US2200497A - Tuyere - Google Patents

Description

G. FOX

May 14, 1940.

TUYRE Filed Aug. 28, 193'? INVENTOR. Gordon FOX UM/M747.

Mm wm Patented May 14, 1940 UNITED" STATES Pn'lrle;N1" oFrlcEf il Gordon Fox, Chicago, Ill., assignor f to Freyn Engineering Company, Chicago, I1l. a corporation of Maine Application August 2s, 1937, seriarNo. 161,435 I 3 claims. v(C1. 12a-6.6)

' The present invention relates to improvements in tuyres.

More particularly the present invention relatesk to tuyres such as are used in blast furnaces. Copper is used most commonly for such purposes because of its high thermal conductivity, but other metals, such as aluminum, having good heat conductivity, may be employed. Flowing water in the tuyre wall serves to cool the tuyre. A frequent-cause of failure of blast furnace tuyres is the splashing of molten metal upon the tuyres, resulting in severe local attack and sometimes in the burning through ofthe material of the tuyre. High thermal conductivity is necessary in a tuyre in order that the heat may be conducted by the material of the tuyre in all directions from the point of hot metal Contact, permittingr said heat to be dissipated into the cooling water over substantial areas of copper-water surface. Commercial copper melts at temperatures between 1800 and 1900 degrees F., whereas the molten metal within the furnace which is liable to contact this copper probably ranges in temperature between 2500 and 2700 .degrees F., being somewhat superheated above the normal melting temperature of about 2300 degrees F. Because of this wide temperature difference the copper in a blast furnace tuyre is notably vulnerable.

Cast iron has a melting temperature in the neighborhood of 2300 degrees F., and it has'been proposed to make tuyres of cast iron. However, such tuyres have not been satisfactory. Their great disadvantage rests in the fact that the thermal resistance of cast iron is about six or seven times that of copper. Therefore, if a splash of molten metal within a blast furnace contacts the outside of va cast iron tuyre, the heat cannot be conducted rapidly to other portions of the tuyre, but is concentrated in the immediate adjacent area. The result is that the iron surface in contact with the cooling water in this adjacent area attains a temperature substantially above the boiling point of water. The water in contact with this surface therefore boils, and a steam film results. This film is an insulator and therefore destroys the effectiveness of the water cooling. This combination of circumstances results in the failure of iron tuyres by melting.

An object of the present invention is to provide a tuyre suitable for a blast furnace in which copper or equivalent metal is employed for its high thermal conductivity, the copper or equivalent metal being armored with a metal having a higher melting point, which tuyre is well adapted to meetthe needs of commercial service.

A further object is to provideI a tuyre well l adapted to meet vemergency conditions which arise in blast furnace practice, which tuyre will be simple and relatively inexpensive.

Furtherobjects will appear as the description proceeds. f

Referring to the drawingy f Figure 1 is a View, partly in section, showing one embodiment of `the present invention;

Figure 2 is a View, partly in section, illustrating a modication; and

Figure 3 is a fragmentary view illustrating another modification. Y i

According to the present invention a tuyre is armored with a steel, wrought iron, cast iron' or other metallic nose. The nose is preferably ferrous and is backed up by a copper body-portion, or a body portion of other metal, such as aluminum, having good thermal conductivity, whereby to provide desirable properties from the viewpoint of distribution of the heat from the region of molten metal contact to extensive copper-water surfaces. In this descriptive text the term copper is used in a broad sense to include aluminum and equivalent metals having good thermal conductivity. Also the term iron is used in a broad sense to include steel, wrought iron, cast iron and other ferrous metals.

Referring first to the construction shown in Figure 1, ya, tuyre is illustrated having the annular body portion I D of copper, aluminum, or the like, which annular portion is cored out'to provide the annular water space II. It will be understood that the water space II has communication with the outside of the tuyre, whereby a circulation of water may be provided through said water space. The copper portion I0 is armored at the nose end of the tuyre by means of the iron member I2.

In the construction shown in Figure l, the inner end of the copper body portion I0 is provided with the nose portion I3 having the conical wall I4. At its base the conical wall I4 communicates with the substantially cylindrical wall I5. 'I'he nose portion I3 at its tip is provided with the annular shoulder I6, which before application ofthe nose I Il` may have cylindrical l inner and outer Walls.

