RU74921U1 - BUCKET FOR BOTTOM METAL BLOWING WITH GAS IN THE DUCK - Google Patents

Abstract

1. A lance for bottom metal purging by gases in a bucket, comprising a refractory plug with an annular row of through longitudinal slotted channels, a resonator exciting elastic acoustic vibrations of the gas located in the refractory plug, a reflector in the form of a lid covering the bottom of the refractory plug with the possibility of formation communicated with through longitudinal slotted channels of the cavity between the inner surface of the lid and the bottom of the refractory plug, a Laval nozzle and a gas supply tube integrated into the reflector, while the resonator, La nozzle the shaft and the gas supply tube are aligned with the refractory plug, characterized in that the refractory plug contains at least one additional annular row of through longitudinal slotted channels located concentrically to the first annular row, and the Laval nozzle has additional peripheral channels for supplying gas into the cavity between the inner the surface of the lid and the bottom of the refractory plug. 2. The lance according to claim 1, characterized in that the diameter of the peripheral channels is 0.5-0.85 of the diameter of the output section of the Laval nozzle.

Description

The invention relates to metallurgy and can be used for out-of-furnace processing of steel in ladles by inert gas purging.

There are known tuyeres for bottom purging of gases by a metal in a bucket with excitation of acoustic gas vibrations, for example, according to RF patents No. 2165986 C21C 7/072, 2001 [1], No. 2238984 C21C 7/072, 2004 [2], No. 2025498 C21C 5/48 1994 [3], No. 2291202 C21C 5/48, 2007 (2006.01) [4].

The closest set of essential features is the lance according to patent No. 2291202 C21C 5/48, 2007 (2006.01) [4]. It contains a refractory plug with an annular row of through longitudinal slotted channels, a resonator that excites elastic acoustic vibrations of gas located in the refractory plug, a reflector in the form of a lid covering the bottom of the refractory plug with the possibility of forming a cavity communicated with through longitudinal slotted channels between the inner surface of the cap and the bottom a refractory plug, a Laval nozzle and a gas supply tube integrated in the cap, the resonator, a Laval nozzle and a gas supply tube being aligned with the fire porn tube. The diameter of the resonator is 1.45-1.60 of the diameter of the output section of the Laval nozzle.

The disadvantage of this lance is the limited throughput, which increases the processing time of the metal and reduces its effectiveness.

The objective of the invention is to improve the processing of metal, increase its quality.

The technical result is to increase the throughput of the tuyeres, reduce the processing time of the metal, improve its quality.

To implement the technical result, according to the claims, the refractory plug contains at least one

an additional annular row of through longitudinal slotted channels located concentrically to the first annular row, and the Laval nozzle has additional peripheral channels for supplying gas into the cavity between the inner surface of the lid and the bottom of the refractory plug.

In accordance with claim 2, the diameter of the peripheral channels is 0.5-0.85 of the diameter of the outlet section of the Laval nozzle.

The essence of the utility model is that an additional annular row of through longitudinal slotted channels increases the total bore of the refractory plug by one and a half times. The peripheral channels of the Laval nozzle can adequately increase the volume of purge gas supplied to the cavity between the inner surface of the cap and the bottom of the refractory plug without reducing the pressure at the outlet of the central channel of the Laval nozzle. An increased amount of gas increases the opening angle of the bubble stream, which eliminates the "dead zones" in the bucket and intensifies the mixing of the metal. The oscillatory movement of bubbles of acoustically excited gas increases its purification.

Changing the diameter of the peripheral channels from the specified limit upwards reduces the rate of gas outflow from the central channel of the Laval nozzle, while the power of the acoustic generator decreases (the amplitude of sound vibrations decreases, up to complete attenuation).

Reducing the diameter of the peripheral channels does not have a noticeable effect on increasing the throughput of the lance.

The invention is illustrated by an example of the lance, presented in the figures of the drawing (figure 1, figure 2). The lance is installed in the bottom of the bucket.

