JPH09262413A - Clogging preventive device for screen installed in tank - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the clogging of a dewatering screen of a precipitation type solid-liquid separation tank. SOLUTION: An overflow path 6 is installed on the side wall of a tank 1, a screen 3 of a vertical grating is installed in a screen wall 4 surrounding the overflow path 6, and solid matter caught by the screen 3 is continuously scraped up by a rake 8. And the settled solid matter is continuously discharged by a conveyor laid in the tank. However, since in the tank 1, treated water of high solid matter concentration is intermittently fed in large quantities and the settled solid matter is raised and goes directly to the screen 3 to clog it. But when a shield plate 11 is installed on a rake fitting frame 10, the treated water flows detouring around it to the screen 3, thus to prevent the clogging.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for preventing clogging of a drain screen provided in a tank installed in a power plant or the like.

[0002]

2. Description of the Related Art Generally, shellfish such as mussels and barnacles attached to seawater intakes of power plants and steelworks grow
It must be removed and cleaned regularly to normalize the seawater intake system. The removal amount is, for example, about 100 each time.
The work to remove it reached 0 tons on the seawater intake channel,
After the water is cut off by partitioning the downstream side by shaving, most of the seawater in the meantime is discharged, and then the shellfish attached to the waterway wall and the like are scraped off.

When the waste containing sea life such as shellfish scraped off at the bottom of the water channel is analyzed, for example, the total amount is 960 tons.
The ratio of shellfish is 320 tons, seawater is 320 tons, and mud sand is 320 tons. And shellfish, its scum, garbage, etc. are accumulated together with sludge-like mud and sand.

Therefore, in order to treat these wastes (also referred to as solids) containing marine organisms, for example, when the waste is carried out to a shellfish treatment facility (see, for example, JP-A-7-309645), a solid-liquid separation facility is previously prepared. Drain by.

Regarding the solid-liquid separation equipment, the inventors of the present invention have shown that a huge steel tank having a sedimentation-type solid-liquid separation function as shown in FIG. 5 (for example, 7.2 m in length × 3.7 m in width × depth) A 4.5 m long service tank or stock tank) 1 was used to treat a large amount of material in a short period of time.

That is, the waste that has been scraped off in the intake channel and accumulated at the bottom of the tank, together with the remaining seawater, is sucked up by a vacuum cleaner and the tank 1
Carry on and intermittently throw in one after another.

This tank 1 utilizes a so-called sedimentation type solid-liquid separation function. It deposits shellfish and sludge-like mud sand that are heavier than seawater, and lays this at the bottom of the tank, which is an endless flight conveyor type quantitative discharge. It is discharged one after another by the conveyor 2. Then, when the input seawater reaches a certain standard water level H or higher, a vertical gutter (also called an overflow channel, which is surrounded by a bar screen 3 standing upright on the front side in FIG.
(Not shown).

[0008] Therefore, by using the sedimentation-type solid-liquid separation tank 1 as described above, a large amount of wastes containing marine organisms, which are scraped off and accumulated in the intake channel, are taken out from the intake channel in a short period of time. Moreover, it is possible to drain water, which is suitable for the periodic cleaning and maintenance work schedule of the power plant.

In the figure, 4 is a steel screen casing projecting from the tank wall. The screen casing 4 surrounds a vertical gutter, and a bar screen (so-called drainer) is provided on the front surface of the vertical gutter. Screen 3 is provided. Therefore, the introduced seawater overflows into the downspout only through the bar screen 3, and the solid matter at that time is captured by the bar screen 3.
Reference numeral 5 denotes a traveling tunnel of the fixed quantity carry-out conveyor 2.

[0010]

However, in such a sedimentation type solid-liquid separation tank 1, a large amount of seawater containing a large amount of wastes such as sea life is intermittently introduced one after another by a hose of a vacuum car. Therefore, the seawater suspended in the screen 3 suddenly rises to the standard water level H, and floating substances such as floating dust are trying to go straight to the screen 3 at one time. Immediate clogging of the entire screen 3,
I found the problem.

Therefore, the clogged bar screen 3
It has been necessary to scrape the captured solid matter with a bear hand, a nail, or the like by a worker's manual work, or to spray high pressure water on the back surface of the base screen 3 for cleaning.

It has been found that this results in poor workability and, in turn, drastically reduces the drainage treatment capacity, thus disturbing the cleaning work schedule for power plants and the like.

