US1936161A - Cooling system for furnace walls - Google Patents

Description

1933- 0. H. 'HEDRICH COOLING SYSTEM FOR FURNACE WALLS Filed July 6, 1931 2 Sheets-Sheet l INVENTOR OTTO H. Heomcn QZCI M (I /m0 A ITORNEYS.

I Nov. 21, 1933. o. H. HEDRICH COOLING SYSTEM FOR FURNACE WALLS 2 Sheets-Sheei? 2 Filed July 6, 1931 INVENTOR OTTO H. Heomcu AT ORNEYS.

Patented v Nov. 21, 1933 COOLING SYSTEM FOR FURNACE WALLS Otto H. Hedrich, Altadena, Calif.

Application July 6, 1931. Serial No. 549,034

4 Claims.

This invention relates to improvements in furnaces and particularly to means for cooling the throat of the furnace during combustion.

At the present time fuel burners are provided with means for supplying oil, gas or powdered coal, in the form of a spray which is admixed with air at the throat of the furnace. The throat is usually formed of a. circular body of tile especially designed to effect proper mixture of the fuel and air. Heat radiated from the flame ignited in the furnace becomes very intense and eventually results in distortion or destruction of the tile or failure of the brickwork adjacent thereto necessitating repair or replacement in order to maintain proper combustion conditions.

In the case of certain fuels, destruction of the tile may sometimes be caused by impurities in the fuel, fluxing with the tile under the influence of high temperature and thus causing erosion go of the tile. -Distortion of the tile either from the difference in expansion between the front and back thereof or from erosion due to impurities in the fuel or from any other cause results in a destruction of the circular shape and especial 25 design of the tile and consequently disturbs a proper admixture of the fuel and air.

The present invention therefore, has for one of its objects to provide an improved arrangement of tubular cooling means at the inner side of the throat of refractory material, and between thelatter and the combustion-chamber of the furnace, which tubular means will serve to reenforce the refractory material, as well as absorb a suiiicient amount of the heat, to which the refractory material is ordinarily subjected, to prevent distortion or destruction of the same and prolong its period of effectiveness.

Another object of the invention is to'provide improved means for securing the tubular cooling 40 means in place at the inner combustion-chamberend of the refractory throat.

A further object is to provide improved tubular cooling means for embracing the combustionchamber-ends of a series of tiles that form the throat whereby to reenforce the tiles at the hottest part thereof.

' Other objects and advantages of the invention will become apparent during the course of the following detailed description of the accompanying drawings showing preferred embodiments of the invention and in which] Fig. l is a rear elevation of the throat of a furnace with the invention applied thereto;

Fig. 2 is a transverse sectional view through a portion of a furnace wall and specially constructed throat embodying the invention;

Fig. 3 is a diagrammatic plan view partly in section of a furnace and boiler showing the circulation system;

Fig. 4 is a vertical sectional view through -a portion of a furnace wall, air register, fuel chamber and throat showing another form of the invention;

Fig. 5 is a plan view in elevation showing the cooling device applied to several fuel openings;

Fig. 6 is a view similar to Fig. 5 showing a modification of the invention;

Fig. '7 is a side view of the tube arrangement shown in Fig. 6;

Fig. 8 is a view similar to Fig. 5 of another modification of the invention;

Referring to the drawings and particularly to Figs. 1-2, the numeral 10 indicates the brick wall of the furnace provided with an opening 11 in which is mounted the throat l2 composed of a plurality of tiles 13,-each havinga curved symmetrical face 14 for facilitating or effecting the admixture of air and fuel which pass therethrough.

The embodiment of the invention shown in Figs. 1 and 2 is one of the preferred forms, and the tile throat is especially formed and designed to accommodate the tubes 1516 which are disposed toward the combustion chamber of the fur- 8 nace and adjacent the rear face of the tile throat most of which is recessed as at 1'7 to accommodate an arc of the surface of the tubes. As indicated at 18 the upper and lower tiles are not recessed as the tubes are bent to extend in ap- 9O proximate parallelism above and below the upper and lower tiles.

The flange 19 of the fuel chamber, which is shown complete in Fig. 4, is secured to the furnace by means of the nuts and bolts 20 and the tubes 15 are secured in proper position relative to the recess 17 of the tile throat by the bolts 21, the ends of which are preferably welded at 22 to the tubes. The bolts 21 extend outwardly through the tile to receive the nuts 23. The tile throat 12 is secured in place by means of the hook bolts 24, the hooked ends of which are received in recesses 25 in the tiles, and the screw threaded ends of the bolts receive the nuts 26. It will be noted that there is an annular space between the throat and the furnace walls in which the gas seal ring 27, backed by an asbestos gasket, is inserted. Any other open space except that between the tube and tile may be filled with fire clay or the like.

