US2041535A - Burner - Google Patents

Description

May 19, mm FRlScH 2,041,535

BURNER Filed Dec. 13, 1930 5 Sheets-Sheet l 60 INVENTOR May 19, 1936.

M. FRISCH BURNER Filed Dec. 13, 1930 3 Sheets-Sheet 2 M. FRISCH May 19, 1936.

BURNER I Filed Dec. 13, 1930 3 Sheets-Sheet 5 Patented May 19, 1936 UNITED STATES PATENT OFFICE BURNER poration of New York Application December 13, 1930, Serial No. 502,115

12 Claims.

My invention relates tothe art of fuel combustion and particularly to apparatus for promoting the combustion of powdered fuel.

One of the objects of my invention is to pro- 5 vide burner apparatus wherein the mixture of fuel and all the air is given a rotary whirling motion.

Another object of my invention is to provide means whereby the burner may be protected 10 from radiant heat from the furnace while the burner is out of operation but other burners are being operated.

Further objects and advantages of my invention will be apparent from the following descrip- 15 tion considered in connection with the accompanying drawings on which:

Fig. 1 is a longitudinal sectional view taken on the line |I of Fig. 2 of a preferred embodiment of my invention;

20 Fig. 2 is a front view, partially in section, taken on the line 2--2 of Fig. 1;

Fig. 3 is a cross-sectional detailed view taken on the line 3-3 of Fig. 1;

Fig. 4 is a cross-sectional view similar to Fig. 3

25 except that certain elements are shown in a different position;

Fig. 5 is a view of a preferred form of vane used in carrying out my invention;

Fig. 6 is a cross-sectional view taken on the 30 line 66 of Fig. 2;

Fig. '7 is a longitudinal sectional view of a somewhat modified embodiment of my invention and is taken on the line 1-1 of Fig. 8;

Fig. 8 is a cross-sectional view-taken on the 35 line 88 of Fig. '7; and

Fig. 9 is a longitudinal sectional View taken on the line 9-9 of Fig. 8.

Referring to the drawings, and more particularly to Fig. 1, reference character l designates 40 the brick wall of a furnace. Extending into a cylindrical aperture in the wall It) is a cylindrical shell I I provided at its inner end with an annular flange member l2 to which is secured, as by bolts l3, an end member [4 provided with a 45 central aperture. Secured within the central aperture is a burner mouth piece l which extends the rest of the way through the furnace wall and opens into the combustion chamber of the furnace. Additional brick work I 6 is provid- 50 ed around mouthpiece l5 and completely fills the annular space between the mouth piece and the wall l0.

Secured to the outer end of member I l is a secondary air chamber IT. This chamber comprises 55 a top l8, a front I9 and sides 20. The central portion of front I9 is provided with an opening axially in line with mouth piece l5. This opening is closed by a circular plate member 2! which is bolted to the outside of front l9. Secured to the inside of front l9 by means of bolts 22, which 5 bolts also secure plate 2| in position, is a fuel housing 23 which is provided with an annular chamber 24 formed outside of a cylindrical portion 25. A fuel supply conduit 26 passes through the top l8, as shown, of secondary air chamber I1 and communicates with annular fuel chamber 24. Vanes 21 and 28 are provided at the point where conduit 26 communicates with chamber 24 for the purpose of causing air and fuel admitted into the chamber to be given a whirling motion therein.

A series of bolts 29 extend from a flange 30 formed on the inner end of fuel chamber 24 and have their opposite ends secured to end member I4. A vane 3| is rotatably mounted on each bolt 29, the vanes being disposed about the fuel housing outlet and in close proximity thereto as clearly shown in the drawings. The shape of the vane is shown clearly in Fig. 5 and it will be seen that the inner corner of the vane adjacent to the outlet from fuel chamber 24 is cut away, as is designated by reference character 32. Accordingly that part of each of the vanes which is immediately adjacent the fuel housing outlet is disposed outside the zone of the fuel housing outlet and the other part of each vane has a portion which, extends farther toward the axis of the burner and when the vanes are fairly well open, projects into the zone of the fuel housing outlet as shown in Figs. 1, 3 and '7. By the expression zone of the fuel housing outlet as used herein and in the claims, is meant that area which extends directly outwardly or beyond the fuel housing outlet, or to the right of the fuel housing outlet as seen in Figs. 1 and 7, to the limits of, or to the right hand edges of the vanes as seen in the last mentioned figures.

