JPH0721555B2 - Filtration device - Google Patents

Description

The present invention relates to a filter device for filtering insoluble impurities in a radioactive liquid, and more particularly to a backwash water obtained by backwashing a filter material. The present invention relates to a filtration device having an improved transfer method.

(Prior Art) Generally, in a filtration device of a nuclear power plant, as filtration operation is continued, insoluble impurities adhere to the surface of the filtration membrane of the filtration material to increase the filtration differential pressure of the filtration device. It is necessary to backwash.

Conventionally, as a method of transferring backwash water obtained by backwashing the filter material of the filter to the radioactive waste treatment facility, a method of directly transferring from the filter to the radioactive waste treatment facility by utilizing the natural head,
If this direct transfer is difficult, it is temporarily received by the backwash water receiving tank installed below the filtration equipment area, and the backwash water is boosted by a pump to forcibly transfer it to the radioactive waste treatment facility. There was.

(Problems to be solved by the invention) However, due to the recent construction of a separate building for radioactive waste treatment equipment, and the addition of filtration equipment to existing equipment, the filtration equipment has been replaced by radioactive waste treatment equipment. There are many cases where it is difficult to directly transfer backwash water due to the natural head.

In addition, in these cases, in the conventional method, the space required to install a backwash water receiving tank capable of receiving one or more batches of backwash water, a backwash water receiving pump, etc., under the filtration apparatus installation area. In addition to the above, there is a problem that the backwash water receiving pump needs to be regularly maintained.

Therefore, the present invention has been made in view of the above circumstances, and an object thereof is to provide a small-sized filter device capable of transferring backwash water from a filter to a radioactive waste treatment facility with a simple configuration. is there.

[Structure of Invention]

(Means for Solving Problems) The present invention includes a stock solution chamber for containing a radioactive liquid, a filter material for filtering the radioactive liquid, and a water purification chamber for containing purified water filtered by the filter material. In a filtration device in which the filter is configured to be backwashable, a backwash water receiving tank for receiving the backwash water obtained by backwashing the filter material, an air supply source, and the air supply on the side wall of the stock solution chamber of the filtration device. A first air supply pipe for communicating the air supply source, a second air supply pipe for communicating the air supply source with the water purification chamber of the filtration device, and a third air supply pipe for communicating the air supply source with the backwash water receiving tank. And having.

(Operation) First, when pressurized air is pressure-fed from the air source to the water purification chamber of the filter through the second air supply pipe, the purified water flows backward through the filter material of the filter and adheres to the filter material. Is removed from the filter material to prevent clogging of the filter material, and the backwash water containing these deposits flows into the stock solution chamber and is then temporarily transferred to the backwash water receiving tank.

Next, when pressurized air is pressure-fed to the backwash water receiving tank through the third air supply pipe, the backwash water in the backwash water receiving tank is forcibly transferred to the radioactive waste treatment facility.

Therefore, according to the present invention, it is not necessary to provide a natural head at least between the backwash water receiving tank and the radioactive waste treatment facility, or to provide a pump for backwash water transfer, and simplify the configuration. it can.

Also, when backwashing the filter, pressurized air is pumped from the side into the stock solution chamber of the filter through the first air supply pipe, so the filter is vibrated laterally to facilitate backwashing of the filter. can do. When the filter material is a hollow fiber membrane module, this backwash effect is suspended in the main body of the filter, and therefore the effect of removing the deposits due to the lateral vibration is remarkable.

(Embodiment) An embodiment of the present invention will be described below with reference to FIGS. 1 to 4. In the figure, common parts are given the same reference numerals.

FIG. 1 shows a main part of an embodiment of the present invention. A filter 1 having a filter material (not shown) for filtering radioactive liquid is divided into a water purification chamber 1y and a stock solution chamber 1x with the filter material at the center. Then, a stock solution inlet nozzle (not shown) for introducing the radioactive liquid into the filter 1 is provided on the upper side wall of the filter 1 to communicate with the stock solution chamber 1x, and the purified water obtained by filtering the radioactive liquid with a filter medium is discharged. An unillustrated purified water outlet nozzle is provided at the top of the filter 1 so as to communicate with the purified water chamber 1y, and the inlet pipe 2 is connected to the undiluted solution inlet nozzle and the outlet pipe 3 is connected to the purified water outlet nozzle.

The tip of the inlet pipe 2 is connected to the stock solution source A, and the radioactive liquid is introduced from here to the stock solution chamber 1x in the filter 1.

In addition, a backwash water transfer pipe 4 is provided to a backwash water drain nozzle (not shown) that backwashes a filter material (not shown) at the lower part of the filter 1 and discharges backwash water containing adhered substances adhering to the filter material. A radioactive waste treatment facility C is connected to the backwash water transfer pipe 4.

