JPS5938819B2 - Magnetic powder separation device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for separating magnetic particles or particles containing magnetic particles from a fluid such as cooling water.

The following explanation takes as an example the radioactive cloud contained in the primary and secondary cooling water of a nuclear power plant (CRUD=CANADIAN R
This paper describes the case where the powder (abbreviation of EACTORUNKNOWNDEPO8IT) is separated into particles.

The cooling water of nuclear reactor plants contains magnetite (Fe3O4) and magnetite (γ-F e 203 ) generated from iron materials such as containers, fuel rods, and pipes.
"'" Tight (Hemate; a-Fe20
Contains cloud powder particles (iron rust) composed of 3), etc.
Same as cooling water circulation (flowing).

When a plant is operated for a long period of time, these cloud particles become enormous in quantity, and they are radioactive, resulting in an extremely high amount of radiation in the air.

Therefore, the removal of these cloud particles during periodic or repair work requires the labor of many people, that is, by human-force tactics, and is ignored in nuclear reactor plants that have only recently been in operation.

However, as mentioned above, cloud powder particles have extremely high radioactivity, which poses major safety problems such as exposure of workers to radiation.

The present invention solves the above-mentioned problem and effectively removes cloud particles, by connecting a separation pipe extending downstream to a pipe that guides a fluid, and magnetically attaching a magnetic material around the pipe located upstream of a branch point. A magnet for magnetizing powder particles is installed, and an AC traveling magnetic field is generated by a two-layer full-section coil connected to a three-phase AC power source around the piping and separation tube from the downstream end of the magnet to the starting end of the separation tube via multiple branch points. The present invention is characterized by a traveling magnetic field generating device that generates .

The present invention will be described in detail below based on the drawings.

A bypass pipe 2 is provided in the main stream 1 of the reactor primary or secondary cooling water system, and a separation pipe 3 is provided in the bypass pipe 2.
Valves 4 and 5 are provided in the main flow 1 and the bypass pipe 2 downstream from the branch point of the bypass pipe 2.

The bypass pipe 2 and the separation pipe 3 are each made of a non-magnetic material, and a DC electromagnet 7 (or a permanent magnet) is arranged around the bypass pipe 2 upstream of the branch point 6 of the bypass pipe 2 and the separation pipe 30.

An AC traveling magnetic field generator 8 is disposed around the bypass pipe 2 and the separation pipe 3 that extend from the downstream side of the electromagnet 7 through the branch point 3 to the starting end of the separation pipe 3. Phase matching and energization are performed to generate an alternating current magnetic field 9 that advances from 2 to the downstream direction of the separation tube 3.

A DC electromagnet 10 (or permanent magnet) is disposed in the separation tube 3 downstream of the magnetic field generator 8, and a cloud containment vessel 11 for shielding radiation is installed at the end of the separation tube 3.

Next, the operation of the above embodiment will be explained.

Valve 4 is closed and valve 5 is opened to circulate furnace cooling water through bypass pipe 2.

The DC electromagnet 7, the magnetic field generator 8, and the DC electromagnet 10 are energized and excited.

Cloud powder particles 12 floating in cooling water are magnetized by a DC electromagnet 7, and a magnetic field flow 9 is generated by a magnetic field generator 8.
Accordingly, the cloud particles 12 are separated into the separation tube 3.

Since the end of the separation pipe 3 is closed by the containment vessel 11, the cooling water flows through the bypass pipe 2 and joins the main stream 1.

The separated cloud powder particles 12 fall and settle due to their own weight, are magnetically reliably collected by a DC electromagnet 10, and stored in a containment vessel 11.

At this time, by moving the DC electromagnet 10 up and down, the sedimentation speed can be accelerated and the collection efficiency can be increased.

FIG. 3 shows another embodiment in which a bypass pipe 2 and a separation pipe 3 are directly connected and arranged, and a separation pipe 3 equipped with a valve in the main stream 1 can be used even without providing a bypass pipe. A direct current magnet 7.10 and a magnetic field generator 8 may be provided in communication with each other in the same manner as described above.

A magnetic field generating device 8 used in the above embodiment is shown in FIG.

A coil 15 is wound in two layers on a U-shaped magnetic core 14 made of cut air, etc., and a three-phase AC source is connected to the terminals 11U, 111v and 11w as shown in the figure, so that the AC traveling magnetic field advances in the direction of the arrow 13. This is what I did.

