US1300374A - Furnace. - Google Patents

Description

J. W. GATES.

FURNACE.

APPLICATION FILED OCT- 30, I916.

Patented Apr. 15,1919.

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JOHN W. GATES, OF MONTREAL, QUEBEC, CANADA.

FURNACE.

Specification of Letters Patent.

Patented Apr. 15, 1919.

Application filed October 30, 1916. Serial No. 128,498.

To all whom it may concern:

Be it known that I, JOHN W. GATES, a subject of the King of Great Britain, and resident of the city of Montreal, in the Province of Quebec and Dominion of Canada, have invented certain new and useful Improvements in Furnaces, of which the following is a full, clear, and exact description.

This invention relates to improvements in furnaces for boilers and the like, and the object is to provide a furnace so constructed that it will resist burning out for a much longer time than ordinary, and when so burnt out may be relined with a minimum of trouble and expense and without in any way disturbing the remaining brickwork.

A further object is to provide a furnace having a smooth interior surface with a minimum number of joints, whereby the possibilit -of gas leakage and short circuiting will e reduced to a minimum.

A still. further object is to provide a furnace so constructed that the lining blocks thereof will not tip into the furnace nor be forced into the furnace by accumulations of rit. g Another object is to provide a furnace having the brick structure around the door so arranged as to be much stronger and more durable than usual, and very easily renewed when burnt out.

At the present time, brick furnaces for boilers and the like are built of ordinary red brick and lined with bricks of fire-clay or similar refractory material. This lining quickly burns out in the lower part of the furnace and requires frequent renewal. The

removal of bricks for renewals has the effect of loosening all the brickwork above which of course supports the weight of the boiler, with the result that in a short time the whole furnace becomes full of cracks and passages, through which the hot gases escape. Frequently these cracks are in such a position that they short circuit a considerable amount of the furnace gases, so that the same passes directly from the furnace to the stack without heating the boiler. In addition, the brick arch over the fire door frequently burns out, and 'is diflicult to re-' new, or else is so much unsettled by removal of the lining that it breaks down.

,According to this invention, the brick casing is built with a recess -inthe bottom where the lining requires renewing, the brick above this lining being built in a cornice so as to be self supporting. The lining is then irisorted in the form of large interlocking blocks of special design which fitunder the cornice and carry no weight, so that they may be removed without in any way disturbing the brick casing. Special blocks are used in the construction of the door arch, which are designed to transmit the lateral thrust of the arch directly to the casing and to be supported by the casing, so that the skewback blocks which line the sides of the door opening may be removed with the other lining blocks without disturbing the arch. In the settings of all boilers, there is constant movement or working due to vibrations set up by the boiler itself and to the expan- SlOIl and contraction of the brickwork. With ordinary brickwork or flat slabsv of firebrick, such as are sometimes used for lining furnaces, vertical seams or ]O1I1tS of conslderable extent are formed, and as the working of the brick goes on, small particles of grit from the bricks themselves or from the mortar are constantly dropping into these vertical seams. bind the lining, and in a short time, the lining becomes forced out of place into the firebox. The action in reality is, that when the lining contracts, the vertical joints or fissures enlarge, and the grit settles down in them, preventing the lining from being forced back to its proper position. When This grit accumulates be-.

next the lining expands, all the expansion is into the furnace. The lining moves unequally, so that individual bricks vor blocks thereof present edges which become rapidly burned away. -With a boiler which is cooled off, every night, the furnace lining will be destroyed in a few months. The special lining blocks used in this invention have stepped or broken rear faces which present horizontal ledges to catch any such droppings of grit, and thereby prevent the displacement of lining from this cause. In addition, a considerable rearward extension is provided at the base of each block which catches under the cornice of the brickwork and prevents any tipping of the block.

In the drawings which illustrate the in- Vention:

Figure 1 is a perspective view of a furnace constructed according to this invention, parts of the brickwork being broken away.

Fig. 2 is a plan view of the furnace front showing the arrangement of the door arch with parts of the arch omitted.

" this cornice, the brickwork continues up- Figs; 4, 5 and 6 show slight modifications of the lining block shown in Fig. 1.

Referring more particularly to the drawings, 11 designates a furnace havm walls or casing 12 of brickwork, constructe 1n the ordinary manner. From. the level of the grates for a suitable distance upwardly, brickwork casing is built in the form of a cornice 13, which is self-supporting. From wardly in a vertical or other direction as required by the particular type of furnace. It will thus be seen that when the casing of the furnace is complete, there is a groove or recess around the bottom thereof. The linlng in the form of comparatively large blocks 14 is inserted in this recess, and since the brickwork is self-supporting, it will be readily seen that the lining carries none of the load of the furnace walls above it.

Each of these lining blocks is stepped on the rear face 15, so as to cooperate with the stepped contour of the cornice construction. This stepping provides a number of short,

horizontal surfaces 16 alternated with a-- number of comparatively short vertical surfaces 17. The stepping is away from the front face 18 of the block, so that a very large rearwardly extending base 13 is formed, giving the block great stability. This stability may be further increased by slightly sloping the front face 18 from near the bottom to the top toward the rear. The ends 20 of the blocks may be plain or may be provided with interengaging means, such as a vertical groove 21 in one end of a block and a vertical tongue 22 on the opposite end, adapted to engage the groove of the adjoining block. This tongue and groove arrangement holds the blocks against individual movement, and further enables a gas tight joint to be made between the blocks.

