JPS6160815A - Furnace gas blowing tuyere - Google Patents

Abstract

PURPOSE:To execute a uniform cooling in a tuyere use pipe body by constituting a titled tuyeye so that a gap for securing a gas flow path is formed uniformly in the peripheral direction between a needle part and a thin diameter part, when the needle part of a rod body has been inserted into the has been inserted into the thin diameter part of the tuyere use pipe body. CONSTITUTION:A furnace gas blowing tuyere is provided with a tuyere use pipe body 20 consisting of a thin diameter part 16 whose tip part is opened in a furnace 10 and a large diameter part 18 communicating to said part, a rod body 26 which has formed a needle part 24 of a smaller outside diameter than an inside diameter of the thin diameter part 16 on its tip part and inserted partially into the tuyere use pipe body 20, and a rod-shaped driving mechanism 28 for inserting and separating the needle part 24 into and from the thin diameter part 16. Also, when the needle part 24 has been inserted into the thin diameter part 16 of the tuyere use pipe body 20, a gap S for securing a gas flow path is formed between the needle part 24 and the thin diameter part 16.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a needle portion of a rod that is removably inserted into a narrow diameter portion of a tuyere tube opening into a refining furnace. The tuyere for blowing gas into the furnace is configured to adjust the flow rate of gas supplied into the furnace by adjusting the opening area of the tuyere, and the needle portion is configured to be correctly positioned with its axis aligned with the narrow diameter portion. The present invention relates to a tuyere having a simple structure that achieves uniform cooling of the tuyere tube body and can be manufactured at a low cost.

BACKGROUND ART In various types of molten steel refining furnaces, porous plugs have conventionally been generally used as a mechanical means for blowing inert gas such as argon to stir the molten metal in the furnace. However, since this porous plug is made of porous refractory material, it has disadvantages such as not being able to obtain a sufficient gas supply flow rate and being less effective in stirring the molten metal. For this reason, inert gas (Ar) is used together with *i gas.

In argon-oxygen smelting furnaces (AOD furnaces), etc., which decarburize while suppressing oxidation loss of Cr by injecting Cr) into the steel bath,
As shown in the figure, a pipe-shaped tuyere 12 is provided on the side wall near the bottom of the furnace body 10, and a mixed gas of oxygen and argon is blown into the molten metal 13 in the furnace through the tuyere 12. There is.

According to the tuyere 12, a large flow rate of the mixed gas can be blown and supplied, but when the gas supply flow rate is reduced, the gas flow velocity also decreases, and the molten metal 13 in the furnace flows back into the tuyere 12, blocking the tuyere. There are inherent problems such as damage and melting. In addition, in a refining furnace equipped with an arc electrode as a heating means, there is a demand for reducing the gas flow rate in order to suppress vigorous stirring of the molten metal while the electrode is being heated, and to avoid electrode melting due to splash and overcarbonation. In order to meet the industry's demand for adjusting and changing the gas flow rate over a wide range, the applicant has proposed a tuyere for blowing gas into a furnace as shown in FIG. 2, and has already filed a patent application. Showa 59-6953
The patent application was completed as No. 9. That is, in FIG. 2, a tuyere tube body 20 consisting of a narrow diameter part 16 whose tip opens into the furnace and a large diameter part 18 communicating with the narrow diameter part 16 is horizontally mounted on the side wall 14 of the furnace main body 10. A pipe body 22 for supplying an inert gas such as argon is connected to the rear end of the large diameter part 18. This tuyere tube body 20 includes a needle portion 2 having an outer diameter d smaller than the inner diameter of the narrow diameter portion 16.
A round rod-shaped rod 26 having a tip 4 is partially inserted therethrough. The rear end of the rod 26 is connected to a piston rod 30 of a rod drive mechanism 28 consisting of a hydraulic cylinder, and the needle portion 24 is inserted into the narrow diameter portion 16 under the biasing action of the drive mechanism 28. By separating, the opening area in the narrow diameter portion 16 can be decreased or increased, and the gas flow rate can be adjusted without reducing the flow rate of the supplied gas. However, in the tuyere for blowing gas into the furnace, the needle part 24 is accurately positioned at the center of the narrow diameter part 16, and the tuyere tube body 20 is caused by one-pass gas flow.
Uniform cooling is extremely important to ensure a long service life. For this purpose, as shown in FIGS. 2 and 3, for example, a suitable number of stainless steel wires 32 are fixed through the needle portion 24 in the longitudinal direction with a predetermined phase angle, and both ends thereof are extended in the radial direction. I'm letting it come out. The total length of the stainless steel wire 32 is set to be slightly shorter than the inner diameter of the narrow diameter portion 16, so that the needle portion 24 can be inserted into the narrow diameter portion 16 as shown in FIG. At this time, eccentricity of the needle portion and partial overheating of the tuyere tube body 20 and backflow of the molten metal due to eccentricity can be prevented.