Rotatably mounted on flange 30 is a ring 33 to the lower front portion of which is secured an arc-shaped member 34 provided with gear teeth which mesh with teeth formed on a pinion 35 carried by a shaft 36. Shaft 36 is journalled at 31 and 38 and is provided at its outer end with a worm wheel 39 which engages a worm 40 mounted on a shaft 4| to which is secured a hand wheel 42. An indicator 43 is secured to the front end of shaft 36 in order that the operator may know the position of the shaft.

Each vane 3| is provided with an arm 44 rigidly secured thereto. The other end of arm 44 is provided with a slot 45 which engages a pin 46 affixed to ring 33. Thus by rotating hand wheel 42, ring 33 is caused to rotate and arms 44 and vanes 3| are caused to rotate about bolts 29 and thus the inclination of the vanes and the area of the passageway between adjacent vanes is varied. In Fig. 3 the vanes are shown in open position while in Fig. 4 they are shown closed.

A secondary air conduit 41 communicates with the lower part of chamber I! and supplies air under pressure thereto from a blower or fan. Chamber I1 is supported in any suitable manner, as by I-beams 48.

Slidably mounted within cylindrical member 25 is a sleeve 49. A lug 59 is secured to the inner side of sleeve 49 near its front end and is provided with internal screw threads. A shaft extends through, and is journalled in, plate 2| and is provided with threads which engage the threads in lug 50. A cylindrical casing 52 is secured to lug 59 and encloses that portion of shaft 5| which extends beyond the lug. The outer end of shaft 5| is provided with a hand wheel 53,for manual rotation of the same. A collar 54 secured to the shaft cooperates with the hub 55 of wheel 53 toprevent axial movement of shaft 5| in plate 2|. By rotating wheel 53, lug 50, and consequently sleeve 49, are caused to move longitudinally. In the position shown in Fig. 1, the sleeve is in its extreme left hand, or withdrawn position. By rotating wheel 53 in the proper direction, sleeve 49 may be caused to advance toward the furnace until a shoulder 56 strikes a ball 51. In this position the inner end of the sleeve 49 will be in line with the inner ends of vanes 3|, and the sleeve will thereby protect the vanes from heat radiating from within the furnace. Sleeve 49 may also be used to affect the mixing of the fuel and the air by moving it a short distance from the position shown, to thereby direct the flow of the pulverized fuel subsequent to its discharge from the fuel outlet as will be explained later.

A sleeve damper 58 is slidably mounted within cylindrical member 25 near the outer end thereof. The inner side of sleeve damper 58 is provided with a lug 59 having internal screw threads formed therein. A shaft 60 passes through and is journalled within plate 2| and has a hand wheel 6| secured to the outer end thereof. A collar 62 is secured to shaft 60 and cooperates with hub 63 of wheel 6| to prevent axial movement of the shaft in plate 2|. Shaft 60 is provided with threads which engage the threads in lug 59 and a stop member 84 is secured to the inner end of the shaft. Thus, by rotating wheel 6|, sleeve damper 58 is caused to move longitudinally and, if moved to the right from the position shown in Fig. 1, will serve to decrease the area of an arcuate passage 65 formed in cylindrical member 25. Thus the quantity of air passing from chamber into cylindrical member 25 may be regulated at will.

An aperture 66 is formed in plate 2| and is closed by a window 61 through which the operation of the burner may be observed. If desired, an oil or gas burner tip may be placed in the center of the burner so that oil or gas, as well as powdered fuel, may be burned. In this event, the conduit supplying oil or gas to the burner tip would pass through plate 2| which would be the only part of the burner it would be necessary to alter.

The operation of the above described apparatus is as follows:

Powdered fuel and primary air is introduced into fuel chamber 24 through conduit 26. The presence of plates 21 and 28 at the inlet to chamber 24 causes the mixture of fuel and air to whirl about within chamber 24 and it passes out of the annular opening at the inner end of the chamber with a whirling motion.

