USRE19980E

USRE19980E - Tuyxre

Info

Publication number: USRE19980E
Authority: US
Publication date: 1936-05-26

Description

G. FOX ET AL May 26, 1936.

I TUYERE Original Filed May 14, 1954 4 Sheets-Shet 1 Inzfentfirs' Gordon May 26, 1936. I G. FOX ET AL TUYERE Original Filed May 14, v1934 Sheets-Sheet 2 Invenifirs Gordon F634.

rfiiur Jl/hifiomb.

G. FOX ET AL May 26, 1 936.

TIJYERE Original Filed May 14, 1954 4 Sheets-Shet 4 Infnf'a 601-5071 F52.

Reissued May 26, 1936 UNITED STATES TUYERE Gordon Fox and Arthur J. Whitcomb, Chicago, Ill., assignors to Freyn Engineering Company, Chicago, 111., a corporation of Maine Original No. 1,969,693,

dated August 7, 1934,

Serial No. 725,622, May 14, 1934. Application for reissue February 14, 1935, Serial No. 6,598

22 Claims.

The present invention relates to improvements in tuyres.

More particularly the present invention relates to improvements in tuyres such as are used in blast furnaces. Such tuyres are subjected to very high temperatures. Such high temperatures are due in part to direct radiation and conduction from the flames within the furnace and from the hot blast and in part to the conduction of heat directly from molten metal which has been splashed upon the tuyre or has otherwise contacted therewith. It has been common to cool blast furnace tuyres by attempting to circulate water through the interior chamber of the tuyre. It is a well known fact that a given amount of water which passes along a surface slowly has less cooling effect than water which passes that surface rapidly. Moreover, a given amount of water in a thick stream is less effective than in a thin stream which has more intimate contact. Also, as water is an extremely poor conductor of heat, unless the circulation of the water is good, it is very probable that steam is generated by the evaporation of a layer of water which lies immediately adjacent to the hot tuyere wall surface. This steam expands and thereby acquires a larger surface in contact with the cooling water. The heat of the steam is rather slowly absorbed by the water, causing the steam to be condensed and the temperature of the cooling water to be raised. According to certain prior practice with which applicants are familiar, the flow of water has not been effective in removing bubbles of steam from the wall surfaces, and the bubbles doubtless form a fairly efiicient heat insulation between the inner wall surface and the water, further exaggerating the required temperature difference to give the required heat transfer. A further objection which has applied to water-cooled tuyeres of designs with which applicants are familiar is that there is considerable danger that the steam generated will not be sufficiently promptly condensed but that because of its great volume it may diminish the amount of water circulated and cause the tuyere to become steam-bound.

An object of the present invention is to provide a water-cooled tuyere having improved means to cause the cooling water to take a circuitous path through passages of restricted area, thereby increasing the velocity of flow of said cooling water and increasing its cooling effectiveness.

A further object is to provide a tuyere which will expose increased area of cooling surface to the cooling water of the tuyere, particularly in those portions of the tuyere exposed to the most heat, such cooling surface having effective metallic connection for flow of heat from the exposed outer surfaces to the extended inner surfaces.

A further object is to provide a tuyere in which the stream of cooling medium is caused to pass in a relatively thin stream and thus to make intimate contact with the metal surfaces.

A further object is to provide a tuyre in which all of the water passing through the tuyere is caused to traverse all parts of the nose portion of the tuyere and thus to be available to meet emergency cooling requirements, such as splashes of molten metal.

A further object is to provide a tuyere which will combine the advantages of increasedvelocity of water flow with increased cooling area for dissipating the heat from the nose of the tuyere.

A further object is to provide a tuyre having means for dissipating heat from one portion of the tuyere to the other, thereby tending to equalize the temperatures of the various portions of the tuyre.

A further object is to provide an improved tuyere in which the temperature-equalizing means above referred to also serve to mechanically strengthen the tuyere to resist expansion and contraction stresses.

A further object is to provide an improved tuyere having the advantage that cooling water will be directed therethrough at relatively high velocity, the means for directing the cooling water at such high velocity also serving to minimize temperature differences in various parts of the tuyere, and also serving to increase the mechanical strength of the tuyre.