On the other hand, the tip portion of the air supply pipe 5 connected to the air source B that supplies pressurized air of a predetermined pressure is branched into three forks 5a, 5b, 5c,
The first branch pipe 5a is connected in the middle of the inlet pipe 2 and is connected to the filter 1
Of the stock solution chamber 1x, the second branch pipe 5b is connected in the middle of the outlet pipe 3 to the water purification chamber 1y of the filter 1, the third branch pipe 5c is connected to the upper portion of the backwash water receiving tank 6. Done, third
It is configured in the air supply pipe.

The backwash water receiving tank 6 is composed of a pressurizing small tank having a smaller capacity than the filtration tank of the filter 1, and is connected in the middle of the backwash water transfer pipe 4 via a connecting pipe 7, and through the connecting pipe 7, the filter 1 The backwash water is received and temporarily stored, and the backwash water is transferred to the radioactive waste treatment facility C.

The air supply pipe 5 is provided with an air pressure control valve 5V on the upstream side of the branch portions of the first and second branch pipes 5a and 5b.
Air supply on-off valves 5aV, 5bV, 5cV are respectively provided in the respective branch pipes 5a, 5b, 5c.

Also, the inlet pipe 2 has an inlet valve 2V and the outlet pipe 3 has an outlet valve 3V.
To the backwash water transfer pipe 4 and the backwash water outlet valve 4aV and the connecting pipe 7
Each has a communication valve 7V.

In FIG. 1, reference numeral 8 indicates a third branch pipe 5c of the air supply pipe 5,
It is a vent pipe linked to the downstream side of the supply air opening / closing valve 5cV for venting the air from the pressurized backwash water receiving tank 6, and a vent valve 8V is provided. This is a backwash water transfer valve installed in the backwash water transfer pipe 4 on the downstream side of the connecting portion connecting the connecting pipes 7.

Next, the operation of this embodiment will be described.

First, when performing the filtration operation, the inlet valve 2V is opened, and the radioactive liquid from the undiluted source A is introduced into the filter 1 through the inlet pipe 2.

Thereby, the radioactive liquid is filtered by a filter material (not shown) in the filter 1 and discharged as purified water through the outlet pipe 3.

Next, when performing backwash operation, inlet valve 2V and outlet valve 3V
On the other hand, while closing the valve, the opening degree of the air pressure control valve 5V is adjusted and opened so that the pressure higher than the pressure resistance value of the filter material in the filter 1 is not opened, and the first and second branch pipes 5a of the air supply pipe 5 Open the on-off valves 5aV, 5bV for air supply of 5b.

As a result, pressurized air having a predetermined pressure is supplied from the air supply source B through the first branch pipe 5a, the inlet pipe 2 and the second branch pipe 5b from above and in the lateral direction of the filter 1.

Pressurized air from above is pressurized against the filter medium in the filter 1 from the water purification chamber 1y side to the stock solution chamber 1x side, so the purified water in the water purification chamber flows backwards through the filter medium and the stock solution chamber. Flows to the side,
During the filtration operation, backwashing is performed in which the deposits on the filter material are peeled off and pushed into the stock solution.

In addition, the compressed air is laterally supplied to the filter medium to vibrate the filter medium to promote backwashing of the filter medium. When this filter medium is a hollow fiber membrane module, this hollow fiber membrane is used. Since the module is generally suspended inside the filter body, the effect of flaking off the deposits due to the lateral vibration of the module due to the pressurized air becomes remarkable.

Then, when the backwash water outlet valve 4aV and the communication valve 7V are opened with the backwash water transfer valve 4bV of the backwash water transfer pipe 4 closed, the stock solution chamber in the filter 1 to which pressurized air is pumped The backwash water is pressurized and is forcibly transferred into the backwash water receiving tank 6 through a part of the backwash water transfer pipe 4 and the connecting pipe 7.

When the backwash water in the backwash water receiving tank 6 is transferred to the radioactive waste treatment facility C, first, the water level in the filter 1 is reversed in equilibrium with the water level in the backwash water receiving tank 6. Flush outlet valve
4aV and communication valve 7V are closed, and on-off valve 5a for air supply
Close V, 5bV.

Next, the air supply on-off valve 5cV of the third branch pipe 5c is opened to supply the pressurized air from the air supply source B to the backwash water receiving tank 6, and the connecting valve 7V and the backwash water transfer valve 4bV are connected. Open.

As a result, the backwash water in the backwash water receiving tank 6 is pressurized by the pressurized air and is forcibly transferred to the radioactive waste treatment facility C through the communication pipe 7 and the backwash water transfer pipe 4.

The transfer is completed by repeating the transfer of the backwash water between the filter 1, the backwash water receiving tank 6, and the backwash waste treatment facility C a plurality of times.

Therefore, according to the present embodiment, a filter having a simple structure is provided without providing a natural head between the backwash water receiving tank 6 and the radioactive waste treatment facility C or providing a pump for backwash water transfer. Backwash water from 1 is radioactive waste treatment facility C
Can be forcibly transferred to.

