US1868329A - Furnace - Google Patents

Description

W. .LULOFS July 19, 1932.

FURNACE Filed Dec. 17, 1926 '2 Sheets-Sheet l iNVENTO R' WAR/YER LULOFS Y j% PM ATTORNEYS July 19, 1932. w. LULOFS I 1,868,329

' FURNACE Filed Deg. 17, 1926 2 Sheets-Sheet 2 INVENTOR WflR/YER L UL oFs B Maw/f- J I ATTORNEYS Patented July 19; 1932 UNITED, STATES PATENT OFFICE. j

WARNER LULOFS, OF AMSTERDAM, v NETHERLANDS, ASSIGNOR TO THE BAIBCOCK & WILCOZ COMPANY, OF BAYONNE, NEW JERSEY, 'A. CORPORATION OF NEW JERSEY FURNACE Application flied December 17, 1926, Serial No.

My invention relates to improvements in a furnace for burning finely divided fuel, such as pulverized coal or oil.

The invention will be best understood from the following description and the annexed shows a modification in a section similar to that of Fig. 1.

Like reference characters indicate like parts throughout the drawings.

Certain embodiments of my invention are illustrated in the drawings in connection with a portion only of a furnace of the fuel nozzle gype. In the form of my invention shown in igs. 1 and 2, a furnace chamber 10 is provided with a roof 11 through which one or more fuel nozzles 12 project to introduce the fuel into the chamber 10. The front wall 13 is cooled with the usual water tubes 14 connected to headers and to the boiler in the usual manner, the upper header 15 only being shown. The roof 11 is similarly protected by and partly supported on boiler water tubes 16 with header connections of which the header 17 only is shown.

The front wall 13 is shielded by air heater ducts 19 contacting at their sides ,with the wall tubes 14. These ducts have elbows 20 extending through the wall 13 and communicating with a pressure box 21 receiving air from a suitable fan 22. Each duct 19 has at its upper end, a goose-neck 23 terminating in a nozzle 25 to discharge heated air from ducts 19 into the fuel entering from the nozzles 12.

These air ducts 19 preferably contact with the water tubes over approximately the entire surface of the water tubes to insure a good heat transfer from the air ducts to the water tubes. Fins 26 of any shape or arrangement extend from the interior face of theexposed or heated wall of each of these air ducts to supply a better heat transfer to the air within the ducts. The exterior faces of ducts 19 are preferably flat and form a relatively continuous inner face to the wall.

At the bottom of each air duct 19 is a ledge or book 27 attached to the elbow portion 20 of 155,373, and in Great Britain March 12, 1926.

the duct. This ledge supports a cap 28 of refractory material to protect the elbow and to impart a suitable finish to the top of the masonry wall 29 on which the elbows20 of ducts 19 are supported. These ducts may be of metal, such as cast iron, or of refractory material, as desired. The space 30 between the ducts l9 and the exterior of the wall may, if desired, be filled in by any suitable masonry construction. 1

The modification of Fig. 3 permits the heating of the combustion air without exposing the metal heater ducts to the hottest portion of the flame or for such an extent or over so great a portion of the wall area in the furnace chamber as in the formshown in Fig. 1. These air heater ducts 31 have elbows 32 extending through the outside wall of the furnace to the pressure box 21, andresting on the masonry wall 29. The ducts are placed between and in contact with the water tubes 14 as are the air ducts 19 of Fig. 1, but are shorter than the ducts 19 and .extend through only a limited vertical distance.

The water tubes are embedded above the ducts 31 in the center of a refractory wall 33, carried. on the upper elbow sections 34 of the air ducts 31. This wall is spaced from the outer wall 13 of the furnace, thereby forming an air space 35, wherein air rises from nozzles 37 of the air ducts. This air is discharged into the fuel through suitably arranged outlets38. in the top of wall 33. In all other respects the furnace disclosed in Fig. 3 is similar to that of Fig. 1.

Since the air is heated by radiant heat, the quantity of heat supplied to the combustion air is substantially constant, so that, at low rates of combustion, the smaller quantity of air used can be heated to high temperature, an advantage at light loads.

It is obvious that various changes may .be made within the limits of this invention without departing from the scope thereof and within the limits of the appended claims.

I claim:

1. In a furnace, metallic air heater ducts forming a substantia iy continuous wall surface exposed to the radiant heat in the furnace, said ducts having inlets to admit air to the bottom of the ducts and outlets to sup-- ply air from the upper portions of the ducts to the furnace chamber, and water tubes between said ducts and separate therefrom.

2. In a furnace, air heater ducts forming a substantially continuous metallic wall surface exposed to the radiant heat in the furnace, said ducts having inlets at their lower portions to admit air to: the ducts, a fuel burner at the upper part of the furnace, said ducts having outlets at their upper ends to supply heated air to the incoming fuel, and water tubes between said ducts and separate therefrom.

3. In a furnace, metallic air heater ducts forming a substantially continuous wall surface exposed to the radiant heat in the furnace, said ducts having inlets to admit air to the ducts and outlets to supply air from the ducts to the furnace chamber, and water tubes separable from said ducts contacting a portion of the wall of each of said ducts and extending'beyond the ends thereof.

4. In a furnace, metallic air heater ducts forming a substantially continuous wall surface exposed to the radiant heat in the furnace, said ducts having inlets to admit air to the ducts and outlets to supply air from the ducts to the furnace chamber, and water tubes contacting a portion of the wall of each of said ducts, each duct having a depression in the wall thereof enclosing approximately one-half of the circumferential area of one of said water tubes.

5. In a furnace, metallic air heater ducts forming a substantially continuous wall surface exposed to the radiant heat in the furnace, said ducts having inlets to admit air to the ducts and outlets to sup 1y air from the ducts to the furnace chamber, and water tubes contacting a portion of the wall of each of said ducts, each duct having a depression in the wall thereof enclosing approximately one-half of the circumferential area of one of said water tubes, said ducts being supported so as to be free to expand longitudinally when heated.

6. In a furnace, a wall having an outer and an inner portion spaced apart, metallic air heater ducts forming a substantially continuous wall surface exposed to the radiant heat in the furnace, said air ducts forming at least a part of the inner wall, said ducts 8. In a furnace, a vertically-extending metallic' air duct forming part of the wall of the furnace, the lower portion of the duct having an elbow extending out through the furnace wall, a refractory wall on which said elbow rests to support the duct, said elbow having a projection adjacent the inner surface of the wall, and a refractory tile attached to said projection to protect the elbow tubes.

- WARNER LULOFS.

having inlets to admit air to the ducts and outlets communicating with the space between the inner and the outer walls, said inner wall. having openings connecting said space with the furnace chamber.

7. In a furnace, a furnace wall, a vertically extendin metallic air duct forming part of 'a wall 0 the furnace,,the lower portion of the duct having an elbow extending out through the furnace wall, and a refractory wall on which eibo'w ranets to support the duct.

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