JPH09978A - Strainer - Google Patents

Abstract

PURPOSE: To provide a strainer in which the inflow quantity of waste water to a filter is increased to improve efficiency. CONSTITUTION: A strainer is provided with a screen board 3 to which a filter 31 is cylindrically fitted and which is rotatable, dispersing boards 4, 5 in plural steps for scattering waste water to the filter 31 from inside the cylindrical body, an original water intake pipe 6 for feeding waste water to the dispersing boards 4, 5, a backwashing device for jetting backwashing water to the surface of the filter 31, and a treated water outlet 7. The filter 31 is formed of a wire net, and a water collecting cylinder 37 for separating backwashing water from the treated water to cause it flow is provided on the screen board 3.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to strainers used to filter wastewater. In particular, the present invention relates to a strainer suitable for filtering white water in paper mills and a large amount of wastewater containing relatively large solids.

[0002]

2. Description of the Related Art Conventionally, as a rotary filtration device suitable for treating a large amount of waste water containing a relatively small amount of solids, a rotary sieve basket having a filter made of a wire mesh attached to a cylinder is rotated to rotate the filter. There is known a method and an apparatus for concentrating waste water by spraying filthy water and separating water and solid suspended matter by centrifugal force (see, for example, JP-A-47-292). The waste water concentrating device comprises a rotary sieve basket, an inflow pipe, an inflow substance collision plate or a deflecting device, a driving device, a flow outlet, a concentrate outlet, and the like, which are put in a cylindrical housing. In this conventional rotary filtration device, wastewater is introduced from the inflow pipe to the inside of the rotary sieve cage, adjusted by the inflowing substance collision plate so as to obtain a required flow rate, and dispersed on the rotary sieve cage surface. Then, the deflecting device adjusts the recirculation amount of the influent that rebounds from the rotary sieve cage and the ratio of the influent that enters from the supply pipe to improve the efficiency.

[0003]

As described above, the conventional rotary filtration device sprays the influent on the filter surface and collects the influent that collides with the rotary sieve basket and bounces back from the feed pipe. Recycle by adjusting the ratio with the thing.
If the influent filtration rate is high and the bounced inflow rate is low, the rate of the bounced influent will decrease and the amount of recirculation will decrease, the filter surface will not be able to be used effectively, and an excessive filter will be used. Efficiency is reduced.

The present invention is intended to solve the conventional problems and to provide a strainer capable of increasing the inflow amount of wastewater and improving the efficiency.

[0005]

In order to solve the above-mentioned problems, a strainer according to the present invention has a rotatable screen plate having a filter attached in a cylindrical shape and sprays waste water from the inside of the cylindrical shape to the filter. A disperser, a raw water intake pipe for supplying wastewater to the disperser, a backwash device for injecting water for backwashing onto a filter surface, and a strainer having a treated water outlet, wherein the dispersers are provided in a plurality of stages. The screen is provided with a water collecting cylinder in which the filter is formed of a wire mesh and the backwash water is separated from the treated water to flow.

[0006] In the strainer, it is preferable that the dispersion plates are provided in two stages at intervals in the vertical direction.

In the strainer, it is preferable that the backwash device comprises a spray nozzle and an adjusting device for intermittently feeding the backwash water to the spray nozzle.

[0008]

The strainer of the present invention comprises a rotatable screen plate having a filter attached in a cylindrical shape, a dispersion plate for spraying waste water from the inside of the cylindrical pipe to the filter, and raw water for supplying waste water to the dispersion plate. A strainer having an intake pipe, a backwashing device for spraying water to be backwashed onto a filter surface, and a treated water outlet, wherein the dispersion plate is provided in a plurality of stages, the filter is formed of a wire mesh, and the backwashing water is provided. A water collecting cylinder which is separated from the treated water and flows is provided on the screen board.

The wastewater taken in from the raw water intake pipe is directed in the radial direction by the dispersion plate and evenly distributed on the rotating filter surface, collides with the filter to separate the solid matter, and centrifugal force is applied to filter it. The treated water is discharged from the treated water outlet. The solid matter separated by the filter is washed off by the water sprayed by the backwash device and discharged as backwash water through the water collecting tube. Since the wastewater is dispersed by the dispersion plate, the supply of the wastewater to the filter surface becomes uniform, the filter surface can be used evenly, and the filtration efficiency can be improved. Further, since the wastewater is sprayed from a plurality of stages, the collision area of the wastewater is increased, so that the efficiency of the filter can be improved and the damage of the filter can be reduced.

