US2281310A - Tuyere shield - Google Patents

Description

April 8, 1942. T. H. KENNEDY TUYERE SHIELD Filed July 25, 1941 2 Sheets-Sheet l [mm liar." 7 UMfl/V H KEN/V50),

April 28, 1942.

T'. H. KENNEDY TuYEaE SHIELD Filed July 25, 1941 2 SheetsSheet 2 Patented Apr. 28, 1942 l I UNITE TUYERE SHIELD Truman H. Kennedy, McKeesport, Pa., assignor to National Tube Company, a corporation of New Jersey 6 Claims.

The present invention relates to an improved tuyere shield for the protection of workmen in the vicinity of the penstock, blow pipe and tuyres of a blast furnace.

As is well known to those skilled in the art, in the normal operation of a, .blast furnace used for the smelting of iron, admixtures of fuel coke and a limestone fiux are combusted by the introduction of huge quantities of preheated air forced into the furnace under pressure. This air is heated in conventional blast furnace stoves and is fed through a bustle pipe surrounding the furnace. From the bustle pipe branches, known as penstocks, air is led through blow pipes directly into the furnace through hollow sleevelike elements known as tuyeres. Conventional tuyres are detachably mounted in tuyere coolers embedded in the walls of the furnace and the inner extremities of the tuyere project beyond the inner wall of the furnace.

To prevent the untimely burning out of the tuyere or the untimely melting thereof under the intense heat of the furnace, provision is usually made for the continuous circulation of cooling,

water through both the tuyere and the tuyere cooler. Generally an eye piece or peep sight is mounted in the lower portion of the penstock to permit the furnace operator to observe the condition of the molten metal in the crucible of the furnace.

In normal operation, during the operation of the furnace the burden therein slowly moves downwardly in a more or less continuous or intermittent manner. The gravitational movement, coupled with other internal activities within the furnace, gradually erode the interior wall surfaces of the furnace. The tuyeres projecting beyond the inner surface of the furnace Walls are therefore normally exposed to the scouring action of the downwardly moving burden, and are also exposed to the destructive action of the ebullient molten metal. When the circulation of cooling water fails to properly function, or when the walls of the tuyere become fractured or worn thin by abrasion, or when they are unable to longer resist the internal forces within the furnace directed against them, they occasionally burn out and become either wholly or partially destroyed.

Such accidental occurrence, while infrequent, nevertheless does happen at intervals during the normal life of a furnace. Upon the failure of a tuyere, cooling water frequently escapes into the furnace and the contents of the furnace have a tendency to rush to the accidental exit point thus provided, the molten metal thus tending to rapidly flow from the furnace with a violent or volcanic eruptive force. Upon such occurrence, the hazards are three-fold; the escape of heavy hot fluid masses, the escape of hot gases, and the escape of steam generated by the tuyre cooling water contacting the hot metal flowing from the furnace.

The present invention aims to provide an improved means for protecting the workmen at the time of tuyere failure by the provision of an improved shield so designed and arranged that it will not interfere with the normal furnace operation or interfere with the view of the furnace operator, and also so arranged that the protective device can be readily attached and coordinated with conventional types of blast furnace equipment. From an economic standpoint it is important that any protective device be of simple design and rugged construction and that it be adaptable to conventional types of furnace equipment, since the capital investment for a blast furnace runs into very high figures. The present invention is believed to meet these practical and economic requirements because of its simplicity of construction and its adaptability to attachment to standard equipment.

The invention will be fully apparent from the following detailed disclosure when read in connection with the accompanying drawings, and will be defined with particularity in accordance with the requirements of the patent statutes in the subjoined claims.

In the drawings: 7

Figure 1 is a fragmentary view showing the lower portion of a conventional type of blast furnace equipped with the improved shield of the present invention;

Figure 2 is an enlarged detail view showing a portion of the penstock, blow pipe and improved tuyre shield;

Figure 3 is a detail view of the improved shield detached from the furnace, the view being taken on line III-III of Figure 2;

Figure 4 is a fragmentary detail of one of the component parts of the improved shield illustrating the specific construction and mounting of pintle pins and related parts in the vicinity thereof to facilitate assembly and detachment of the parts;

Figure 5 is a detail section on line V--V of Figure 3 illustrating means for detachably looking the shield plates to one another; and

Figures 6 and '7 are detail sections on the correspondingly numbered lines of Figure 3.

Referring in detail to the drawings, the numeral It] represents the portion of a blast furnace within which there is mounted a plurality of conventional water cooled tuyere coolers i2. Each tuyere cooler has detachably mounted therein a tuyere [4 which is also of hollow construction and water cooled in a conventional manner. inner nose [6 of the tuyere projects beyond the inner surface l8 of the hearth or crucible wall in accordance with standard practice. Because of this necessary inward projection of the tuyere it occasionally happens that the same burns away and causes the undesired expulsion of hot metal and gas as hereinabove referred to.

Surrounding the furnace there is the usual bustle pipe 29 through which the blast air is supplied. At regular intervals around the furnace there are branches in the form of conventional penstock fittings 22. Connecting each penstoc with each tuyere there is normally provided a blow pipe 24 and there is a detachable joint sleeve-like structure 25 to facilitate breaking the connection between the blow pipe, tuyere and 1 penstock. The lower end of the penstock is yieldingly pressed into engagement by means of a spring 28 surrounding a rod 38 which has a pivotal connection with a fixed jaw 32 secured to the furnace structure. stock, blow pipe tuyere and tuyere cooler are all of standard conventional form well known to those skilled in the art and no claim is made to the structure thereof apart from its combination with the protective shield to now be referred to.

