direction orthogonal to the rotation direction of the filter element. A fluid control body (Japanese Patent Laid-Open No. 50-69657) and the like are known.

Further, in order to remove the adhering layer that is inevitably formed as the filtration progresses, a brush is attached at a fixed position on the wall side of the filtration tank so as to be able to advance and retreat in the radial direction, and the brush is attached to the rotary shaft. There is one that is inserted between the filter elements to remove the adhesion layer on the surface of each filter element.

[Problems to be solved by the device]

However, although the above conventional rotary filtration device can suppress the formation of an adhesion layer on the surface of the filtration element, the rotary filtration element and the fixed filtration element, the scraping blade, the flow control body, etc. are alternately arranged, and as few as possible. Since it needs to be installed in a gap, and its structure becomes extremely complicated and precise, there is a problem that a complicated procedure is required for its assembly and disassembly.

Further, in order to remove the adhesion layer that is inevitably formed as the filtration progresses, when a brush is provided at a fixed position on the filtration tank wall side, between the brush inserted from the filtration tank wall side and each rotary filtration element, It is required that the relative positions of the above-mentioned filters are accurately assembled, and that each rotary filtration element is not distorted. Further, it is necessary to provide a brush storage space on the filter tank side, which causes a problem that the outer shell becomes large.

The present invention has been made in view of the above-mentioned problems in the conventional device, and an object thereof is to provide a rotary filtration device having a simple structure and capable of easily and reliably cleaning and removing the adhering layer formed on the surface of the filtration element. is there.

[Means for Solving the Problems]

In order to achieve the above-mentioned object, the rotary filtration device of the present invention has a center hole communicating with a filtration liquid take-out means in a filtration tank configured to continuously feed the raw liquid, and is driven to rotate. A hollow rotary shaft connected to the device is provided, and a plurality of disk-shaped filter elements having hollow small chambers inside are mounted on the hollow rotary shaft in a concentric manner with a space allowing free passage of liquid, and these filters are installed. In a rotary filtration device in which a small chamber of an element and a central hole of a hollow rotary shaft are in fluid communication with each other, a space between each of the filter elements, one end of which is individually rotatable about the hollow rotary shaft A rod-shaped brush, which is supported and has the other end projecting outward from the outer periphery of the filter element, is arranged in the radial direction, and can be pivotally retracted into the space between the inner peripheral surface of the filter tank and the outer periphery of the filter element. Provide a stopper for the rod-shaped brush, and It is obtained by connecting the frequency converter to the motor of the drive unit.

The stopper of the rod-shaped brush is arranged so as to be rotatable in parallel with the hollow rotation shaft, and the stopper protrudes in the radial direction on the outer circumference of the rotation shaft, and the rotation direction of the rotation shaft is different from that of the rotation shaft. It may be composed of a plurality of stop plates that are protruded with different angular phases.

〔Example〕

 Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a front sectional view showing a main part of a rotary filtration device according to an embodiment of the present invention, and FIG. 2 is a sectional view taken along line II-II of FIG.

In FIGS. 1 and 2, (1) is a filtration tank,
This filtration tank (1) is a hermetically sealed pressure vessel equipped with an inlet pipe (1a) communicating with a stock solution supply means (not shown) and an outlet pipe (1b) communicating with a concentrated filtration solution collecting / circulating means (not shown). Is.

(2) is a hollow rotary shaft, the hollow rotary shaft (2) is freely inserted into the filtration tank (1) through the shaft sealing device (7) and is watertightly inserted into the filtration tank (1). Rotating drive at outer end (8)
It is driven and rotated by an electric motor (9) connected to the rotary drive device (8), and is connected to the filtration tank (1).
At the outer shaft end, a filtrate outlet pipe (2a) communicating with a filtrate recovery means (not shown) is provided. Further, the electric motor (9) is connected to the frequency converter (10), and by changing the frequency of the alternating current input via this frequency converter (10), its rotation speed can be arbitrarily changed. It is supposed to be possible.