At the mouth or door of the furnace, the lining blocks 23 are of slightly different formation to'produce what is known as a skewback, and provide for an increase in the opening as it progresses inwardly from the door, to facilitate the distribution of fuel at the front corners and sides of the furnace. These special blocks 23' are slightly non-rectangular in form, as will be seen in Figure 2, in order to have the outer and inner ends thereof in line with the outer and inner surfaces of the furnace when the blocks are set out of perpendicular to the surface of the ,wall or skewed. The rear face 24 of each of these blocks is that most remote from the doorway, and is stepped similarly to the blocks 14, except that it is not usually necessary to have as many steps. Under ordinary circumstances a single step 25 will be sufficient, and this ste .does not extendthe full depth of the bloc for the reason that the outer end of the block must also be considthe ered in a sense as the rear surface, since it is that most remote from the inner front surface of the furnace and the inner' end of the block. It will obviously be diflicult to reconcile a cylindrically curved arch with the inclined or skewed sides. In order to overcome this, special end blocks 26 are provided for the arch. These blocks may be described as slightly trough-shaped, having one side or wing 27 adapted to occupy a horizontal plane and the other wing 28 an inclined plane, being the commencement of the arch proper. The lower surface 29 of the wing 28 is slightly twisted, so as to connect the lower surface of the arch 30 with the front surface of the side block 231 This special formation of the end blocks 26 provides for an arch of good appearance, and at the same time eliminates unnecessary projecting corners or edges, which rapidly burn away. In building the front wall of the fur hanging portion which will cooperate with the step 25. This cornice in the front wall of the furnace also provides support for the block 26, so that this block is almost entirely independent of the block 23. The end surface 31 of the block 26 is substantially normal to the wall, and therefore transmlts the lateral thrust of the arch directly and squarely to the casing proper, so that the block 23 may be removed without disturbing the arch. The remaiining bricks or blocks 32 of the arch are similar, and are preferably provided with interlocking means 33 on their abutting surfaces, such as the groove and tongue arrangement shown. In

the same way, the wing 28 of one arch end' is provided with a groove, and the other arch, end with a tongue to cooperate with the arch blocks, or if preferred, both end blocks may have grooves, and the arch be suitably keyed in the center. The particular arrangement of this detail is immaterial to the invention- It will be noted in Fig. 1 that the steps of the blocks 14 are approximately uniform in width and depth. This is, however, not essential, as the steps may be of any desired number and of any proportion. In Fig. 4, one of the steps is shown considerably higher than the others, while in Fig. 5, only a sinreadily seenthat the objects set forth at the commencement of this specification will be attained. The entire lining of the furnace including the doorway lining blocks 23 may be removed without affecting the wall above orthe door arch in any way, owing to the special construction of the casing proper and the blocks themselves. The structure of the blocks is such that accumulations of.

grit at the base of the blocks are prevented, and the blocks thereby retained in their proper alinement. The extended base provides great stability, and .holds the blocks against tipping. The large blocks in themselves greatly-reduce the number of cracks or seams through which gas leakage occur, and in addition, the self-supporting structure of the casing, which is .not interfered with by removal of the lining, prevents the formation of cracks by settling.

Having thus described my invention, what I claim is 1. In a furnace, a casing having a recess therearound from the level of the grate upward, the casing above said recess" being supported by a stepped cornice, and lining blocks in said recess having the rear faces thereof formed to mesh with the cor- 111GB.

2. In a furnace, a casing having a recess therearound from the level of the grate upward, the casing above said recess being supported by a stepped cornice, removable lining blocks located in a recess each having a stepped rear face forming a series of ledges Which engage With the stepped cornice, said ledges operating to exclude accumulations.

of grit from the base of the block and to hold the block against tilting into the fun nace.

3; In a furnace, a casing having a doorway, a recess entirely around the casing from one side of the doorway to the other, the casing above the recess being supported by a stepped cornice, an arch supporting the casing above the doorway and resting at its ends on the casing at each side of the doorway, and a series of lining blocks in said recess having stepped rear faces engaging the cornice of the casing, said stepped rear faces forming ledges excluding from the base of the blocks grit fallen from the casing, and projections engaging the casing and holding the blocks against tipping into the furnace, and lining blocks at the sides of the doorway having stepped faces engaging the casing, said blocks being removable without disturbance of the arch.

4. In combination with a furnace having a recess therearound from the level of the grate upward, a lining block having the base thereof extending farther to the rear than the top and having the rear face formed in a plurality of ledges, each lower ledge extending farther to the rear than the ledge next above.

5. In combination with a furnace having a recess therearound from the level of the grate upward, a lining block having a rearwardly projecting ledge below the top thereof adapted to catch grit falling from the casing and exclude same from the base of the block, and a second rearwardly projecting ledge below the first adapted to engage the top of the casing recess and hold the block against tipping into the furnace.

6. In combination with a furnace having a. recess therearound from the level of the grate upward, the top and rear of said recess being stepped, a removable lining block having a front face rearwardly sloping in its upper portion and having a base extend ing farther to the rearvthan thetop, and a stepped rear face meshing with the recess surface, the upper of said steps forming lodgment for grit fallen from the casing and the lower engaging the recess surface and holding the block against tipping into the furnace.

In witness whereof, I have hereunto set In hand. y J OHN W. GATES.

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