JPH0510883Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to an automatic backwash strainer, and more particularly to the structure of a backwash arm of an automatic backwash strainer.

Prior art The automatic backwash strainer has a relatively simple structure and has the advantage of automatically cleaning the filter member and being able to operate continuously, so it is used for removing dust from factory wastewater or when taking in cooling water. is widely used. The structure of the automatic backwash strainer according to the present invention is as shown in, for example, Japanese Utility Model Publication No. 7297/1983. That is, a main body having a raw water inlet and a treated water outlet, a cylindrical cage installed in the main body and having a large number of water passage windows, a wavy screen extending inside the cage, and a wavy screen installed inside the main body. It consists of a hollow backwash arm that rotates slowly close to the inner peripheral surface of the screen. The raw water that enters from the raw water inlet flows radially outward through the cylindrical wavy screen, and dust in the raw water flows into the recesses (hereinafter referred to as pockets) of the wavy screen.
This trapped dust is discharged outside the machine by flowing treated water into the backwash arm using the differential pressure between the pocket and the backwash arm (atmospheric pressure). The backwashing arm is attached to a drive shaft that is vertically supported in the center of the main body, and rotates at a slow speed of 1 to 6 rpm due to rotation of the drive shaft.

Problems to be solved by the invention The backwash arm of the automatic backwash type strainer described above has the following problems to be solved. The backwashing arm is a hollow, thin, rectangular parallelepiped, and a longitudinal suction port is provided along the entire length of the arm opposite to the inner peripheral surface of the screen. The length of this suction port is the same as the overall length of the screen, and dust from the pocket portion of the screen is sucked through this suction port. In this case, if the strainer is small, the diameter of the cylindrical screen is small and the overall length is short, so the distance between the inner circumferential surface of the screen and the opposing end surfaces of the adjacent backwash arms can be made smaller over the entire length. There is no risk that a large amount of raw water will partially flow in from a place with a large gap and the backwashing effect will deteriorate. However, if the strainer becomes large, the size of the cylindrical screen should be 2 to 3 mm in diameter.
meters, and the length can be 3 to 4 meters. The screen is made by lining a cylindrical cage mentioned above by bending a thin plate with a thickness of 1 to 3 mm, which has many holes with a diameter of 5 mm or less perforated over the entire surface, into a wave shape. Due to the fact that the screen is a can, or due to dimensional errors during corrugation of the screen, the roundness of the inner circumferential surface of the screen adjacent to the backwash arm suction port is considerably low. Since the end faces of the screen and backwash arm are made of metal, contact between the two during rotation must be avoided. For this reason, when the strainer becomes large, it is necessary to assemble the space between the inner peripheral surface of the screen and the end face of the backwash arm to be considerably large. This means that not only is it uneconomical, but the amount of suction of treated water that is effective for cleaning the pockets of the screen is reduced. If backwashing is not carried out effectively, the screen will gradually become clogged, and this may eventually lead to a situation where the operation must be stopped, the interior inspected, and the screen cleaned manually.

Conventionally, as a means to reduce the gap between the inner peripheral surface of the screen and the end surface of the backwash arm as described above, for example, a narrow sealing member that is biased radially outward by a spring is embedded in the end surface on both sides of the suction port. A method has been proposed, but when the backwash arm rotates, this sealing member comes into contact with the corrugations (uneven parts) of the screen and moves in and out frequently, making it easy to break down and having to be replaced frequently, making it impractical. be.

Means for Solving the Problems The present invention was made in view of the above circumstances, and proposes a backwash arm for an automatic backwash strainer with a new structure that eliminates the drawbacks of the conventional backwash arm. Its gist is that it comprises a screen 1 in which corrugated perforated plates are arranged in a cylindrical or arc shape, and a backwashing arm 2 that rotates with its end surface close to the inner peripheral surface of the screen, In an automatic backwash strainer that backwashes the screen by suctioning treated water through a suction port 6 provided on the end surface, a port seal is provided on the end surface of the backwash arm 2 and faces the inner peripheral surface of the screen. 4, and brushes 7 are attached to both the left and right sides of the suction port 6 of the port seal. This is an automatic backwashing strainer that enables long-term continuous operation with a high backwashing effect.

Embodiments The contents of the present invention will be explained in detail below based on drawings showing embodiments.

