JPS607916A - Precoated filtration apparatus - Google Patents

Abstract

PURPOSE:To obtain a precoated filtration apparatus with increased capacity by forming an original water overflowing part which is opened to an original water inflow chamber above the upper end of a filter element. CONSTITUTION:A wall 9, whose upper end is situated higher than the upper end of a filter element 5, is provided on an intermediate bottom 2 along the inner circumference of a vessel 1. In addition, an original water overflowing part 10 which is opened to an original water inflow chamber 3 above the upper end of the filter element 5 is formed between the wall 9 and the inner circumference of the vessel 1. And an original water supply pipe 6 is provided to the side surface of the vessel 1 to be communicated with the lower part of the original water oveflowing part 10. In this way, a filter aid and the original water supplied into the original water overflowing part 10 from the water supply pipe 6 extend radially and inwardly from the upper end of the overflowing part 10, and then flow down in the original water inflow chamber 3. Accordingly, a precoated layer having almost uniform thickness in the vertical direction can be formed on each filter element 5, and the capacity of the apparatus can be increased.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention filters cooling water and other water used in nuclear reactors and other facilities that handle radioactive materials through a precoated layer of a filter aid, such as a powdered ion exchange resin, to eliminate impurities in the water, such as crud. , relates to a prerecorded filtration device for removing ionic impurities.

As shown in Fig. 1.2, the conventional pre-recorded filtration device is equipped with a middle bottom plate 2 at the inner bottom of the vessel 1, with the top of the middle bottom plate serving as the raw water inflow chamber 3, the bottom as the treated water collection chamber DA, and the upper end. By fixing the lower end of a large number of hollow filtration elements S... through the inner bottom plate, the filtration elements are arranged in a row in the raw water inflow chamber, and the treated water collection chamber is connected from the bottom l' of the vessel. A water supply pipe 6 is provided that penetrates through the chamber and opens at the center of the inner bottom plate, and at the beginning of operation, slurry IJ-' containing ion exchange resin powder is supplied from the water supply pipe into the raw water inflow chamber 3 in an upward flow, and the slurry is The water permeates through the pipe wall of each filtration element, the resin powder is attached to the outer periphery of the pipe wall, and the water that permeates through the pipe wall flows down to the treated water collection chamber and drains outside through the drain pipe 7. After a precoat layer of an appropriate thickness of ion exchange resin powder is formed on the outer periphery of each filter element, steady operation is performed by supplying raw water in an upward flow from the water supply pipe into the raw water inflow chamber. When the ion exchange phase J]>i constituting the precoat layer is saturated by long-term steady operation, air is blown into the treated water collection chamber through the air pipe g, and washing water is supplied from the waste water v7. rt y, 1%9 of each passing element permeates from the inner periphery to the outer periphery to form the υ precoat layer (2:l
Remove the water from the water supply pipe 6 and perform backwashing. Once the backwashing is complete, fill the raw water inflow chamber and the treated water collection chamber with water, then draw out the water and perform the precoat layer adhesion process as described above. Repeat operation.

Conventional equipment (1) Slurry containing ion exchange resin powder is flowed upward in the raw water inflow chamber to form a precoat layer around the outer periphery of each FJ element. The amount of water permeation increases toward the bottom, and the thickness of the precoat layer formed on the outer periphery of the precoat layer should be thick and uniform as the bottom ends.For this reason, the amount of water passing through the tube wall of each filter element should be gradually increased from the bottom to the top. It is also proposed to make the thickness of the pre-coat layer uniform from top to bottom to make it easier to penetrate.
However, in such a place, during steady operation, the lower end of the precoat layer captures more cladding and ionic impurities, so the lower end becomes saturated while the upper end is not yet saturated, and the bleed layer There is a waste of having to backwash the entire unsaturated portion at the upper end. In addition, the element itself becomes contaminated with crud, etc., and requires frequent replacement.

Further, the raw water flowing upward through the water supply pipe spreads radially from the upper end of the water supply pipe inside the lower end of the raw water inflow chamber and flows upward. Since the filtration elements are arranged in concentric circles around the water supply pipe (Fig. 2), the inner surface allows more moisture in the slurry and raw water during steady operation to pass through, and this also helps prevent the formation of the precoat layer. The thickness, cladding, and the amount of ionic impurities captured are not uniform, and even if there are still unsaturated parts of the precoat layer, there is a waste of having to backwash the entire precoat layer if it becomes saturated. .