Therefore, the present invention has as its main object to solve the above identified problems.

[0014]

The gist of the present invention for that purpose is as follows: 1) A screen provided with an overflow channel in a tank having a sedimentation type solid-liquid separation function, and a screen wall surrounding the overflow channel. A vertical grid-shaped draining screen is provided on the draining screen so that the solid matter when the treated water in the tank flows through the overflow passage is captured by the draining screen, and the draining screen is provided in front of the draining screen. Scrape up the solids captured with the screen,
Moreover, by providing a rake that runs endlessly and providing a shielding plate in front of the rake, it is possible to prevent the large amount of treated water intermittently introduced into the tank from going straight to the draining screen. And a screen clogging prevention device provided in the tank. 2) The solid matter in the treated water according to claim 1 is provided in the tank having a volume ratio of about 2/3 (weight ratio). It is in the screen clogging prevention device.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail with reference to embodiments shown in the accompanying drawings.

FIG. 1 is a side view of a main part of an embodiment of the present invention, FIG. 2 is a view taken in the direction of arrow A in FIG. 1, FIG. 3 is a detailed view of part B in FIG.
FIG. 4 is a view taken in the direction of arrow C in FIG. 3, and the same parts as those of the prototype example shown in FIG.

In the present embodiment, in order to cool the condenser of the thermal power plant, the shellfish and the like grown and attached to the water channel for taking in seawater are removed, and the shellfish is drained before being sent to the shellfish processing facility. Suitable for equipment.

As shown in FIG. 5, this drainer uses a huge sedimentation-type solid-liquid separation tank 1 and discharges the shellfish integrated with the sludge-like mud sand that has settled at the bottom thereof by a quantitative carry-out conveyor 2. However, the seawater is made to overflow from the downspout 6 by an amount exceeding the standard water level H, and this overflow seawater is discharged to the drain pipe 29.
And is discharged through a predetermined water treatment device.

The sedimentation type solid-liquid separation tank 1 is shown in FIG.
This screen is equipped with a screen device.
Device to the tank 1 intermittently (for example, 10
The amount of air sent from one vacuum pump of KIROLITA) The amount of solid matter such as shellfish and dust in the injected seawater is captured, and only the seawater is made to overflow into the downspout 6.

This screen device has a tank vertical wall 1a.
In addition, a steel screen casing 4 protruding from the inside of the tank (not necessarily the casing, the wall surface may be a recess. These are referred to as a screen wall in the present specification), and this screen Box 4
A bar screen 3 (also called a so-called drain screen) attached to the front surface of the tank
And a vertical gutter 6 surrounded by the screen casing 4.

By the way, the bar screen 3 is in the form of a vertical lattice, and a large number of metal bars 7, 7, ... Are arranged in parallel in the vertical direction at a predetermined interval (for example, 15 mm). However, clogging is caused by the above-mentioned temporarily large amount of solid matter and by floating things such as sludge that has been settled by temporarily large amount of seawater.

Therefore, an endless running rake 8 continuously scrapes up the solid matter captured by the bar screen 3 and discharges it to the upper take-out pan 9 provided above. .

By the way, in a general continuous rake-equipped bar screen, the water flow containing suspended matter flows in a substantially steady state, and the solid matter to be trapped is also a special case such as the invasion of jellyfish. Except for the above, since the amount is substantially constant, the rake drive load is also substantially constant, and the screen work is performed according to the design value. However, in the sedimentation type solid-liquid separation tank 1 of the present embodiment, In the attached rake screen 3 with a rake, as described above, a large amount of waste containing seawater, which is pressure-fed from the vacuum car and introduced, is intermittently introduced at a time and shocked. When the water is thrown in, the water level (H) is rapidly increased, and not only the suspended matter but also the sludge that has settled up, and these flow toward the entire surface of the base screen 3. Therefore, the screen
It was found that the button 3 was immediately closed, and the raking operation by the rake 8 was stopped due to an excessive load.

Therefore, in the rake bar screen 3 of the present embodiment, a steel plate shielding plate 11 is attached to the front surface of the rake mounting frame 10 which constitutes the rake 8. Then, the introduced seawater bypasses the side and bottom surfaces of the rake mounting frame 10 to flow in. Therefore, suspended solids such as dust in seawater and waste such as sludge-like mud sand that has flown up by throwing in will bypass the raked bar screen 3 without hitting it (directly) and will flow in the wastewater. -In the screen 3, the flow of seawater becomes steady as much as possible, and thus, the rake 8 is not pressed against the screen 3 and the scraping load is not sharply increased. Therefore, the draining work is continuously performed.

