US1733829A - Furnace - Google Patents

Description

7 Oct. 29, A, -r 1,733,829

FURNACE Filed Feb. 14. 1927 2 Sheets-Sheet 1 dzexanderjf'mone INVEN'rbR ATTORNEY;

Oct. 29, 1929.

SIMONET FUVBNACEL-L. Fil e d P's- 514? I927 2 Shqets-Sheet 2 INVENTOR Arromwsv Patented Oct. 29, 1929 PATENT OFFICE ALEXANDER SIMONET, OF MINNEAPOLIS, MINNESOTA FURNACE Application filed February 14, 1927. Serial No. 168,038.

My invention contemplates an arrangement which in one instance provides for protect ing against hightemperatures that part of the surrounding wall or lining of the furnace on a line with the normal melting level of the charge to prevent corroding of the lining,

and in another instance provides for moderating the temperature of the front and back walls which are usually subjected to the .20 greatest amount of heat or changes in temperature.

' Other objects and advantages ofmy invention will hereinafter appear, and what I de sire to protect by Letters-Patent is particularly set forth in the appended "claims. v

In the accompanying drawings:

Fig. 1 is a transverse sectional view showing my improved construction of open-hearth furnace.

Fig. 2 is an enlarged detail vertical sectional view through the back wall of the furnace.

Fig. 3 is a similar view illustrating a modific'ation in the formation of the removable back wall.

Fig. 4 is a vertical sectional view through the front wall of the furnace, and

Fig. 5 is a sectional view on the line 5--5 of Fig. 4.

*In the ordinary type of open-hearth furnace the intense heat of the molten metal at the normal melting level causes deterioration of the furnace structure at this point on account of the formation of slag and consequent corrosion of the refractory material and therefore the life of the furnace or its working quality is impaired in a comparatively short time requiring repairs that add considerably to the cost of upkeep. It is customary in the construction of a furnace of this general type to employ refractory material or refractory brick that will not only offer the greatest resistance possible against melting but also resist spalllng or chipping off by disintegration resulting from sudden changes in temperature as for instance by the admission of cool air by the opening of the doors leading into the furnace, and it appears that the front and back walls are affected in this manner to a greater extent that the end walls. For convenience my improvements are shown applied to this particular type of furnace, but it will be understood without further illustration or description that they can be applied to various other types of furnaces, as electric furnaces, &c.

In carrying out my invention I propose to provide an open-hearth furnace in which the walls or linings which are subjected to the greatest amount of heat or changes in temperature are cooled to moderate the temperature thereof imparted by the heat employed in melting the charge so as to resist the tendency of the refractory material to disintegrate or spall, and to also make it possible to employ brick of a refractory material having a lower fusing point and consequently less liable to spall or crash. Furthermore, the cooling of the walls in the manner hereinafter described allows the thickness of the walls to so be materially reduced as compared with the walls of the conventional construction of furnace, and as will be obvious from the following description my improved construction may be employed in connection with the front 35 and back walls only, or applied entirely around the furnace; for instance, as illustrated in the drawings the front and back walls only are constructed to resist disintegration, spalling, &c., inasmuch as these walls are the parts of the furnace which are usually subjected to the greatest amount of heat or changes in temperature.

Referring to Fig. 1 of the drawings it will be seen that I provide the bed or bottom 21 of the open-hearth furnace illustrated therein with a metal trough 22 on a line with the normal melting level a and locate it at the back of the furnace to extend longitudinally from one end wall, as 23, to the other, with the refractory material of the bedbottom built up in front of said trough (as at 21) to a po nt on a plane with the upper horizontal port on 22 of the trough, said horizontal portion forming a seat for the removable baclcwall, hereinafter described, and formed with a longitudinal groove or pocket 24 at its rear edge adapted to cooperate with a part of the rear wall to retain the latter in place. The bottom of the trough inclines outwardly to the vertical wall 22 thereof'so that when water is used as the cooling medium it will collect in the lower part of the trough and be carried off by the drain pipes 25, the s1ze of the trough and drain pipes being such with respect to the quantity of water supplled for cooling the back wall as to prevent possibility of leakage to the interior of the furnace. Thistrough is connected at its ends to vertical plates 26 set into the end Walls of the furnace and connected at their upper ends to a longitudinal L-beam 27 supporting the arched roof 28, the space'between the trough, L-beam and end plates being occupied by a removable wall 29 forming the back wall of the furnace, and for coolingthat part of the back of the furnace contiguous to the trough there is a water pipe 30 extending longitudinally within the trough and having openings suitably spaced for spraying the water. A simple form of back wall is illustrated in Fig. 1 in which refractory brick 29 are laid one upon another above the horizontal portion 22 of the trough and adjoining portion 21 of the bed bottom, said brick being held in place by a backing plate 31 seated in the aforementioned groove or pocket 24 in the upper portion of the trough and at its upper edge bearing against the L-beam 27 and held in place by metal cleats 32 bolted to said L-beam. It will be understood that the construction at the back of the'furna'ce may be such as to provide for stacking the brick 29 to form either an inclined back wall, as shown in Fig. 1, or a vertical end wall, and although it may be necessary to only cool the back of the furnace at the normal melting level, as by water spray from pipe 30, it may be found desirable in some instances to cool or moderate the temperature of the entire back wall, for which purpose I propose to provide the backing plate 31 with rearwardly projecting baflleplates 31! (Fig. 2) to direct the water from the auxiliary Water pipe 30 against the back of the plate.

