JPH06209960A - Magnet for attracting foreign material in stomach - Google Patents

Abstract

PURPOSE:To provide a magnet for attracting a foreign material in a stomach which suppresses the corrosion of a case without deteriorating the attractive force by a cylindrical magnet. CONSTITUTION:A magnet for attracting a foreign material in a stomach is constituted so that a plurality of disc shaped permanent magnets 2 each of which is magnetized in the axial direction are arranged in an integral rod form in the axial direction so that the same poles are opposed, having each yoke 3 interposed, in a case 1 which is formed to a hollow cylindrical form from a corrosionproof nonmagnetic material which consists substantially of Fe containing at most 0.1% C, at most 2.0% Si, at most 3.0% Mn. 10-16% Ni, 15-19% Cr, 0.5-4.0% Mo by weight ratio.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is for adsorbing and removing foreign substances made of magnetic materials such as nails, needles, wires and magnetic powder accumulated by ruminants, especially cows, in the rumen when swallowed with feed. The present invention relates to a magnet for attracting foreign substances in the stomach.

[0002]

2. Description of the Related Art Cows that feed on pasture in pastures are
Since they are typical ruminants, they tend to swallow the feed without chewing during feeding. Therefore, long, sharp metal pieces such as nails, needles, wires, and magnetic powder that are mixed in the feed, which is grass, or are falling on the pasture, etc., are also ingested together with the feed or grass and gather in the rumen. As a result of exercise, the metal piece punctures the stomach wall, resulting in various diseases including gastritis or digestive disorders, and in extreme cases, perforation of the stomach wall or suppuration of the stomach wall may lead to a fatal accident.

In order to prevent the above-mentioned accidents, metal foreign substances, particularly steel pieces, are detected from the feed conventionally administered to cattle, and the feed is controlled by a sorting device, and the metal foreign substances are detected on the pasture. , Is being maintained. However, despite the above-mentioned management and maintenance, cattle death accidents often occur as a result of the inclusion of foreign matter in the feed. For this reason, conventionally, a means for retaining a rod-shaped permanent magnet in the rumen of a cow, adsorbing a foreign substance of a magnetic material that was mistakenly ingested, and preventing the stomach wall from being punctured and damaged by a sharp magnetic metal piece is adopted. ing.

As the gastric foreign matter adsorbing magnet used for the above-mentioned processing, disk-shaped magnets having magnetic poles of different polarities on both end surfaces are alternately inverted and magnetic plates are provided between the magnets. Proposals have been made of a magnet for adsorbing a foreign substance in the stomach provided and coaxially coupled (for example, Japanese Utility Model Publication Nos. 57-53550, 57-128817 and 57-165117,
No. 60-61703, Japanese Utility Model Laid-Open No. 3-101920, etc.). As an example, the structure of the gastric foreign matter adsorption magnet disclosed in Japanese Utility Model Laid-Open No. 3-101920 will be described with reference to FIG. In FIG. 1, a corrosion resistant non-magnetic material (SUS304)
A plurality of permanent magnets (rare earth / iron / boron-based magnets) 2 formed in a disk shape in a case 1 formed in a hollow cylindrical shape by providing different magnetic poles on both end surfaces, and a yoke 3
It has a structure in which magnetic poles of the same polarity are arranged so as to face each other with the magnetic poles sandwiched therebetween, and a lid 4 made of a corrosion-resistant non-magnetic material is arranged at both ends of the case. With such a structure, since a plurality of magnetic poles are formed not only at both ends but also in the middle part, even in the case of an elongated magnetic metal piece, the longitudinal direction is approximately parallel to the axis in the middle part of the attraction magnet. As a result of being adsorbed in the same direction, it is expected that the effect of puncturing the stomach wall is reduced.

[0005]

The magnet for attracting foreign substances in the stomach is retained in the stomach for a predetermined period of time. However, for the convenience of breeding, it is desirable that the period of retention is long. From this point of view, SU which is austenitic stainless steel is conventionally used as a case for accommodating and holding a disk-shaped magnet.
S304 was used exclusively. However, SUS304
It was found that even if the magnet for adsorbing foreign substances in the stomach used in the case was left in the stomach for about one year, it was severely corroded by the gastric juice of cattle, and in some cases the disk-shaped permanent magnet was exposed. It was When this corrosion progresses, the magnet itself is also corroded and the attractive force is reduced. In order to prevent the progress of corrosion, it is conceivable to increase the thickness of the case, but it is difficult to use because it reduces the adsorption force of metal pieces. Therefore, it is an object of the present invention to provide a gastric foreign matter adsorption magnet in which corrosion of the case is reduced without reducing the adsorption force of the disc magnet.

