JPS6236730B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic separator that collects magnetic particles dispersed and suspended in a fluid such as a liquid or gas.

Conventional filters for collecting magnetic particles dispersed and suspended in liquids, gases, or pipe steam include filter cloth, metal nets with small holes, thin wires, sintered metals with small holes, etc. In most cases, magnetic particles are mechanically removed using a filter having a structure with very small hole diameters. However, in order to remove minute magnetic particles using such mechanical methods, it is necessary to make the hole diameter of the filter cloth, metal mesh, sintered metal, etc. extremely small, and when using a thin wire, the diameter of the hole must be made extremely small. It is necessary to pack extremely densely. With this type of filter structure, the filter becomes clogged in a short period of time, so the filter has to be washed or replaced frequently, and even if the filter is washed, the mesh is too fine and the washing is insufficient. It is often difficult to do so, and the filter may have to be discarded after each use, which is very uneconomical. Furthermore, because the filter is too fine, the pressure loss of the fluid becomes large, and it is often impossible to use the filter. In addition to such mechanical filters, various filter structures have been used to collect magnetic particles using magnetic force, such as drum-type separators with built-in permanent magnets, and filters that collect magnetic particles using magnetic force. There are filters that use electromagnets to apply a magnetic field to a filter that is densely packed with thin stainless steel wires. The drum type uses the magnetic field and magnetic field gradient generated near the outer circumferential surface of the drum by built-in permanent magnets, etc., but the magnetic field gradient and magnetic field are small, so it is effective for capturing fine magnetic particles. Although it has some collection effect when it is difficult to collect and the flow velocity of the fluid is very low, it cannot be applied to collect magnetic particles in gases or pipes. In addition, the structure of filters densely packed with fine wires such as stainless steel has recently been attracting attention in various fields, but most of them utilize electromagnets.
The drawback is that power consumption is large and the device is also large. When increasing the size of the filter structure in order to increase the throughput, it is necessary to widen the spacing between the two poles of the electromagnet, and in order to obtain a large magnetic field with the spacing widened, power consumption increases, which is uneconomical. On the other hand, even when using a permanent magnet, if the two magnetic pole faces are close to each other, the stainless steel placed between them may become magnetized and be able to collect magnetic particles, but the generated magnetic field is small and the collection ability is inferior to that using an electromagnet. Furthermore, as the distance between the two magnetic pole faces increases, the magnetic field in the middle portion of the magnetic poles becomes significantly smaller, making it difficult to effectively separate the magnetic particles.

The purpose of the present invention is to have a simple structure, which can be sufficiently used even with permanent magnets, which causes less pressure loss than conventional mechanical filters such as sintered metal filters, which can be used continuously for long periods of time, which has low power consumption, and which has magnetic properties. An object of the present invention is to provide a magnetic separator having a structure with extremely high particle collection efficiency.

The magnetic separator according to the present invention has a structure in which liquid or gas containing magnetic fine particles collides with a plurality of simply shaped baffle plates and then passes through a ferromagnetic net. On the other hand, a magnetic separator is constructed by applying a magnetic field from outside of this element. This element is usually housed in a non-magnetic container. When a liquid or gas containing magnetic fine particles enters a magnetic separator with such a structure, it collides with a baffle plate placed in a magnetic field and the particles repeatedly collide with each other. The magnetic aggregation of the particles is promoted, and the aggregation of the particles progresses ten times faster than when the magnetic field does not act only with a baffle plate. When these particles then pass through a fine wire network made of magnetic material such as stainless steel (SUS410), they are easily captured magnetically even in a low magnetic field from a permanent magnet. With this structure, even if a permanent magnet (magnetic field of about 3000G) is used, the electromagnet's 10000G
Magnetic separation with performance comparable to the collection efficiency achieved by the thin wire placed in the magnetic field described above can be obtained. At the same time, the filling rate of thin ferromagnetic wires can be as low as a few percent, so pressure loss is less likely to occur. Next, the present invention will be explained in detail by way of examples based on the drawings.