A further object is to provide a tuyere having means for increasing the effectiveness of heat transfer from the inner surfaces of the water chamber to the cooling water by increasing the velocity of flow of said water, and, in combination therewith, having conducting material of sufficient section, suitably disposed and suitably proportioned to bring to those water chamber surfaces, with moderate temperature gradients, the additional amounts of heat which they are enabled to dissipate because of the increased velocity of flow of cooling water past said surfaces.

A further object is to provide a tuyre having in the nose region thereof a liberal amount of metal which in normal operation will have low temperature and which will have good conductive relation (through close proximity and ample metallic section) with the exposed outer surfaces in the nose region of the tuyre as a means for absorbing heat from molten metal in a blast furnace or the like which may occasionally contact the tuyere in the nose region thereof.

A further object is to provide a tuyere which is economical to manufacture and which will have a relatively long life in service.

A further object is to provide a tuyere which will effectually meet the needs of commercial service.

Further objects will appear as the description proceeds.

Referring to the drawings- Figure l is an end view showing the base of a tuyre embodying the principles of the present invention;

Figure 2 is a longitudinal sectional view'taken along the plane indicated by the arrows 2-2 of Figure 1, the dotted lines representing the for ward barriers being omitted for clarity;

Figure 3 shows the nose end of the tuyere, the circle representing the base of the tuyre and the dotted lines representing the rearmost barriers being omitted for clarity;

Figure 4 is a view on an enlarged scale showing a portion of the structure illustrated in Figure 2;

Figure 5 is a fragmentary view showing a section taken along the plane indicated by the arrows 5-5 of Figures 2 and 4;

Figure 6 is a fragmentary view showing a section taken along the plane indicated by the arrows 6-6 of Figure 2;

Figure 7 is a fragmentary view showing a development on a plane surface of the curved surface indicated by the arrows l-l of Figure 6;

Figure 8 is an end view showing the base of a tuyere embodying a modified construction;

Figure 9 is a longitudinal sectional view taken along the plane indicated by the arrows 9-9 of Figure 8;

Figure 10 is an end view of the tuyere shown in Figures 8 and 9 but showing the nose end of said tuyre;

Figure 11 is a view on an enlarged scale showing a portion of the structure illustrated in Figure 9;

Figure 12 is a sectional view taken along the plane indicated by the arrows |2-|2 of Figure 9;

Figure 13 is a sectional view taken along the plane indicated by the arrows |3-|3 of Figures 9 and 11; and

Figure 14 is a sectional view taken along the plane indicated by the arrows I l-l4 of Figures 9 and 11.

Referring first to the embodiment of the present invention disclosed in Figures 1 to 7, said embodiment of the invention involves a twopart construction including the conical portion 20 and the back wall 2|. It is at present preferred to embody the tuyere in these two parts for convenience of manufacture, though if preferred the tuyre could be cast in one piece. According to the illustrated construction, however, the conical portion 20 and the back wall 2| are welded or otherwise united to form a rigid unitary construction. The conical portion of the tuyere 29 includes the outer wall 22 and the inner wall 23, which walls are coaxially disposed relative to each other. Said

walls

22 and 23 are united at the outer end of the tuyere by the nose wall'24. The annular space defined by the outer wall 22, inner wall 23 and nose wall 24 and back wall 2| constitutes a space for cooling fluid, and the present invention contemplates a construction of tuyre in which the cooling fluid is caused to enter from the rear end of the tuyere, passing directly to the nose portion of the tuyere, circulating back and forth longitudinally of the tuyre while it circulates circumferentially of the tuyere to the discharge point.

According to the structure shown in Figures 1 to 7, cooling fluid is admitted through the inlet opening 25 in the back wall 2| of the tuyere and is discharged through the outlet opening 26 located adjacent to said inlet opening 25. A partition wall 21 extends longitudinally of the tuyere between the coaxially disposed

Walls

22 and 23 from the back wall 2| to the nose wall 24. Said partition wall 21 is disposed between the inlet opening 25 and the discharge opening 25. Though only one inlet opening and one discharge opening are illustrated, it will be clear that a plurality of inlets and a corresponding number of outlets may be provided if preferred, a sufficient number of partition walls 21 being provided to insure the predetermined course of water from a certain inlet opening to a certain discharge opening, or that the inlet and outlet might be located in diametrically opposite parts of the back wall 2| and the water might pass in two parallel paths around the two halves of the tuyre, though the construction last mentioned is not preferred.