(3) is a filter element, and this filter element (3) has a disk shape with a hollow small chamber inside, and a stock solution inlet near the center of rotation.
(3a) is provided, and the hollow small chamber and the central hole of the hollow rotary shaft (2) are in fluid communication with each other, and three filtrate pipes (6) are arranged at equal angles in the circumferential direction. Connected to the hollow rotary shaft (2), and a plurality of the hollow rotary shafts (2) are arranged in series at right angles to the hollow rotary shaft (2) at equal axial intervals. It can be rotated together with.

(4) is a rod-shaped brush, this rod-shaped brush (4), the main body portion (4a) in which brush bristles are planted uniformly and densely on the outer peripheral portion of the rod body.
And a hollow rotary shaft provided on the main part of the main body (4a).
The ring-shaped rotating part (4b) rotatably mounted on the outer periphery between the filtering elements (3) of (2) and the brush bristles on the side of the body part (4a) opposite the ring-shaped rotating part (4b) are not planted. With the stopped rod portion (4c), the stopped rod portion (4c) is provided between the respective filtering elements (3).
While projecting c) outward from the outer circumference of the filter element (3),
To the extent that this rod-shaped brush (4) can rotate together with the filtering element (3), the brush bristle tips of the main body part (4a) of the rod-shaped brush (4) on both sides are filtered.
(3) Lightly abutted on the side surface and arranged in the radial direction.

(5) is a stopper, and this stopper (5) is provided on the rotation shaft (5a) and on the outer periphery of the rotation shaft (5a) so as to project in the radial direction and be long in the axial direction. One flat stop plate (5
b) (5c) and (5d), in the space between the inner peripheral surface of the filtration tank (1) and the outer periphery of the filtration element (3), in parallel with the hollow rotary shaft (2), the shaft seal. A rotary shaft (5) that is freely and freely water-tightly inserted and arranged through the device (11) and that is located outside the filtration tank (1).
One end of a) is connected to a rotating means (not shown).

In addition, three stopper plates (5b) of this stopper (5) are in a flat plate shape.
(5c) and (5d) are explanatory diagrams thereof, and FIG. 3 and IV in FIG.
As shown in FIG. 4 which is a −IV cross section, the rotational axes of the rotary shafts (5a) are projected so that the angular phases thereof are different from each other by 90 degrees. Then, the rotating shaft (5a) is rotated at a 90 degree pitch, and these stop plates (5b), (5c), and (5d) are sequentially and individually positioned in the direction toward the center of rotation of the hollow rotating shaft (2). When they are rotated, the stop plates (5b), (5c), and (5d) come into contact with the stopped rod portions (4c) of the plurality of rod brushes (4) corresponding to the respective stop plates (5b) (5c) (5d), and the rod brushes (4 ) Rotation is stopped for each group,
Then, when retracting in the other direction, the rod-shaped brush (4)
It is supposed to allow free rotation of the. That is,
This stopper (5) stops the rod-shaped brushes (4) arbitrarily in a group unit at its installation position by its rotation.

In the filtration by the rotary filtration device of the present embodiment having the above configuration, the stock solution was pressure-supplied from the inlet pipe (1a) into the filtration tank (1) and filtered by each rotating filtration element (3). The filtrate is taken out of the system from the filtrate outlet pipe (2a) through the filtrate pipe (6) and the central hole of the hollow rotary shaft (2), while the filtration tank
The stock solution concentrated by filtration in (1) is appropriately
Emitted from b). Further, the undiluted solution in contact with the surface of the rotating filtration element (3) receives the rotational force of the filtration element (3) according to its viscosity, flows together with the rotation direction of the filtration element (3), and its rotation. The centrifugal force generated by the flow also causes the filter element (3) to flow in the outer peripheral direction, that is, in the radial direction of rotation.

Due to this flow of the stock solution, the suspended fine particles in the stock solution that are attached to the surface of the filtration element (3) are pushed in the outer diameter direction,
Formation of an adhesion layer on the surface of the filtration element (3) is suppressed.

Then, the undiluted solution flowing in the outer peripheral direction of the filter element (3) is filtered by
It flows along the wall surface of (1) and is filtered from both side wall parts (3)
Flow toward the center of rotation of each of the filter elements (3) via the undiluted solution flow through port (3a) provided near the center of rotation of each filter element (3).
It is made to flow back from the center of (3) to the gap between the filter elements (3).

