JPS6243724B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is an electromagnetic filter for the purpose of removing crud in high-temperature, high-pressure water systems in thermal power plants, nuclear power plants, etc., and in particular, is filled with ferromagnetic steel wool as a matrix, thereby reducing high gradients. The present invention relates to a cleaning process for a so-called high gradient electromagnetic filter that generates a magnetic field.

More specifically, the present invention mainly applies to temperatures of 130°C.
The above describes an improved cleaning method and cleaning device for electromagnetic filters that pass high-temperature, high-pressure water with a pressure of 3 kg/cm ² or more.

Generally, an electromagnetic filter is equipped with a matrix and an electromagnetic coil that magnetizes the matrix, and performs an overstep in which suspended particles (cruds) of ferromagnetic and weakly magnetic substances in a fluid are captured by the matrix using magnetic force, and then separated and removed. However, if overcontinuation causes crud to accumulate in the matrix and the differential pressure increases, or if the overwater quality deteriorates due to overfunction, it is necessary to stop the overflow and clean the matrix. No. For this cleaning, there is a cleaning method in which high-temperature, high-pressure water is flushed in the opposite direction using its own energy without using an external cleaning source.

That is, on the outflow side of the matrix of the electromagnetic filter, there is provided a space at least equal to or larger than the volume of the matrix, preferably 2 to 5 times the volume, and on the other hand, a wash drain valve is provided in the flush passage on the inflow side of the matrix, so that the space is filled with excess water. By keeping the high-temperature, high-pressure water in a sealed state and opening the cleaning drain valve to reduce the pressure inside the flush tank, the pressure of the high-temperature, high-pressure water is reduced and a part of it evaporates, and the water in the space is evaporated by volume expansion. rapidly circulate within the matrix,
This is a cleaning method that uses the shearing force to peel off and remove the crud adhering to the steel wool.

However, the self-energy of the high-temperature, high-pressure water in the overwater outflow space is too high, and if flushing is continued as is, thermal stress will occur in the flush drain piping and flush tank in addition to stress due to pressure, and the amount of steam generated will be may become large and cause damage to the piping and flush tank.
This requires thick piping and a large-capacity flush tank, which is not practical and economically disadvantageous.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method and apparatus for cleaning a high-gradient electromagnetic filter that uses the self-energy of such high-temperature, high-pressure water to safely and economically clean a matrix.

The method for cleaning an electromagnetic filter of the present invention is that when cleaning a high-gradient electromagnetic filter that magnetizes a matrix and passes high-temperature, high-pressure water, the high-temperature, high-pressure water held in the space on the outflow side of the matrix is heated to a temperature corresponding to the saturation temperature. It is characterized in that after the pressure is reduced to near the pressure, the matrix is flushed to the inflow side.

An embodiment of the present invention will be described with reference to the drawings. In FIG.
is held by the pole piece 3, and spaces 4 are provided on the inflow side of the water to be treated and the outflow side of the excess water.
and a space 5 are defined. A perforated plate or the like is used for the pole piece 3, but the pole piece 3 is made of a matrix 2 made of steel wool or the like.
At the same time, it serves as a uniform distribution of water flow. The exterior of the matrix 2 is surrounded by an electromagnetic coil 6, and when a direct current flows through the electromagnetic coil 6, the matrix 2 is magnetized, and magnetic flux lines converge on the sharp portions of the steel wool. The structure is such that high gradients occur. Furthermore, the space 5 on the outflow side of the matrix has a volume that is at least more than the volume of the matrix 2, preferably two to three times as large. Note that 7 is a return frame for preventing the magnetic lines of force generated from the electromagnetic coil 6 from spreading.

Furthermore, in the space 4, an inflow pipe a of the water to be treated is provided.
and a flush pipe c are connected to the space 5, and an overwater outflow pipe b is connected to the space 5, respectively. In addition,
11 is an inflow valve, 12 is an outflow valve, 13 is a pressure reduction valve,
14 is a quick-opening valve (flash valve), and in this case, the pressure reducing valve 13 needs to be provided upstream of the quick-opening valve 14.

