US1760694A - Roasting-furnace construction - Google Patents

Description

May 27; 1930.

H. J. HARTLEY ROASTING FURNACE CONSTRUCTION Filed Nov. 10 1928 INVENTOR fie/z/yJ17a/Z%% ATTORNEY-3 Patented May 27, 1930 HENRY. J'. HARTLEY, OF NEW YORK, N. Y.,

ATE? 'FITCE' ASSIGNOR TO NICHOLS COPPER COMPANY,

OF NEW YORK, N. Y., A CORPORATION OF NEW YORK ROASTING-FURNACE CONSTRUCTION Application filed November 10, 1928. Serial No. 318,397.

This invention relates to multiple hearth roasting furnaces and more particularly to features of the rabble arm construction and methods and means for controlling temperature conditions at the various hearths, of such furnaces.

' The objects of the invention include the provision of furnace constructions of the class indicated, andalso methods of operating such furnaces, which willbe dependable,

relatively simple and eflicient under various conditions, and in which the treatment of variouskinds and gradesof material may be accurately controlled.

Various further and more specific objects, features and advantages will clearly appear from the detailed description given below taken in connection with the accompanying drawings which form a part of this specification and illustrate merely by way of example one embodiment of the apparatus of the invention.

The invention consists in such noyel features, arrangements and combinations of partsaslmay be shown and described in connection with the furnace features herein disclosed by .way of example. only and as illustrative ofa preferred embodiment.

In the drawings, Fig. 1 is a vertical sectional view showing the details of constructioirof a portion of a rotatable central shaft including an arm socket and a cooling arm mounted therein and illustrates the relatlonship of the latter with the hearth of a roasting furnace; and

Fig. 2 is a horizontal sectional view through a furnace construction showing. one example of the invention hereof.

The furnace in which the improvements comprising this invention may be embodied may be of the same general class as that shown in numerous patents to J. B. F. Herresholf, as for example No. 976,175, of November 22,

1910, and may incorporate, if desired, va-

riousimprovements, such as for. example the improved shaft and rabble arm construction covered by the patent .of Dudley Baird, No. 1,669,925, of May 15, 1928.

Furnaces of the class above referred to may include .a plurality of vertically spaced or superposed hearths, asindicated at 10 and 11. These hearths may be surrounded andsupported in the conventional manner, as by a cylindrical furnace wall 1.3. A rotatable and internally cooled central shaft 14 extends ed successively over each hearth down through the furnace.

The central shaft 14 as here illustrated, may be provided with an internal conduit as at 18, the rabble arms being also provided with inner conduits of any desired well known form communicating with the conduit 18, whereby cooling fluid such as air, carried by the conduit 18, may be allowed to pass through the conduits of the various rabble arms and thence back into an annular-space 19 between the conduit 18 and the walls of the shaft 14. The flow of air into the conduit 18 and out of the space 19 may be regulated in any well known manner.

At various of the hearths, or if desired at all or substantially all of the hearths,'the shaft 14 may be provided with a plurality of sockets or attaching means as at21 sutlicient in number to receive at. each hearth notonly a plurality of rabble arms, but also a desired plurality ofheat absorbing or radiating arms as at 22. The socketsas at 21 may be conveniently designed as to size, shape and position to interchangeably receive either a single rabble arm, such as the rabble arms- 15 and 16, or a single cooling or radiat ng ..arm as at 22 (see Fig. 1), or a'double radlating arms or units may be made communicative through the sockets 21 with the cooling fluid conduit 18 at their inlet ends and with the annular space 19 at their outlet ends,

whereby a circulatory path is provided through the radiating units, thus permitting the control or alteration of the temperature conditions on hearths which are provided with such radiating means. In certain processes it may be desirable to maintain some of the hearths at a relatively low temperature, or combustion conditions may be such as to require a considerable cooling effect on certain hearths. This may be generally accomplished by using from one to four of the radiating units as at 22 and 23 over such hearths. Or, if these prove insufficient to accomplish the desired cooling, sockets may be provided at certain hearths for even a greater number of these units, or similar but'larger units might be used.

