SU29936A1 - Tuyere for cupolas - Google Patents

Description

Until now, the determination of the cross-sectional area of the tuyeres does not yet have a solid scientific base. A whole number of indications in the literature gives such a large range of air velocities in the lances (from 3 to 30 m / s) that when designing new cupolas, each designer is provided with his own instinct and own experience. If the latest data and indicate the ratio of the cross-sectional area of the tuyeres to the cross-sectional area of the mine is -0,2-0,5, then the latest designs of cupolas also give the value of this coefficient equal to 0.06 (Weier).

Taking into account that, on the one hand, the course of the cupola process depends on a large number of variables and, on the other; all raw materials must be used, one must strive for such a design of the cupola, which would ensure the possibility of a quick adjustment of the smelting process. Replacing the fuel (coke, anthracite, peat), changing the quality of the charge material (fines) requires a change in speed and, therefore, pressure to blow.

In addition, the foundry industry is faced with the question of better use of fuel, depending on its physical qualities (flash point, porosity, etc.), and this is entirely related to the rate of injection.

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of air. The operation on anthracite requires an increase in the speed of the blow and, consequently, the pressure. Under actual operating conditions, the speed of blowing can be increased either by changing the tuyeres or by increasing the power of the fan. The latter, however, is associated with an increase in the amount of air supplied and, therefore, with a change in the melting mode itself. The change of the tuyeres is associated with large works that cannot be performed in the working environment, and therefore melting is carried out under the same conditions, which, of course, affects the results of the cupola furnace process.

By means of the proposed tuyere to the cupolas, it is intended to achieve the possibility of changing the cross-sectional area of the air jet from to –d (0.33 to 0.11), leaving the former streamlining of the shaft.

In FIG. 1 shows a tuyere in longitudinal section; FIG. 2 is the same, a section along the lines AB, CD, EH in FIG. 1 and 3 are the same, front view with a partial cut.

The change in cross sections is achieved by installing special cast iron or iron liners that are bolted to the outside of the cupola.

Three interchangeable side inserts 5, 4 and 5 are arranged vertically and are inserted outside, for which the lid is made, which is attached to seven studs. Horizontal two bottom liners 2 w. 6 is inserted from the inside of the cupola.

Changing the tuyere cross section is possible one time before melting or testing the cupola.

Devices for turning off the tuyere, for the purpose of cleaning, are designed according to the principle of the Bestenbostel system, however, with the change that each tuyere can be turned off individually without air loss to the outside.

In this construction, the flap rotates on an axis and is constantly flowing around with cold air, which prevents its curvature and ensures a snug fit.

The advantage of this device, according to the inventors, lies in the possibility of individual shutdown, with free observation of the cleaning progress (shutdown is performed above the headpiece) and in the possibility of using it for cupola plates of any diameter. Left one row of tuyeres, it is possible to turn off alternately, retaining the almost complete flow around the shaft, with the normal design of the air box.

The shape of the tuyere itself can be admixed with any structure (circle, triangle, torn) with the only feature that

one must either construct it from two parts, connected in the plane of the casing of the cupola, or give it a smooth transition towards the air box, which would ensure a tight fit of the valve.

The construction is overlapping; its structure is that the lance / is located under the air box. The length of the protruding part of the tuyere corresponds to the width of the air box in which the hole is made against the tuyere. Above the orifice, there is a closing flap 14 fixed to the axis J3. The latter rotates in two bearings 7 and 8. To eliminate possible air loss, one of the bearings has a JO seal. The flap axis is rotated by the handle 12, the position of which will serve as an indicator of the position of the flap 14.

The lance designed according to the second principle can be made independently. To do this, it is enough to use a lance without interchangeable plates and holes for fastening the latter.

The subject matter of the invention.

Tuyere for cupolae, characterized by

the use of interchangeable lateral 3, 4, 5 and bottom 2, 6 liners serving to change the air jet cross-section within wide limits.