Fig. 1 is an overall vertical cross-sectional view of the strainer according to the present invention, Fig. 2 is a transverse cross-sectional view taken along line A-A in Fig. 1, and Fig. 3 is a cross-sectional view of the strainer according to the present invention.
The figure is a cross-sectional view of the backwash arm, which is the main part of the present invention. In the figure, 1 is a screen with a hole diameter of 1
It is made by bending a thin plate into a wavy shape with holes of ~3 mm perforated all over the surface and stretching it on the inner surface of a cylindrical cage 8 having a number of windows to form pockets 5 in the radial direction. . In a large strainer, a plurality of cages 8 (three in FIG. 1) each having a unit length of about one meter are connected to form a screen with a total length of several meters. Reference numeral 2 denotes a backwashing arm made of a thin hollow rectangular parallelepiped, one longitudinal side of which is integrated with a shaft 3 that is vertically supported at the center of the main body casing 6, and the other longitudinal side of which is A port seal 4 having a longitudinal suction port for suctioning treated water as backwash water is provided opposite to the pocket 5 of the screen. The surface of the port seal 4 facing the screen has the same curved surface as the inner circumferential surface of the screen, and a brush 7 is attached to that surface. The material for the port seal is preferably synthetic rubber or synthetic resin, and the material for the brush 7 is preferably water resistant and elastic, such as synthetic fibers such as nylon or animal hair. To attach the brush, attach a thin seal with a brush attached to both the left and right sides of the suction port of the port seal. In the case of a small machine, there is only one backwash arm, but in the case of a large machine, as in this embodiment, two backwash arms are installed symmetrically on the left and right sides of the shaft 3, and the upper arm is The arm below the top half of the screen backwashes the bottom half of the screen.

The operation of the strainer having the above configuration will be explained. The raw water containing dust is removed from the main casing 6.
The water enters through the raw water inlet 9 attached to the lower part of the cage, flows upward in the radial direction while rising inside the cylinder of the screen 1, and dust is captured in the pocket 5 of the screen, becomes treated water, and descends around the outer periphery of the cage 8. The treated water is discharged to the outside of the machine from a treated water outlet 10 attached to the lower part of the main casing 6. The backwash arm 2 is driven by an electric motor installed at the top of the shaft 3 and rotates slowly, and the dust trapped in the pocket 5 facing the opening of the port seal 4 is backwashed from the opening along with the treated water. Flows down into the arm. The lower part of the backwash arm communicates with the atmosphere via a discharge pipe 11, and the treated water flows down into the backwash arm only under its own pressure. At this time, the brush 7 attached to the opposite surface of the port seal 4 makes good contact with the convex surface of the pocket 5 and closes the gap, thereby preventing raw water from flowing in from this part. It also functions to flush dust adhering to the convex surface into the pocket 5. In the embodiments described above, the screen 1 is cylindrical and the raw water enters from below, but a structure in which the screen 1 is arcuate and the raw water is introduced horizontally from the cutout part of the screen may also be implemented.

Effects According to the present invention having the configuration and operation described above, the following effects can be obtained. That is, port seal 4
The brush 7 attached to the opposing surface of the screen pocket 5 reduces the distance between the end surface of the backwash arm and the convex surface of the screen pocket 5, thereby reducing the inflow of raw water and increasing the flow rate of treated water effective for backwashing the pocket 5. This increases the efficiency of backwashing the screen, and when the backwashing arm rotates, the brush 7 also removes dust adhering to the convex surface of the pocket 5 and flushes it into the pocket 5, so the convex surface can be thoroughly cleaned. I can go there.

[Brief explanation of the drawing]

Fig. 1 is an overall vertical cross-sectional view of the strainer according to the present invention, Fig. 2 is a transverse cross-sectional view taken along line A-A in Fig. 1, and Fig. 3 is a cross-sectional view of the strainer according to the present invention.
The figure is a cross-sectional view of the backwash arm. 1...Screen, 2...Backwash arm, 3...
Shaft, 4... Port seal, 5... Pocket, 6... Suction port, 7... Brush, 8... Cage, 9... Raw water inlet, 10... Treated water outlet, 11
...Discharge pipe, 12...Body casing.

Claims (1)

[Scope of utility model registration request] It is equipped with a screen 1 in which a corrugated perforated plate is arranged in a cylindrical or arc shape, and a backwashing arm 2 that rotates with an end surface close to the inner peripheral surface of the screen, and a suction port 6 provided on the end surface. In an automatic backwash strainer that backwashes the screen by sucking water, a port seal 4 facing the inner peripheral surface of the screen is attached to the end face of the backwash arm 2,
Brushes 7 are installed on both the left and right sides of the suction port 6 of the port seal.
An automatic backwash strainer characterized by being equipped with.