JPH0340430Y2 - - Google Patents

Description

[Detailed explanation of the idea] [Industrial application field]

This invention relates to metal tubes for lance pipes such as colorizing pipes, oxygen tubes, oxygen arc cutting rods, etc. for steel manufacturing.

[Conventional technology]

This type of lance pipe is easily worn out because it is exposed to high temperatures close to 1800°C, and requires airtightness at high temperatures to prevent oxygen leakage. Conventionally, techniques related to lance pipe insertion and connection methods include, for example, Japanese Patent Publication No. 57-5994 and Japanese Utility Model Publication No. 57.
There is a method described in Japanese Patent No. 33266, etc., which is illustrated in FIGS. 3 and 4. However, these techniques, as illustrated,
The joint sleeve 8 side is processed, and the metal pipe 9 to be connected is not processed at all.

[Problem that the idea aims to solve]

Therefore, in the conventional plug-in connection described above, the joint sleeve 8 and the metal tube 9 in the plug-connected state can only obtain a line contact or a narrow strip-shaped contact surface, and there is a problem that they are likely to come off during operation. It was hot. In addition, a connection method has been proposed in which a metal pipe with a chamfered edge is press-fitted into a joint sleeve with a uniform inner diameter, but lance pipes, etc.
Generally, the diameter is small and the wall thickness is thin, so it is difficult to process with high precision.
Since the wall thickness of the end portion is thinner, there is a problem that the end portion may get inside during press-fitting, and that part may become an obstacle to the fluid flowing inside. In view of the above circumstances, the inventor of this invention after intensive study prepared a metal tube with a tapered surface with an inclination angle of 1° or less formed on the outer circumferential surface of the tip by swaging or pressing, and It has been found that it is sufficient to fit the tube from both sides of a coupling sleeve having a uniform inner diameter. In other words, if you do the above, the thickness of the tip of the metal tube will be precisely formed to be almost the same as the other parts, so it can be press-fitted easily, and the tip will not turn inward during press-fitting. It has been found that the pull-out strength is four times greater than that of the conventional method, as the metal tube is not stuck in place and the outer circumferential surface of the metal tube is in surface contact with the inner wall surface of the joint sleeve. However, even if the above method is used,
If the press-fitting between the metal pipe and the fitting sleeve is poor, there may be a gap between them, or the pipe may have a small diameter and the slope angle of the tapered part may be less than 1°, making it difficult to distinguish the press-fit length. There was a risk that the degree of press-fitting of one metal tube was so great that it would become impossible to press-fit the other metal tube to a predetermined length. Therefore, the object of this invention is to provide a new metal tube for a lance pipe that solves the above problems.

[Means to solve the problem]

In order to achieve this purpose, this invention has been developed to provide metal tubes for lance pipes that are fitted from both sides of the joint sleeve and connected via the joint sleeve, with a 1° A tapered part with the following slope angle is formed, and the outer diameter of the outermost end is slightly smaller than the inner diameter of the joint sleeve, and a heat-resistant part is provided near the proximal end of the tapered part in the circumferential direction. The gist of the present invention is a metal tube for a lance pipe, characterized in that it is filled with a sealing material having elasticity and thermal expansion properties, and is also formed with a groove that serves as a guide for the length of press-fitting into the joint sleeve.

[Effect]

As a result of the above measures, when the tapered part of the metal pipe is press-fitted into the fitting sleeve by a predetermined length using the groove as a guide, the fitting sleeve widens along the tapered part, and the tapered part and the fitting sleeve are fitted. The inner wall surfaces are in surface contact. Furthermore, if the groove is filled with a sealing material, the space between the joint sleeve and the tapered portion is immediately closed by the sealing material.

【Example】

This invention will be explained in detail below with reference to drawings showing examples thereof. FIG. 1 shows a side cross-section of the tip of the metal tube according to this invention. As shown in the figure, the tip of the metal tube 1 is swaged or pressed.
A tapered portion 2 having an inclination angle α of 1° or less (the angle is exaggerated in the figure for convenience) is formed on its outer peripheral surface. A groove 3 is formed in the circumferential direction near the base end of the tapered portion 2, that is, near the interface between the metal tube body and the tapered portion 2. The groove 3 is filled with a sealing material 4 having heat resistance and thermal expansion properties. As shown in FIGS. 2a to 2c, this metal tube 1 is
and then connected. That is, the joint sleeve 5 has an inner diameter slightly larger than the tip of the metal tube 1 and smaller than the maximum diameter of the metal tube 1.
2 with the sealant 4 filled in the groove 3.
A joint sleeve 5 is attached to a metal tube 1 from both sides thereof until the tapered portion 2 is approximately at the groove 3.
It is designed to be connected by being press-fitted so as to fit inside. The groove 3 can be formed by swaging at the same time as forming the tapered portion, for example, by forming a convex protuberance on a swaging die in advance. In addition, the joint sleeve 5 into which the metal pipe 1 is fitted
is deformed by plastic deformation, elastic deformation, or a mixture of these due to the tapered portion 2 of the metal tube 1, but since the slope angle α of the tapered portion 2 is set to be 1° or less, it will not be significantly deformed. There is no. Therefore, the outer peripheral surface of the tapered portion 2 is in surface contact with the inner peripheral surface of the joint sleeve 5. Moreover, the groove 3 serves as a guide, the length of the press-fit can be made constant, and the sealing material 4 can improve the airtightness of the connection part. The metal tube 1 and the joint sleeve 5 are preferably made of mild steel, and the metal tube 1 is preferably formed thicker than the joint sleeve 5. The table below shows dimensions of preferred embodiments of the metal tube 1 and the joint sleeve 5.

[Table] In order to confirm the degree of adhesion of the above examples, the pull-out strength was measured and found to be 250 kg. This exhibited more than four times the pull-out strength compared to the conventional example.

[Effect of the idea]

The metal tube for lance pipes according to this invention is constructed as described above, and since the tapered portion is in surface contact with the inner circumferential surface of the joint sleeve, it has several times the pull-out strength compared to conventional ones. At the same time, it can be press-fitted into the joint sleeve using the groove as a guide, so it is possible to avoid over- or under-press-fitting. Additionally, the sealing material improves the airtightness of the connection. Therefore, there is no risk of the connected metal pipes being pulled out or fluid leaking during operation, providing excellent safety. Furthermore, since the tapered part of the metal tube is formed by pressing or swaging,
The wall thickness of the metal tube remains almost the same even at the tapered part. Moreover, since the tapered part has a gentle slope angle of 1° or less, there is little resistance when inserting it, and there is no possibility that the tip of the metal tube will get stuck inside.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing the tip of the metal tube according to this invention, FIGS. 2 a to c are explanatory diagrams showing the process of connecting the metal tube with the joint sleeve according to this invention, and FIGS. 3 and 4. FIG. 2 is an explanatory diagram showing a connection state of a conventional example. 1, 9...metal tube, 2...tapered part, 3...
Groove, 4... sealing material, 5, 8... joint sleeve.

Claims (1)

[Scope of utility model registration request] In metal tubes for lance pipes that are fitted from both sides of the joint sleeve and connected through the joint sleeve, a tapered part with an inclination angle of 1° or less is formed at the end by pressing or swaging, and The outer diameter of the outermost end is slightly smaller than the inner diameter of the joint sleeve,
A sealing material having heat resistance and thermal expansion properties is filled in the circumferential direction near the base end of the tapered part, and a groove is formed to serve as a guide for the length of press-fitting into the joint sleeve. A metal tube for lance pipes featuring: