US2111929A - Burner - Google Patents

Description

March 22, 1938.

R. M. HARDGROVE BURNER 5 Sheets-Sheet 1 Original Filed Aug. 14, 1930 W-IWIK M ATTORNEYS NVENTOR I 777,

.Illllv March 22, 1938. R. M. HARDGROVE- 2,111,929

BURNER Original' Filed Aug."14, 1930 3 Sheets-Sheet 2 ATTOR N EYS March 22, 1938.

R. M. HARDGROVEv 2,111,929

BURNER l Original Filed Aug. 14, 1930 Y 3 Sheets-Sheet 3 u y Ma 22% Patented Mar. 22, 1938 BURNER Ralph M. Hardgrove, Westfield, N. J., assigner, by mesne assignments, to The Babcock & Wilcox Company, Newark, N. J., a corporation of New Jersey Application August 14, 1930, Serial No. 475,155

Renewed September 6, 1934 i 13 claims.

This invention relates to a burner which is especially useful for burning nely divided solid fuel, such as pulverized coal.

The invention will be understood from the description in connection with the accompanying drawings in which Fig. 1 is a vertical section through an illustrative embodiment of the invention, taken on the line I--l of Fig. 3; Fig. 2 is a View from within thefurnace of the structure lo shown in Fig. l.; Fig. '3 is a plan View partly in section showing the burner; and Fig. 4 is a vertical section 'taken on the line 4*-4 of Fig. 1.

In the drawings, reference character I indicates a furnace having a series of transversely l5 spaced vertically disposed tubes 2 extending along one of its vertical walls. The tubes 2 have their ends connected to a header outside of the furnace and may have water or other cooling fluid circulated through them in the well known o Way. The tubes are covered with blocks 4 at their furnace sides to provide a continuous wall. Some of the blocks 4 are omitted to provide a horizontally elongated rectangular burner port across which the tubes 2 extend inyuniformly spaced relation. A pulverized fuel burner is arranged to discharge pulverized fuel and Avcombustion air throughv theintertube spaces of the burner port. The fuel burner comprises a downwardly inclined `distributing conduit 5for pul- 30 verized fuel and primary air which tapers vertically and vflares horizontally to its lower end which extends across substantially all of the tubes 2 within the burner port.

The conduit 5 is connected at its outer and upper end to a supply connection 6 providedwith a `sloping impact plate I against which the mixture Yof air `and pulverized fuel from Yany convenient source impinges so that the mixture will, be spread out laterally and substantially uniformly distributed in the conduit 5. `An outlet ory nozzle section 8, preferably a metal casting, is detachably connected to the exit end of the conduit 5. The outlet section` 8 extends the full width of the conduit 5 and is provided withV diverging upper and lower walls having curved recesses therein fitting closely against the tubes 2 to provide good thermal contact therebetween and thus maintain the section 8 at a satisfactory operating temperature by preventing it from being overheated by 50 radiant heat from the furnace. The portionsof alternate tubes 2 within the limits of the outlet section 8 have Vcrescent shaped shields 8a, as shown in Fig. 3, along their cuter sides. The described bur-nerpartsk andtubes jointly define a 55 series of transversely spaced {vertically elongated fuel nozzles discharging through the intertube spaces of the burner port.

The portions of the intertube spaces above and below the outlet section 8 serve as secondary air inlet ports I0 and Il respectively. The lower air 5 port I I is of greater cross-sectional area than the corresponding upper port l0 permitting Ymore air to be introduced below the entering fuel and primary air stream than above it. The introduction of a greater quantity of'air below the fuel stream lo is generally desirable-'as there is a better resultant mixture securedasthe fuel streams are discharged downward while the tendency for the heated air is to rise toward the furnace outlet. In this way there is less possibility of air short-circuiting` to 15 the furnace outlet before coming in contact with the fuel and there is less possibility of the coarse fuel particles that are discharged dropping to the furnace floor or not coming into contact with the proper amount of combustion air before leaving .20 the furnace.

Drip ledge blocks 9 are mounted 'on the wall cooling tubes 2 directly above the upper secondary air ports I0 with their side towards the furnace sloping so that they extend inwardly a short distance into the furnace. TheseY blocks provide a ledge projecting out from the plane of the burner wall from which the molten slag, which runs down the wall, may drip and therefore obviates plugging up either the subjacent fuel nozzles or the secondary airports I0 and Il.

Angle-irons I2 and I3'are mounted on and extend along the outside of the furnace wall and are connected to brackets I4 on the conduit 5 by means of turnbuckle rods l5 to hold the conduit y35 5 and outlet section 8 in position relative tothe furnace wall.

A row of deil'ecting blocks I6 is provided along the furnace side of the tubes-2 opposite theafuel nozzles, These blocks I6 may be held `in place 40 against the tubes 2 by means of U-bolts II extending around the shields 8a, The blocks I6 are provided with curved surfaces to t against the tubes and with countersunk openings I9 for nuts on the ends of the U-bolts Il. Heat conducting cement is preferably placed between the curved surfaces and the tubes 2- to secure good thermal contact. The sides of the blocks IB toward the fuel nozzles are rounded, as indicated atZ, to divide the corresponding streams of incoming fuel into two sections, one inclined upwardly and the other downwardly, so that these streams of fuel will be struck by the air enteringl through the ports ,I0 and I I substantially at right angles. Theblocks I6 are shaped to divide each 55 stream of fuel into two unequal portions and deect the larger portion downwardly into the furnace. Adajacent upper fuel stream portions tend to merge after leaving the deflector blocks into a substantially continuous sheet extending the full width of the burner port. The lower fuel stream portions similarly form a lower sheet of fuel.

By maintaining the blocks I6 and the outlet section 8 in a cool condition, the pulverized fuell is prevented from depositing and coking on them. Such a deposit would not only interfere with the proper functioning of the burner with respect to the discharge of fuel but this coking would cause rapid destruction of the burner metallic parts.

Dampers 23 are pivoted at 24 to a bracket 25 above the air ports IU and dampers 26` pivotally attached at 21 to arms 28 pivoted at 29. Rods 3U are provided for operating the dampers 23 and 26, so that the secondary air inlets Ill andV Il kcan be partially or entirely closed.

A secondary air casing 3| surrounds the burner port and describedk burner parts and may be supplied with air under pressure in any convenient way. The casing 3| is supported on the furnace Wall tubes by means of angle bars so that it and the conduit will move Vup and downwith the tubes 2 as they expand and contract due to changes in temperature.

A tubular member 32 for a lighter may extend through the air casing 3| into proximity to the fuel nozzles for lighting olf the burner. The outlet of the tubular member 32 is located at or near the centerof the burner port, as shown in Fig. 2, so that the lighter flame willv be directed beneath the middle of the lower set of coal and air streams. A sleeve 33 having air ports 34 is mounted near the lower end of the tubular member 32 so that secondary air from the casing 3| may be allowed to flow through the tubular member 32 when the burner is in normal operation, thereby keeping the tubular member 32 cool and also preventing pulverized coalV or neash or slag from finding its Way back into this tube from the opening in the furnace. The sleeve 33 can be rotated by a rod 35 that extends to the outside of the casing 3| through a pair of spaced cams 36 on the rod fitting between and moving spaced pairs of lugs 31 on the sleeve 33 so that the air openings 34 can be brought into register with corresponding openings through the wall of the tubular member 32, or the sleeve 33 can be turned to decrease the amount of air entering or shut it off entirely.

With the described burner construction, the flame of the burning fuel is projected into the furnace somewhat downwardly, which direction is especially useful where such burners are installed on opposite sides of the furnace as this will result in a very thorough mixing of the products of combustion and air. Also, by inclin- Ving the burner fuel conduit parts downwardly, the danger of fuel particles lying or lodging therein is obviated, even when the velocity of the incoming air is small. An inclination of about 16 from the horizontal has been found to be quite satisfactory in operating a burner of this type, although other inclinations may be used.

Certain subject matter disclosedherein is disclosed and claimed in my prior copending application Serial No. 387,214, filed August 20, l1929.

I claim:

1. In a furnace wall, upwardly disposed spaced tubes, a burner having a nozzleportion extending transversely across a plurality of said tubes to discharge streams of fuel and air therebetween, and means in thermal Contact with said tubes to divide each stream of fuel and air from said burner into two unequal sheets and project the greater sheet downwardly within the furnace.

2. In a furnace wall, upwardly disposed spaced tubes, a burner having a nozzle portion extending transversely across a plurality of said tubes to discharge streams of fuel and air therebetween, and a deflecting block in thermal contact with said tubes in front of said nozzle portion to divide each stream of fuel and air from said burner into two sheets, said deflecting block havlng a greater extent downwardly of the furnace than upwardly in order to project the greater portion of the fuel and air stream downwardly within the furnace.