The nose member I2 is interiorly formed to contact with the conical wall I4 and the cylindrical Wall I5 of the nose portion of the copper body I0. However, the tip of the nose portion I2 adapted to 'be disposed adjacentto the annular shoulder I6 will preferably be liared outwardly, as indicated by the numeral IGa..

In assembling the nose I2 onto the copper body portion I0, said nose will readily seat itself upon the conical Wall I4, the extremity of said nose I2 being disposed in surrounding relationship with the annular shoulder I6 of the copper body portion I0. The shoulder I6 can then be swedged outwardly whereby said annular shoulder `II will be disposed in holding relationship with the flaring Wall IBa of the tip portion of the nose I2, as shown in Figure l. Said annular shoulder I6 will hold the nose I2 securely in assembled position.

In the construction shown in Figure 2 the iron nose I2a is attached to the copper body portion ID merely by a tight fit. To this end the copper body portion I0 has at its noseend the annular shoulder I'I providing the cylindrical inner surface I8 and the cylindrical outer surface IS. The iron nose I2a vis recessed annularly to provide the inner wall 20, the outer wall ZI and the nose wall Y22. Due to the fact that lthe temperature coefficient of expansion of copper is higher than that of iron, the tendency will be for the iron nose I2 to t tightly when hot, thereby accentuating the heat transfer between the iron .nose and the copper body. y f

In the construction illustrated in Figure 3 a combination is shown resulting from the casting of the copper or equivalent of the tuyre body directly into an armoring ring, which may be made of cast iron. According to the construction illustrated in Figure 3, the ironncse indicated by the numeral 23 is recessed `annularly, providing the inner wall 24, the outer wall 25 and the nose wall 26, the inner surfaces of said walls being joined by means of fillets having relatively large radii. The copper or equivalent of the tuyre body may be poured into the recess provided by the walls 24, 25 and 26 after the iron ring 23 has been preheated to a temperature approaching the melting point of Vthe copper or equivalent. When the metal comprising the tuyre body is poured into the mold it will adhere to the iron nose if the latter is clean andnot oxidized. To prevent oxidation a little flux or a reducing agent can be employed. It may be 'mentioned at this point that the cast iron nose 23 may be preheated while said nose is incorporated in the mold by inducing electric currents therein by means of alternating current magnetization.

Asa third feasible method of applying the iron armor to the nose of the copper tuyre body, a metallic spray unit may be used. At the present time units of this type are being employed to build up molten metal on cold receiving surfaces.

As indicated above, the iron nose has a melting temperature substantially higher than the melting temperature of copper. Attendant with this higher melting temperature the iron nose will have a substantially higher resistance to the flow of heat. The thermal resistance of the iron is about six or seven times that of copper.

As shown in the drawing, the iron nose extends from the outer extremity of the tuyre to a region located inwardly of the outer extremity of the water space II whereby to be in protective relationship with the copper of the body portion of the tuyre from the forward extremity thereof to a region disposed rearwardly of the `forward extremity of said water space.

According to the present invention, in which the iron nose is backed up by the copper body 4.face bounding the water space II.

portion, decided advantages are had from the viewpoint of distribution of the heat from the region of molten metal contact to the extensive copper-water surfaces defining the water space I I. The iron nose thus backed up by the copper body portion can be effectively chilled and kept below the melting point of the iron. Moreover, the iron can be kept at a sufficiently low temperature so that lt will not be subject .to chemical action of the furnace or to a combination with the molten metal within the furnace.