However, it is to be understood that the shield of the present invention is purposely so designed and arranged that it can be readily mounted for use in combination with the conventional forms of blast furnace equipment operated in connection with many steel plants throughout the country.

The improved tuyere shield of the present in-. vention consists essentially of two oppositely disposed substantially semicircular plates 34 and 33 whose interior portions are provided with semicircular notches 38 and 49 which make a neat fit around the joint element 25 in the region where the penstock 22 connects with the blow pipe 24. Secured at diametrically opposite points on the penstock, by means of bolts 42 and 44, there are respective hinge elements 46 and 48 having respective pairs of hubs 59 and 52 each formed with substantially vertical openings therein adapted to receive the respective pairs of hinge pintles 54 and 58 which depend from hinge lugs 58 and 69 welded or otherwise secured to the shield plates 34 and 35. To facilitate assembly and disassembly of the hinge plates 34 and 36, the latter are notched as indicated at 82 and 64 in the region of the lower pintle pins.

As thus notched, the plates can be lifted vertically so as to free the pintle pins after each half plate has been rotated 90 and brought into a position substantially parallel to the axis of the tuyere or blow pipe.

To facilitate the turning of the plates on the hinge, a plurality of bars or handles 66 and 68 are provided as shown.

Each plate 35 has welded thereto a striker strip 10 which is arranged for overlapping relationship with the inner vertical edge of the coacting plate 34. Means are provided for detachably locking the shield plates to one another. This means may conveniently take the form of aper- The The bustle pipe, peniii) tured lugs 12 secured to the striker strip '10, the lugs being arranged to pass through slots 14 formed in the plate 34. Keepers or looking pins 76 are adapted to pass through the apertures in the lugs 12 so as to thus detachably lock the shield plates to one another. The locking pins are conveniently held captive by flexible members, such as chains E8, the extremities 80 of which are welded or otherwise secured to the plate 34.

The structure shown and described is of simple yet rugged construction, and can be easily and quickly mounted on conventional blast furnace equipment. When in the locking position shown, the shield will serve to adequately protect workmen operating the furnace, yet it will not interfere with normal furnace operation nor will it interfere with the removal of the blow pipe or tuyeres, it being understood that at the time of tuyere changes the locking pins '16 will be removed and the plates 34 and 36 will be swung out of the way about the hinged mountings described.

It will be understood that the shield of the present invention is not expected or intended to hold back permanently any violent effiux of liquid or gaseous materials coming from the furnace at the time of the accident. However, it is intended to, and in practice actually does, materially check or bafile the initial fiow of metal or gases so that operators working in proximity to the tuyere will have ample opportunity to escape to a point of safety before the shield itself becomes destroyed by the onrunning molten metal or hot destructive gases. It will be understood by those skilled in the art that at the time of the accident, the gases and steam emitted from ruptured tuyeres travel with great rapidity and these accidents usually occur without much previous warning. However, the initially escaping gases do produce loud audible sounds which serve to forewarn the operators of the impending danger so that they can escape to a point of safety.

It is during this initial danger period that the tuyere shield of the present invention effectively serves to protect the workmen. Usually in case of accident a prearranged procedure is followed, including the shutting off of the air blast and the taking of other protective measures known to those skilled in the art.

While I have described quite precisely the embodiment of the invention herein illustrated, it is to be understood that the drawings and descriptive matter are to be interpreted in an illustrative rather than a limiting sense.

I claim:

1. In a blast furnace, the combination with the penstock, blow pipe and tuyere thereof, of a shield comprising two coacting notched plates hingedly mounted between the penstock and the tuyere and surrounding the blow pipe.

2. In a blast furnace, the combination with the penstock, blow pipe and tuyere thereof, of a shield comprising two plates with their inner portions arcuately notched to make a neat fit around the structure where the blow pipe joins the penstock, the inner portions of the plates overlapping, and respective means for pivotally supporting each of said plates for movement about upright axes on opposite sides of the penstock.

3. In a blast furnace, the combination with the penstock, blow pipe and tuyere thereof, of a shield comprising two coacting notched plates hmgedly mounted between the penstock and the tuyere and surrounding the blow pipe, and coacting means on said plates detachably locking them to one another.

4. In a blast furnace, the combination with the penstock, blow pipe and tuyre thereof, of respective plates hingedly mounted on upright hinges secured to diametrically opposite parts of the penstock, the inner portions of said plate being notched so as to make a neat fit with the structure in the region where the penstock connects with the blow pipe, and coacting means on said plates detachably locking them to one another.

5. In a blast furnace, the combination with the penstock, blow pipe and tuyre thereof, of a shield comprising two approximately semicircular plates with approximately semicircular notches formed in the interior thereof, respective hinge elements secured to opposite sides of the penstock, each plate having respective pintles for engagement with said elements, and means detachably locking the plates to one another.

6. In a blast furnace, the combination with the penstock, blow pipe and tuyere thereof, of a shield comprising two approximately semicircular plates each formed at their interior with an approximately semicircular notch, one of said plates having striker strips secured thereto overlapping the other plate, an apertured lug mounted by one of said striker strips and extending through an opening formed in the plate overlapping it, and a keeper pin engageable with the aperture in the lug for detachably locking the coacting shield plates to one another.

TRUMAN I-I. KENNEDY.

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