Water from the inlet opening 25 to the discharge opening 26 is directed in a predetermined path by means of a plurality of barriers, certain of which, indicated by the numerals 28-28, extend longitudinally from the back wall 2| toward the nose end of the tuyre. Said barriers 28-28 are radially disposed and are integrally united with the outer wall 22 and inner wall 23. Extending from the nose wall 24 toward the rear end of the tuyere are a plurality of radially disposed barriers 29-29, which barriers are integrally united with the nose wall 24, the outer wall 22 and the inner wall 23. Said barriers 29-29 are equispaced with respect to the barriers 28-28. Said barriers 29-29 extendto the region of and preferably beyond the extremities of the barriers 28-28, whereby water passing said barriers is forced to take a circuitous path, as clearly illustrated in Figure 7. In other words, there is preferably, tho-ugh not necessarily, an

overlapping relationship between the furthermost' extremities of the barriers 28-28 and the rearmost extremities of the barriers 29-29. The barriers 29-29 are connected to the nose wall by rounded corners and tapered from the nose wall 24 in such a manner as to permit the ready flow of heat thereto from said nose wall 24. The forward extremities of the barriers 28 are spaced from the inner surface of the nose of the tuyere a distance approximately equal to the spacing of the barriers 28 from the barriers 29-29, whereby the flow of cooling medium outwardly past one side of a barrier 28 and inwardly past the other side of said barrier is substantially uniform. This structure in combination with the tapering of the barriers 29-29 and the rounding of the corners between said barriers 29-29 and the nose wall results in substantially uniform cross-sectional area in the passageway in the nose of the tuyere out between each barrier 29 and an adjacent barrier 28 and back between said barrier 28 and the next barrier 29 and insureseffective contact at high velocity between the cooling medium and all portions of the metallic surfaces in the nose portion ofthe tuyere and practically eliminates the possibility of stagnant water and the formation of steam bubbles.

In addition to the barriers 28-28 and barriers 29-29, a partition 39 is provided, which partition is disposed coaxially with respect to the tuyre and extends inwardly from the nose wall 24 of the tuyere. Said partition is integral with the radially disposed barriers 29 and merges into said barriers in the manner illustrated in Figure 5. Said partition 30 is'also integral with the forward extremities of the radially disposed barriers 28-28. Said partition 38 forms a circumferential series of channels 3| adjacent to the inner wall 23, which channels are bounded by the radially disposed barriers 29-29. Said partition 38 also forms a circumferential series of channels 32 with respect to the outer wall 22, said channels being bounded at their extremities by the radially disposed barriers 29-29. Said partition wall 38 adjacent to each channel 3| and channel 32 tapers as it approaches the radial barriers 29-29 to effect the efficient transfer of heat from the nose wall 24 and the region adjacent thereto to the cooling water being circulated through the channels 3| and 32. The barriers 28-28 are tapered from their region of juncture with the partition 39 to the back wall 2|.

The partition 38 serves a quintuple function in that it helps to conduct heat from the nose portion of the tuyere in the vicinity between the barriers 29-29 to said barriers 29-29 and to said barriers 28-28. Said partition 38 also occupies a substantial amount of space and thereby restricts the oross-sectional area of the channels 3| and 32, thereby increasing the velocity of the cooling medium through these water channels. Said partition further divides the stream of cooling water into thin streams which thus have intimate contact with the cooling surfaces. Said partition 38 has the further function that it provides additional cooling surface. This partition further increases the amount of cool metal in the nose region of the tuyre, contributing to the absorptive ability of the metal of the tuyre to resist the substantially instantaneous effect of the splashing of molten metal within a blast furnace or the like.

It is preferred to so proportion the parts of the tuyere that the cross-sectional area of the chan nels 3| and 32 combined is only a small fraction of the water area of an ordinary watercooled tuyere of the same outsidedimensions. Inasmuch as all of the cooling fluid entering through the inlet 25 and discharging through the outlet 25 must pass through the channels 3| and 32, the velocity of the given quantity of water will be increased many times in that portion of the tuyere adjacent to the nose. This means that the heat dissipating surfaces in this portion of the tuyere will be many times as effective as they are in the ordinary water-cooled tuyere. Moreover, due to the radially disposed barriers 29 and the partition 30, the heat dissipating surfaces in the nose portion of applicants tuyere have been increased very materially. The increase in cooling surface and the increase in velocity over prior practice and the forced intimacy of contact of a thin stream results in a multiplication of heat dissipating ability. As a result, the relatively high heat transfer according to the present invention between the tuyere and the water will be accomplished with a relatively small difference in temperature between the metallic wall and the cooling medium. In practice, due to the eflicient heat transfer from the wall of the tuyere to the cooling fluid, no portions of the tuyere can attain a high temperature above the cooling medium. The low operating temperature of the tuyere metal has the advantage that it will greatly increase the safe absorptive ability of the metal in the nose part of the tuyere against the instantaneous effect of splashing of molten metal.