Next, the respective parts of the screen device will be described in detail. The bar screen 3 is formed in a vertical lattice shape,
As shown in FIGS. 2 and 3 (for a pair of right and left, only one side will be described), a bar screen frame 13 is fixed to a steel frame 12 made of an angle member provided at the front end of the screen casing 4, A large number of bars 7, 7, ... Are arranged side by side in a vertical direction on a beam 14 provided horizontally on the bar screen frame 13.

The rake 8 is shown in FIGS. 1, 2, 3 and 4.
As shown in FIG. 1, a pair of left and right rake chains 15, 15 are provided with a rake support piece (angle member) 16 laterally at a predetermined interval. A large number of claws 17 that can be inserted between -7 are fixed. That is, one side of the angle of the rake support piece 16 is bolted to one of the links 18 of the rake chain 15 via the mounting member 19, and the claw 17 is welded to the other side of the angle.

The rake chain 15 is driven by a handle 20 installed on the ground. That is, the handle 20 drives the rake chain 15 via the speed reducing mechanism (power boosting mechanism) 21. This reduction mechanism 21 drives a large chain wheel 23 integrated with an upper sprocket wheel 22 with which a rake chain 15 is meshed with a drive chain 24, and this drive chain 2
4 is a small chain wheel 25 integrated with the handle 20.
Is engaged with. Of course, the handle 20 may be an electric motor.

The rake chain 15 meshes with the lower sprocket wheel 26, and the lower sprocket wheel 26 is mounted on the rake mounting frame 10 via a bearing portion 27.

Therefore, this screen device can be made extremely simple and inexpensive as compared with a general bar screen with a rake for intake channels.

A pair of rake guides 28, 28 are fixed to the rake mounting frame 10 with the rake chain 15 sandwiched between the rake chain 15 and the bar screen 3 side. ing. The vertical gutter 6 is formed in a vertical duct shape, and a drain pipe 29 is connected to the lower end thereof.

In the rake 8 as described above, when the operator rotates the handle 20, the claw 17 of the rake 8 moves from the bottom to the top of the berth screen 3 to cause the berth screen 3 to move. Wastes containing sea creatures that are clogged are scraped up and collected in the upper pan 9 to prevent the clogging of the bar screen 3 and accelerate the outflow of seawater.

The parts constituting the screen device are made of steel such as stainless steel.

[0033]

EFFECTS OF THE INVENTION According to the present invention, a large amount of solids intermittently added to the drainage screen and treated water containing a large amount of solids are not allowed to go straight. Even if an object soars, the scraping load caused by the screen rake does not increase sharply.

That is, since only a shield plate is added,
Although it can be made extremely simple and inexpensive, the remarkable effect of preventing clogging can be obtained.

[Brief description of drawings]

FIG. 1 is a side view of essential parts of an embodiment of the present invention.

FIG. 2 is a view taken in the direction of arrow A in FIG. 1;

FIG. 3 is a detailed view of a portion B in FIG. 2;

FIG. 4 is a view taken in the direction of the arrow C in FIG. 3;

FIG. 5 is a prototype example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Tank, 1a ... Side wall, 3 ... Bar screen, 4 ... Screen housing, 6 ... Downspout, 8 ... Lake, 10 ... Lake mounting frame, 11 ... Shield plate

Claims (2)

[Claims] 1. A tank having a sedimentation-type solid-liquid separation function is provided with an overflow channel, and a screen wall surrounding the overflow channel is provided with a vertical grid-like draining screen, and the draining screen is used to The treated water in the tank is designed to capture the solid matter when flowing through the overflow channel, and the solid matter captured by the drainage screen is scraped up on the front surface of the drainage screen, and endlessly. A tank characterized in that a traveling rake is provided and a shield plate is provided in front of the rake so that a large amount of treated water intermittently introduced into the tank is prevented from going straight to a draining screen. A screen clogging prevention device installed inside. 2. The solid matter in the treated water according to claim 1 is ⅔.
A screen clogging prevention device installed in the tank at a weight ratio.