However, in the over-process, the high-pressure heater drain (temperature 189℃, pressure
17.6Kg/cm ² ) passes through the inflow valve 11 to the canister 1.
During its passage through the matrix 2, the crud is removed and the excess water returns to the system from the space 5 via the outflow valve 12. If this overflow continues, crud will accumulate in the matrix 2 and the differential pressure will increase, or the overwater quality will deteriorate due to overfunctioning, so when these are detected, the overflow is interrupted and the cleaning step is started.

When entering this cleaning process, first the pressure reducing valve 13
The pressure inside the pipe between the quick-open valve 14 and the quick-open valve 14 is kept at atmospheric pressure, and cleaning is performed in the following procedure.

(1) Close the inflow valve 11 and outflow valve 12.

(2) Cut off the current to the electromagnetic coil 6. (3) Open the pressure reducing valve 13. With this operation,
The high-temperature, high-pressure water in the space 5 is reduced to a pressure close to the saturation pressure.

(4) Quickly open the quick-open valve 14. With this operation,
The water in the space 5 rapidly flows down within the matrix 2, and the shearing force thereof effectively peels off and removes the crud adhering to the steel wool.

(5) After closing the pressure reducing valve 13, close the quick-opening valve 14 to bring the pressure inside the pipe between these two valves to atmospheric pressure.

(6) Energize the electromagnetic coil 6.

(7) Open the inflow valve 11 and then open the outflow valve 12 to restart the overstep process.

Here, a supplementary explanation of the above operation is that the temperature
The saturated (steam) pressure of high temperature water at 189℃ is approximately 12.7Kg
/cm ² , so in the operation (3) above, the pressure reducing valve 13 should be fully opened slowly for about 30 to 60 seconds to reduce the pressure to about 13 kg/cm ² . Next, the quick-open valve 14 may be opened fully in 1 to 5 seconds, preferably 2 to 3 seconds.

In this embodiment, a pressure reducing valve 13 and a quick opening valve 1 are used.
4 are arranged in series via piping, and this piping section is for obtaining the volume necessary to reduce the pressure of high temperature and high pressure water in space 5 to a pressure close to the saturation temperature. The internal volume of the pipe is space 5
The inner diameter and length of the pipe (the distance between the two valves) are set taking these into account. It is important to do so.

In the above embodiment, the space inside the pipe is used as the space for the pressure reduction operation, but if desired, a small-capacity container may be branched and connected to the pipe.

To describe an example of a cleaning operation performed using the apparatus shown in Figure 1 above, the temperature was 210°C and the pressure was 58 kg/cm ^2.
In the electromagnetic filter for high-temperature and high-pressure water in the water supply system of a BWR nuclear power plant, the space 5 was
20Kg/cm ² of water (saturation pressure is 19.5Kg/cm ² )
When flushing was carried out under reduced pressure, effective cleaning was achieved.

In addition, in the present invention, "reducing the pressure to a pressure near the saturation temperature" means that the pressure is the same as the saturation temperature, and also includes cases where the pressure is slightly higher or lower than the pressure corresponding to the saturation temperature.

Next, a device according to another embodiment of the present invention will be explained with reference to FIG. 2. In this case, a pressure reducing valve 13 and a quick-opening valve 14 are arranged in parallel in the flash pipe c,
The procedure for the cleaning process is to open the pressure reducing valve 13 and close it after a predetermined period of time after step (2) in the example in Figure 1 above, and then quickly open the quick-open valve 14, or After a period of time has elapsed, flushing is performed by opening the quick-opening valve 14 while keeping it open. After flushing is completed, in either case, the pressure reducing valve 13 and the quick-opening valve 14 are closed and the overstep is restarted.