The lance includes a refractory plug 1 with annular rows of through longitudinal slotted channels 2, a gas supply tube 3, a Laval nozzle 4 with a central channel 5 and additional peripheral channels 6 for supplying gas, a resonator 7, a reflector 8. The reflector is made in the form of a metal cap with a spherical surface covering

bottom of the refractory plug. Between the inner surface of the reflector and the bottom of the refractory plug there is a cavity in communication with the slotted channels 2. A Laval nozzle is integrated into the reflector through the puller 9. The puller 9 is designed to remove the tuyere from the bottom of the steel pouring ladle when it is replaced. A gas supply tube 3 is connected to the Laval nozzle. The lance is enclosed in a metal casing 10. The resonator, the Laval nozzle and the gas supply tube are located on the same axis in the center of the lance. Calculations and experiments established the dependence of the frequency of acoustic vibrations and, accordingly, the diameter of the resulting gas bubbles on the linear parameters of the resonator and Laval nozzle.

The diameter of the resonator is 1.45-1.60 of the diameter of the output section of the Laval nozzle, and its length is 15-100 mm. The diameter of the outlet section (central channel) of the Laval nozzle is 4-12 mm. The distance from the nozzle exit section to the resonator is 3–8 mm. The diameter of the peripheral channels is 0.5-0.85 of the diameter of the outlet section (central channel) of the Laval nozzle. With geometric dimensions that vary within the stated limits, the amplitude-frequency characteristics of sound vibrations are in the range of 100-4000 Hz, and the gas flow rate is up to 700 liters / min.

Tuyere works as follows. A purge gas under a pressure of 0.8-1.5 MPa is supplied through a gas supply tube 3, a central channel 5 and additional peripheral channels 6 of the Laval nozzle 4 into the cavity between the inner surface of the reflector and the bottom of the refractory tube. In this case, the gas flowing out at a high speed from the central channel 5 enters the resonator 7. Elastic acoustic vibrations are generated in the resonator 7, which ensures the formation of a pulsating wave structure in the gas flow.

The reflector 8, reflecting the acoustic waves, directs the pulsating gas flow into the through longitudinal slotted channels 2 of the refractory plug 1. At the exit from the through longitudinal slotted channels

2, the gas flow is split into bubbles, the optimal diameter of which is given by the size of the slotted channels and the amplitude-frequency characteristic of sound vibrations. The movement of bubbles in a liquid metal is carried out in an oscillatory mode, which positively affects the homogenization of the composition and the quality of metal cleaning.

The oscillatory movement of gas bubbles at the exit from the through longitudinal slotted channels also prevents penetration of metal into the slots and their overgrowth when the purge mode is changed, which increases the service life of refractory plugs and reduces the preparation time for the tuyere for purging.

The bottom purge lance is a replaceable device that can be replaced after wear of the refractory plug. As a refractory mass for the manufacture of cork, for example, high-alumina low-cement thixotropic mass is used.

Tests of the proposed tuyeres at Seversky Pipe Plant OJSC confirmed the increased tuyere throughput, a reduction in the purge time, and a decrease in the content of non-metallic and gas inclusions in the metal.

Information sources:

1. RF patent No. 2152441 C21C 7/072, 2000 [1];

2. RF patent No. 2186858 C21C 7/072, 2002 [2];

3. Patent No. 2025498 C21C 5/48, 1994 [3].

4. Patent No. 2291202 C21C 5/48, 2007 (2006.01) [4].

Claims (2)

1. A lance for bottom metal purging by gases in a bucket, comprising a refractory plug with an annular row of through longitudinal slotted channels, a resonator exciting elastic acoustic vibrations of the gas located in the refractory plug, a reflector in the form of a lid covering the bottom of the refractory plug with the possibility of formation communicated with through longitudinal slotted channels of the cavity between the inner surface of the lid and the bottom of the refractory plug, a Laval nozzle and a gas supply tube integrated into the reflector, while the resonator, La nozzle the shaft and the gas supply tube are aligned with the refractory plug, characterized in that the refractory plug contains at least one additional annular row of through longitudinal slotted channels located concentrically to the first annular row, and the Laval nozzle has additional peripheral channels for supplying gas into the cavity between the inner the surface of the lid and the bottom of the refractory cork. 2. The lance according to claim 1, characterized in that the diameter of the peripheral channels is 0.5-0.85 of the diameter of the output section of the Laval nozzle.