3. In a furnace wall, upwardly disposed spaced tubes, a burner downwardly inclined to the plane of the wall, said burner having a nozzle portion extending transversely across a plurality of said tubes to discharge streams of fuel and air therebetween, and a deflecting block in thermal contact with said tubes in front of said nozzle portion to divide each stream of fuel and air from said burner into two sheets, said deflecting block having a greater extent downwardly of the furnace than upwardly in order to project the'greater portion of the fuel and air stream downwardly within the furnace.

4. In a furnace wall, upwardly disposed spaced tubes, a burner downwardly inclined to the plane of the wall, said burner having a nozzle portion extending transversely across a plurality of said tubes to discharge streams of fuel and air therebetween, and a deflecting block in thermal contact with said tubes in front of said nozzle portion to divide each stream of fuel and air from said burner into two sheets, said deflecting block having a greater extent downwardly of the furnace than upwardly in order to project the greater portion of the fuel and air stream downwardly within'the furnace, in combination with means to cause one stream of air to enter the furnace through the furnacewall above said nozzle portion and a larger stream offair to enter the furnace beneath said nozzle portion.

5. In combination, a Vertical furnace wall, a fuel burner arranged to discharge a stream of fuel through said wall, means for dividing said fuel stream into two unequal portions and deecting the larger portion downwardly within the furnace, an air port in said wall above said fuel burner, and an air port in said wall below said fuel burner ofrgr'eater cross-sectional area than said first named airport.

v6. In combination, a vertical furnace wall, a fuel burner arranged to discharge a stream of fuel through said wall, means for dividing said fuel stream into two unequal portions and deiiecting the larger portion downwardly within the furnace, an air port in said wall above said fuel burner, an air port in said wall below said fuel burner of greater cross-sectional area than said first named air port, and means for introducing air for combustion through said air ports in streams impinging on corresponding portions of said fuel stream.

7. In combination, a vertical furnace wall, a

'fuel burner arranged to discharge a stream of fuel through said wall, means for dividing said fuel stream into two unequal portions and deiiecting the larger stream downwardly within the ffurnace, air ports in said wall above and below said fuel burner, means for introducing air for combustion through said air ports in streams impinging on corresponding portions of said fuel stream, and damper means for controlling each of said air ports.

8. In combination, a vertical furnace wall comprising a pair of vertically arranged transversely spaced cooling tubes, a fuel burner arranged to discharge a fuel stream between said tubes, and means in thermal contact with said tubes for dividing said fuel streams into two unequal portions and deflecting the larger portion downwardly at the inner side of said furnace wall.

9. In combination, a vertical furnace wall comprising a pair of vertically arranged transversely spaced cooling tubes, a fuel burner having a downwardly inclined conduit terminating in a nozzle arranged to discharge a fuel stream between said tubes, and means for dividing said fuel stream into two unequal portions and deflecting the larger portion downwardly at the inner side of said furnace wall.

10. VInv combination, a vertical furnace wall having a fuel burner port formed therein and a Y series of vertically arranged horizontally spaced cooling tubes extending across said burner port,

a fuel burner having a downwardly inclined conduit terminating in a nozzle portion extending across said tubes and arranged to discharge fuel streams between said tubes, means in thermal contact with said tubes for dividing each fuel Astream into two portions, and said burner port providing openings for the passage of combustion air between said tubes above and below said nozzle portion.V

11. In combination, a vertical furnace wall comprising a pair of vertically arranged transversely spaced cooling tubes, a fuel burner arranged to discharge a fuel stream between said tubes, means in thermal contact with said tubes for dividing said fuel stream into two unequal portions and deiiecting the larger portion downwardly, openings for the passage of combustion air between said tubes above and below said nozzle, and the opening below said nozzle being of greater area than that above said nozzle.

12. In combination, a furnace wall, a fuel burner arranged to discharge a fuel stream through said wall, an air box surrounding said fuel burner, means for discharging combustion air from said air box through said wall adjacent the point of fuel discharge and in a direction to commingle with the fuel stream adjacent said wall, a lighting torch conduit extending through said air box and opening through said wall adjacent the point of fuel discharge, and said conduit having an opening therein for the entrance of air from said air box.

13. In combination, a furnace wall having a series of vertically arranged spaced cooling fluid tubes, a fuel burner arranged to discharge a fuel stream between said tubes, an air box surrounding said fuel burner, means for discharging cornbustion air from said air box between said tubes adjacent the point of fuel discharge and in a direction to commingle with the fuel stream adjacent said wall, a lighting torch conduit extending through said air box and opening between said tubes adjacent the point of fuel discharge, and means forming an adjustable opening for the passage of air from said air box into said conduit.

RALPH M. HARDGROVE..

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