At the time of filtration described above, all three stopper plates (5b) (5c) (5d) of the stopper (5) are rotated and retracted, and a rod-shaped brush is used.
Rotate (4) freely. At this time, each rod-shaped brush (4)
The filter element (3) rotates in association with the rotation and the flow of the stock solution in the direction of rotation, and since these rod-shaped brushes (4) are arranged in the radial direction, the stock solution and suspended fine particles in the stock solution It does not hinder the movement in the radial direction of rotation.

On the other hand, when the adhesion layer of fine particles is formed on the surface of the filtration element (3) as the filtration progresses and the filtration resistance increases, the stopper (5) is rotated while continuing the rotation of the filtration element (3). , The stop plate (5b) to the stopped rod portion (4c) of the rod-shaped brush (4)
The rotation of the rod-shaped brush (4) is stopped by contacting the rod-shaped brushes (4), and the relative movement between the filter element (3) and the rod-shaped brush (4) causes the adhesion of fine particles formed on the surface of each filter element (3). The layer can be easily peeled off and resuspended in the stock solution in the filtration tank (1), and the stock solution with an increased suspended concentration of fine particles is
It can be discharged and removed from the system through the outlet pipe (1b).

However, in the rotary filtration device, as described above,
Since the essential point is to suppress the formation of an adhering layer by generating a turbulent flow or a vortex in the stock solution due to the relative speed difference between the stock solution and the filter element (3), it is necessary to filter the filter element during the filtration.
(3) is relatively high speed rotation (specifically, 3 to 5 at the peripheral speed)
m / sec.) and the stock solution is also rotating. Therefore, while continuing the rotation at the time of this high-speed filtration, when the stopper (5) is rotated and the rotation of all the rod-shaped brushes (4) is stopped at the same time, the stopper (5) and the rod-shaped brush (4)
A big shock is applied to. And in this case, stop the stopper (5) and the rod-shaped brush (4) so as not to deform and lose the original function of the self, or to damage the filtering surface of the filtering element (3). It is necessary to make it sturdy enough to withstand the impact of time, and as a result, it is difficult to achieve the intended purpose of a simpler and more compact structure.

Here, in the present embodiment, when cleaning the filter element (3), the frequency of the alternating current input to the electric motor (9) is converted to a low value by the frequency converter (10), and the filter element (3 The rotation speed of) is significantly lower than that during filtration (specifically, 0.3
~ 0.5 m / sec.), And then, by rotating the stopper (5) to stop the rotation of the rod-shaped brush (4), the impact caused by the stop is alleviated and the stopper is also stopped.
The rotation shaft (5a) of (5) is rotated at a pitch of 90 degrees, and the three stop plates (5b), (5c), and (5d) are used, and a plurality of rod-shaped brushes (4) corresponding to each of them are provided. By stopping the rotation of in group units,
The load on this stopper (5) will be lower. As described above, the rod-shaped brushes (4) are configured to be able to wash the filter element (3) in the group unit by the rod-shaped brushes (4) stopped in the group unit at the low speed rotation.
In addition to lowering the load on the stopper and the stopper (5) to make them relatively delicate and compact, it also protects the filtering surface of the filter element (3) and reduces the power required for cleaning. Obtainable.

Incidentally, in order to change the number of rotations of the filter element (3) to a low value, it is conceivable to respond by changing the gear ratio of the rotation drive device (8) that transmits the rotation of the electric motor (9), but In the rotary filtration device, since a relatively large output is required to rotate the filtration element (3), the gear ratio of the rotary drive device (8) can be reduced to about 1/10 as described above. If the shift width is wide, the outer dimensions and the cost thereof are significantly increased as compared with the case where the frequency converter (10) is provided.

As described above, the rotary filtration device of the present embodiment has a simple structure in which a rod-shaped brush is rotatably and arbitrarily stopped between the respective filtration elements, which does not require relatively high assembly precision. Thus, the adhered layer formed on the filtration surface of the filtration element can be removed and washed easily and reliably without lowering the filtration efficiency, and stable filtration can be continued for a long time. Further, when cleaning the filter element, the rotation of the filter element can be reduced, and the rod-shaped brushes can be stopped in group units, and the rod-shaped brushes and stoppers can be made relatively delicate and compact. It also has the effect of protecting the filtration surface and reducing the power required for cleaning.