Secondary air is admitted through conduit 41 into air chamber I! and passes through cylindrical member II and between adjacent vanes 3|. The fuel and primary air issuing from chamber 24 is attacked in the region of the cut-away portions of vanes 3| by secondary air passing between the vanes. Thus secondary air passes in a tangential direction due to the inclination of the vanes, as is shown in Fig. 3, and thus increases the whirling of the fuel and air mixture. Additional air, likewise passing in a tangential direction, enters between the remaining portions of the vanes and the whirling effect is further increased. By adjusting the inclination of vanes 3| by means of hand wheel 42 both the velocity of air and the amount of whirling may be regulated to any desired degree. In fact, the whirling and turbulence may, under certain conditions, be so great as to bring the flame back to the mouth of the burner, which is undesirable. In order to prevent this, provision is made whereby secondary air may be admitted through cylindrical member 25. Air so admitted has no whirling motion. Thus air is admitted through arcuate passageway 65 by moving sleeve damper 58 so as to open this passageway more or less. Ordinarily, it is not necessary to admit air through member 25 but it has been found in practice that it is desirable to provide means whereby such air may be admitted.

Further regulation of the whirling and mixing action may be obtained by moving sleeve 49 to the right from the position shown in Fig. 1, so that the fuel and air emitted from chamber 24 will be forced to pass between the vanes before passing to the center of the burner.

Means are thus provided for controlling the turbulence of the fuel and air mixture in two separate zones or stages after the discharge of the primary air and fuel mixture from the fuel housing outlet. The first zone or stage is defined by the cut-out portions 32 of the vanes 3| and the second zone or stage is defined by the remaining portion of the vanes 3|. The first zone or stage is thus immediately adjacent the fuel housing outlet while the second is remote from the fuel housing outlet and adjacent the first zone or stage. In each zone, the vanes 3|, control the turbulence of the fuel and air mixture by controlling the velocity of the secondary air passing between the vanes and by controlling the radius of the whirling fuel and air mixture. Since turbulence is directly dependent upon the product of the velocity and the radius of the whirling fluid or mixture, the control of the position of the vanes 3|, controls both the radius and velocity of the whirling mixture in both zones or stages and accordingly controls the turbulence of the mixture in both zones. Except when the vanes are in their closed or nearly closed position, the radius of whirl is greater in the first than in the second zone. As a result, this inven tion provides a control of the turbulence of the fuel and air mixture by means of a single set of vanes which is substantially equivalent to the control that would be obtained with two separate sets of vanes. As a result, great flexibility and range of control of the burner is obtained,

thus providing stable combustion at lower burner ratings or capacities as well as at high ratings. Consequently, with the burner of the present invention, it is possible to burn low volatile fuels at low ratings with stable combustion.

In Figs. 7 through 9 is illustrated a modified embodiment of my invention. The device here shown is the same as that shown in Figs. 1 through 5, except that the arrangement of the sleeves in the central part of the burner is modified. This form of the device comprises a fuel housing 23 provided with a cylindrical portion 25 around which is formed the annular chamber 24. Housing 23 is secured to the front wall of the secondary air chamber I! by means of bolts 22. Bolts 29 extend through the flange 30 formed on housing 23 and through the end member I4. Rotatably mounted on bolts 29 are vanes 3|, only two of which have been shown in Fig. '7, inasmuch as the construction in this respect is the same as that shown in Fig. 1.

Mounted within cylindrical portion 25 is a longitudinally movable sleeve member 10. Sleeve 10 is mounted on a plurality of ball bearings H and H. Ball bearings H are retained in a groove 12 formed in cylindrical member 25 and in a groove 13 formed in sleeve 10, while ball bearings H are retained in groove 12 and in a depression 13. Ball bearings H and H are disposed around sleeve ID at a number of equally spaced points, as is shown in Fig. 8. Secured to the inner lower part of sleeve 10 is a lug 14 in which is formed a screw thread. A shaft 15 is journalled in plate member 2| and is provided with a screw thread which engages the thread in lug M. The outer end of shaft 15 is provided with an operating handle 16 and the shaft is provided with collars TI and 18 which prevent axial movement of the shaft. A casing 19 is secured at one end to lug l4 and serves to enclose the portion of shaft 15 which extends through the lug. Thus by rotating shaft 15, sleeve ill may be caused to move in a longitudinal direction and may be moved to the position shown by the dash-dot line shown in Fig. 7 or to any intermediate position. Further movement to the right is prevented by the end of groove 13 coming in contact with ball bearing 1 l.