The high thermal resistance of the iron nose has a further value in that it interposes a shield between the molten metal and the cooling water. The temperature of a splash of molten metal which may contact the outside of the tuyre body may be in the neighborhood of 2500 degrees F. Assuming a temperature of the flowing water within the water space II of approximately degrees, there is a difference of approximately .2400 degrees between the outside surface of the tuyre and the copperwater sur- If the resistance to transfer of heat from the outside of the tuyre to the water is low, the temperature difference of 2400 degrees F. can exist only in the presence of a tremendous heat transfer, sufficient to bring about this high heat gradient through a path of such low resistance. A heavy nose tuyre has an advantage in this respect, in that the length of path for heat transfer through copper is multiplied. A tuyre according to the present invention with the iron nose further magnies this effect. For instance, if the nose lis one-half inch thick, it is equivalent to the addition of approximately three inches of copper because of the high heat resistance of theiron. For this reason there is less likelihood that the copper-water surfaces in the tuyre will attain temperatiues substantially above the boiling point of Water. Hence the tendency of the tuyre to generate steam, destroying its cooling ability, is substantially diminished.

It has been proposed to protect the nose of a copper tuyre with a coating of refractory material. Unless this refractory material is held securely between bounding shoulders such a coating will not stand up in service. In blast furnace operation tuyres are subject to extreme conditions of temperature, chemical reaction and abrasion. A refractory coating, unless held in place by bounding shoulders, will wear olf, due

Vprobably to erosion produced by the high velocity of the gases and the solid material within the furnace, and will spall off due to high temperature conditions. Moreover, expansion and contraction difficulties cause the separation of the coating from the copper of the tuyre. It has been impossible in practice to get a strong mechanical bond between a refractory coating and a copper tuyre. Moreover, a refractory coating, unless protected within bounding shoulders, is not commercially feasible for the reason that it cannot withstand the rough handling to which tuyres are normally subjected. The nose of the tuyre according to the present invention has ahigher melting point than copper and may be chosen to have a higher melting point than cast iron. In other Words, the nose may be chosen of steel or wrought iron having a melting point of 2600 to 2800 degrees F., Whereas cast iron has a melting point of 2200 to 2400 degrees F. The nose according to the present invention is mechanically stronger than copper. Furthermore, said nose has a higher resistance to heat flow thancopper, but much lower than the resistance to heat 'flow in refractory material. The vcoefficient of expansion of the ferrous metal contemplated according to the present invention is slightly less than that of copper, so that when the tuyre heats and expands, the bond between the copper and the ferrous metal ring en-circling said copper becomes more intimate.

Relative to the matter of heat conductivity, since the' nose according to the present invention is metallic and therefore has relatively high heat conductivity (compared to refractory for example), the surface of the nose never attains a temperature high enough to permit Ichemical action between the outer surface thereof and the gases, slag, et cetera, in the furnace. On the other-hand, refractory material, being a heat insulator, may become so hot in atuyre that chemical reactions take place leading to the destruction of such refractory material. Such refractory material even becomes so hot as to soften and drop off unless supported. An example of means for supporting refractory material is illustrated in the patent to Beaton No. 1,517,185.

The present invention combines the advantages of a nose member highly resistant to melting with the advantage of a copper nose portion which will eciently carry the heat units from the iron nose to the copper-water surfaces in a tuyre which has suicient heat conductivity to distribute the heat units locally applied to the exterior of the nose (for example by a splash of molten metal) to a relatively wide area of ironcopper Contact, whence these heat units are spread to a very wide area of copper-water contact.

'I'he thickness of the iron nose should be suicient to constitute ay protective shield for the copper so that the heat units from a splash of molten metal will not be communicated directly to the copper but only through a medium and path of sufiicient resistance so that the temperature in the copper under ferrous metal nose does not exceed the melting temperature of copper (that is-1800 degrees F'. or thereabouts) when the surface of the iron is4 subjected to a temperature in the neighborhood of 2500 degrees F. To this end, at the most vulnerable region of the tuyre the ratio of the thickness of the ferrous metal nose to the total length of path from the exterior of the nose to the copper-water surfaces is preferably between one-quarter and three-quarters. In other words, referring to the figures of the drawing, in which the letter X indicates the shortest distance from the point of greatest vulnerability of the outer surface of the tuyre to the iron-copper surface, and where the letter Y indicates the shortest distance from the point of greatest vulnerability of the exterior of the tuyre to the copper-water surface, the ratio between X and Y may vary between one-quarter and three quarters.