Problems to be Solved by the Invention In the structure shown in FIG. 3, a large number of stainless steel wires 32 are fixed through the thin needle portion 24.

Furthermore, it has been pointed out that ensuring that the protruding dimensions at both ends are slightly smaller than the inner diameter of the narrow diameter portion 16 involves many difficulties in terms of manufacturing technology, and also has drawbacks such as increasing manufacturing costs. ing.

Purpose of the Invention The present invention has been proposed in view of the above-mentioned drawbacks inherent in the conventional tuyeres for blowing gas into a furnace, and has been proposed to solve these problems well. A gap for ensuring a gas flow path is easily formed between the narrow diameter part of the body and the needle part, and the needle part is correctly positioned within the narrow diameter part to uniformly cool the tuyere tube. It is an object of the present invention to achieve this and also to make it possible to manufacture a tuyere with a simple structure at a low cost.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention provides a tube body for a tuyere consisting of a narrow diameter part whose tip opens into the furnace and a large diameter part communicating with the narrow diameter part. a rod body having a needle portion having an outer diameter smaller than the inner diameter of the narrow diameter portion at its tip and partially inserted into the tuyere tube; and a rod body for inserting and removing the needle portion into the narrow diameter portion. In a tuyere for blowing gas into a furnace having a drive mechanism.

When the needle portion of the rod is inserted into the narrow diameter portion of the tuyere tube, gaps are formed approximately evenly in the circumferential direction to ensure a gas flow path between the needle portion and the narrow diameter portion. It is structured like this.

EXAMPLE Next, the details of the tuyere for blowing gas into a furnace according to the present invention will be described below with reference to a preferred example and the accompanying drawings. 4 to 8 show preferred embodiments of the combination of the needle part and the narrow diameter part according to the present invention in the tuyeres for blowing gas into the furnace described in connection with FIGS. 1 and 2, Therefore, the same reference numerals will be used to designate the parts of the system. That is, when the rod body 26 is driven forward under the biasing action of the drive mechanism 28 and the needle portion 24 provided at the tip of the rod body 26 is inserted into the narrow diameter portion 16 formed in the tuyere tube body 20. A gap S is formed between the needle portion 24 and the narrow diameter portion 16 to ensure a gas flow path.

For example, as shown in FIG. 4, the needle portion 24 is formed of a long prismatic member having a rectangular cross section, and the narrow diameter portion 16 forming a part of the tuyere tube body 20 is formed in the cross section. It is composed of a circular tubular hollow member. Then, the dimensions are set so that the outer surface portion having the maximum outer diameter of the needle portion 24 comes into contact with the inner circumferential surface of the narrow diameter portion 16 in a substantially sliding manner (
By satisfying the condition (inner diameter D of the narrow diameter portion≧maximum outer diameter L of the needle portion), the gap S serving as the gas flow path is secured as shown in the figure. FIG. 5 shows another embodiment in which the needle portion 24 is constituted by a long prismatic member having a hexagonal cross section. As can be seen from FIGS. 4 and 5, when a tubular body having a circular cross section is used as the narrow diameter portion, the needle portion is constructed of a long prismatic member having a polygonal cross section. However, the outer surface portion having the maximum outer diameter of the needle portion is set to such an extent that it comes into contact with the inner circumferential surface of the narrow diameter portion in a substantially sliding manner.

Next, in FIG. 6, the needle portion 24 is formed of a cylindrical rod member having a circular cross section, and the narrow diameter portion 16 is formed of a square pipe having a rectangular cross section. In this case, the dimensions are set so that the outer circumferential surface of the needle portion 24 having a diameter is substantially in sliding contact with the inner surface having the minimum inner diameter of the narrow diameter portion 16 which is rectangular in cross section (the minimum diameter of the 100 diameter portion). (inner diameter D≧diameter L of the needle portion).

A gap S serving as the gas flow passage is secured as shown in the figure. FIG. 7 shows another embodiment in which the narrow diameter portion 16 is formed of a square pipe having a hexagonal cross section. In other words, in FIGS. 6 and 7, when a cylindrical bar member is used as the needle part, the narrow diameter part is constituted by a square vibrator having a polygonal cross section, and the outer circumferential surface of the needle part has a small diameter. The content is to be set to such an extent that it comes into approximately sliding contact with the inner surface that has the minimum inner diameter of the part.