In the example in Figure 2 above, the example in Figure 1 is a flash piping c.
The pressure reducing operation is performed with the flush pipe c closed, whereas the flushing is performed immediately after the flush pipe c is opened to atmospheric pressure or while it is open, and the pressure reducing valve 13 has a small diameter ( It is necessary to use a pipe with a diameter of 10 to 15 ^A (preferably 10 to 15 A). Especially when flushing is performed with the pipe open, if the diameter is large, the pressure will suddenly decrease and the related piping may be damaged, resulting in a dangerous situation. Therefore, setting the aperture is important. Note that the diameter of the quick-open valve 14 and its connecting piping is preferably about 300 ^A to 400 ^A.

On the other hand, in the example in FIG. 3 and the example in FIG. 4, the pressure reducing valve 13,
This is a case in which an exhaust valve for pressure reduction operation is installed in addition to the quick-open valve 14, and the example in FIG.
3 and an exhaust valve 15 are arranged in series on the downstream side thereof, and the example in FIG. 4 is one in which these are arranged in parallel.

To explain the cleaning operation in the example in Fig. 3, first open the exhaust valve 15 and then close it to bring the pressure inside the connecting pipe between the pressure reducing valve 13 and the exhaust valve 15 to atmospheric pressure (with the pressure reducing valve 13 closed). ), steps (1) to (4) in the example in FIG. 1 may be performed. After flushing is completed, the quick-open valve 14 and the pressure reducing valve 13 are closed, and then the exhaust valve 15 is closed to bring the pressure inside the connecting pipe to atmospheric pressure, and then the steps (6) in the example in Figure 1 are carried out. (7) restarts the overstep process. The cleaning operation in the example shown in FIG. 4 is the same as that in the example shown in FIG. In this case, the downstream piping e of the pressure reducing valve 13
The caliber should be 50 ^A or more.

In this way, the examples in FIGS. 1 and 2 are cases in which a part of the piping connected to the space 4 side is subjected to a cleaning operation at atmospheric pressure, and the examples in FIGS. This is a case where cleaning is performed by setting a part of the piping connected to the side to atmospheric pressure.

In the example shown in FIG. 2 and the example shown in FIG. 4, it is preferable to provide an orifice immediately after the outlet of the pressure reducing valve 13 to adjust the reduced pressure state.

As described above, according to the present invention, it is possible to safely and economically clean the matrix of an electromagnetic filter using an extremely simple device and operation without requiring complicated control, and to maintain the operation of the electromagnetic filter. It simplifies maintenance and management, greatly improves cleaning functionality, and allows for highly safe work.

[Brief explanation of the drawing]

1 to 4 are flow sheets showing each embodiment of the present invention. 1... Canister, 4, 5... Space, 11...
Inflow valve, 12...Outflow valve, 13...Pressure reduction valve, 1
4...Quick opening valve, 15...Exhaust valve, a...Inflow piping, b...Outflow piping, c...Flush piping, d
...Exhaust piping.

Claims (1)

[Claims] 1. In a method of cleaning an electromagnetic filter that passes high-temperature, high-pressure water by magnetizing a matrix, the high-temperature, high-pressure water held in a space on the outflow side of the matrix is depressurized to a pressure near the saturation temperature. A method for cleaning an electromagnetic filter, characterized in that the matrix is then flushed to the inflow side. 2. In an electromagnetic filter that passes high temperature and high pressure water and is equipped with a canister, an electromagnetic coil, and a matrix, a quick-opening valve is provided on the inflow side of the matrix, and a pressure reducing valve is provided on the inflow side or the outflow side of the matrix. An electromagnetic filter cleaning device featuring: 3. The cleaning device according to claim 2, wherein the pressure reducing valve is arranged in series with the quick-opening valve and upstream of the quick-opening valve at appropriate intervals. 4. The cleaning device according to claim 2, wherein the pressure reducing valve has a small diameter of about 10 to 15 ^A , and is arranged in parallel with the quick-opening valve.