JPS6156008B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electromagnetic filter that removes suspended solids containing magnetic substances by excitation of a magnetic filter medium.

2. Description of the Related Art Electromagnetic filters are used as means for capturing turbidity containing magnetic substances in water for thermal power generation, nuclear power generation, condensate treatment, steel wastewater treatment, and the like. FIG. 1 is a vertical sectional view showing a conventional electromagnetic filter, in which 1 is a cylindrical container in which a packed layer 2 made of powder or granular magnetic filter material is formed on a porous support plate 3; An excitation coil 4 is placed outside so as to be surrounded by a magnetic shielding plate 5.

In the electromagnetic filter configured as described above, while the excitation coil 4 is energized and the packed bed 2 is excited, water is passed through the raw water pipe 6 and suspended solids containing magnetic substances are filtered in the packed bed 2. , the treated water is obtained from the treated water pipe 7. When the packed bed 2 is clogged, the packed bed 2 is demagnetized, backwash water is sent from the backwash water pipe 8, the packed bed 2 is developed and backwashed, and the backwash waste water is discharged from the drain pipe 9.

By the way, in the conventional electromagnetic filter, in order to uniformly distribute the magnetic flux in the filling layer 2, a magnetic shielding plate 5 made of a magnetic material is provided, and the end portion of the magnetic shielding plate 5 is connected to the filling layer 2.
However, in the packed layer 2, the lines of magnetic force are distributed in an arc centered on the excitation coil 4, so the magnetic flux density at the center is small in the upper and lower parts of the packed layer 2. Become. Therefore, in order to maintain the magnetic flux density necessary for capturing suspended solids even in the center of the packed bed 2, it is necessary to increase the height of the packed bed 2 and the excitation coil 4.
There was a problem of high equipment costs.

This invention is intended to solve the problems of the conventional ones.By providing magnetic pole pieces on the upper and lower parts of the filling layer, magnetic flux can be uniformly distributed even if the height of the filling layer and excitation coil is reduced. The purpose of the present invention is to provide an electromagnetic filter that can distribute the energy.

This invention includes a packed layer of granular or powdered magnetic filter media formed inside a container, an excitation coil placed outside the container to excite this packed layer,
magnetic pole pieces disposed above and below the packed layer, at least the upper magnetic pole piece and a developing section in which the magnetic filter medium can be expanded inside the container above the upper magnetic pole piece extend radially from the center side. A filter medium having a wheel shape having an extending radial part and an annular part connecting the radial parts, having a small aperture ratio on the center side and a large aperture ratio on the peripheral side, and having an overall aperture ratio when backwashing the packed bed. This is an electromagnetic filter characterized by an aperture ratio of 30 to 90% to allow the development of.

The present invention will be explained below with reference to illustrated embodiments.
FIG. 2 is a vertical sectional view showing an electromagnetic filter according to an embodiment of the present invention, and the same reference numerals as in FIG. 1 indicate the same or corresponding parts.

The electromagnetic filter of this embodiment basically has almost the same structure as the one in FIG.
An upper magnetic pole piece 10 is placed on top of the filling layer 2.
A lower magnetic pole piece 11 is arranged below the support plate 3. The ends of the magnetic shielding plate 5 made of a magnetic material are provided so as to face these magnetic pole pieces 10 and 11. Inside the container 1 above the upper magnetic pole piece 10, a developing section 12 is formed in which a magnetic filter material constituting the packed layer 2 can be expanded.

FIG. 3 is a plan view showing the upper magnetic pole piece 10,
The upper magnetic pole piece 10 is made of a magnetic material, and is formed into a wheel shape by a plate-like body having a constant height and having a radial part 10a extending radially from the center side and an annular part 10b connecting the radial part 10a. The aperture ratio is small, and the aperture ratio on the peripheral side is large. The overall aperture ratio is set to 30 to 90% to allow expansion of the filter medium during backwashing of the packed bed 2. The larger the aperture ratio is, the easier it is to expand the filter medium, but if it is too large, the magnetic flux cannot be made uniform, so it is desirable to keep it within the above range. It is desirable that the plate-like body 10a has a thickness of 1 to 10 cm and a height of 10 to 15 cm.

FIG. 4 is a vertical cross-sectional view showing the support plate 3 and the lower pole piece 11, which are in a superposed state with the filling layer 2.
is located at the bottom of the. FIG. 5 is a perspective view of the support plate 3, and FIG. 6 is a perspective view with a part of the front cut away. It has a structure. This support plate 3 is not limited to the structure described above, but may be made of a porous material having another structure as long as it has a structure that allows water to pass through but does not allow the passage of the magnetic filter medium forming the packed layer 2. may have been done.

FIG. 7 is a plan view of the lower magnetic pole piece 11. The lower magnetic pole piece 11 has a perforated plate structure in which an opening 11b is formed in a plate-like member 11a of a constant thickness made of a magnetic material, and the opening ratio is 2 to 20%. It is said that If this opening ratio is small, the water rectification effect will be good, but if it is too small, the pressure loss will be high and it will be inappropriate. The thickness of the plate-like body 11a is preferably 5 to 20 cm.