Due to the construction in which the outer wall 22 and inner wall 23 are connected by the barriers 28-28 and 29-29, which barriers are connected together by the partition 38, the advantage is obtained that the rate of heat transfer from the very hot portions of the tuyere to the cooler portions thereof is very greatly increased over prior practice. The

barriers

28 and 29 and the partition 38 therefore have the function of facilitating the maintenance of relatively uniform temperatures throughout the tuyere, and in addition they act as mechanical struts to resist the compression and tension stresses in the various parts of the tuyere set up by such temperature differences that do exist in actual service.

According to the preferred construction, the

outer wall 22 and inner wall 23 should be tapered,

that is-they should have a greater thickness in that portion of the tuyere adjacent to the nose wall 24 than in that portion of the tuyere adja cent to the base. This design has a double function of improving the ability of heat to pass from the nose wall 24 toward the base of the tuyere and restricting the passage for the flow of water near the nose of the tuyere, thereby increasing the velocity of the cooling fluid near the nose of the tuyere. The increased velocity near the nose of the tuyere is due to the reduced cross-sectional area of the passageway in the nose portion. The passageway in the nose defined by the barriers 29-29 and the adjacent end of the intermediate barriers 28-28 is less than half of the averageu cross-sectional area of said passageway in the base portion of the tuyere. In Figure 7 the broken line indicated by the letter A defines a plane located approximately at the region of mean crosssectional area of the base portion of the tuyere.-'

It will be noted that in the tuyre above described, the water passing through the. channels 3| and 32 is caused to impinge upon the surfaces of the barriers 29-29 and against the inner surface of the nose wall 24. The cooling medium, therefore, has a. scrubbing action upon the walls referred to, tending to carry away quickly any bubbles which might be formed. This characteristic is valuable in emergencies when hot molten metal contacts with the nose of the tuyere. In such cases the greatly accelerated heat dissipation and the scrubbing action referred to are very valuable in preventing the rapid accumulation of steam bubbles at the nose of the tuyre.

Though under all ordinary conditions the accumulation of bubbles of steam within the tuyere will be avoided in the practice of the present invention because of its low operating temperature, emergency conditions may be encountered such that bubbles of steam will be formed. To avoid the possibility of the tuyere becoming steambound,

small openings

33 and 34 may be provided in the barriers 28-28 at the region adjacent to the rear portion 2|. Referring to Figure 4, it will be noted that the barrier 28 illustrated therein has an opening 33 therethrough at its corner adjacent to the rear wall 2| and the inner wall 22. Said barrier 28 also has the opening 34 extending therethrough at the corner adjacent to the rear wall 2| and the outer wall 23. Said openings 33 .and 34 in the various barriers 28-28 will permit .steam or air to pass readily around the tuyere the numerals 2|, 22, 23 and 24 indicate, respectively, the rear wall, the outer wall, the inner wall, and the nose wall of the tuyere, said rear wall 2| being welded or otherwise rigidly united to the rear extremities of the outer wall 22 and the inner wall 23. The rear wall 2| is provided with the inlet opening 25 and the outlet opening 26. A partition wall 21 is provided between the inlet opening 25 and the outlet opening 26, which partition wall is disposed radially of the tuyere and is integrally united with the outer Wall 22 and the inner wall 23. Said partition wall extends the length of the tuyere from the rear wall 2| to the nose wall 24 to prevent the short-circuiting of the cooling fluid from the inlet opening 25 to the outlet opening 26,