Therefore, the present invention solves the above problems by providing a raw water overflow section on the middle bottom plate along the inner circumference of the vessel, the upper end of which opens into the raw water inlet chamber above the upper end of the filtration element. .

FIG. 3 shows an embodiment of the present invention, in which the same components as in FIGS. 1 and 2 are given the same reference numerals.

In the present invention, a wall wall whose upper end is located above the upper end of the filtration element s is provided on the middle bottom plate Ω along the inner circumference of the vessel l, and the upper end of the filtration element is positioned between the wall and the inner surface of the vessel. The raw water overflow part opens into the raw water inflow chamber at the top.
Form. The raw water supply pipe 6 is installed on the side of the vessel so as to communicate with the lower end of the raw water overflow part 10.

If necessary, a porous dispersion plate may be placed on the upper end of the wall.
The filter aid is removably installed, and the filter aid is placed on the dispersion plate from the top of the wall.
For example, a wall made by dispersing slurry of ion exchange resin powder or raw water? The flow may be made to flow uniformly downward into the interior surrounded by.

Due to this, the slurry and raw water supplied from the water supply pipe 6 to the raw water overflow part io spreads radially inward from the upper end of the overflow part 10 and flows downward throughout the raw water inlet part. The water in the slurry or the precoat layer that permeates through the pipe wall of the filtration element, and the water in the raw water that permeates through the pipe wall of the filtration element flows downward inside the filtration element and exits into the treated water collection chamber. The slurry and raw water are p
It contacts the over-element or the pre-coat layer around its outer periphery.

Therefore, in the process of supplying slurry to the water supply pipe and forming a precoat layer on the outer periphery of each filtration element, both the inner surface filtration element and the outer filtration element are coated with a precoat layer with a uniform thickness in the vertical direction on the outer periphery. Can be formed. In addition, during steady operation where all filtration is performed, the cladding and ionic impurities are captured evenly on the upper and lower sides of the outer periphery of the inner filtration element and the pre-coat layer of the filtration element for foreign cars, so saturation progresses uniformly. , the precoat layers of all filter elements are saturated at the same time.

In this way, the thickness of the precoat layer is uniform throughout, so
Treated water of uniform water quality can be obtained, and there is no need to repeatedly backwash the water because some parts are saturated even though there are still many unsaturated parts.

Although it may be wrong to provide the raw water overflow f'A10 along the inner circumference of the vessel, it is not necessarily necessary to provide it along the entire inner circumference;
It may be partially interrupted as shown in FIG. and,
On the surface of the vessel 1111 corresponding to this interruption, there is a water supply pipe 6 and a discharge pipe /2 for discharging backwash water and peeled precoat layer during backwashing. : Provided, connected to the water supply pipe 6 and discharge pipe /-r in a branched manner, and the pipe from there to /
When supplying slurry or raw water to the water supply pipe, open the water supply pipe valve 6' and close the discharge pipe valve 72'. When backwashing, close the water supply pipe valve and close the discharge pipe valve. All you have to do is open it.

The embodiment shown in Fig. 5 is a case where the raw water overflow part /Q is provided all around the inner circumference of the vessel. In this case, the discharge pipe /2 passes through the side of the vessel and the raw water bath flow part, The opening may be made on the inner surface of the tube.

Of course, the discharge pipe/- is not limited to being provided as shown in FIGS. 4 and 5, but may be provided so as to open on the upper surface of the inner bottom plate as shown by the broken line in FIG. The valve 72' may be opened at times, and then closed at other times.

In this manner, it is possible to form a precoat layer having a uniform thickness in the vertical direction on any filtration element of a foreign car under its own weight, and to provide a precoat filtration device with improved throughput.

[Brief explanation of the drawing]

Claims (1)

[Claims] Inside the vessel, the entire inner bottom plate functions as a raw water inlet chamber and a treated water collection chamber below it, and a large number of filtration elements with a pre-coated layer of filter aid attached to the outer periphery of the inner bottom plate. Is it possible to fix the lower end of the p-type element in a penetrating manner? In the precoat filtration device, which separates impurities in the raw water supplied to the raw water inflow chamber with a precoat layer, flows down through the moisture trapping element, and drains the water through the treated water collection chamber. A pre-coat filtration device characterized in that a monkey-shaped raw water inflow portion is provided on the middle bottom plate along the inner periphery and has an upper end above the upper end of the filtration element and is open into the raw water inflow chamber.