US1868512A

US1868512A - Attempering finely divided solid material

Info

Publication number: US1868512A
Application number: US444518A
Authority: US
Inventors: Ahlmann Nikolai
Original assignee: FLSmidth and Co AS
Current assignee: FLSmidth and Co AS
Priority date: 1929-04-16
Filing date: 1930-04-15
Publication date: 1932-07-26
Anticipated expiration: 1949-07-26

Description

July 26, N. ANN

ATTEMPERING FINELY DIVIDED SOLID MATERIAL Filed April 5. 1930 5 Sheets-Sheet 1 Z avwcwtoz 03%;; JIM/f QVCOWW 3 Sheets-Sheet 2 m4; C1 Ho: ngifl w M w Q ATTEMPERING FINELY DIVIDED SOLID MATERIAL July 26, 1932.

July 26, 1932. N. AHLMANN 1,868,512

ATTEMPERING FINELY DIVIDED SOLID MATERIAL Filed April 15. 1930 3 Sheets-Sheet 3 glvweutoz Patented July 26, 1932 UNITED STATES PATENT OFFICE,

NIKOLAI AHLMANN, OF COPENHAGEN, DENMARK, ASSIGNOR TO 1. L. SMID'IH & (30., OF NEW YORK, N. Y., A CORPORATION OF NEW JERSEY ATTEMPERING FINELY DIVIDED SOLI D MATERIAL Application flled April 15, 1930, Serial No. 444,518, and in Great Britain April 16, 1929.

In various industries it is sometimes neces- 'ases of combustion from a cement kiln of sary to provide for the attempering, that is, finely divided raw cement material or meal,

the heating or cooling, of solid substances which are in a pulverulent or granulated or 5 finely divided state, such, for example, as cement raw materials or iron oxide which is to be reduced. The attempering of such materials is sometimes accomplished by the introduction of a gaseous medium, capable of supplying or of absorbing heat, as the case -may be, into the material within a suitable vessel, either stationary or rotary. The use of a rotary drum is preferable because the heat-transmitting medium is thereby brought 5 into more intimate contact with the material and the attempering is more rapidly accomplished. The gaseous medium employed, consisting sometimes of combustion gases, may have an injurious effect upon the material and it is therefore preferable to effect the attempering indirectly, that is, with avoidance of direct contact between the attempering medium and the material to be attempered. In accordance with the present invention the material to be treated, in order that the desired effect may be produced within a reasonable period of time, is maintained, by the introduction of air and by mechanical stirring or agitation, in a condition of fluidity and at the same time is subjected to the action, either direct or indirect, of the attempering medium. The maintenance of the material in a condition of fluidity permits a constant circulation of the material and the rapid transmission of the heating or cooling effect throughout every part of the mass. The maintenance of the mass in a condition of fluidity is eflected in a manner known in the preparation of homogenous mixtures of pulverulent substances, that is, by the admixturerof a relatively slight quantity of air or other gaseous medium while the material is at the same time subjected to mechanical stirring, whereby the attempering of the material is carried on in substantially the same manner as would be the case if the material were actually liquid.

As indicated above, the attempering in the manner described might be applied for the purpose of pre-heating, by means of the hot as it is commonly termed, before its discharge into the cement kiln. It mi ht also be applied for the purpose of brin ing about a reaction between two or more finely divided solid substances, as for example, a reduction of finely divided iron oxide by means offine- 1y divided carbon, a method which is commonly performed in furnaces or in a rotary kiln. In a furnace the materials or the mixture, in order that the reaction may be effected, must be given the mobility of a liquid as by infusing one or more of the materials, while in a rotary kiln the required degree of intimate mixture will be accomplished by the rotation of the kiln, the mixture being exposed meanwhile to the action of the burning fuel, which might have an injurious effect on the materials being treated. Such effect may be avoided in the practice of the present method by the indirect application of the heating medium.

In the method for reduction of iron oxide, above referred to, the iron oxide is fed into the container or vessel, in which the method is carried on, in a pulverulent state and the carbon is added either in the pulverulent state or granulated and when the mixture is heated to the required temperature (such as 700 C. to 1000 C.) the reaction will take place between the iron oxide and the carbon without the occurrence of any fusing or sintering of the material which would make the stirring of the mixture diflicult or impossible. The reaction in this instance is accompanied by absorption of heat so that a constant renewal of heat will be necessary during the progress of reaction.

The attempering of the material, whether heating or cooling, may be accomplished by any convenient application of the attempering medium, but in the apparatus which has been chosen for illustration of the invention the attempering medium is supplied through hollow heat-transmitting bodies, which may be the hollow arms of the mechanical stirring device, or conduits passed through the container and the mass of material within it. In some cases it may be desirable to provide heat transmitting bodies of refractory material, as for example, 1n the heating and calcining'of raw Portland cement materialr r In the accompanying drawings in which v of the attempering apparatus.