Since the separated solid matter is washed off by the water jetted by the backwashing device and discharged as backwash water through the water collecting tube, the separated solid matter is usually removed without removing the filter. Since this is performed, the separated solid matter can be easily removed.

According to the construction in which the strainers are provided in two stages at intervals in the vertical direction, the dispersers need only be provided in two stages, and the structure of the apparatus is not complicated, and The effect that the supply of waste water to the filter becomes uniform and the filtration efficiency can be improved can be obtained.

In the above strainer, according to a preferred construction, the backwash device comprises a spray nozzle and an adjusting device for intermittently feeding the backwash water to the spray nozzle.
In addition to the effect, the separated solid matter can be removed more efficiently, and the efficiency of the filter can always be kept high.

[0013]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of an embodiment of the strainer, FIG. 2 is a plan view thereof, and FIGS. 3 and 4 are views for explaining a part of the structure. The strainer 1 includes a tank body 2 and
A rotating screen board 3 arranged in the tank main body 2; dispersion boards 4, 5 arranged in the screen board 3;
A raw water intake pipe 6 for supplying wastewater to the dispersion boards 4, 5, a treated water outlet 7 for guiding the water treated by the filter 31 of the screen board 3 to the outside of the apparatus, and a reverse jet for injecting water for backwashing the surface of the filter 31. A washing device 8 and a drive device 9 for rotating the screen board 3 are provided.

As shown in FIGS. 1 and 2, the tank main body 2 is formed of a steel plate in the present embodiment in an octagonal cylindrical shape, and has a side wall 11 forming a side surface and a backwash for discharging treated water. A bottom 12 inclined so as to collect water is fixed in a watertight manner, and a ceiling 13 is removably attached to the upper part. A treated water outlet 7 is provided at the lower end of any ridge of the side wall 11 of the tank body 2, and a viewing window 15 is provided slightly above one surface forming this ridge. Also, above the side wall 11,
A spray pipe 81 of the backwashing device 8 is provided so as to penetrate the side wall, and the footrest 16 is attached to every other lower ridge. The viewing window 15 can be opened and closed by a hinge and can be watertightly closed by a stopper.

A raw water intake pipe 6 is erected up through the bottom 12 of the tank body 2 and extends along the axis. Further, a washing water collecting wall 17 is installed around the raw water intake pipe 6 upright from the bottom 12 in a watertight manner, and a washing water taking-out pipe 19 for discharging the backwash water collected on the collecting water wall 17 is collected. It is provided below the portion of the bottom 12 partitioned by the water wall 17. An annular flange 18 is provided at the upper end of the water collecting wall 17 to prevent rebound. A water collecting cylinder 37 of the screen board 3 which can rotate in the central portion of the collar 18 extends downward.

An upper end portion of the raw water intake pipe 6 penetrating the bottom 12 of the tank body 2 is open, and an upper supply pipe 61 is provided by being inserted concentrically from the opening. The upper end of the upper supply pipe 61 is open, and the wastewater flowing through the central portion of the raw water intake pipe 6 flows into the upper supply pipe 61 and overflows from this upper end. Dispersers 4 and 5 are provided on the outer circumferences of the upper ends of the raw water intake pipe 6 and the upper supply pipe 61, respectively. It should be noted that the raw water intake pipe 6 can be erected by bending its lower portion as in the present embodiment to lower the height of the apparatus, but it may be straight if sufficient space is available.

Raw water intake pipe 6 for supplying waste water to the dispersion plate 3
(Not shown) communicates with a wastewater source or a wastewater storage tank. The water pressure of waste water supplied to the strainer is 0.2 to 1
It is set to 0 kg / cm ² . 0.3 to 8 kg in order to reduce the pressure loss in the piping and to constantly supply the wastewater to the dispersion plates 4 and 5 and to disperse it uniformly in the filter 31.
/ Cm ² is preferred. In this case, if the waste water is supplied from a waste water storage tank installed so as to have a height difference of 3 to 10 meters without providing a transportation device such as a pump, the power for waste water transportation can be saved. Also, the upper supply pipe 6
The supply ratio of the waste water to the dispersion plate 4 of No. 1 is preferably 35 to 70% in order to effectively use the filter surface, and more preferably 40 to 60%.

On the upper side of the ceiling 13 of the tank body 2, the motor 90 and the speed reducer 91 of the drive unit 9 are placed, and
An inspection door 21 is provided. The inspection door 21 is provided with a handle and a hinge so that it can be easily opened and closed, and a packing is provided so as to be watertightly closed. Further, a bearing 94 is provided on the outside of the ceiling 13 to support the drive shaft 92 that penetrates the ceiling 13 and is connected to the screen panel 3. Further, a plurality of crane hooks (not shown) are provided at a plurality of places so as to move the ceiling 13 so that members inside the tank body 2 can be taken in and out, and to suspend the entire rotary filtration device.