The upper magnetic pole piece 10 is limited to the above structure because it is necessary to allow the expansion of the filter medium and to average the magnetic field line distribution, but the lower magnetic pole piece 11 is not limited to the above structure because it does not need this, and the magnetic pole material part It is sufficient if the structure has a uniform distribution of openings, such as wheel-shaped,
It can be a grid, perforated plate or other similar structure.

The packed bed 2 is formed by filling a magnetic filter medium in the same manner as in the prior art, but the bed height is preferably 20 cm to 1 m. The magnetic filter medium can be in the form of granules or powder, and its shape can be spherical, ellipsoidal, cut from wire, or other shapes.

The method of operating the electromagnetic filter constructed as described above is almost the same as that shown in FIG. in this case,
When the excitation coil 4 is energized, the magnetic flux passes through the magnetic shielding plate 5
The magnetic field passes through the upper and lower pole pieces 10, 11 uniformly. Generally, magnetic lines of force are dense on the excitation coil 4 side and sparse on the center side, but in the wheel-shaped upper magnetic pole piece 10 as shown in Fig. 3, the aperture ratio on the center side is small, so the distribution of magnetic lines of force on the center side is high. . Therefore, the magnetic flux distribution passing through the packed layer 2 is approximately averaged, and the passing direction is linear.

According to experimental results, the magnetic flux density at the center of the filled layer 2 when the magnetic pole pieces 10 and 11 are provided is 2 to 4 times that when no magnetic pole pieces are provided, and the change due to the height of the filled layer 2 is There was almost no change in the radial direction, and the inside of the packed bed 2 had the same magnetic flux density as a whole.

In this way, the entire packed bed 2 is magnetized uniformly, so when the raw water is poured from the raw water pipe 6 to remove the magnetic suspended matter, the entire packed bed 2 captures the magnetic suspended matter. Therefore, even if the height of the packed bed 2 is lowered, the suspended matter removal rate becomes higher. By lowering the height of the packed bed 2, the height of the excitation coil 4 can be lowered, reducing equipment costs, reducing power consumption, and reducing pressure loss during water flow, reducing operating costs. can also be lowered.

Backwashing when the packed bed 2 becomes clogged can be done in the same way as in the case shown in Fig. 1. At this time, the filter medium is
It is developed into the development section 12 through the opening of 0 and cleaned. In this case, since the upper magnetic pole piece has a wheel shape with the above structure, the aperture ratio is set to 30
~90%, which allows for complete expansion of the filter medium and efficient cleaning.

As described above, according to the present invention, the magnetic pole pieces are arranged above and below the packed layer, and at least the upper magnetic pole piece is formed into a wheel shape having a radial part and an annular part, so that the aperture ratio on the center side is small and the aperture ratio on the peripheral side is small. Increase the
In addition, since the overall aperture ratio is 30 to 90%, the magnetic flux density passing through the filled layer can be made uniform, so even if the height of the filled layer is low, the entire filled layer can be magnetized uniformly. Magnetization efficiency can be increased, and magnetic turbidity can be captured more efficiently. It is also possible to backwash the filter medium, and by lowering the layer height, pressure loss can also be reduced.

[Brief explanation of the drawing]

FIG. 1 is a vertical sectional view showing a conventional electromagnetic filter, FIG. 2 is a vertical sectional view showing an electromagnetic filter according to an embodiment of the present invention, FIG. 3 is a plan view showing an example of an upper magnetic pole piece, and FIG. 4 5 is a perspective view of the support plate, FIG. 6 is a perspective view of a portion of the support plate with its front cut away, and FIG. 7 is a plan view of the bottom pole piece. . In each figure, the same reference numerals indicate the same or equivalent parts, 1 is a container, 2 is a filling layer, 3 is a support plate, 4 is an exciting coil, 5 is a magnetic shielding plate, 10 is an upper magnetic pole piece,
11 is a lower magnetic pole piece.

Claims (1)

[Claims] 1. A packed layer of granular or powdered magnetic filter medium formed inside a container, an excitation coil placed outside the container to excite this packed layer, and an upper part of the packed layer. and a magnetic pole piece disposed at the lower part, and an expanding part in which the magnetic filter medium can be expanded inside the container above the upper magnetic pole piece, and at least the upper magnetic pole piece has a radial part extending radially from the center side and a radial part extending radially from the center side. It is wheel-shaped with an annular part connecting radial parts, and has a small aperture ratio on the center side and a large aperture ratio on the peripheral side, and has an overall aperture ratio that allows expansion of the filter medium during backwashing of the packed bed. An electromagnetic filter characterized by an aperture ratio of 30 to 90%. 2. The electromagnetic filter according to claim 1, wherein the lower magnetic pole piece is a perforated plate. 3. Claim 1 or 2 comprising a magnetic shielding plate having ends facing the upper and lower magnetic pole pieces and arranged so as to surround the excitation coil.
Electromagnetic filter described in section. 4. The electromagnetic filter according to any one of claims 1 to 3, wherein the filling layer is formed on a porous support plate.