In the present embodiment, the rod-shaped brush (4) was arranged linearly in the radial direction, but the stock solution between the filter elements (3) is, as described above, the filter element (3). ), Which is a combined flow of the flow in the direction of rotation accompanying the rotation and the flow in the direction of rotation radius due to the centrifugal force associated with the rotation, forming a spiral flow in the outer peripheral direction of the filter element (3). Because it will be washed away,
For example, as shown in FIG. 5, the rod-shaped brush (54) may be bent into a curved shape protruding in the rotation direction A of the filtration element so as to follow the spiral flow of the stock solution. This is a preferable example because the resistance to the flow of the stock solution between the filtration elements in the outer peripheral direction can be made smaller. Also,
The filtration device of the above embodiment is provided with the undiluted solution throughflow port (3a) near the center of rotation of each filtration element (3), but this is an example, and the present invention is limited to this configuration. It is not something that will be done.

[Effect of device]

As described above, the rotary filtration device of the present invention has a simple structure which does not require relatively high assembly precision, in which the rod-shaped brushes are rotatably and arbitrarily stopped between the respective filtration elements. , Without reducing the filtration efficiency
It is possible to easily and surely wash and remove the adhesion layer of fine particles that is inevitably formed on the surface of the filtration element, and to continue stable filtration for a long period of time. Further, when cleaning the filter element, the rotation of the filter element can be reduced, and the rod-shaped brushes can be stopped in units of groups, and the load on the rod-shaped brushes and stoppers can be reduced to make it relatively delicate and compact. Also, the effect of protecting the filtration surface of the filtration element and reducing the power required for cleaning can be obtained.

[Brief description of drawings]

1 is a front sectional view showing a main part of a rotary filtration apparatus according to an embodiment of the present invention, FIG. 2 is a sectional view taken along line II-II of FIG. 1, and FIG. 3 is a rotary filtration apparatus according to an embodiment of the present invention. FIG. 4 is an explanatory view of a stopper for stopping the rod-shaped brush, FIG. 4 is a sectional view taken along line IV-IV of FIG. 3, and FIG. 5 is an explanatory view of another embodiment of the present invention. (1) …… Filtration tank, (2) …… Hollow rotary shaft, (3) …… Filtration element, (4) …… Bar brush, (5) …… Stopper, (5a) …… Rotating shaft, ( 5b) (5c) (5d) …… Stop plate, (8) …… Rotary drive device, (9) …… Motor, (10) …… Frequency converter.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display location B01D 33/44 33/58 65/04 8014-4D

Claims (2)

[Scope of utility model registration request] 1. A hollow rotary shaft, which has a central hole communicating with a means for taking out filtrate and is connected to a rotary drive, is provided in a filtration tank configured to continuously feed the stock solution. A plurality of disk-shaped filter elements having hollow small chambers inside are mounted concentrically on the hollow rotary shaft with a liquid flowing free space therebetween, and the small chambers of these filter elements and the central hole of the hollow rotary shaft are formed. In a rotary filtration device which is in fluid communication with each other, between each of the filtration elements, one end of the filtration element is individually rotatably supported by the hollow rotary shaft, and the other end of the filtration element outer periphery is provided. A rod-shaped brush protruding outward is arranged in the radial direction, and a stopper for the rod-shaped brush that can be rotated and retracted is provided in the space between the inner peripheral surface of the filtration tank and the outer periphery of the filter element, and the rotary drive is performed. Connect a frequency converter to the machine's motor. Rotary filtration device, characterized in that the. 2. A stopper for a rod-shaped brush is provided with a rotary shaft rotatably arranged in parallel with a hollow rotary shaft, and a rotary shaft of the rotary shaft projecting radially on the outer periphery of the rotary shaft. The rotary filtration device according to claim 1, wherein the rotary filtration device comprises a plurality of stop plates protruding from each other with different angular phases with respect to the moving direction.