The jacket provided by the rear wall 2|, outer wall 22, inner wall 23 and nose wall 24 is provided with a plurality of barriers to cause the cooling medium flowing from the inlet opening 25 to the outlet opening 26 to take a circuitous path, the flow of cooling medium adjacent to the nose of the tuyere being at high velocity. One of the barriers referred to is indicated by the numeral 35, which barrier is disposed circumferentially of the tuyre and. is for the greater part of its length circular in cross section, dividing the space between the outer wall 22 and the inner wall 23 into two annular spaces disposed coaxially with respect to the tuyre. Said barrier is intended to merge with the inner wall 23 at a region 36 adjacent to and between the inlet opening 25 and the outlet opening 26 whereby to provide an inlet pocket 31 communicating with the inlet opening 25 and an outlet pocket 38 communicating with the outlet opening 26. Said barrier 35 extends from the rear wall 2| to a region adjacent to but spaced from the inner surface of the. nose Wall 24.

.Disposed in spaced relationship with the region 36 and with one another are a plurality of radial barriers 39 extending from the inner wall 23 to said barrier 35. Said barriers 39-"9 extend from the rear wall 2| to the nose wall 24, merging into said nose wall 24 and being integral therewith. Radially disposed relative to the tuyere are a plurality of barriers 40-40 extending between the barrier 35 and the outer wall 22 of the tuyere. Said barriers 48-46 extend from the rear wall 2| to the nose wall 24, merging into said nose wall 24 and being integral therewith. Said barriers 40-40 are disposed symmetrically with respect to the barriers 39, the radial planes marking the barriers -40 being spaced substantially midway between the radial planes marking the barriers 39-39. Disposed in radial planes coincident with the barriers 39-39 are short barriers extending from the inner surface of the nose wall 24' to the plane indicated by the numeral 4 I. Said short barriers are indicated by the numerals :39a-39a and extend'between the inner Wall 23 and the annular barrier 35.

of the nose wall 24 to the plane indicated by the numeral 4|.

These last mentioned short barriers are indicated by the numerals Mia-40c and extend between the annular barrier 35 and the outer wall 22.

The barriers 46 form a plurality of passages adjacent to the rear end of the tuyere, which passages are disposed just inside of the outer wall 22 of the tuyere. Said passages, reading in a counterclockwise direction in Figure 12, bear the numerals 42 (which is a continuation of the inlet pocket 31), 43, 44, 45, 46, 41 and 48. Said passage 48 communicates with the outlet pocket 38 communicating with the outlet opening 26. Disposed symmetrically with the passages 42 to 48, inclusive, is a series of passages defined by the barriers 39-39, which passages are located adjacent to the inner wall 23 of the tuyere. Said passages, reading in a counterclockwise direction in Figure 12, bear the

numerals

49, 50, 5|, 52, 53 and 54. The barriers 39a and We provide a plurality of channels communicating with the passages 42 to 48, inclusive, and the passages 49 to 54, inclusive. Said channels, reading in a clockwise direction in Figures 13 and 14, bear the

numerals

55, 56, 51, 58, 59, 60, BI, 62, 63, 64, 65 and 66 disposed circumferentially in proximity to the outer wall 22 of the tuyere and the

channels

61, 63, 59,16, 1|, l2, 13, 14,15, 16,11 and 18 disposed circumferentially in proximity to the inner wall 23 of the tuyere. Remembering that the annular barrier 35 stops short of the nose wall 24 of the tuyre, it will be noted that a. continuous circuitous path is provided for the cooling medium from the inlet opening 25 to the outlet opening 26, which path conducts the cooling medium back and forth longitudinally of the tuyre along the short barriers 39a and 460. through the channels just referred to.

Tracing the course of the cooling medium, entry is made through the inlet opening 25 and inlet opening pocket 31 to the passage 42 into the channel 55. Said cooling medium passes around the forward extremity of the annular barrier 35 into the channel 61 in the-direction of the arrow between said channels in Figure 14. Said cooling medium passes rearwardly around the rear extremity of the corresponding short barrier 45a, thence forwardly in channel 68, past the forward extremity of the annular barrier 35 into the channel 56, thence rearwardly around the rear extremity of the short barrier 39a, and then forwardly in the channel 51, rearwardly in channel 69, forwardly in channel 19, rearwardly in channel 58, forwardly in channel 59, rearwardly in channel I I, forwardly in channel 12, rearwardly in channel 66, forwardly in channel 6|, rearwardly in channel 13, forwardly in channel l4,

rearwardly in channel 62 forwardly in channel 63, rearwardly in channel 15, forwardly in channel 26, rearwardly in channel 64, forwardly in channel 65, rearwardly in channel 11, forwardly in channel 18, rearwardly in channel 66. Said channel 66 communicates with the passage 48, outlet pocket 38 and outlet opening 26.

