US2295069A

US2295069A - Tuyere

Info

Publication number: US2295069A
Application number: US404443A
Authority: US
Inventors: Francis J Zippler
Original assignee: LAWRENCE COPPER AND BRONZE COM
Current assignee: LAWRENCE COPPER AND BRONZE Co; LAWRENCE COPPER AND BRONZE COM
Priority date: 1941-07-29
Filing date: 1941-07-29
Publication date: 1942-09-08
Anticipated expiration: 1959-09-08

Description

Sept. 8, 1942. F. J. ZIPPLER TUYERE Filed July 29 1941 INVENTOR Franc/Ls J: Z/p o/er g zmu Patented Sept. 8, 1942 UNE'EED STATES PATENT OFFICE TUYERE Application July 29, 1941, Serial No; 464,443

Claims.

My invention relates to metal-reducing fur-' naces, such as cupolas and blast-furnaces, and consists in improvements in the structure of the tuyres that deliver the essential blast of air into such furnaces, and in refinements in method.

The object of the invention is to increase the metal-reducing efiiciency of such furnaces.

Another object is to provide a tuyre that is more effective and more enduring in service.

The invention is of particular, though not exclusive, utility in the operation of blast-furnaces, and in such association it will be described. In the accompanying drawing, Figure I is a fragmentary, vertical sectional view of the porticn of a blast furnace side wall that extends between the bosh and the hearth of the furnace. Ordinarily, from eight to sixteen tuyres are arranged in circumferential succession in such wall of a blast furnace, and in Fig. I two of the.

tuyeres are shown in elevation;

Figure II is a fragmentary view, showing to larger scale the tuyere of the invention in conventional assembly with a cooler and a blowpipe. The tuyere and the cooler appear in axial section, and the blowpipe in side elevation;

Figure III is a view in end elevation of the tuyere, as seen from the right of Fig. II;

Figure IV is a view of the tuyre in horizontal section, the plane of section being indicated at IVIV in Fig. III; and

Figure V is a view comparable with Fig. III, illustrating a modified form of the tuyere of the invention.

It will be understood that in the operation of a blast furnace the circumferential line of' tuyeres delivers jets of preheated air into the portion of the furnace chamber that is located below the bosh, the bosh being the portion of the structure that chiefly sustains the weight of the columnar charge of iron ore, limestone, and coke. The air thus introduced into the lower portion of the furnace chamber percolates upwardly through the body of the charge, and in no way efiects the reduction of the ore in the charge, the molten metal thus produced draining from the charge and collecting in a pool on the furnace hearth at the bottom of the furnace chamber. As the operation progresses the body of the charge, progressively diminished by the metallurgical reactions within the furnace, descends gravitationally, while replenishment of the charge is made at the top of the furnace.

In accordance with the invention, I form. at

the nose of each tuyre a nozzle portion that provides an extension of the axial bore of the tuyere body through which air is delivered into the furnace. Additionally, I provide in the tuyere body an auxiliary passageway for air. The auxiliary passageway extends upwardly from the axial bore of the tuyere, and opens through the tuyre body in a plane which is perpendicular to the axis of the tuyere at the base of the extending nozzle portion. Through such passageway an auxiliary stream of. air is projected upwardly into the bottom of the furnace charge that is sustained above the tuyereline, with the consequence that I effect more thorough penetration of the air blast into the charge, with increase in the depth of the zone of metallurgical reaction within the furnace. The auxiliary stream of air sweeps the'projecting nozzle portion of the tuyere in a direction from base to tip, and thereby protects the body of the tuyere in the region where it is most vulnerable to the conditions of heat and attrition within the furnace.

Referring to the drawing, I illustrate a tuyere Zin which and in the operation of which the invention may be realized. The body of the tuyre is in this case of frusto-conic'al form, including at its larger end 2a an annular seat 3, upon which the tuyere is supported in engagement with a complementary seat 4 formed. in the bore of a tuyere' holder or cooler 5, secured in the blast furnace wall 6. The bore lot the tuyere is provided with the usual annular seat 8 that receives the outlet end of an air-deliver- .ing blow-pipe 9. The tuyre may be formed, as is customary, of copper or bronze, and its walls may be hollow, providing a chamber ID for a body of cooling water. Threaded openings ll provide for the connection of water pipes. to the tuyre, so that a continuous circulation of water may be maintained in the chamber Ill,

The bore 1 ofthe tuyere is of circular cross section, and its wall tapers to a cylindrical nozzle portion l2 that extends on the axis of the bore l forwardly, beyond the vertically disposed wall 2b of the tuyere. An auxiliary passageway I3 extends upwardly from the taperedbore of the tuyere, and opens through the wall 222'. While the nozzle portion I2 is of smaller external diameter than the inner end of thetuyerev body from which it extends, the bore la of such nozzle portion provides the main air-delivering passage of the tuyre; Th outlet of such nozzle portion extends in a planeperpendicular to the axis of the tuyere, and it will be noted that the sponding increase in the danger that the tuyre will fail under the deleterious conditions within the furnace. The extending nozzle portion I2 provides accurate directional control of the blast of air delivered into the furnace, and the stream of air flowing from the auxiliary passage [3 sweeps the nozzle portion longitudinally from base to tip, and protects it from access of the molten metal and slag that trickle and rain from the furnace charge above.

The angle of the passage [3 with respect to the vertical axis of the furnace is so determined that the stream of air jetted upwardly by the passage is directed into the charge above the tuyere-line of the furnace, with the good effect already described, that better penetration of the air blast into the furnace charge is obtained, and the depth of the zone of metallurgical reaction in the furnace substantially increased.

