JPH0115114Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial field of application] This invention relates to a connecting part that has a structure that allows a smooth and proper threaded state to be obtained at all times when connecting graphite electrodes for steel making through nipples. .

[Conventional technology]

In steelmaking electric furnaces, as the graphite electrode in use (hereinafter referred to as the "lower electrode") wears out, a new graphite electrode (hereinafter referred to as the "upper electrode") is connected and replenished to continue operation. has been done.
The connection work is usually carried out by lifting the upper electrode with a crane and transporting it to just above the lower electrode, then gradually lowering it, and screwing the nipple, which has been previously connected half-length to the upper electrode socket, into the lower electrode socket. It will be done.

However, this connection work was done artificially in a furnace with high heat and unstable footing, and in addition, the electrodes themselves were under a high load, making it difficult to align the upper and lower electrodes, and the impact of impact was sometimes applied. This can lead to damage to the nipple and/or socket threads. When such thread damage occurs, the fragments get into the thread groove and prevent smooth and proper threading, causing thread loosening or stress fracture at the connection part during the operation process, and the lower electrode being immersed in molten steel. This can lead to serious accidents such as falling off.

In order to avoid the above-mentioned situation, a nipple structure has been proposed in which a groove is recessed in the axial direction from the end face along the threaded surface of the nipple, and the generated thread fragments are stored in the groove and dropped downward ( Jikko 45-
No. 32203).

[Problem that the invention attempts to solve]

However, in the above-mentioned conventional structure, there is a thread on the socket side facing the nipple groove, so especially in the socket part of the lower electrode that forms a tapered surface, debris stored in the nipple groove may interfere with the socket thread. A phenomenon occurs in which the object gets caught and does not fall easily. At this time, if coarse debris gets caught or debris accumulates in the open area, smooth threading will be inhibited again, making it impossible to obtain a proper connection state.

This invention solves these problems and provides an electrode connection part with a structure that can extremely efficiently remove generated thread fragments from the threaded surface.

[Means for solving the problem, examples]

This invention will be explained below based on an illustrated embodiment.

Partially cut away vertical sectional view in Figure 1 and 1 in Figure 2
In the horizontal sectional view taken along the line A-A' in the figure, 1 is an upper electrode, 2 is a lower electrode, and 3 is a nipple screwed into the socket portion of the upper and lower electrodes.

A plurality of longitudinal grooves 4 are formed in the threaded surface of the nipple 3 along the axis. The appropriate number of vertical grooves 4 is two to three, and they are provided symmetrically at equal intervals on the circumference of the nipple as grooves having a width and depth slightly larger than the threads.

Reference numeral 5 denotes a vertical groove recessed in the threaded surface of the socket portion of the upper electrode 1 and the lower electrode 2 along the axis. In a connection structure using a tapered nipple, screwing is completed by screwing in 2 to 3 turns, but the vertical groove 5 of the socket part is machined and installed at a position that matches the vertical groove 4 of the nipple during this screwing process. be done. The number of vertical grooves 5 to be installed is the same as the number of vertical grooves 4 of the nipple, and the groove shape is preferably cut into a circular cross section so that the thread fragments stored therein can easily slide and fall.

[action, effect]

Since the connecting portion of the graphite electrode according to this invention has the above-described structure, when the nipple is screwed into the socket portion, the vertical groove 5 of the socket portion and the vertical groove 4 of the nipple are sure to meet and match. When the longitudinal grooves 4 and 5 match each other, a large diameter continuous hole with no obstruction is formed in the wall surface, and this continuous hole accommodates all intervening foreign objects such as screw fragments that move on the thread surface as the screw is engaged. This allows the lower electrode 2 to fall into the socket play space 6 very smoothly.

As a result, the phenomenon of debris stored in the nipple groove getting caught in the socket thread, which was a problem with conventional structures, is eliminated, and a smooth and proper connection is always achieved, which greatly reduces the chance of the lower electrode falling off. The practical effect is that the width can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway longitudinal sectional view showing an embodiment of this invention, and FIG. 2 is a horizontal sectional view taken along line A-A' in FIG. 1... Upper electrode, 2... Lower electrode, 3... Nipple, 4... Vertical groove of nipple, 5... Vertical groove of socket portion, 6... Socket play space.

Claims (1)

[Scope of utility model registration request] Nipple 3 with multiple longitudinal grooves 4 recessed on the threaded surface
and a socket portion having a vertical groove 5 recessed in the threaded surface that matches the vertical groove 4 of the nipple when screwed together.