Mounted within sleeve 10 is an inner sleeve 80 which is mounted for longitudinal movement on ball bearings 8| and 82. Ball bearings 81 are placed between cylindrical portion 25 and a flange 83 formed on the end of sleeve 80. Ball bearings 82 are placed between sleeve 80 and sleeve 10. Sleeve 80 is formed with an offset portion 84 at the point adjacent to lug 14 on sleeve 10. This offset portion allows a space for the shaft 15 and lug 14. A plate 85 may be provided and secured to sleeve 10 to substantially close the passageway between sleeves 18 and 80 at the place of the offset portion 14.

A lug B6 is secured to the interior of sleeve 80 and is provided with an internal screw thread. A shaft 81 extends through plate member 2! and is provided at its outer end with an operating handle 88. Shaft 81 is provided with a screw thread which engages the screw thread formed in lug 86. A casing 89 is secured to lug 8S and encloses the inner end of shaft 81.

The operation of this device is similar to the device shown in Figs. 1 through 6. A mixture of primary air and powdered fuel is introduced into fuel housing 24 and passes therefrom through the annular opening into the space surrounded by vanes 3|. Secondary air is admitted to chamber l1 and passes between vanes 3| and attacks the fuel and produces whirling of the fuel and air before the mixture is admitted to the furnace. If the whirling is greater than desired, secondary air may be admitted to the central part of the burner by moving sleeve 80 to the position shown in full in Fig. 7, so that air may pass through openings 65 in housing 25 and thence through sleeve 80 to the space surrounded by the vanes. However, such air is not ordinarily required and to prevent its admission, sleeve 80 may be moved to its extreme left hand position, whereupon it blocks off passages 65. When sleeve 80 is in this closed position, a small amount of air will leak between sleeves 80 and 10 and thus find its way into the central portion of the burner. This leakage is kept at a minimum by extending sleeve 80 a substantial distance within sleeve 10 so as to provide a long narrow passageway between the two which offers a large resistance to the passage of air therethrough. The air which does pass through this passage has a high velocity, due to the small cross-sectional area of the passage, and hence serves to prevent the accumulation of fuel dust between the sleeves and. between the outer sleeve and the fuel housing. The amount of air passing into the central portion of the burner in this manner is not sufficient to affect the mixing action of the burner and is highly desirable from the point of view of scavenging. Inner sleeve 80 is necessarily offset at 84 in order to provide a space for shaft 15. In order to prevent undue leakage of air through this space, plate 85 may be arranged to substantially block off the opening. Sufficient air will, however, leak past plate 85 to keep the space free from fuel dust.

I have found that a vane designed with the corner cut away as herein described, greatly increases the whirling and turbulence of the mixture of air and fuel over that which is obtainable through the use of a vane having a straight face. Such a design provides an annular gap within which the mixture of fuel and primary air may be attacked by tangential jets of secondary air, which intensifies the whirling of the fuel mixture and forces it toward the center of the burner where the rest of the secondary air entering the burner in a series of high velocity tangential jets between the straight portions of the vanes completes the mixing and increases the whirling to any degree desired.

While I have shown and described two preferred forms of apparatus for carryingout my invention, it is to be understood that changes may be made in the form, location and arrangement of the several parts thereof without transcending the principle of the invention and that no intention is entertained to limit the invention except by the scope of the appended claims.

What I claim is:

l. A burner for pulverized fuel comprising a fuel housing having an annular outlet, means for supplying pulverized fuel to the housing for discharge through said outlet, means for imparting a whirling motion to the fuel in said housing so that the fuel is in whirling motion when discharged from said outlet, a plurality of inclined vanes disposed about the fuel housing outlet in close proximity thereto and means for supplying air to said vanes for passage therebetween and mixture with the pulverized fuel discharged from said outlet, each of said vanes being arranged so that the portion thereof immediately adjacent the fuel housing outlet is disposed outside of the zone of the fuel housing outlet to provide a space immediately adjacent the fuel housing outlet, wherein the air passing between said portions of said vanes may attack the fuel to increase the whirling motion of the fuel, each of said vanes having a portion spaced from said fuel housing outlet which extends farther toward the axis of the burner than the portion immediately adjacent the fuel housing outlet so that the air passing between the last mentioned portions of the vanes may further increase the whirling motion of the fuel.