In further elaboration of usual tuyere construction, a second auxiliary passageway, l4, may be provided in the tuyere. This passageway extends downwardly from the tapered throat of the tuyere and opens, as the passageway l3 opens, in the end wall 21) of the tuyre body. Thus, the nozzle portion of the tuyre is swept both above and below by protecting streams of air.

The air streaming downwardly from the passage l4 plays upon the surface of the bath of molten metal on the furnace hearth, accelerating the combustion of the unburned coke that normally floats on the bath, and in consequence maintaining the molten metal at higher temperature and in more uniformly fluid condition.

The tapered form of the bore 1 of the tuyere is important. The bore, so formed, provides with the cylindrical passageway of the nozzle portion I2 a Venturi-shaped throat, whereby the air delivered by the blow-pipe 9 flows from the tuyere passageways with accelerated velocity.

The wall of the nozzle portion l2 of the tuyere will ordinarily be hollow, as shown in Figs. II and IV, to the end that such nozzle portion, as Well as the main body of the tuyere, may be Water cooled. And the engineer will perceive that the tuyre structure may be formed either of assembled sections, or of an integral casting, as herein illustrated, with openings I5 for the passage of cooling water between the chamber Ill and the recess within the hollow walls of the nozzle portion. However, it is to be noted that the protection, which the auxiliary streams of air afford the nozzle portion, is so effective in my structure that the wall of the nozzle portion may be, and in many cases will be, of solid construction.

Referring particularly to Fig. I, it will be seen that the tuyere holder 5 is built into the furnace wall 6 with its inner end flush with the inner surface of the furnace wall; that the tuyere, seated in the holder, projects from the furnace wall inward; and that the emergence of air into the furnace charge, both through bore 1a of the nozzle portion and through the auxiliary passageways l3 and I4, is into a portion of the charge that is spaced inwardly and remote from the furnace Wall. Thus, while the depth of the zone of metallurgical reaction is increased, the region of intense reaction is carried inwardly from the furnace wall toward the centre of the charge, leaving the furnace wall protected by intervening material from such intensity of reaction as would effect its rapid destruction. Furthermore, the nozzle portion I2 is swept externally by the streams of air that emerge from passageways l3 and I4, and is thus hielded from the high temperature of the reaction zone.

Fig. V serves to illustrate that the extending nozzle portion of the tuyre may be varied in cross-sectional form. Here the nozzle portion I20, is shown to be elliptical, with the outlets of the auxiliary air passages l3a and Ma appropriately modified in shape and in position.

To the extent that the protection of the centrally extendng nozzle portion of the tuyre is of prime importance, the number of the auxiliary passages (I3, l4) may in some .cases be increased, with the efiect that substantially the entire exposed surface of such nozzle portion will be enveloped by a protecting curtain or sleeve of air. And if it should be found in particular installations that the effect of the auxiliary streams of air upon the metallurgical reactions within the furnace is only of subsidiary importance, the directions of flow of the auxiliary air streams may be modified, with the protection of the extending nozzle portion of the tuyre the primary consideration.

I claim as my invention:

1. In the operation of a metallurgical furnace that involves chemical reaction under aeration at the base of a gravitationally descending charge by means of an air nozzle that projects inwardly from the furnace wall, the method herein described of protecting the nozzle and extending the depth of the zone of reaction which consists in releasing within the charge and at a point remote from the furnace wall an inwardly directed stream of air, and, at a point to rearward of the point of release of such stream, but also a point inwardly remote from the furnace wall, releasing an inwardly and upwardly directed supplementary stream of air.

2. In a metallurgical furnace that includes a hearth, a bosh arranged at an interval above the hearth and adapted to sustain a furnace charge, and a tuyre arranged beneath the bosh and adapted to deliver through its main orifice and to a charge within the furnace and above the pool of molten metal collecting on the hearth a reaction-sustaining stream of air, the invention herein described which consists in an elaboration of tuyere structure in the form of a supplementary orifice opening on the upper side of the assembled tuyre and torearward of the main orifice and adapted to deliver an upwardly and inwardly directed supplementary stream of air, whereby such supplementary stream sweeping and protecting the upper surface of the forward portion of the tuyere penetrates the charge and increases the depth of the zone of metallurgical reaction.

3. In a metallurgical furnace that includes a hearth, a bosh arranged at an interval above the hearth and adapted to sustain a furnace charge, and a tuyere arranged beneath the bosh and adapted to deliver through its main orifice and to a charge within the furnace and above the pool of molten metal collecting on the hearth a reaction-sustaining stream of air, the invention herein described which consists in an elaboration of tuyere structure in the form of supplementary orifices opening one on the upper the other on the lower side of the assembled tuyere and to rearward of the main orifice and adapted to deliver upwardly and inwardly directed and downwardly and inwardly directed supplementary streams of air, whereby such supplementary streams sweeping and protecting the upper and lower surfaces of the forward portion of the tuyre penetrate the charge and increase the depth of the zone of metallurgical reaction.

4. A tuyre for a metal-reducing furnace having a forwardly tapering bore, a cylindrical nozzle portion constituting a main air-delivering passage extending on the axis of the bore and forwardly therefrom and an auxiliary passageway extending from the forwardly tapering bore and delivering externally of and at the rearward end of said cylindrical nozzle portion.

5. A tuyre for a metallurgical furnace that consists of a body of frusto-conical form with an interior passageway correspondingly tapered, and adapted to be mounted in inwardly projecting position in a furnace wall and with the smaller base of the frustum disposed in Vertical plane and spaced inward from the furnace Wall, the tuyre having a cylindrical nozzle portion forming an axial continuation of the said tapered passageway and an auxiliary passageway extending from such interior tapered passageway obliquely forward and opening through the smaller base of the frustum exterlorly of and at the base of said nozzle portion.

FRANCIS J. ZIPPLER.