As appears hereinabove. the present invention contemplates a tuyre having a heavy nose of a material having a high heat conductivity. This heavy nose is protected by the armoring nose l2, which has a higher melting point and lower heat conductivity than the material of said heavy nose of high heat conductivity. By reason of the construction referred to, globules of molten iron or the like which may momentarily encounter the armoring nose I2 do not immediately burn through said armoring nose. Heat communicated locally to the armoring nose l2 by such globules of molten material is (1) restrained by the relatively high heat resistance of the armoring nose to a suicientY extent so,

that thelunderlying copper is not quickly subjectedto` a melting temperature (for copper), `(2) conducted by the armoring nose back `into the copper with sufcient rapidity to prevent the iron noseitself from reaching a melting temperature (for iron), (3) distributed to some extent by the armoring nose so that the area of the copper body to which the heat is transmitted is greater than it would be if the globule contacted the copper body directly, (4) conducted around the tuyre by the heavy copper nose in a manner to distribute the heat to a wide area of copperwater surface, (5) restrained bythe long path through iron having high resistance and through copper to cause 'a heat gradient or temperature drop which prevents excessive temperatures at thelcopper-'water surfaces, which temperatures would be liable to cause formation of a steam lm and consequent loss. of cooling effectiveness, and (6) absorbed by the large mass of relatively cool copper which lies intermediate between the iron nose and the copper-water surfaces. 'Ihe armoring nose extends radially a sufficient distance substantially to conform to the conical outer surface of the body portion of the tuyre. In other words, said armoring nose extends radially at least to the locus of the outer periphery of the body portion of the tuyre.

In the claims forming part of this specification the heavy nose of copper and the like and its relation to the remainder of the body portion off the tuyre and to the armoring nose is expressed in different ways. As clearly disclosed in the drawing, the radial dimension Aacross the face of the armoring nose wall is less than the longitudinal dimension along the side of the outer side wall of said armoring nose. As also clearly shown in the drawing, the amount of iron or the like in the cross-section of the tuyre in the region forwardly of the water space is substantially equal to the amount of copper or the like in that region. As also shown in the drawing, the nose of ycopper and iron or the like extends beyond the extremity of the water space a distance not less than the radial section of the tuyrev at the extremity of said water space. Also, the nose of copper or the like extends beyond the water space av distance not less than half the distance from said water space to the forward extremity of the tuyre. The thickness of the nose wall of copper or the like forward of the water space l I is greater than the average thickness of the inner or outer side walls of the tuyre. The section of the nose of copper or the like in a transverse plane adjacent to the extremity of the water spa-ce is more than half the radial thickness of the tuyre wall in said plane.

Though certain preferred embodiments of the present invention have been described in detail, many modifications will occur to those skilled in the art. It is intended to cover all such modifications that fall within the scope of the appended claims.

What is claimed is- 1. A tuyre comprising a body portion of metalr having relatively high heat conductivity, said body portion having a water space therein and a preformed nose for said body portion in protective relationship to the nose region thereofand to the extremity of the outer side wall dening said water space, said preformed nose being secured to said body portion by surface adhesion,

said preformed nose comprising metal having a higher melting point and lower heat conductivity than the material of said body portion.

2. A tuyre comprising a body portion of copper, said body portion having a water space therein, said body portion having a solid, heavy annular nose portion projecting beyond the extremity of said Water space, and an armoring metal nose inI protective relationship to said heavy annular nose portion and to that section of said body portion encircling the outer extremity of said Water space, said armoring nose being of material having a higher melting point and lower heat conductivity than the material of said body portion, said armoring metal nose being secured to said copper body portion by surface adhesion, said armoring nose being sutilciently thick so that when its exterior surface is contacted by a globule of molten iron its copper contacting surface will have a temperature below the melting point of copper.

3. A tuyre comprising a body portion of copper, said body portion having a water space therein, said body portion having a solid heavy annular nose portion projecting beyond the extremity of said Water space, and a preformed armoring metal nose in protective relationship to said heavy annular nose portion, said armoring nose being of material having a higher melting point and lower heat conductivity than the material of said body portion, said armoring portion being secured to said copper body portion by surface adhesion, said armoring nose being suiciently thick so that when its exterior surface is contacted by a globule of molten iron its copper contacting surface will have a temperature below the melting point of copper.

GORDON FOX.

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