2. A burner for pulverized fuel comprising a fuel housing having an annular fuel outlet, said housing being provided with an air passage having an outlet disposed interiorly of the annular fuel outlet, means for supplying pulverized fuel to the housing for discharge through said fuel outlet, a plurality of inclined vanes disposed about the fuel housing outlet in close proximity thereto, means for supplying air to said vanes for passage therebetween and mixture with the pulverized fuel discharged from said fuel outlet, each of said vanes being arranged so that the portion thereof immediately adjacent the fuel outlet is disposed outside of the zone of the fuel outlet and another portion of the vane spaced from said outlet extends farther toward the axis of the burner than the portion immediately adjacent the outlet, and means for introducing air into said air passage so as to flow therethrough toward the vanes.

3. A burner for pulverized fuel comprising a fuel housing having an outlet, an air passage in said fuel housing having an inlet and an outlet, the air passage outlet being disposed interiorly of the fuel housing outlet, means for supplying pulverized fuel to the housing for discharge through said fuel outlet, a plurality of vanes disposed about the fuel housing outlet in close proximity thereto, means for supplying air to said vanes for passage therebetween and mixture with the pulverized fuel discharged from said fuel outlet, a sleeve movably mounted in the fuel housing in said air passage, means for moving said sleeve into the area bounded by said vanes, a movable sleeve disposed outside of said air passage, and means for moving said last men-' tioned sleeve toward and from the inlet end of said air passage to vary the area of said air passage inlet and thereby control the volume of air admitted into said air passage.

4. A burner for pulverized fuel comprising a fuel housing having an outlet, an air passage in through said fuel outlet, a plurality of vanes disposed about the fuel housing outlet in close proximity thereto, means for supplying air to said vanes for passage therebetween and mixture with the pulverized fuel discharged from said fuel outlet, a sleeve movably mounted in the fuel housing in said air passage, means for moving said sleeve into the area bounded by said vanes, a second sleeve disposed in said air passage, and meansfor moving said second sleeve to extend beyond the inlet of said air passage to vary the area of the inlet of said air passage to thereby control the volume of air admitted into said air passage.

5. A burner for pulverized fuel comprising a fuel housing having an outlet, means for supplying pulverized fuel to the housing for discharge through said outlet, a plurality of movable inclined vanes disposed about the fuel housing outlet in close proximity thereto, and means for supplying air to said vanes for passage therebetween and mixture with the pulverized fuel discharged from said outlet, said vanes being so constructed that the portions thereof which are more remote from the fuel housing outlet extend farther toward the axis of the burner than the portions immediately adjacent the outlet when the vanes are in open position.

6. A burner for pulverized fuel comprising a fuel'housing having an outlet, means for supplying pulverized fuel to the housing for discharge through the outlet, a plurality of inclined vanes disposed about the fuel housing outlet in close proximity thereto, the vanes being movable about axes substantially parallel to the longitudinal axis of the fuel housing outlet, means for supplying air to the vanes for passage therebetween and 15 mixture with the pulverized fuel discharged from the outlet, said vanes being so constructed that the portions thereof which are more remote from the fuel housing outlet extend farther toward the axis of the burner than the portions immediately proximity thereto, the vanes being movable about axes substantially parallel to the longitudinal axis of the fuel housing outlet, means for supplying air to the vanes for passage therebetween and mixture with the pulverized fuel discharged from the outlet, said vanes being so constructed that the portions thereof which are more remote from the fuel housing outlet extend farther toward the axis of the burner than the portions immediately adjacent the outlet when the vanes are in open position, means for moving the vanes about their respective axes to vary the turbulence of the fuel and air mixture, the fuel housing having an axially disposed passage, and means disposed in said passage and movable beyond the fuel housing outlet for directing the fuel discharged from the outlet into the space between the vanes and for protecting the vanes against heat radiated toward the burner.

