US812619A - Method of preserving the inner walls of furnaces. - Google Patents

Description

BEST AVAILABLE COF" PATENTED EEB. 13, 1906.

P. C. W. TIMM.

METHOD OE PRESERVING THE INNER WALLS 0F EURNAGES.

APPLICATION FILED Amm, 1905.

I l I l l I MMJJITT,

ym/IQ BEST AVAILABLE COF" UNITED 4snrarns ieAnNT onirica.

FRIEDRICH CARL l/VILHELM TIMM, OFfIAMBURG, GERMANY.

METHOD OF PRESERVING THE INNER WALLS OF FURNACES..

Specification of Letters Patent.

Patented Feb. 13, 1906.

Application led April 2l, 1905. Serial No. 256,823. 4

i ing treated which in a soft or molten state l. eat into and disintegrate the lining. In

many cases the cooling is applied from outside in the shape of Waterjackets or by spraying, to ether with a specially thick structure of ining. The mean temperature f the lining is lowered by the cooling, and its mechanical solidityis thereby increased, and

`by. lessening the pores the ldisintegration is made difficult.

These methods are, however, frequently insufficient, and the idea of applying the method of continuously-working or perpetual furnaces had therefore to be abandoned notwithstanding that otherwise in many processes everything was favorable.

The present method allows of the furnace bein worked uninterruptedly under the most :30

di ficult conditions and witha perfect preservation of the inner lining, it being at the same time avoided that the mass be made impure by disinte rated lining.

. The method wil be understood by reference to the accompanying drawings, in which- Figure l is a vertical cross-section. Fig. 2

is a horizontal section on line a l) of Fig. l.

A is the shaft of the furnace of iireproof material and which is inclosed in a casing B of metal. The material to be burned or smelted and the combustible substance (coke) are filled into the shaft from above. The air for combustion is fed through the nozzle C. Underneath the latter collects the melted or softened material, which is covered exteriorly with a crust and by continuous cooling gradually hardens or sets in the under part of the shaft. In this condition the block of finished material appears before the openings D. Through these openings spindles S are from time to time inserted by means of hand-wheels T and which s indles :'.rmly hold the block` with the rest of t e connts of thel furnace over same above D. reupon the ram F is lowered and the under u of th e block is removed through the doors l G, the ram F being then again pressed against the block and the spindles drawn back.

After closing the doors G the ram F is given a p slow downward movement corresponding to the extent necessitated by the continuous burning process before the twyers. YThe movement of the rain`can be effected hydraulically or by racks, screws, or the like, and the spindles S, serving for holding the contents of the furnace, can be replaced by,`

any other suitable device.

The peculiarity of the present method consists in the melted contents of the furnace bef ingalowe iningwith In order to efthe re r o rnace-wall fec s, an inc osure of bricks 1s arranged i between the walls A and the ring J, held the brackets IJ. The manner of carrying this p formation to be 25 by 12 by 6.5 centimeters,.fv 34- 1 a ring of twelve centimeters height is fitted-l..

out is as follows: Supposing the known stone against. the furnace-walls. Stone on stone is then laid round same, each one of which contacts with the wall A on a surface oftwelve centimeters height and twenty-five centimeters length circumferential measurement. Against this ring the charge is thrown into the interior4 in such quantities .that the contents of the furnaces lies flush with the upper edge of the' ring, the said contents having beenthus raised twelve centimeters. Thereupon another ring of twelve centimeters height isbuilt on the previous one, and the furnace is again charged as before, the same thing being continued uninterruptedly or with intervals, according as to the level of the contents of the furnace being lowered by the working of the fire. i

In this way the charge arrives at the twyers without having come into contact with the walls A over same. their totality an inner protective casing E, which keeps the contents of the furnace separated from the lining proper. This perfect cover is, however, partly destroyed before.

the twyers C by inserting hand or machine tools through the latter, making holes in the casing E, through which the air can have access to the charge. Seeing the casing E is constantly moving downward and the tools are constantly making holes in same, it will be The single rings form in ICO clear that the said casing must have slits` underneath the level of the twyers and running parallel to its axis. that no injurious contact of the fluid or softhrough these slits, cooling-boxes H are ar` In order, however,-y

mf Y

i 1o4 tened mass can-take place with the wall A A BEST AvAiLABLE coP progress of the fire can be observed and the lowering of the finished contents in the lower.

part of the furnace, as also the charging from the'mouth of same can be regulated accordingly, as previously described.

In order to extract the waste gases, ataking-o apparatus is arranged, the construction of which, having regard to the construction of the casing E, differs from the apparatus usually used in blast-furnaces. A` cylindrical rin J is secured to the fur-nace or the .top plat orm by means of several brackets L. Several rods I), supported onthe brackets, carry' the carrying-0H pipe Q `for the wastegases.v The charge, in the forni of se arate layers or mixed, is thrown to thetop be l' apparatus M and guided byalternately raising and lowering same, as also the bellfaplparatus'N by means of the chains R in the interior ofthe furnace in the samemanner as in any other takin -off apparatus. The chains R, secured to t e bells, lead to levers (not shown) which eect the raising or. lowering in the usual way. The distance between the ring J and the casing E is the saine as the thickness of the rotective casing, The stonesformi'ng the atter are constantly set on each-other, so, thatl the lining is perfectlclosed up to about the level ofthe nouth. f the casing is then lowered fora certain distance, owing to the working of the furnace, a new layer is added. In thisl way the part of the casingbehind the ring T prevents the escape' 4of gas.

l As regards the nature of the stones used for forming the rotective lining it maybe mentioned that t ey can consist of the known iireproof materials of a suitable consistency for the particular purpose orwerial of the charge itself; The atter can be use w en solidiied' or when itis desired that there shouldl be an entire ab,- sence of foreign bodies. Where itis a uestion, for instance, of the production of si 'cid of iron of high percentage, it is advantageous t'o use bri uets out of' easily-reducibl es with strong silicious additions and with powdered coke. The ore briquets and heatingco e are led in the interior of the protective casing, while the latter likewise consistl of ore briquets.