The particular form of radiating unit shown by way of example in Fig. 1 may comprise a U-shaped conduit member as at 24- detachably mounted within an adaptor member 25. The adaptor member 25 may include an inlet passage 26 for communicating with the conduit 18 and with one branch of the cooling arm, and an outlet conduit 27 for communicating with the other branch of the cooling arm and with the annular space 19. The external wall of the adaptor member 25 may be provided as at 28 with a side opening, permitting communication between the annular space 19 and the cavity 27 The external contour of the adaptor member 25 may be similar to that of the socket engaging portions of rabble arms, such for example as disclosed in detail in the above mentioned patent to Baird. Accordingly such rabble arms may be interchanged with the adaptor members 25 when desired. The two arms of the U-shaped member 22 may be slidably received within sockets as at 29 and 30 respectively at the ends of the conduits 26 and 27 the member being secured in place as by a detachable pin 31. The two arms of the U-shaped member may be cast integrally with strengthening and radiating fins as at 32.

Although the radiating arms as here shown comprise a single conduit having a single continuous fluid passage, it will be understood that various other forms and-shapes of radiating units might be utilized to secure the desired cooling effect, the same being interchangeably mounted in the adaptor member 25. Also, it will be understood thatthe invention is applicable equally to varlous furnace constructions well known in the art having central shaft arrangements other than the particular double'concentric wall construction shown.

'If for particular processes 1t is found to be'unnecessary to use radiating units as above described at certain hearths, the socket provisions such as at 21 may bestill provided for manufacturing convenience and standardization of shaft parts, the unused sockets being then sealed either temporarily or permanently by suitable plug members fittingwithin the sockets as at 29 and 30.

At other hearths, the lowermost hearths for example, it will in some cases be found to be suitably plugged as above described, while the cavity 27 is left open at the socket 30 or provided with suitable air deflecting means whereby a part of the relatively warm air from the annular space 19 is discharged over such hearths. The air or other fluid medium thus discharged will of coursebe preheated to a considerable extent by reason of having previously passed through the radiating units and the rabble arm cavities at other hearths. A convenient means is therefore provided for reducing the temperature on certain hearths to the extent desired and for transferring theheat thus acquired in the cooling medium to other hearths where the efficiency of operation may be enhanced by an increase over the temperature, which would otherwise prevail. If desired for certain roasting operations the furnace temperatures at the various hearths may be substantially equalized in this manner.

The above described radiating or heat absorbing arms are particularly useful in many roasting operations when placed at the intermediate hearths, since there is often 'a tendency for the intermediate hearths to become overheated as a result of the rapid chemical actions taking place in the materials under treatment when they arrive at the mid-portion of the furnace. On the other hand, as the ores or other materials arrive at the lower hearths of the furnace, there is often a tendency for the temperatures to become too low to insure thorough treatment, inasmuch as the heat of oxidation will usually be lessat the lower hearths, the material having been previously exhausted of most of its combustible or oxidizable substances in the upper or intermediate hearths. This invention therefore provides a convenient means for transferring the excess heat of the intermediate hearths to the lower hearths'where such heat is often needed to give the ores orother material a complete and final roasting.

The heat absorbing arms embodying this invention should of course be clearly distinguished from the mere use of air cooled rabe ble arms in which the function of the circulated air is to merely maintain the rabble arms and teeth at temperatures which will prevent their deterioration or distortion. While the rabble armsat the various hearths may ordinarily be made substantially alike as to form, number and arrangement, in order to insure a uniform flow through the fun of such arms on the other hearths. as to form number, and arrangement. The cooling arms provide a cooling effect substantially in excess of any normal cooling effect arising from the use of the usual air cooled rabble arms, since the heat absorbed from the fur nace through the necessarily relatively thick Walls of the rabble arms is small as compared with the heat which may be transferred through cooling arms as at 22 designed particularly for that purpose.