Example 1 In FIG. 1, a liquid containing magnetic particles (in the experiment, fine particles of magnetite (average particle diameter approximately 0.3 μm) flows in from the inlet 2 of a non-magnetic container 1 (the flow of the liquid is indicated by line 3). As a result, the liquid collides with a plurality of baffle plates 4 having surfaces almost perpendicular to the flow of the liquid, the flow is disturbed, and at the same time, the contained magnetic particles collide with each other and coagulate. Since a magnetic field of approximately 3000 G is applied (using the magnetic field), the magnetic particles significantly agglomerate together. Next, along the flow, ferromagnetic thin wire (stainless steel SUS4100.1mmφ)
It passes through a fixed bed 6 of a mesh (filling rate about 5%) and exits at an exit 7.
It exits as flow 8. Using a magnetic separator with this structure, dispersed magnetite (Fe ₃ O ₄ ) particles (average particle diameter approximately 0.3 μm - amount of magnetite contained 250
mg/) was passed through at a flow rate of 50/Hr. As a result, 0.5mg/magnetite leaked out. A liquid with the same properties as the stock solution used in this example was used.
Approximately 5% of 0.1mmφ stainless steel (SUS410)
When the liquid is poured at a flow rate of 50/Hr through a magnetic separator filled with a magnetic field of 11000G (Gauss) using an electromagnet, the amount of magnetite flowing out in the passing liquid is approximately 0.65mg/Hr.
Therefore, the structure of this example can achieve the same collection efficiency.
This was achieved using a magnetic field as low as 3000G (Gauss). Also, compared to sintered metal with an average hole diameter of about 10 μm, the magnetic separator of this example lasted 130 hours, and the sintered metal filter
After 15 minutes, a pressure loss occurred and the liquid volume decreased rapidly.

Example 2 The difference from Example 1 is that the angle of the baffle plate and the liquid containing magnetic particles are in the lower part of the container in Example 1, whereas in Example 2 it is in the upper part of the container. In FIG. 2, a liquid containing fine magnetite particles (average particle size of about 0.3 μm) flows in from the inlet 12 of a non-magnetic container 11 (the flow of the liquid is shown by a line 13), causing the liquid to increase its flow rate. After passing through six pairs of baffle plates 14 arranged at such an angle, the particles gradually collide and aggregate, and the aggregation is further promoted by the influence of the magnetic field (generated by the magnet 15) to form a large floc. The magnetic particles that have become flocs flow together with the ferromagnetic material with a small diameter of 16 (stainless steel).
When passing through the SUS410, 0.1 mφ fine wire) net, it is magnetically collected, and the clean liquid exits as a flow 18 through the outlet section 17. Now, using a magnetic separator with this structure, a liquid containing dispersed magnetite (Fe ₃ O ₄ ) particles (average particle diameter of approximately 0.3 μm - amount of magnetite contained: 250 mg/hr) was flowed at a rate of 50/hr. the result
The outflow of 0.35mg/magnetite resulted. A solution with the same properties as the stock solution used in this Example 2 was added at 0.1
About 5% of mmφ stainless steel (SUS410)
When the liquid is filled at a flow rate of 50/hr through a magnetic separator to which a magnetic field of 13,000 G (Gauss) is applied using an electromagnet, the amount of magnetite released in the passing liquid is approximately 0.3 mg/hr. 0.35 as above at 3000G (Gauss) low magnetic field with permanent magnet
mg/, making it clear that this structure is superior. Furthermore, compared to the sintered metal with an average hole diameter of about 10 μm, the magnetic separator of this example caused a pressure loss in about 182 hours, and the sintered metal filter caused a pressure loss in about 15 minutes, causing a rapid decrease in liquid volume.

Compared to Examples 1 and 2, it was clear that the present magnetic separator was superior even when air containing about 100 mg/magnetite was flowed. Further, the shape and size of the baffle plate may be any shape depending on the amount of liquid, the amount of magnetic material contained, etc.

[Brief explanation of the drawing]

1 and 2 are sectional views, respectively, showing a magnetic separator according to the present invention. 1, 11... Container of non-magnetic material, 2, 12... Inlet part, 3, 13... Flow, 4, 14... Baffle plate,
5, 15... magnet, 6, 16... ferromagnetic thin wire mesh, 7, 17... outlet, 8, 18... flow from the outlet.

Claims (1)

[Claims] 1 In the flow direction of the fluid containing magnetic particles,
A magnetic separator comprising means for disturbing the flow path of the fluid and an adsorption section made of a magnetic material.