The backwash device 8 includes a spray pipe 81, a plurality of spray nozzles 82 provided in a portion of the spray pipe 81 facing the filter 31, an electromagnetic valve 83 for adjusting the backwash water, and the like. It consists of an adjusting device. The spray pipe 81 penetrates the upper portion of the side wall 11 and is introduced into the tank main body 2, and extends downward outside the filter 31. The opening / closing of the solenoid valve 83 is driven by a timer provided in a main adjusting device (not shown). In this embodiment, only one spray pipe 81 is provided so as to extend downward. This number depends on the size of the screen board 3 and the solid matter in the removed waste water, but normally it is 1. ~ 4 is enough.

When the filter 31 is washed by the backwashing device 8, backwashing water is maintained at a constant pressure in the range of 5 to 20 kg / cm ² and continuously sprayed. As the backwash water, fresh water or treated water is used, and the amount of water used is preferably about 1 to 15% of the waste water. The amount of backwash water used depends on the quality of the wastewater to be treated.
This backwash water spraying may be performed intermittently if the amount of backwash water can be saved intermittently. As a result, the amount of backwash water can be saved. There is no problem even if the spray pressure of the backwash water is changed.

The treated water outlet 7 passes through the filter 31 and is blown to the inner peripheral surface of the side wall, and is provided at the lowest portion of the bottom 12 for discharging the collected filtered water. The treated water outlet 7 is
Connect to a water tank, not shown, for reuse,
It communicates with the discharge destination so that it can be discharged as it is. Also,
The wash water withdrawal pipe 19 provided below the bottom 12 surrounded by the water collecting wall 17 treats the solid matter separated from the waste water,
Whether it directly communicates with the treatment equipment for high-concentration solids-containing treated water,
Or it communicates with the storage tank.

The drive unit 9 is composed of a motor 90 and a speed reducer 91 mounted on the upper side of the ceiling 13, and a connecting flange 93 connecting the screen board 3 and the drive shaft 92. The drive shaft 92 is supported on the ceiling 13 by a bearing member 94, and the exposed portion of the drive shaft 92 is protected by a cover 95.

The speed reducer 91 decelerates and shifts the rotation of the motor 90 so that the number of rotations of the screen board 3 is 50 to 250 rp.
Adjust to m. Since the centrifugal force can be changed and the filtration pressure can be changed by this rotation speed, high filtration efficiency can be maintained.

As shown in FIG. 3, at the upper part of the screen board 3, a mounting plate 33 is fixed to the lower surface of the upper plate 32, and the mounting plate 33 is mounted on the supporting plate 3 for mounting the filter.
Eight 4 are erected. In the lower part of the screen board 3, a filter support plate 36 is attached to the upper surface of the annular plate 35, and the columns 34 are fixed upright on the upper surface of the annular plate 35. A water collecting cylinder 37 is provided extending downward from the lower surface of the annular plate 35. Further, two bolts 39 are fixed to each of the columns 34 to fix the filter pressing member 38, and a wing nut 40 is attached to the bolt 39.

As the filter 31, a wire net of about 10 to 350 mesh is used. The mesh changes depending on the water quality, but in white water it is about 165 to 350 mesh, and if it is too fine,
It is not preferable because clogging is likely to occur and durability is deteriorated. The filter 31 can be attached using the wing nut 4
After loosening 0, the gap between the column 34 and the filter pressing plate 38 is widened, the filter 31 is inserted into the gap between the adjacent columns 34, and then the wing nut 40 is tightened and fixed to form an octagonal cylinder.

The filter pressing member 38 for mounting the filter 31 on the support column 34 is prismatic, and the pressing surface has an opening angle of about 135 corresponding to the ridge formed by the adjacent filters 31.
It is formed in a concave shape of °. The inner surface facing the filter 31 and the outer surface facing the filter are provided with holes through which the bolts 39 are inserted. The filter support plate 36 is bent downward to the outside and formed into an L-shape.
No gap is formed between the annular plate 35 and the filter 31 when the No. 1 is attached.

Bolts (not shown) are erected on the upper surface of the upper plate 32. The screen board 3 and the drive device 9 are connected by inserting the bolt into the mounting hole of the connection flange 93 of the drive device 9 and fastening the bolt.