Although for convenience and for obtaining substantial uniformity of cooling effects throughout the area of the hearths it is desirable to arrange the rabble arms and cooling arms alternately as shown, it will be un derstood that approximately equivalent results might be obtained by other arrangements or by providing the radiating units as substantially unitary structures in conjunction with the rabble arms.

Referring in further detail to Fig. 2, both of the cooling arm members of each pair as at 23 may be constructed in a manner similar to the above described construction. The adaptor members as at 32 may be provided with two pairs of sockets such as at 29 and 30, whereby both of the arm members 23 may provide a circulatory path for the cooling fluid. If it is desired on certain hearths to use but one of the arms 23, then one pair of openings of the U-shaped adaptor member 22 may be plugged either temporarily or permanently.

Also if desired certain of the adaptor members may be used to carry a rabble arm in addition to one or more of the radiating arms.

is to the design and constructional details of other parts of the furnace not specifically referred to herein, the usual practice may be followed as in the construction of other well known furnaces of this general type.

While the invention has been described with respect to certain particular preferred examples which give satisfactory results, it will be understood by thoseskilled in the art after understanding the invention, that various changes and modifications may be made without 5 eparting from the spirit and scope of the invention and it is intended therefore in the appended claims to cover all such changes and modifications.

What is claimedas new and desired to be secured by Letters Patent of the United States is:

1. A roasting furnace comprising a plurality of superposed hearths, a rotatable shaft extending vertically of the furnace and carrying pluralities of rabbling arms cooperating with each hearth, said shaft and rabbling means having communicating cavities providing a circulatory path for cooling fluid, said rabbling'means being detachably secured to the shaft withinshaft sockets, additional socket means on the shaft at one or more hearths, and adaptor means interchangeable as to the various sockets, said adaptormeans in turn each being provided with a plurality of sockets for carrying either one or a plurality of radiating arms, said adaptors also being provided with cavities for bringing said radiating arms into communication with the interior of theshaft.

V 2. A roasting furnace comprising a plurality of superposed hearths, a rotatable shaft extending vertically of the furnace and carrying pluralities of rabbling arms cooperating with the hearths, said shaft being formed with sockets, and heat absorbing arms carried in said sockets at one or more hearths, said heat absorbing arms being detachably secured to the shaft and made communicative with a supply of cooling medium therein through said sockets, certain of said sockets being formed with a plurality of arm receiving openings whereby a plurality of said heat absorbing arms may be mounted in a lesser number of said sockets and supplied with the cooling medium therethrough.

3. A roasting furnace comprising a plurality of superposed hearths, a rotatable shaft extending vertically of the furnace and carrying heat absorbing arms and also pluralities of rabbling arms cooperating with the hearths, said arms being mounted in sock-' ets on the shaft and made communicative through said sockets with a source of cooling fluid within the shaft, a number of said sockets being provided at certain hearths in eX- cess of the number of rabbling arms, each of certain of said socket-s being provided with adaptor means for carrying a plurality of heat absorbing arms interchangeably with rabble arms and communicative with the source of cooling fluid within the shaft.

'4. In a roasting furnace construction a rotating shaft including conduit means extendingfrom a source of supply of a fluid cooling medium, socket means on said shaft, and a plurality of arms extending divergently from each of said socket means and in generally radial directions in respect to said socket means, and made communicative through said socket means and shaft with the source of cooling medium.

5. In a roasting furnace construction a rotatable shaft'including conduit means extending from a source of supply of a fluid cooling medium,socket means on said shaft, and adaptor means engaging said socket means, said adaptor means having a plurality'of divergent outlet openings for carrying P arm members, said adaptor also having internal cav1t1es for bringing said conduit means into communication With each of the arms carried by the adaptor.

6. Means for absorbing heat Within a furnace comprising a U-shaped integrally cast tubular arm member having integrally formed strengthening and radiating fins interconnecting its sides, and means at one end of said member for movably supporting the same and for conducting cooling fluid to and from the interior thereof.

In testimony whereof I have signed my name to this specification.

HENRY J. HARTLEY.

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