[0006]

Means for Solving the Problems The present inventor has conducted various studies on the composition of the case in order to solve the above problems, and has found that Mo exhibits high corrosion resistance to gastric juice of cattle. The present invention has been made based on the above findings, and in a weight ratio, C0.1% or less, Si2.0% or less, Mn3.0% or less, Ni10-16%, Cr15-.
A plurality of disc-shaped permanent magnets magnetized in the axial direction are formed in a hollow cylindrical case made of a corrosion-resistant non-magnetic material consisting of 19%, Mo 0.5 to 4.0% and the balance substantially Fe.
It is a magnet for adsorbing a foreign substance in the stomach, which is arranged integrally in the axial direction in such a manner that the same poles face each other across the yoke.

The reasons for limiting the components of the corrosion-resistant non-magnetic material constituting the case of the gastric foreign matter adsorption magnet of the present invention will be described below. C
Is added for the purpose of improving strength and promoting austenitization, but if it exceeds 0.1%, carbides produced by C cause intergranular corrosion and deteriorate corrosion resistance. Therefore, 0.1% or less. Si is added for deoxidation, but if it exceeds 2.0%, many oxide-based non-metallic inclusions are formed. Therefore, it is set to 2.0% or less.
Mn is added as a deoxidizing, desulfurizing, and austenitizing element, but even if added over 3.0%, its effect is saturated. Therefore, it is 3.0% or less. Ni is
In austenitic stainless steel, it is an austenite forming element necessary for maintaining the austenite structure, improving corrosion resistance and preventing stress corrosion cracking. If it is less than 10%, delta ferrite is likely to be formed, while if it exceeds 16%, the above effect cannot be further improved. Therefore, 1
0 to 16%. Cr forms a passive film on the surface of the material to improve corrosion resistance. If the Cr content is less than 15%, the corrosion resistance will be insufficient. If it exceeds 19%, delta ferrite is likely to be formed. Therefore, the Cr amount is 15 to 1
9%. Mo is an element showing excellent corrosion resistance to cattle gastric juice. However, if it is less than 0.5%, the effect of improving the corrosion resistance is not sufficient, while if it exceeds 4.0%, delta ferrite is likely to be formed, so the content is made 0.5 to 4.0%. Next, known permanent magnets such as ferrite magnets, samarium-cobalt magnets, and neodymium-iron-boron magnets can be used for the gastric foreign matter adsorption magnet of the present invention.

[0008]

EXAMPLES The present invention will be described below based on examples. Figure 1
A magnet for adsorbing a foreign substance in the stomach having the structure shown in FIG. At that time, in case 1, the materials shown in Table 1 were used. In FIG. 1, reference numeral 1 denotes a case, which is formed of a material having each composition shown in Table 1 into a hollow cylindrical shape having an outer diameter of 16 mm, an inner diameter of 14 mm and a length of 76.2 mm. Reference numeral 1'denotes a curling finish portion at the tip of the case, and the case end is bent along the shape of the lid. 2 is an Nd-Fe-B system magnet (HS-made by Hitachi Metals)
30 BV), formed into a disk shape with an outer diameter of 14 mm and a thickness of 4 mm, magnetized in the thickness direction, and a pair of magnetic poles NS on both end faces.
To provide. Reference numeral 3 denotes a yoke, which is formed of soft iron (SS-41) into a disc shape having an outer diameter of 14 mm and a thickness of 6.5 mm.
4 is a lid, made of the same stainless steel as the case 1,
It is formed into a truncated cone shape with an outer diameter of 14 mm and a thickness of 6.5 mm.

24 after administration of the above-mentioned magnet for attracting foreign substances in the stomach to cattle
It was collected after a lapse of months and the weight loss of corrosion of the case was measured. The results are also shown in Table 1. Note that the corrosion weight loss is
304 (No. 5) is shown as 100. From Table 1, No. 1 according to the present invention. Nos. 1 to 4 are conventional Nos. It can be seen that the corrosion resistance is remarkably improved as compared with No. 5.

[0010]

[Table 1] wt. %

[0011]

According to the present invention, since the corrosion resistance of the case is improved, the retention period in the stomach can be lengthened.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing an example of a foreign substance attraction magnet in a stomach.

FIG. 2 is a vertical cross-sectional view showing another example of a foreign substance adsorption magnet in the stomach.

[Explanation of symbols]

 1 case, 2 magnets, 3 yokes, 4 lids

Claims (1)

[Claims] 1. A weight ratio of C 0.1% or less, Si2.
0% or less, Mn 3.0% or less, Ni 10-16%, Cr
15-19%, Mo 0.5-4.0%, balance substantially F
A plurality of disk-shaped permanent magnets magnetized in the axial direction are integrally formed in a rod shape in the axial direction so that the same poles face each other with a yoke in between, in a hollow cylindrical case made of a corrosion-resistant non-magnetic material made of e. A magnet for adsorbing a foreign substance in the stomach, which is provided.