Furthermore, FIG. 8 shows another embodiment of the present invention,
A plurality of longitudinal grooves 34 are formed at a predetermined distance in the circumferential direction on the outer periphery of the needle portion 24 having a circular cross section. in this case,! The II diameter portion 16 is formed circular in cross section, and the dimensions are set such that the outer circumferential surface of the needle portion 24 comes into approximately sliding contact with the inner circumferential surface of the narrow diameter portion 16. As a result, between the outer peripheral surface of the needle portion and the inner peripheral surface of the narrow diameter portion, the gap IvS as the gas flow path is secured as shown in the figure due to the presence of the plurality of longitudinal grooves 34.

Effects of the Invention With the above-described configuration, the tuyere for blowing in-furnace gas according to the present invention allows the needle portion to be positioned correctly within the narrow diameter portion of the tuyere tube with its axes aligned. A gap for ensuring a gas flow path is easily formed between the inner surface of the narrow diameter portion and the outer surface of the needle portion. Therefore, uniform cooling in the tuyere tube body is achieved, and the service life of the tuyere can be set to be sufficiently long. Moreover, as explained in connection with the prior art, it is not possible to fix the stainless steel wire through the aluminum needle part and ensure accuracy so that the protruding dimensions at both ends are slightly smaller than the inner diameter of the narrow diameter part of the tuyere tube. However, according to the present invention, since the addendum is extremely simple, it can be manufactured with a low floor space and cost I.

Further, in the above-described embodiment, the gap for ensuring the gas flow path may be formed in a spiral shape, or the gap for ensuring the gas flow path may be formed as shown in FIGS. 9 and 10. effect can be obtained.

[Brief explanation of drawings]

Fig. 1 is a vertical cross-sectional view showing the schematic structure of a scouring furnace equipped with a tuyere for blowing gas into the furnace, Fig. 2 is a longitudinal cross-sectional view of a tuyere for blowing in-furnace gas according to the prior art, and Fig. 2 is a cross-sectional view of the needle portion and the narrow diameter portion, FIGS. 4 to 9 are cross-sectional views of the tuyere for blowing gas into the furnace according to the present invention, and FIG. 10 is the cross-sectional view of the furnace shown in FIG. 9. It is a longitudinal cross-sectional view of the tuyere for internal gas blowing. 16... Narrow diameter part 20... Tuyere tube body 24... Needle part 26... Rod body 28...
...Drive mechanism

Claims (4)

[Claims] (1) A tuyere tube body consisting of a narrow diameter part whose tip opens into the furnace and a large diameter part communicating with the narrow diameter part, and a needle with an outer diameter smaller than the inner diameter of the narrow diameter part at the tip. In the furnace gas blowing tuyere, the tuyere has a rod body formed with a part and partially inserted into the tuyere tube body, and a rod drive mechanism for inserting and removing the needle part into and out of the narrow diameter part. When the needle portion of the rod is inserted into the narrow diameter portion of the tuyere tube body, gaps are formed almost evenly in the circumferential direction to ensure a gas flow path between the needle portion and the narrow diameter portion. A tuyere for blowing gas into a furnace, characterized in that: (2) The gap serving as the gas flow path is formed by forming the needle portion in a polygonal cross section, and forming the narrow diameter portion in a circular cross section, and forming the outer surface portion that forms the maximum outer diameter of the needle portion. The tuyere for blowing gas into a furnace according to claim 1, wherein the tuyere is set to a degree that the tuyeres substantially rub against the inner circumferential surface of the narrow diameter portion. (3) The gap serving as the gas flow passage is formed by forming the needle portion in a circular cross section, and forming the narrow diameter portion in a polygonal cross section, such that the outer circumferential surface of the needle portion is formed in the narrow diameter portion. The tuyere for blowing gas into the furnace according to claim 1, which is secured by setting the tuyere to a degree that it substantially rubs against the inner surface having the minimum inner diameter. (4) The gap serving as the gas flow passage is formed by drilling a plurality of longitudinal grooves at a predetermined distance in the circumferential direction on the outer periphery of the needle portion having a circular cross section, and forming a narrow diameter portion circular in cross section. The tuyere for blowing gas into a furnace according to claim 1, wherein the tuyere is secured by setting the outer circumferential surface of the needle portion to such an extent that the outer circumferential surface of the needle portion substantially rubs against the inner circumferential surface of the narrow diameter portion.