8. A burner for pulverized fuel comprising a fuel housing having an outlet, means for supplying pulverized fuel to the housing for discharge through the outlet, a plurality of inclined vanes disposed about the fuel housing outlet in close proximity thereto, the vanes being movable about axes substantially parallel to the longitudinal axis of the fuel housing outlet, means for supplying air to the vanes for passage therebetween and mixture with the pulverized fuel discharged from the outlet, said vanes being so constructed that the portions thereof which are more remote from the fuel housing outlet extend farther toward the axis of the burner than the portions immediately adjacent the outlet when the vanes are in open position, means for moving the vanes about their respective axes to vary the turbulence of the fuel and air mixture, the fuel housing having an axially disposed passage through which air is conducted to the area bounded by the vanes, and movable means cooperating with the inlet end of the passage for controlling the quantity of air admitted to the passage.

9. A burner for pulverized fuel comprising a fuel housing having an outlet, means for supplying pulverized fuel to the housing for discharge through the outlet, a plurality of inclined vanes disposed about the fuel housing outlet in close proximity thereto, the vanes being movable about axes substantially parallel to the longitudinal axis of the fuel housing outlet, means for supplying air to the vanes for passage therebetween and mixture with the pulverized fuel discharged from the outlet, said vanes being so constructed that the portions thereof which are more remote from the fuel housing outlet extend farther toward the axis of the burner than the portions immediately adjacent the outlet when the vanes are in open position, and means for moving the vanes about their respective axes to vary the turbulence of the fuel and air mixture, said fuel housing having an axially disposed passage through which air is conducted axially to the area bounded by the vanes.

10. A burner for pulverized fuel comprising a fuel housing having an outlet, means for supplying pulverized fuel to the housing for discharge through the outlet, a plurality of inclined vanes disposed about the fuel housing outlet in close proximity thereto, the vanes being movable about axes substantially parallel to the longitudinal axis of the fuel housing outlet, means for supplying air to the vanes for passage therebetween and mixture with the pulverized fuel discharged from the outlet, said vanes being so constructed that the portions thereof which are more remote from the fuel housing outlet extend farther toward the axis of the burner than the portions immediately adjacent the outlet when the vanes are in open position, means for moving the vanes about their respective axes to vary the turbulence of the fuel and air mixture, said fuel housing having an axially disposed passage through which air is conducted to the area bounded by the vanes, and means for controlling the quantity of air admitted to said passage.

11. A burner for pulverized fuel comprising a fuel housing having an outlet, means for supplying pulverized fuel to the housing for discharge through the outlet, a plurality of inclined vanes disposed about the fuel housing outlet in close proximity thereto, the vanes being movable about axes substantially parallel to the longitudinal axis of the fuel housing outlet, means for supplying air to the vanes for passage therebetween and mixture with the pulverized fuel discharged from the outlet, said vanes being so constructed that the portions thereof which are more remote from the fuel housing outlet extend farther toward the axis of the burner than the portions immediately adjacent the outlet when the vanes are in open position, means for moving the vanes about their respective axes to vary the turbulence of the fuel and air mixture, said fuel housing having an axially disposed passage through which air is conducted axially to the area. bounded by the vanes, and means for controlling the quantity of air admitted to said openmg.

12. A burner for pulverized fuel comprising a fuel housing having an outlet, means for supplying pulverized fuel to the housing for discharge through the outlet, means for imparting a whirling movement to the fuel discharged from the fuel housing outlet, a plurality of inclined vanes disposed about the fuel housing outlet in close proximity thereto, the vanes being movable about axes substantially parallel to the longitudinal axis of the fuel housing outlet, means for supplying air to the vanes for passage therebetween and mixture with the pulverized fuel discharged from the outlet, said vanes being so constructed that the portions thereof which are more remote from the fuel housing outlet extend farther toward the axis of the burner than the portions immediately adjacent the outlet when the vanes are in open position, means for moving the vanes about their respective axes to vary the turbulence of the fuel and air mixture, said fuel housing having an axially disposed passage through which air is conducted without rotation to the area bounded by the vanes, and means for controlling the quantity of air admitted to said passage.

MARTIN FRISCH.

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