US1576621A - Electric rotating resistance furnace - Google Patents

Description

BEST AVAELA BLE 005 3 F. ANDERSEN ELECTRIC ROTATING RESISTANCE FURNACE March is ma.

' Filed March 22, 1925 Patented Ma. .16, 1926. 8'58! UNITED STATES coa I PATENT OFFICE,

rmn'rJor ANDYIIJRSEN, or 'rRoLLHA'r'rAN, SWEDEN, ASSIGNOB 'ro "rRoLLHiT'rAus' mnx'rnornnnmsxa AKTIEBOLAG, OFHSTOCKHOLM, SWEDEN.

ELECTRIC nora'rnfe :ansxsrancn rormacn Application filed March 22, 1923. Serial No. 628,975.

To all whom it may concern.

Be it known that'I, FRmTJor ANnnRsnN, a subject of the King of Norway, and residing at Trollhattan, Sweden, have invented certain new and useful Improvements in- Electric Rotating-Resistance Furnaces, of-

which the following is a specification.

Zinc powder, also called zinc pou'ssiere, when subjected to heat and to acertain agi- 10 tat-ion or rubbing, may be caused, as known, to be converted into spelter or crude zinc to its greater part, whereby it has been shown that the conversion of the powder into liquid metal is performed in the simplestv manner in an electrically heated resistance furnace having a rotating,.rocking or oscillatory motion.

However, in order to obtain a suitable current are made'the electric resistance or.

the resistor must be quite different from the resistance in those parts of the resistor which are situated within the furnace or iii-the,-

\ [furnace chamber-proper.

By duly arrangingthe sectional'area of the resistor or by using a different composition of the'resistor mam in the current-sup- 40 plying part of the resistor, situated outside of'or in the furnace wall, in relation to the part of the same situatedwithin the fur nace chamber p'roperit will be possible to obtain a heating effect of the,zinc powder mass to be converted into liquid metal, which isadvantageou's'from the point of view of the technics of-heataswell as for the carrying out of the process As a common rule for the different elec- 'tric resistance in the inner andfouter parts of the resistor obtained by differentcross sections or in any other manner, it may be;

stated that the electric resistance oftheinmeans.

eross sections are shown;

is formed with a red a greater resistance than the end parts A nerheat-producing part of the resistor must .be proportioned inrelation to the electric resistance of the outer part of the resistor at ,least as 2:1. -No maximum limit for said difference of theelectric'resistance may be statedas said mutual proportion is determined by the existing mechanical arrange mentsland by the space afforded in the furnace in question. j

For obtaining different electric resistances in different parts of a resistorhaving the same cross sectionalyalrea all over its length,

a,resistor mass may"be-'used,which in the parts where the higher resistance is required is composed of carbon powder leaving a rel 'atively great amount of ashes, whereas in the'parts where a-- lower resistance is re- 9 qulred a res1stormassis used composed of -carbon materials, as pure aspossible, such asgraphite, retortgraphite and petroleum coke.

The transition from a better conducting part of the resistor to a less conducting part may either-bemade abruptly, whereby the heating of the furnacechamber or of the powder may be defined to a certain desired place, or by; gradually decreasingpr increasing the electric. resistance alone: that length .of-jthe resistor it will be possible/to obtain-an evenly augmented changeof tern- 'p.erature within the furnace chamber.

This change of temperature along the .lengthof .theresistormay be obtained by meana'of different cross sectional areas or by; different compositions of the resistor mass, or'by a'eombination of these two In the accompanying drawing some con structional forms of resistors 'with different.

In Figures 1,2, 3, 4 and 5, And C indicate the current-su'pplying'parts ofthe resistor, whereas B iifdicates the-heat generat'- ing part of the same, e

-In Figure 1,.the partB has a less cross sectional area than the parts A and C.

In Figure-"2 the IGS lSlfiIf jSZhiCh'hQS a uniform outer diameter lgng its whole length j part B opposing andC. f In Figure;3the intennediatdpart Bhas increased sectional. areas-from the enema BEST AVAILABLE CO PX A to C, so that a decreasing resistance is obtained in the intermediate part between A and C. i

In Figure 4 the intermediate part Bhas a decreasing sectional area from the end parts A and 0 towards the middle of the in termediate part so that the greatest resist ance willbe obtained at the middle.

In F igure. 5. the resistor has the same sectional areas along its whole length Whereby its intermediate part B is formed by a material of greater resistance than the parts A and C. v I

By making the intermediate part Bof another sectional area and'also of another material than A and C the desired difference of resistance may be obtained.

It the relation between the cross sections of the end parts A, C and the intermediate part B is greater or equal to the proportion 2 :1, the end andintermediate parts A, B, C apparently may consist of the same homogeneous material J Y of the resistor in the material, constituting the current-supplying I parts of the resistor, islower than that of the I material constituting the intermediate part 2. A resistor for electric furnaces in which proportion of at least the material of the current-supplying parts I of the resistor is composed of pure carbon, Whereas the material of the intermediate partof the resistor is composed .of carbon leaving a great amount of'ashes. I

In testimony whereof 'Ihave signed-my .name to this specification.

'FRIDTJOF ANDERSEN,

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