US1729075A - Tuyere for slag-blowing furnaces - Google Patents

Description

Sept. 24, 1929- A. LAIST 1,729,075

- TUYERE FOR S LAG BLOWING FURNACES Fild Aug. 4, 1928 2 Sheets-Sheet 1 Sept. 24, 1929. AL LAIST TUYERE FOR S LAG BLQWING FURNACES Filed Aug. 4, 1928 2 Sheets-Sheet 2 awuwtoz v l-EX LA/J 7':

Patented Sept. 24, 1929 UNITED STATES PATENT OFFICE ALEX LAIST, OF HELENA, MONTANA, ASSIGNOR TO ANAGONDA COPPER MINING COM-.

PANY, A CORPORATION OF MONTANA TUYERE FOR SLAG-BLOWING FURNACES Application filed August 4, 1928.

In tuyercs for slag-blowing furnaces and similar apparatus, a stream of air is caused to flow in a horizontal direction immediately at. orpr1orto,1ts passage through the tuyere and 5 a downwardly flowing stream of pulverized fuel, suspended in air, is caused to enter the air stream at an angle. In tuyeres heretofore used, the impinging of the stream of powdered coal on the air stream deflected the re- 10 sultant stream downwardly from the horizontal, and thus caused the mixed stream and the particles of suspended fuel to strike the wall of the tuyere. The striking of the suspended particles on the wall of the tuyere caused a 15 rapid erosion or wearing away of the tuyere and, therefore, necessitated frequent repairs or replacement.

This advantage is obviated in my present invention which provides a tuyere and an air 2 and fuel supply means that avoids any impingement of fuel, or other particles, on the wall of the tuyere and thus preserves the tuyere against erosion, and that enables the mixed air and fuel stream to flow substantially horizontally or parallel to the tuyere passages.

The various features of the invent-ion are illustrated in the accompanying drawings, in which 3 Fig. 1 is a plan View of a tuyere embodying a preferred form of the invention.

Fig. 2 is a vertical sectional view of the tuyere taken on the line 22 of Fig. 1.

Fig. 3 is a vertical section taken on the line 3-3 of Fig. 2, and

Fig. 4: is an end view of the tuyere In the type of tuyere to which my present invention is applied air under pressure is supplied downwardly through a vertical pipe to a casting 11 into which the pipe is threaded. The air is received in a chamber 12 which is formed in the outer end of the casting and is closed by an end plate 13. From the chamber 12 the air flows through a passageway let into a mixing chamber 15 of a somewhat rounded or globular shape. In the chamber 15 the air is joined by'a stream of fuel suspended in air and then passes through an outlet passage 16 into a tuyere Serial No. 297,451.

pipe 17 that leads through the wall of the converter or furnace.

A stream of powdered fuel suspended in a carrying current of air, under pressure, is supplied downwardly through a pipe 18 positioned between the air pipe 10 and the wall 19 of the converter. From the pipe 18 the air is received in an expansion chamber 20 formed 1n the castingll immediately aboveand openin g downwardly into the mixing chamber. 15. The expansion chamber 20 is of considerably larger horizontal cross section than is the fuel admission pipe 18 and also increases in cross sectional area downwardly towards the mixing chamber 15. It is preferably of rectangular cross section having parallel walls 21 and 22 at right angles to the horizontal direction of flow of the air through the mixing chamber 15, and having a pair of diverging walls 23 and 24 that meet the outermost part of the mixing chamber 15 at approximately a the expansion chamber 20, the cross-sectional area of the passage for the air and its suspended fuel is increased and the velocity is correspondingly reduced. As the air and fuel pass downwardly through the chamber 20, the cross-sectional area widens to the diameter of the chamber 15 and the air and suspended fuel, therefore, enter the mixing chamber 15 uniformly distributed across the path of the air passing horizontally therethrough, and at a velocity insufficient to materially deflect the stream of air. The particles of suspended fuel are, therefore, carried horizontally by the passing air without impinging, to any destructive extent, upon the side walls of the tuyere.

The tuyere may be provided with the usual slag-overflow pipe 25 secured in an opening at the lower part of the chamber 15 and sealed therefrom by means of a fusible disc 26 held in place by a bushing 27. The end plate 13 may also be provided with an inlet check valve 28 of usual construction.

As changes of construction could be made within the scope of my invention, it is in tended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

In previous applications of Garred No. 181,979 filed April 8, 1927, and of myself No. 284,462 filed June 11, 1928, there are described apparatus for recovering zinc and other metals from slags or the like, by blowing through the molten material a mixture of air and finely divided coal or otherfuel. The present improvement is designed par-,

ticularly for use in such blowing operations,

though it may be used with advantage wherever similar conditions exist.

Having now described my invention, what lclaim as new and desire to secure by Letters Patent is 2.

1. A tuyere of the type described which comprises a horizontal air passage, and a fuel passage entering said air passage at an angle. said fuel passage being enlarged adjacent its entrance to said air passage to reduce the velocity of fuel prior to its on- 'trance to said air passage.

2. A tuyere of the type described which comprises a horizontal air passa e, and a fuel passage entering said air passage at a' right angle, said fuel passage being enlarged adjacent its entrance to said air passage to reduce the. velocity of fuel passing therethrough prior to its entrance to said air passage.

3. A tuyere of the type described which comprlses an a1r passage, a fuel passage opening into said a1r passage at an angle,

* the cross sectional area of said fuel passage increasing towards said air passage.

4. A tuyere of the type described which comprises a casting having an air passage therethrough, a fuel passage opening at right angles to said air passage and having parallel front and back walls at a right angle to the direction of flow through said air passage, and side walls diverging towards said air passage.

In witness whereof, I have hereunto signed my name.

ALEX LAIST.

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