The outer Wall 22, the inner wall 23, the annular barrier 35, and the

radial barriers

39, 30, 3911 and 4311 all decrease in thickness from the region of the nose of the tuyre toward the rear of the tuyere, there-by facilitating the transfer of heat from the nose toward the cooler portions of the tuyere.

The radially disposed barriers serve not only as struts for resisting mechanical stresses but act as efficient heat conveyers to convey heat units'from very hot portions of the tuyere to the cooler portions thereof, preventing-the raising of any portion of the tuyere to destructive temperatures and minimizing the tendency to produce internal stresses. By reason of the radially disposed barriers and the annular barrier, a large area of cooling surface is provided and the velocity of the cooling medium through the tuyere, and particularly in the nose portion thereof, is increased over prior practice. Moreover, the water is caused to pass the surfaces in a thin stream and thus to make intimate contact therewith. Moreover, all the cooling water is caused to pass all areas of the nose portion of the tuyere. Though only one inlet opening and one discharge opening are illustrated, it will be clear that a plurality of inlets and a corresponding number of outlets may be provided if preferred, a sufficient number of partition walls 21 being provided to insure the predetermined course of water from a certain inlet opening to a certain discharge opening, or that the inlet nd outlet might be located in diametrically opposite parts of the back wall 2| and the water might pass in two parallel paths around the two halves of the tuyere, though, as stated above, the construction last mentioned is not preferred.

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. In a tuyere, in combination, walls providing an annular jacket for cooling medium, one of said walls having therein a water inlet and a water outlet, radial barriers in said jacket adjoining the nose of said tuyre, and means in said tuyere including partition means extending throughout the length of said annular jacket for causing cooling medium to flow back and forth in a single stream along said barriers while traveling circumferentially with respect to said tuyre from said inlet opening to said outlet opening.

2. In a tuyere, in combination, walls providing an annular jacket for cooling medium, one of said walls having therein a water inlet and a water outlet, a plurality of radially disposed barriers in said jacket extending rearwardly from the nose of said tuyere, a plurality of other radially disposed barriers extending from the rear of said tuyere to the region of the rearmost extremities of said first-mentioned barriers, said other barriers being spaced circumferentially with respect to said first-mentioned barriers, and partition means extending throughout the length of said annular jacket for limiting the flow of cooling medium from said inlet to said outlet to a single stream.

3. In a tuyere, in combination, walls providing an annular jacket for cooling medium, a plurality of radially disposed barriers in said jacket extending rearwardly from the nose of said tuyre, a plurality of other radially disposed barriers extending from the rear of said tuyere to the region of the rearmost extremities of said first-mentioned barriers, said other barriers being spaced circumferentially with respect to said first-mentioned barriers, and a circumferential partition wall extending from the nose of said tuyre into said jacket coaxially disposed with respect to said tuyre and dividing said jacket adjacent to the nose of said tuyre into radially spaced channels, said partition forming a junction between said first-mentioned barriers and said other barriers.

4. In a tuyere, in combination, walls providing an annular jacket for cooling medium, a plurality of radially disposed barriers in said jacket extending rearwardly from the nose of said tuyere, a plurality of other radially disposed bar- 5 riers extending from the rear of said tuyere to the region of the rearmost extremities of said first-mentioned barriers, said other barriers being spaced circumferentially with respect to said first-mentioned barriers, and a circumferential 10" partition wall extending from the nose of said tuyre into said jacket coaxially disposed with respect to said tuyre and dividing said jacket adjacent to the nose of said tuyere into radially spaced channels, said first-mentioned barriers 1 5 tapering in cross-sectional area from the nose end to the rear end of said tuyere.

5. In a tuyere, in combination, walls providing an annular jacket for cooling medium, one of said walls having therein a water inlet and a water outlet, a plurality of radially disposed barriers in said jacket extending rearwardly from the nose of said tuyere, a plurality of other radially disposed barriers extending from the rear of said tuyre to the region of the rearmost ex- 25' tremities of said first-mentioned barriers, said other barriers being spaced circumferentially with respect to said first-mentioned barriers, and partition means extending throughout the length of said annular jacket for limiting the flow of cooling medium from said inlet to said outlet to a. single stream, said other barriers having openings therein adjacent to the rear of said tuyere.