As shown in FIG. 4, the dispersion plate 4 has a fitting cylinder 41.
And a partition plate 42 and a bottom plate 43, and the fitting cylinder 41 is fitted and attached to the upper supply pipe 61 of the raw water intake pipe 6. In this case, a packing may be provided between the outer circumference of the upper supply pipe 61 and the inner circumference of the fitting cylinder 41 to eliminate the gap. In this way, even if the processing accuracy is poor, the raw water can be prevented from flowing to the lower stage and dispersed in the upper part of the filter.

Next, the filtration conditions by the strainer having the same external dimensions as the conventional one of the present embodiment configured as described above will be described. Solid matter in waste water is 0.05 ~
White water containing 0.12 g / m ³ and 50% or more of 44 microns or more was treated at a rate of 2000 to 2800 m ³ / day. With 165-mesh metal gauze filter 31, a screen plate 3 is rotated at 150 rpm, the supply pressure of the white water and 0.3 kg / cm ^2, the backwash water and 120 m ³ / day, the spray pressure at 10 kg / cm ² It was fixed.

As a result of treating white water with the above strainer, the particle size was 5 even at 2400 to 2800 m ³ / day.
98% or more of solids of 0 micron or more could be removed, and 90% or more of solids could be removed in total. The treated water was used as machine shower water as fresh water substitute water and as backwash water. This strainer is 1 compared to the conventional one
0 to 20% more efficient.

As described above, in the strainer of the present invention, since the wastewater is sprayed from a plurality of stages, the collision area of the wastewater becomes large, which makes it possible to increase the filtration rate and
The damage to the filter can be reduced. If the dispersers are provided in two stages at intervals in the vertical direction as in the above embodiment, the dispersers need only be provided in two stages, and the waste water to be supplied to the filter can be provided without complicating the structure of the apparatus. The supply becomes uniform and the filtration efficiency can be improved.

Further, in the strainer of the present invention, the separated solid matter is washed off by the water jetted from the backwash device and discharged as backwash water through the water collecting cylinder, so that the separated solid matter is Since the filter does not have to be removed and removed, the separated solid matter can be easily removed. Moreover, since the solid matter is concentrated, this treatment can be economically performed.

[0033]

The strainer of the present invention can effectively utilize the filter surface and can improve the filtration efficiency. Further, since the wastewater is sprayed from a plurality of stages, the collision area of the wastewater is increased, so that the filtration efficiency can be improved and the abrasion caused by the collision of the solid with the filter can be reduced.

Further, in the strainer of the present invention, the separated solid matter is washed off by the water sprayed by the backwash device and discharged as backwash water through the water collecting cylinder, so that the separated solid matter is filtered by the filter. Since it does not need to be removed and removed, the separated solid matter can be easily removed. further,
According to the configuration in which the dispersers are provided in two stages at intervals in the vertical direction, the dispersers need only be provided in two stages, and the waste water can be uniformly supplied to the filter without complicating the structure of the apparatus. Therefore, the filtration efficiency can be improved.

[Brief description of drawings]

FIG. 1 is a partially cutaway front sectional view showing an embodiment of a strainer of the present invention.

FIG. 2 is a plan view of the strainer of this embodiment.

FIG. 3 is a diagram illustrating a screen panel of the strainer of this embodiment.

FIG. 4 is a diagram illustrating a dispersion disc of the strainer of this embodiment.

[Explanation of symbols]

 1 Strainer 2 Tank Main Body 3 Screen Board 4,5 Dispersion Board 6 Raw Water Intake Pipe 7 Treated Water Outlet 8 Backwash Device 9 Drive Device 31 Filter 34 Mounting Plate 37 Water Collection Tube 81 Spray Nozzle

Claims (3)

[Claims] 1. A rotatable screen board having a filter mounted in a cylindrical shape, a dispersion board for spraying waste water from the inside of the cylindrical shape to the filter, and a raw water intake pipe for supplying the waste water to the dispersion board. A strainer having a backwashing device for injecting water to be backwashed onto a filter surface, and a treated water outlet, wherein the dispersion plate is provided in a plurality of stages, the filter is formed of a wire mesh, and the backwashed water is treated water from the treated water. A strainer characterized in that a water collecting cylinder which is separately flowed is provided on the screen board. 2. The dispersion discs are vertically spaced apart from each other.
The strainer according to claim 1, which is provided in a step. 3. The strainer according to claim 1, wherein the backwash device comprises a spray nozzle and an adjusting device for intermittently feeding the backwash water to the spray nozzle.