Improvement in furnaces for finishing sheet-iron
US RE7547 E
Description (OCR text may contain errors)
W. D. woon.
FURNACES FOR FINISHING SHEET-IRON.
Ressued March G, 1877.
U/Tigewfeu UNITED STATES PATENT OFFICEc W. DEWEES WOOD, OF PITTSBURG, PENNSYLVANIA.
IMPROVEMENT IN FURNACES FOR FINISHING SHEET-IRON.
Specification forming part of Letters Patent No. 46,841, dated March 14, 1865; reissue No. 7,547, dated March 6, 1877; application tiled November 18, 1876.
To all whom it may concern:
Beit known that I, W. DEWEEs Woon, formerly of McKeesport, but now of Pittsburg, in the county of Allegheny, State of Pennsylvania, have invented a new and useful Improvement in Furnaces for Finishing Sheet- Iron; andIdo hereby declare the following to be a full, clear, and exact description thereof, reference being'had to the accompanying drawing, making a part of this specification, in Whichl Figurel is a longitudinal vertical section of my furnace. Fig. 2 is a transverse vertical section thereof; and Fig. 3 is a top view of the perforated iioor of the heating-chamber, the appearance of the roof ofthe chamber being similar thereto.
In the several figures like letters of reference denote similar parts.
4'lhe object of my invention is to overcome a practical diiiculty in heating plates of 'sheetiron preparatory to the finishing rolling with suicient uniformity.
After the iron has been reduced to sheets of the requisite degree of thinness, they are heated in a furnace before being operated upon by the finishing-rolls. Being` too thin to be operated upon singly, two or more sheets are placed together in a pack and passed through the rolls, by -which means the sheets can be -rolled thinner than a single sheet could be rolled alone. In order to secure uniformity ol thickness and smooth iinish in the sheets thus rolled in a pack, it is very important that all parts of each ofthe sheets should be, as nearly as possible, at the same degree of heat, and as the sheets, being thin, heat very rapidly, and are only left in the furnace for this purpose two or three minutes, it is important that the heat should be uniform in all parts of the heating-chamber. This it has been found very diticult to accomplish, as that part of the heating-chamber which is nearest to the lire is usually a good deal hotter than the other end near to the door at which the sheets are introduced. I
To remedy this difculty I furnish the heating-chamber with a perforated cover and iioor, and conduct the heat and tire from the furnace in two streams, one above the cover and the other below the door, and as the heat and fire have to enter the chamber to reach the escape-dues they do so through these perforations, which may be uniform in size, but, by preference, gradually increase in diameter as their distance from the fire increases. The sheets of iron to be heated I support on the edge of angular railings raised above the door,
so that the heat may have free access to all parts of the pack of sheets placed in the heating-chamber.
To enable others skilled in the art to coustruct and use my improved heating-furnace, l will proceed to describe its construction more minutely.
In the drawing, a is the tire chamber ofthe furnace, constructed in the usual way; and b represents the gratings or fire-bed. rIhe furnace is built of brick, those parts which are exposed to the action of the tire being constructed or lined with nre-brick. c is the back wall of the furnace, which has an opening, d, extending transversely across it about midway between the tire-bed b and the 'roof e of the furnace, through which opening' all the flame, heatedair, and fuliginous matter pass on their way to the iiues ff, situated ou each side of the furnace near to the front end, at which the sheets of iron are introduced. The
tluesff are made one in each of the side walls g g, and are arched, so as to meet together in one chimney above the furnace.
The flame and heated air are not allowed to pass at once into the heating-chamber h, being prevented from so doing by a perpendicular blank Wall, k, which is placed parallel to and at a little distance from the back wall c of the tire-chamber. The heating-chamber his formed bythe side walls g g, the back Wall k, the front wall l, and a oor, m, and cover n. The door m of the heating-chamber is made of fire-bricks, and is raised above the bottom of the furnace, so as to leave a tlue, p, under the entire floor m, as shown in Figs. l and 2. The door is arched, as shown in Fig. 2, the arch springing from the side Walls g g. The cover n is also made of lire-brick, and is arched in the same manner as .the door. It is situated sufficiently below ,the
roof of the furnace to leave a Hue, g, extending over the entire cover n of the heating-cham ber. The iiues p and g open at their rear ends into the space r between the blank wail lo and the firewall c, so that the llame' and' heat issuing from the fire-chamber a, through the passage d, enter the space r, lwhere they are parted into two streams, one passing upward through the due q over the cover n, and the otherdownward through the iluep under the floor m.
AThe chierl function. of each of the flues ,fp q is `to distribute the heated air, flame, and products of combustion under or over the Hoor or covering, and to the perforations therein, presently to be described, so that they shall enter the heating chamber at various points, respectively below or above the level of the sheets placed in such chamber.
To enable the heated air, tlame, &c., to enter the heating-chamber h so as to produce the best effects, and so as to reach the exitlues ff, openings i z', &;c., are made in the bricks composing the covering n and floor m of the heating-chamber.
These openings ii may be'circular, as shown in Fig. 3, and are smaller at the rear end of the heating-chamber near the lire than at the front end near the door s, gradually increasing in size from'the rear to the front.
The object of the feature last named is to equalize as much as possible the amount of flame and heat which enters the heating-chamber at all points, above and below.
kThese openings may, however, if so pre i'erred, be of uniform size, as shown in Figs.
vl and 2, though l consider this a less advantageous way of carrying out my invention.
,Instead of placing the packs of sheet-iron to be heated on the door of the furnace, they are supported above the licor on the rails t t, about equidistant between the door and cover. These rails, cf which there are two or more. parallel rows, extending from front to rear of the heating chamber,.are made of triangular prisms of .tire-brick, a cross-section of which is shown in Fig. 2. 'lhese prisms tt, constituting raised supports or bearings for the sheets, are sustained by pillars Iu u., built up from the door m, and are so placed on them that one of the angles 'of the triangle forms the top of the rail ou which the sheets of iron rest, so that only a very small part of the surface of the sheets is in contact with the rails, and almost the entire surface above and below is exposed to the direct action of the tire.
The door s opens directly into the heating'- chamher, and through it the sheets of iron are inserted and removed. rBhe tcp of the .rails t t is on a level with the bottom of the doorway s. y
I claim herein as my inventionl. A sheet-metal-heating furnace having a perforated door, and bearin gs elevated above the level of the door to support the sheets,sub
stantially as set forth.
2. A sheet-metal-heating furnace having a perforated covering, u, over the heating-chamber, and bearings to support the sheets, elevated above the level of the door,A and between thetloor and the cover, substantially as set forth.
3. A heating-chamber having a perforated cover and tlocr, arranged relatively to the heat-distributing ues substantially as described, whereby the fire and heated air shall enter the chamber through the openings in the cover and door at vario-ns points above and below't-he level of the sheets placed therein, for the purposes set forth.
4. A heating-chamber having a series of perforations, i c', in the cover and floor, of increasing size from the fire end of the heatingchamber toward the opposite end, substantially as and for the purposes set forth.
In witness whereof I have hereunto setmy hand.
W. DEWEES WOOD.
Wns'r MCMURRAY, GEORGE H. CHRISTY.