6. In a tuyere, in combination, walls providing 35 an annular jacket for cooling medium, an inlet opening and an outlet opening communicating with said jacket, a partition wall dividing said jacket throughout the length thereof to prevent the short-circuiting of coolingmedium from said 40 inlet opening to said outlet opening, and barriers disposed within said jacket for causing cooling medium to flow back and forth longitudinally of the tuyere in passing from said inlet opening to said outlet opening.

7. In a tuyre, in combination, walls providing an annular jacket for cooling medium, an annular barrier disposed within said jacket and extending from the rear of said tuyere to a region adjacent to but spaced from the nose end of said tuyere, and radially disposed barriers joining with said annular barrier and arranged for causing cooling medium in said jacket to flow back and forth longitudinally of said tuyere while traveling circumferentially thereof.

8. In a tuyere, in combination, walls providing an annular jacket for cooling medium, an annular barrier disposed within said jacket and extending from the rear of said tuyere to a region adjacent to but spaced from the nose end of said tuyere, and radially disposed barriers joining with said annular barrier and arranged for causing cooling medium in said jacket to flow in a tortuous course progressively, longitudinally, radially and circumferentially of said 65 tuyere.

9. In a tuyere, in combination, walls providing an annular jacket for cooling medium, an inlet opening and an outlet opening communicating with said jacket, a partition wall dividing said 70 jacket throughout the length thereof to prevent short-circuiting of cooling medium from said inlet opening to said outlet opening, a plurality of radially disposed barriers in said jacketextendingrearwardly from the nose of said tuyere 75 and tapering in cross-sectional area from the nose toward the rear end of said tuyere, and a plurality of other radially disposed barriers extending from the rear of said tuyere, said other barriers being spaced circumferentially with respect to said first-mentioned barriers.

10. In a tuyere, in combination, walls providing an annular jacket for cooling medium, an inlet opening and an outlet opening communicating with said jacket, a plurality of radially disposed barriers in said jacket extending rearwardly from the nose of said tuyere and a plurality of other radially disposed barriers extending from the rear of said tuyre, said other barriers being spaced circumferentially with respect to said first-mentioned barriers and a circumferential partition wall extending from the nose of said tuyre into said jacket coaxially disposed with respect to said tuyere and dividing said jacket adjacent to the nose of said tuyre into radially spaced channels.

11. In a tuyere, in combination, walls providing an annular jacket for cooling medium, an inlet opening and an outlet opening communicating with said jacket, a partition wall dividing said jacket to prevent short-circuiting of cooling medium from said inlet opening to said outlet opening, a plurality of radially disposed barriers in said jacket extending rearwardly from the nose of said tuyere and a plurality of other radially disposed barriers extending from the rear of said tuyre, said other barriers being spaced circumferentially with respect to said,

first-mentioned barriers and a circumferential partition wall extending from the nose of said tuyere into said jacket coaxially disposed with respect to said tuyere and dividing said jacket adjacent to the nose of said'tuyere into radially spaced channels.

12. In a tuyere, in combination, walls providing an annular jacket for cooling medium, an annular barrier disposed within said jacket dividing said jacket into inner and outer compartments, radially disposed barriers joining with said annular barrier, said annular barrier providing communication between said inner and outer compartments at a region adjacent to the nose of said tuyere, said annular barrier and said radially disposed barriers defining a circuitous path for cooling medium back and forth longitudinally of said tuyre and circumferentially of said tuyre.

13. In a tuyere, in combination, an inner wall, an outer wall, a'nose wall, and a back wall providing an annular jacket for cooling medium, a plurality of radially disposed barriers in said jacket extending rearwardlly from the nose of said tuyere and tapering in cross-sectional area from the nose toward the rear end of said tuyre, a plurality of other radially disposed barriers extending from the rear of said tuyere, said other barriers being spaced circumferentially with respect to said first-mentioned barriers, said inner wall and said outer wall decreasing in cross-section from said nose wall toward said back wall,

and a circumferential partition wall extending barriers extending from the rear of said tuyere to the region of the rearmost extremities of said first-mentioned barriers, said other barriers being spaced circumferentially with respect to said first-mentioned barriers, and a circumferential partition Wall extending from the nose of said tuyere into said jacket coaxially disposed with respect to said tuyere and dividing said jacket adjacent to the nose of said tuyere intoradially spaced channels, said first-mentioned barriers tapering in cross-sectional area from the nose end of the tuyere rearwardly.