Here, with reference to FIG. 5, the effect when the coil 15 is energized to generate an alternating current traveling magnetic field will be described.

First, when the terminal 11U is energized, the poles a, b, and e.

d is magnetized and a magnetic field is generated, and then when the terminal 11v is energized, the poles c, d, and e are magnetized and the magnetic field moves by one pole.

As a result, the energized position sequentially moves in circulation and the magnetic field advances.

Here, when the energization position changes and the magnetic field moves, the magnetic fields before and after the movement mostly overlap, making it possible to maintain a uniform magnetic density and magnetic field gradient without interruption of the magnetic field. The cloud powder particles 12 can be effectively placed on the magnetic field and transported.

Furthermore, the transfer effect of the magnetic field generating device 8 using such a two-layer full-pitch coil will become clearer when compared with the magnetic field generating device using a unipolar coil (see FIG. 6) described below.

In the case of a single-pole wound coil, each coil having terminals U, V, W is wound around poles a, b, and c, respectively, and when the energization position changes, the magnetized pole changes from pole a to pole b, for example. , the magnetic field also moves from the pole to C.

In this case, the magnetic fields move in a step-like manner without overlapping, so that interruptions occur in the magnetic fields.

Therefore, if the speed at which the cloud powder particles 12 move and the movement of the magnetic field do not match, a situation may occur in which the cloud powder particles 12 only move in the same position and do not move.

Therefore, in order to effectively move the cloud, it is necessary to energize the coil using a frequency that matches the moving speed of the cloud, and commercial power sources of 50 Hz and 60 Hz cannot be used.

Furthermore, when there is a change in the flow state of the cloud particles, it is not always possible to generate and move the magnetic field in an optimal state.

Although the present invention has been described above for the separation of cloud particles suspended in the cooling water of a nuclear reactor plant, it goes without saying that the present invention can also be applied to the separation of iron powder, etc. contained in a lubricating oil system.

Since the present invention has the above-described configuration, (1) unlike separation and sampling in filters, etc., it is possible to effectively and continuously automatically separate and collect magnetic powder particles without increasing flow path resistance; 1i) GiD can reduce maintenance work such as filter replacement because it does not get clogged.
Extremely fine magnetic powder particles can be separated and collected. +IV) Since only the magnetic powder particles can be separated from the fluid flow and collected, it is not necessary to stop the operation of the main unit when carrying out the collected magnetic powder particles. No. Furthermore, if the present invention is implemented in a nuclear reactor plant, M radioactive materials can be concentrated and safety will be improved. 6/i)
Radioactive materials can be collected in a separate containment container, making post-processing easier, and other excellent effects can be achieved.

[Brief explanation of the drawing]

Fig. 1 is a layout diagram of an embodiment of the present invention in a nuclear reactor plant, Fig. 2 is a sectional view of the embodiment, Fig. 3 is a sectional view of another embodiment, and Fig. 4 is an explanatory diagram of a magnetic field generator. , FIG. 5 is an explanatory diagram of a magnetic field generating device in which a coil is wound in two layers at full pitch, and FIG. 6 is an explanatory diagram of a magnetic field generating device in which a coil is wound in a single pole. 2 is a bypass pipe, 3 is a separation pipe, 7 and 10 are DC electromagnets,
8 indicates a magnetic field generator.

Claims (1)

[Claims] 1. A separation pipe extending downstream is connected to a pipe leading to a fluid, and a magnet for magnetizing powder particles is provided around the pipe located upstream of a branch point, and a magnet for magnetizing powder particles is provided around the pipe located on the upstream side of a branch point. A traveling magnetic field generating device that generates an AC traveling magnetic field by a two-phase full-pitch coil connected to a three-phase AC power supply is installed around the piping and the separating pipe that reach the starting end of the separating pipe via a branch point. Magnetic powder separation device. 2. A separation pipe extending in the downstream direction is connected to the pipe leading to the fluid, and a magnet for magnetizing powder is installed around the pipe located upstream of the branch point, and the separation pipe is connected from the downstream end of the magnet through the branch point. A traveling magnetic field generator that generates an AC traveling magnetic field by a two-layer full-pitch coil connected to a three-phase AC power supply is installed around the piping and separation pipe leading to the starting end, and is located downstream of the magnetic field generator. A magnetic powder separation device characterized in that the separation tube is provided with a magnet for collecting magnetic powder.