The protective casing enables the use of l blasts rich in oxygen, whereby a silicid of iron of high 'percentage is obtained, while without the casing the Wear of the fireproof inner lining would be too great, owing to the high'temperature and acid sla For this reason silicid' of iron of the higher percentages is even today obtained by electric-name arcs.

It is not necessary that the protective castwr.

ing should be made of stones of finished form.

It might be preferable to insert an annular metal templet or ring in the furnace and to fill the charge inside same, while the intermediate space between teinplet or ring and inner lining A isl filled up by stamping-a suitable material in saine. For example, said material may be of the sanie character from which the lining-bricks are formed, and in this way a protective case E is likewise ob# tained.

For the proper working with the casing it is important to gage its thickness correctly. The essence of the casing lies in its acting as a part lof the inner lining A, or, in other words, that the furnace is about the same as another one for a shorter working duration would be with a lining of a thickness of A plusE.

Every lining wears away to suoli extent that the upper surface, which is exposed to the iire and the chemical action, softens up to a given depth. Thisl layery is then removed either by mechanicall friction during the de.- scent ofthe charge or by meltin away orby the simultaneous action of both actors.- For thisV reason places become soft which were previously suficiently solid when they lay sufficiently deep under thel surface. Such a place exists where the lining A and the protective casing E come in contact.

The protective casing is-attached on the in sidel during its movement through the. furnace. Its thickness must, however, besufiicient to prevent any combining with the lining A.- The correct thickness of the protective casing is therefore essential for the proper working of the process, sincewhere the casing-is too weak'there is a danger of a partial fusing of same with the walliA, while in the case of a too-thick casing too great a mass moves unnecessarily through the fire.

TOO

The use ofl the casing makes it possible to I IIO rials-not corrosive, when the usual method of lining is used ,'-but by letting a protective casing of a thickness corresponding to the temerature and the chemical action pass through the furnace the casing is subject to wear, but the lining A proper is preserved.

It is by no means always necessary to provide the furnace with a wall A of iireproof stones. Instead of this under certain circumstances the usual water-jacket may be used with advantage. The process is then present when the material is drawn off from the furnace in a fluid instead of a solid state. There is then no solid connection of the casing underneath the twyers with the content of the furnace, and the casing can pf through the furnace-at a less speed than t BEST AVAILABLE COF" the casing is usually clamped in the under part of the furnace and is then treated in regard to the charges in the same way as the ordinary immovable lining of the furnace. From time to time, however, the casing is allowed to descend with the contents of the furnace, it being then again fastened and the charge delivered and tapped the same as in known furnaces. The piercing of the casing before the twyers takes place exactly as above described. In this modification of the process the casing preferably receives a greater thickness, which disappears in the fire zone gradually to a permissible degree, whereupon the protective casing is moved downward.

For the method of workin as explained coke is assumed to be the com ustible material with the charge; but this can in many cases be deviated from and combustible material in the form of powdered coal-dust, gaseous, or sprayed fluid combustible material can be used. The nature of the combustible material is not essential for the rocess, since it is only a question of the com ustion being effected within the furnace.

The protective casin used in the present process differs essential y from a protective coating applied to a cement furnace notwithstanding that a certain exterior similarity exists. Thewalls of periodically-driven cement furnaces are smeared with mud or slime before charging or a protective lining may be laced in cylindrical furnace's of unbaked ,'ricks for Iortland-cement in a similar way to what is above described, the charge consisting of unbaked bricks and coke. Such furnaces are about twelve meters high' and are so built that the fire zone lies 1.2 to two meters from the top, so that the cooling oif of the burned clinkers takes place at a height of 10.8 to ten meters. Below at the drawingoff o ening for the cold clinkers the air for com ustion enters and rises vertically, thus cooling the contents and heating itself and burns the coke in the fire zone.

The necessity of drawing solid masses out of the furnace, the long cooling-chamber,

the vertical manner of feeding the air in the zone of combustion, and the impossibility of handling such materials which are attacked '5oI in a fluid or pasty state (underneath the iire Zone) by the oxygen of the combustible air represents the difference between the method for cement furnaces and the present process.

In order to increase the protective action 5 5. of the lining, it may consist of a material which decomposes in heat under absorption of the latter. In this way a greater reduction of temperature from inside to outside is obtained. As an example ofthis modification suppose the furnace process lays it down that lime must form a part of the protectivev agent. If, then, this is chosen in the form of carbonate of lime, the heat necessary for driving out the carbonio acid forms an-addi- 6 5 tional protection with regard to the liningconsisting of burnt lime.

Having thus declared the nature of my,` said invention and in what manner it is to be performed, I declare that What I claim'is- 7o 1. A method of preserving inner Walls of shaft-furnaces, which consists in building up against the inner Wall of said furnace during the charge thereof, a gravity-movable casing, and then piercing said casing in front of the twyers as the said casing lowers so that means to sustain combustion can pass through the openings into the interior of the casing.

2 A method of preserving inner walls of A shaft-furnaces which consists in building up 8o against the inner wall of the furnace during the charge thereof, a gravity-movable lining, piercing said lining as the said lining lowers so that means to sustain combustion can pass, into the interior of the furnace and adding to the lining at the top thereof when the lining lowers.

In testimony whereof I have hereunto set my hand in presence of two subscribing witnesses.

FRIEDRICH CARL WILHELM TIMM.

Witnesses:

ERNEST H. L. MUMMENHOFF, O'rTo W. HELLMRICH.

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