15. In a tuyre, in combination, walls providing an annular jacket for cooling medium, radially disposed barriers in said jacket extending rearwardly from the nose of said tuyere, and a plurality of other radially disposed barriers extending from the rear of said tuyere, said other barriers being spaced circumferentially with respect to said first-mentioned barriers, said firstmentioned barriers extending rearwardly to the region of the forward extremities of said other barriers extending from the rear of said tuyereto the region of the rearmost extremities of said first-mentioned barriers, said other barriers being spaced circumferentially with respect to said first-mentioned barriers whereby to provide a series passageway for the flow of cooling medium, the cross sectional area of said passageway in the nose of said tuyere defined by said barriers being less than half of the average crosssectional area of said passageway in-the base of said tuyere defined by said barriers.

17. In a tuyere, in combination, walls providing an annular jacket for cooling medium, radially disposed barriers in said jacket extending, rearwardly from the nose of said tuyere, and a' plurality of other radially disposed barriers extending from the rear of saidtuyre, said other barriers being spaced circumferentially with respect to said first-mentioned barriers whereby toprovide passageways in said jacket at the nose of said tuyere, said passageways in the nose of said tuyere being of substantially uniform crosssectional area in the portions thereof defined by the forward extremity of each of said'other bar-- riers and the neighboring first-mentioned barriers adjacent thereto.

18. In a tuyere, in combination, walls provid-- ing an annular jacket for cooling medium, radially disposed barriers in said jacket extending rearwardly from the nose of said tuyre, and a plurality of other radially disposed barriers extending from the rear of said tuyre, said other barriers being circumferentially spaced with respect to said first-mentioned barriers, said firstmentioned barriers being located only in the nose region of said tuyre, said first mentioned barriers and said other barriers extending substantially to the same region longitudinally of said tuyre.

19. In a tuyere, in combination, a nose wall, an inner side wall, an outer side wall and a back wall'providing an annular jacket for cooling medium, said back wall having an inlet opening and an outlet opening, and means within said jacket for speeding up the flow of cooling medium in the nose portion of said tuyre relative to the flow of said medium in the portion of said tuyre adjacent to said back wall, the thickness of a side wall of said tuyre decreasing from the nose of said tuyre toward the rear thereof, said tuyre including partition means extending throughout the length of said annular jacket and barrier means for causing cooling medium to flow in a single stream back and forth circumferentially and longitudinally of said tuyere from said inlet opening to said outlet opening.

20. In a tuyere, in combination, Walls providing an annular jacket for cooling medium, a circumferentially disposed partition wall in said jacket extending from the nose of said tuyere coaxially with respect to said tuyere and dividing said jacket adjacent to the nose of said tuyere into radially spaced channels, and other partition means within said jacket providing a series passageway for the flow of cooling medium back and forth longitudinally and circumferentially of said tuyere through the nose region and the base region of said tuyere, the cross-sectional area of said passageway in the nose region of said tuyre being less than half the average cross-sectional area of said passageway in the base region of said tuyere.

21. In a. tuyere, in combination, walls providing an annular jacket for cooling medium, a circumferentially disposed partition wall in said jacket extending from the nose of said tuyre coaxially with respect to said tuyere and dividing said jacket adjacent to the nose of said tuyere into radially spaced channels, and partition means within said jacket for causing series flow of cooling medium through the nose portion and the base portion of said tuyere and for speeding up the flow of cooling medium throughout the nose portion of said tuyere relative to the flow of said medium in the portion of the tuyre adjacent to the base portion of said tuyere.

22. In a tuyere, in combination, walls providing an annular jacket, said walls having an in let and an outlet for the flow of cooling medium, and means for directing cooling medium in a single tortuous series path from said inlet to said outlet longitudinally and circumferentially of said tuyere, the thickness of a side wall of said tuyere decreasing from the nose region of said tuyre toward the rear thereof.

GORDON FOX. ARTHUR J. WI-HTCOMB.