Referring to Fig. 3, it will be noted that pipes 28 and 29 are connected at o and i respectively to the Water circulation system which is also connected to the boiler tubes B. The tubes 15 and 16 are connected at 30 to the pipe 29 and at 31 to the pipe 28 so that water will freely circulate through the tubes around the tile throats and adjacent walls of the furnace, it being noted that the water is introduced to the tubes from a point outside of the combustion chamber and is returned to the circulation system after having passed downwardly through pipe 28 and through connection 31 and upwardly through tubes 15 and 16, connection 30 and pipe 29.

In Fig; 4, I have shown the air register A having tapering walls leading to the fuel chamber F which discharges into the throat of the furnace through the openings S. The fuel mixes with a rotating column of air admitted through the air register A and the mixture is carried through the throat opening into the combustion chamber as explained in Patent No. 1,576,537 to E. H. Peabody.

In this form of the invention, the tubes 15', 16, are held against the face of the throat 12 by means of the bolts 21' welded at 22' to the tubes. The bolts pass through the tiles and through the flange 19' of the fuel chamber to receive nuts 23', thus holding the parts together. The gas seal ring 27, backed by an asbestos gasket, is disposed between the tile throat and the wall of the furnace. The tile throat does not have the special recessed face 17 shown in Figs. 1 and 2, but the tubes 15', 16, are disposed adjacent the inner face of the throat between the face and the combustion chamber, and the tubes may be connected to the circulation system of the boiler so that the heat absorbed by the device and imparted to the water becomes a part of the boiler output as previously explained, or the tubes may be connected to a source other than the circulation system of the boiler.

The arrangement of the bolts 21, 21' is calculated not only to space the fluid conduits a given distance from the other parts of the burner but also to center the tube with respect to the tile and to maintain the tubes concentric with the throat. The bolts also hold the fuel chamber and refractory tile in proper position.

In Fig. 5, I have shown a multiple arrangement of burners wherein the upper and lower throats 34 and 35 are served by the tubes 36 and 3'7 which may be connected in the manner disclosed hereinbefore in connection with Figs. 1-7, with a source of supply.

In Fig. 6, I have disclosed a modification wherein a single tube 40 is bent to the approximate size and shape of the throat 41 and then bent over itself as at 42 and continued down and around the throat 43 and then bent upon itself at 44. The inlet and outlet ends of this tube may be connected either to the circulation system of the boiler or to an external source of supply and discharge.

In Fig. 8, I have shown the tubes 45, 46, crossing each other at the top and bottom of each burner throat 47 as indicated at 48 where they may be welded or otherwise secured together.

In all of the embodiments of the invention above described and shown in the accompanying have shown the cooling devices connected to the 1 water circulation system in Fig. 3, it should be apparent that if air is to be used the tubes may be connected to a combustion air fan, or an induced draft fan, or to the wind box which surrounds the air register. If water is used the tubes may be connected into the boiler line as shown or they may be connected to a separate source of supply. Regardless of the specific cooling fluid employed or the source of supply, it should be obvious from the foregoing that the cooling devices will absorb some of the heat radiated from the flame during combustion and thus prevent absorption of all of the heat radiated by the flame by the refractory material, thus prolonging the life of the throat and the bricks adjacent thereto.

It is to be understood that the invention may be practiced in connection with various types of furnaces and that it is not dependent in any way on the kind of fuel and of the particular fluid used as a cooling medium.

I claim:-

1. In combination with a furnace having an opening through its wall from the outer side to its combustion-chamber, of refractory material arranged in said wall-opening to form a throat with a fuel-opening and tubular cooling means embracing the throat of refractory material at the inner combustion-chamber end thereof to reenforce-said refractory material and protect that inner end from distortion.

2. In combination with a furnace having an opening through its wall from .the outer side to its combustionchamber, of a series of tiles arranged in said wall-opening to form a throat with a fuel-opening, tubular cooling means curved to embrace the inner ends of the throat tiles and means extending from the outer side of the furnace to and engaging the tubular means for holding the latter in place around the inner throat-ends of said tiles.

3. In combination with a furnace having an opening through its wall from the outer side to its combustion-chamber, of refractory material arranged in said wall-opening to form a throat with a fuel-opening,said throat of refractory material having a curved recess at its inner end which is spaced from but extends around said fuel-opening and tubular cooling means in the curved recess of said throat of refractory material for reenforcing and protecting said throat material at the combustionchamber end thereof.

4. In combination with a furnace having an opening through its wall from the outer side to its combustion-chamber, of a series of segmental tiles arranged in said wall-opening to form a throat with a fuel-opening,said tiles having curved recesses at their combustion-chamber ends and tubular cooling means seated in said tilerecesses to reenforce the inner ends thereof.

OTTO H. -I-IEDRICH.

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