, A like arrangement to that described with reference to the back wall is provided also for the front wall of the furnace shown in Fig. 1, that is to say troughs 33 similar to troughs 22 are set into the bed or bottom 21 between the frames 34 and refractory material 35 of the doorways 36, the front wall 33 of the troughs being extended under said doorways, and in this instance also the suprefractorymaterial, as at 43*.

likewise any other suitable means for locking said walls in place.

means, as cold air,"

port for the roof is by means of an L-beam 37 and removable walls 38 of refractory brick 38 are interposed between the troughs and nace structure being reinforced in the usual manner by vertical I-beam 54 and tie-rods 55.

The troughs 22 and 33 are preferably made of cast iron or cast steel and are of sufficient strength to support the. superposed brick walls so that the upper part 21 of the bed or bottom will be relieved of the weight of the removable walls and therefore less likely to break down should the refractory material be. affected by corrosion at'thispoint. It will be understood that the bed or bottom is made of refractory material, preferably refractory brick, and that any formationof slag (b) at the normal melting level (a) instead of increasing the tendency to corrode the refractory material will in the present instance provide a protecting layer inasmuch as the temperature of the wall or lining in the rear of the same is moderated by the cooling means described permitting this part of the bottom of the furnace and contiguous walls to be made of less thickness than usual and of a refractory material having a low fusing point. Furthermore, the walls being cooled or the temperature thereof moderated from the intense heat within the furnace they will last considerably longer than the walls of a furnace of ordinary construction, and as the front and back walls are removable they may be conveniently renewed at comparatively small expense; thus my invention provides a furnace structure that can be kept in continuous use. for a longer period of time and 'in which the upkeep is materially reduced stance as illustrated in Fig. 3, which shows the refractory brick 42 secured to the backing-plate 43 by means of bolts 44, the heads of the bolts being let into the inner faces of the brick and the holes filled with suitable Obviously various other forms of construction may be adopted in forming the removable walls, and employed Furthermore, instead of using water as the cooling medium for moderating the temperature of the walls of the furnaceany other cooling etc.,may be employed. The cooling of the wall or lining of the furnace at the normal melting level of the material heated in the pitis effective in increasing the life of the furnace, and conse-' pipe extending quently in some instances the cooling element may be applied only at this point or part of the furnace, as provided for in the form of my invention illustrated in Fig. 1, in other words it may be unnecessary to cool the walls of the furnace above, but when necessary the form of my invent-ion shown in Figs. 2, 3 and 4 may be adopted, in which the auxiliary discharge pipe 30 will deliver the cooling element, as water, against the front and back walls in addition to the cooling'by the water from pipe 30, or cooling by pipe 30 may be started some time in advance of the cooling by auxiliary pipe 30*. Of course when bot- h pipes 30 and 30 are installed the trough will e of suflicient size to collect the water and the drain pipes let into the front wall of the trough at the lower end of the inclined bottom should be of suflicient size to quickly carry off the water.

In the foregoing description I have set forth the principal advantages accruing from the particular construction of furnaces and converters to provide for the application of a cooling element to those walls thei eof Which are subjected to the greatest amount of heat from the fuel, gas, electricity, or other source of heat employed for the purpose of melting the material or subjecting a molt-en mass to an air-blast, and althou h in the drawings I have illustrated the pre erred embodiment of my invention it will be understoodthat I do not limit my protection to details of con struction as they may be modified within'the spirit and scope of my claims.

I claim 1. An open hearth furnace comprising a bottom having a pit in which the material to be heated is placed, walls rising from said bottom at the sides of the pit, a trough embedded in the walls to leave a lining between said trough and interior of the furnace and located approximately on a plane with the normal melting level of the material in the pit with its open top on a linewith the outside of the walls of the furnace, the bottom of said trough being inclined outwardly and downwardly from the wall of the furnace, a longitudinally in the trough and having openings discharging a cooling element against the walls of the trough, and an auxiliary pipe extending longitudinally adjoining the upper part of the Walls of the furnace to discharge a cooling element against the outer surface of said Walls.

2. An open hearth furnace comprising a bottom having a pit in which the material is heated, a trough embedded in the bottom at the side of the pit leaving a lining between said trough and pit, a removable wall above the trough, and a backin -plate for holding saidremovable wall in p ace; together with a pipe extending longitudinally in the trough and having openings discharging a cooling element against the inner wall of the trough,

and an auxiliary pipe at the upper part of the wall at the outside thereof discharging a cooling element against said wall.

3. An open hearth furnace comprising a bottom having a pit in which the material is heated,'a trough embedded in the bottom at the side of the pit leaving a lining between said trough and pit, said trough having an upper horizontal portion, a removable wall resting mainly upon said horizontal portion of the trough, and means for discharging a cooling element against the outside of the furnace and against the inner Wall of the trough.

4. An open hearth furnace comprising a bottomhaving a pit in which the material is heated, a trough embedded in the bottom at the side of the pit leaving a lining between the trough and pit, said trough having an upper horizontal portion with a longitudinal groove at the outer edge thereof, a removable wall resting mainly on said horizontal portion, a backing-plate holding the wall in place and engaging the aforesaid groove at its lower end, and means secured to the fur nace to engage the upper end of the backingplate; together with spraying pipes for discharging a cooling element against the outside of the walls of the furnace and against the inner wall of the trough.

5 An open hearth furnace comprising a bottom having a pit in which the material is heated, a trough embedded in the'bottom at the side of the pit leaving a lining between the trough and pit, and a removable wall interposed between the inner end of the trough and roof of the furnace and comprising refractory brick secured to a backing plate; together with means for dischar 'ng a cooling element against the outside 0 the removable wall of the furnace and inner wall of the trough.

ALEXANDER SIMONET.

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