Further, even if the capacity of the backwash water receiving tank 6 is smaller than that of the filter 1, the backwashing water transfer operation from the filter 1 to the backwashing water receiving tank 6 is repeated a plurality of times. The transfer of wash water can be completed.

FIG. 2 shows another embodiment of the present invention. In the embodiment shown in FIG. 1, an overflow pipe is provided in the middle of the air supply pipe 5.
The backwash water receiving tank 6 is connected to the filter 1A by means of 10, and the backwash water receiving tank 6 is connected to the filter 1. The overflow discharge pipe 11 is connected to the overflow pipe 10 at the downstream side of the communication valve 10V interposed in the middle thereof. Are connected.

The overflow pipe 10 connects the pressure-type backwash water receiving tank 6 to the filter 1 to facilitate the transfer of the backwash water from the filter 1 to the backwash water receiving tank 6 and to bubbling inside the filter 1. Thus, when the water level of the backwash water rises above a predetermined water level, the overflow water is discharged through the overflow discharge pipe 11 to a discharge part (not shown).

The present embodiment is suitable for the filter 1A having a built-in filter medium that cannot be pressurized by pressurized air or the like, and the filter medium is backwashed by gravity.

In the present embodiment, when the backwash water in the filter 1A is transferred to the radioactive waste treatment facility C, as shown in FIG.
As shown in FIG. 3, the communication valve 10 and the backwash water outlet valve 4aV from the state in which most of the valves around 1A and the backwash water receiving tank 6 are closed.
The backwash water transfer valve 4bV is opened, and the backwash water in the filter 1 is first transferred into the backwash water receiving tank 6 by gravity.

When the backwash water in the backwash water receiving tank 6 is almost full, the backwash water outlet valve 4aV and the communication valve 10V are closed, and the filter 1
After being isolated by the backwash water receiving tank 6, the air pressure control valve 5V is opened to pressurize the pressurized air to the backwash water receiving tank 6 as shown in FIG.

As a result, the backwash water in the backwash water receiving tank 6 passes through the connecting pipe 7 and the backwash water transfer pipe 4, and the radioactive waste treatment facility C is installed.
Is forcibly transferred to.

By repeating the above-described backwash water transfer operation, most of the backwash water in the filter 1 is sequentially transferred to the radioactive waste treatment facility C.

Therefore, according to this embodiment, the backwash water in the filter 1 can be forcibly transferred to the radioactive waste treatment facility C by the small-volume backwash water receiving tank 6.

〔The invention's effect〕

As described above, the present invention pressure-feeds the backwash water receiving tank that receives the backwash water in the filter, and forcibly transfers the backwash water to the radioactive waste treatment facility. At least it is not necessary to provide a natural head or a pump for transferring backwash water between the backwash water receiving tank and the radioactive waste treatment facility, and the configuration can be simplified.

Also, when backwashing the filter, pressurized air is pumped from the side into the undiluted solution chamber of the filtration chamber through the first air supply pipe, so the filter medium is vibrated laterally to facilitate backwashing of the filter medium. can do. This backwashing effect is remarkable when the filter medium is a medium-fiber membrane module, because this module is suspended inside the filter body, and the effect of removing the adhering powder due to its lateral vibration is remarkable.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a main part piping system diagram of an embodiment of the filtration device according to the present invention, and FIG. 2 is a main part piping system diagram of another embodiment of the present invention.
FIG. 3 is a main part piping system diagram showing a state in which the backwash water in the filter is transferred to the backwash water receiving tank in the embodiment shown in FIG. 2, and FIG. 4 is the embodiment shown in FIG. It is a principal part piping system figure which shows the state which forcibly transfers the backwash water in a backwash water receiving tank to a radioactive waste processing facility. 1,1A ... Filtration device, 2 ... Inlet piping, 2V ... Inlet valve, 3
...... Outlet pipe, 3V …… Outlet valve, 4 …… Backwash water transfer pipe,
4aV …… Backwash water outlet valve, 4bV …… Backwash water transfer valve, 5 …… Air supply pipe, 6 …… Backwash water receiving tank, 7 …… Communication pipe, 0 …… Overflow piping, 10V …… Communication valve , A ... source of undiluted solution, B ...
… Air source, C… Radioactive waste treatment facility.

Claims (1)

[Claims] 1. A filter comprising a stock solution chamber containing a radioactive liquid, a filter medium for filtering the radioactive liquid, and a water purifying chamber containing purified water filtered by the filter medium is constructed so as to be backwashable. In the filtering device, the backwash water receiving tank for receiving the backwash water obtained by backwashing the filter material, the air supply source, and the first air supply source communicating with the side wall of the stock solution chamber of the filtration device.
And a second air supply pipe for connecting the air supply source to the water purification chamber of the filtration device and a third air supply pipe for connecting the air supply source to the backwash water receiving tank. And a filtration device.