In the apparatus shown in Figures 1 and 2 the container or Vessel 1, in which the attempering is carried on, is shown as a vertical vessel which is provided at its lower end with a series of nozzles 2 through which air, supplied by a pipe 3 from any suitable source, ma be disc arged into the container in relative y small volume for the purpose of rendering fluent the mass of finely divided material within the container, such material being at the same time subjected to a mechanical agitation or stirring by means of a mechanical stirrer composed, in the embodiment of the invention shown, of a'vertical shaft 4 provided with arms 5 and rotated by any convenient means, as through beveled gears indicated at -6. 'In the construction shown the stirring arms 5 are shown as hollow while the shaft 4, with which the arms are connected, is itself hollow and may be supplied with the attempering medium from any convenient source. The material to be attempered may be supplied to the container or vessel 1 through a chute 7 at the top of the container and may be conducted away from the bottom of the container through a chute 8. In this embodiment of the invention there are also shown heat-transmittin bodies 9 consisting of a series of mutua 1y connected hollow arms, the attempering medium being supplied at one end of the series and discharged, when it has absorbed or given up heat, as the case may be, at the other end of the series.

In the embodiment of the invention illustrated in Figure 3 the container or vessel 10, in which the attempering of the material may be carried on, is shown as located in a dust chamber 10 into which are discharged the hot products of combustion from a rotary cement kiln 10 The raw cement material may be fed into the top of the container 10 by a conveyor 11 and may be discharged at the bottom of the container through a chute 11 from which it may be taken and delivered to the kiln by an annular scoop or shovel of ordinary construction, as indicated at 17. 'Within the container 10 is mounted a mechanlcal stirrer shown as composed of hollow, horizontal stirring'arms 12 carried by and connected with a vertical, hollow shaft 13 which may be rotated by any suitable means and may be supplied with the attempering material from any suitable source. I

The bottom of the container 10 is shown as provided with airinlets'14 through which the air or other gaseous medium is provided, in relatively small quantity, for the purpose of rendering fluent the mass of finely divided material. For the purpose of transmitting heat to the fluent mass within the container, the heat transmitting bodies are shown as conduits 15 which pass through the container from side to side and through the material within it. The hot products of combustion from the kiln 10 pass through the conduits from one side of the dust chamber 10 to the other, eventually, when they have given up ed in Figure 4 is substantially like that shown in Figure 3, having a vessel or container 10, located in the dust chamber 10 of the rotary cement kiln 10 fed at the top with finely divided cement raw material by a suitable con veyor 11 and discharging the material from the bottom through a chute 11 from which it may be taken up and delivered to the kiln by an annular lifter 17 In this construction the mechanical stirring devices are shown at 12 as arranged to rotate on horizontal axes, each functioning in a separate chamber 10, each separated from the next by a partial diaphragm 10 the material-passing from one chamber to the next. The dust chamber is also divided into successive chambers l0 by alternate diaphragms 1O on opposite sides of the container 10 so that the hot products of combustion are caused to pass back and forth through the conduits 15 which, as before, are passed through the container 10 from one side to the other, the products of combustion finally passing through the outlet 16 on the way to the stack. In an attempering apparatus of this kind, as will be understood, the cement raw materials may be brought to a very high temperature before they are delivered to the kiln, this result being accomplished by the 1pot products discharged from the kiln itse It will be understood that the invention, so far as it is realized in the method, may be practiced in other forms of apparatus than that shown and that the invention may be embodied in forms of apparatus suited to the conditions of operation.

I claim as my invention:

1. The method of attempering finely divided solid material which consists in stirring III mechanically the material, simultaneously rendering the material fluent by the admixture of air, and subjecting the material in a fluent condition to the action of an attempering medium independent of the air.

2. The method of attempering finely divided solid material which consists in stirring mechanically the material, simultaneously rendering the material fluent by the admixture of air, and subjecting the material in a fluent condition to the action of an attempering medium independent of the air and out of contact with the material.

3. The method of treating finely divided cement raw material which consists in subjecting the material to a mechanical stirring,

simultaneously rendering the material fluent by the admixture of air, and causing hot gaseous kiln products to pass through the mass out of contact therewith.

4. Apparatus for attempering finely divided solid material which comprises a container for the material, means to stir the material in the container, means to supply air to render fluent the material in the container, closed conduits passing through the material in the container, and means to supply an attempering medium to the conduits out of contact with the material in the container.

5. The combination with a cement kiln and a chamber into which the hot gaseous products of combustion are delivered from the kiln, of a container located in said chamber, means to deliver finely divided cement raw material to said container, and closed conduits passing through the material in the container and through which the hot gaseous products of combustion may pass out of contact with the material in the container.

6. The combination with a cement kiln and a chamber into which the hot gaseous products of combustion are delivered from the kiln, of a container located in said chamber, a mechanical stirring device in the container,

l means to deliver finely divided cement raw material to the container, and closed conduits passing through the material in the container and through which the hot gaseous products of combustion maypass outof contact with the material in the container.

7. The combination with a cement kiln and a chamber into which the'hot gaseous products of combustion are delivered from the kiln, of a container located in said chamber, a mechanical stirrin device in the container, means to deliver nely divided cement raw material to the container, means to deliver air to the material in the container to render it fluent, andconduits passing through the material in the container and through which the hot gaseous products of combustion may pass.

This s ification signed this 28th day of March, D. 1930. AHLMAN N.