US994889A - Method of and apparatus for condensing zinc vapor to liquid metal. - Google Patents

Description

c. THI ERRY & J. fnomson; METHOD OF AND APPARATUS FOR UUNDENSING ZINC VAPOR T0 L IQUID METAL.

APPLICATION FILED JULY 15, 1910.

1 Mn 1..- 3m 1 8 mm E J d m a P I J I C. THIBRRY & J. THOMSON. METHOD OF AND APPARATUS FOR OONDENSING ZINC VAPOR TO LIQUID METAL.

APPLICA T ION FILED JflY 15, 1910. 994,889, Patented June 13,1911.

4 SHEETS-SHEET 2.

o. THIERRY & J. THOMSON.

METHOD OF AND APPARATUS FOR GONDENSING ZINC VAPOR T0 LIQUID METAL.

4 SHEETS-131133! 3.

APPLICATION FILED IULY15 1910.

*' Patented June 13, 1911.

c. THIBRRY & J. THOMSON METHOD OF AND APPARATUS FOR GONDENSING ZINC VAPOR T0 LIQUID METAL,

APPLICATION FILED JULY 15, 1910. 994,889, Patented June 13,1911.

4 SHEETS-SHEET 4 Q A EGE Qwkmoww m $31 in v D UNITED STATES PATENT CHARLES THIERRY, 0F PARIS, FRANCE, AND JOHN THOMSON, OF NEW YORK, N. Y.

METHOD OF AND APPARATUS FOR CONDENSING ZINC VAPOR TO LIQUID METAL.

To all whom it may concern:

Be it known that we, CHARLES THIERRY, a citizen of the Republic of France, and a resident of the city of Paris, in said Republic of France, and JOHN THOMSON, a citizen of the United States, and a resident of the borough of Manhattan of the city of New York, in the State of New York, have invented certain new and useful Improve ments in Methods of and Apparatus for Condensing Zinc Vapor to Liquid Metal, of which the following is a specification.

This invention relates to the metallurgy of zinc, and is directed to a method of and means for condensing zinc vapor to liquid metal.

The invention is specifically intended for operation in connection with electrical furnaces in which the reaction is carried on more or less continuously at a rapid rate of evolution.

The dominating objects thereof are to readily and positively adapt and control the thermic conditions of the condenser to either a constant or variable delivery from the furnace; to condense the vapor to a liquid state, without the formation of blue powder and to provide simple apparatus for carrying the invention into effect in a manner readily realizable in practice.

As showing a specific and practical embodiment of our invention reference is made to the drawings forming a part of this specification and in which:

Figure 1 is a plan view of the condenser as on the line A of Fig. 2, the cover being removed; Fig. 2 is a side elevation with certain portions in broken section as on the line B B of Fig. 1, the side wall being re moved. Fig. 3 is an end elevation as on the line C of Fig. 2 the end wall being re moved. Fig. 4 is an enlarged sectional view showing the detail of the tube-joint, and Fig. 5 is a diagrammatic plan view showing how a single condenser may serve a plurality of reaction furnaces.

The changing of zinc from solid or liquid to vaporous conditions presents "practically no ph sical problem as zinc melts at or about 7 75 degrees F. and readily becomes a vapor at or about 1750 degrees F. but if the conditions are reversed, that is, when it is desired to dissipate the heat stored in the vapor and precipitate the vapor asa fluid Specification of Letters Patent.

Application fi1ed July 15, 1910.

Patented June 13, 1911.

Serial No. 572,095.

metal the realization thereof in a ractical operation involves various difficultles. For example, if the heat in the vapor, below its critical point, is withdrawn too suddenly, it

will precipitate as a blue powder, or if. brought in contact with air at a temperature of or about950 degrees F. it will burn to white oxid. The actual temperature at which the zinc vapor reaches the condenser will usually be about the same as that of the reaction in the furnace, which if carbon be the reagent, as in retorts, may range from 2200 degrees to 2600 degrees F. and in the instance of the electric furnace, where iron is the reagent, may range from a minimum of 2000 degrees F. up to the resisting limit of the furnace refractories. Generally speaking, however, it may be said that the temperature of the vapor as evolved will be about 2500 degrees F. and in order to realize a complete precipitation thereof to liquid zinc there mustbe a progressive diminution or withdrawal of the heat-units until said temperature is brought down to or about 775 degrees F. with complete exclusion of atmospheric air from the interior of the condenser. vhpor to liquid metal, exclusive of other gaseous products, when the vapor is about at the higher temperature mentioned and at atmospheric pressure is approximately 4200 to 1. Consequently the elements of area, ve locity and time are necessarily involved in a successful solution of the problem. Thus if a cellular structure is employed with the thinnest possible walls, impermeable to gases and vapor but with the utmost permeability as to conduction of heat, this w1ll permit an exceedingly rapid tendency to balance or reestablish the thermic equilibrium upon the inner and outer surfaces; for condensation of zinc vapor into metallic zinc on the inside simply consists in a progressive disengagement of heat units, and the rate or rapidity of the said disengagement will proceed according to the temperature surrounding the outer surface of the cells.

If the vapor enters the cells at a constant temperature, a constant volume and a constant velocity; and if'the temperature and the thermal receptivity outside of the cells are, for any cause or causes whatever, changeable, then the lineal length and surface of the cell-system must be adequate to The relation by volume of zinc permit such variable extents of vapor-flow and surface contact as will compensate, by the lesser or greater traverses within, for the fluctuating condition without.

If the zinc vapor is received by the cells at an approximately constant rate of vclocity, volume and temperature; and if the temperature and humidity of the atmosphere outside of the inclosing casing is approximately constant, then the thickness and character of the walls which form the chamber in which the cells are mounted may be such as to dissipate, by natural radiation to the atmosphere, the quantity of heat units given off by the vapor. In such an instance, the heat units would be transmitted, first, through the cell-walls; second, through the heated atmosphere of the chamber which contains the cells and, third, through the side-walls, cover and bottom. This represents the ideal state of operation, proceeding more or less automatically, requiring merely nominal attendance and no changes of the heated air within the chamber exterior to the cells; but such a condition would not ordinarily be realizable in regular practice.

Should the relations be such that the radiation to the outer atmosphere is greater than the delivery of heat-units from the cells, then obviously compensating heat must he introduced into the chamber which contains them, in order to prevent such a rapid withdrawal of heat-units as would effect a sudden chilling of the vapor and its precipitation in the form of blue-powder.

The wall of the cellular structure may therefore be considered as a septum which must play the double role of being impermeable to gases and vapors but should be as permeable as possible to heat. Such a septum will therefore permit a very rapid restablishment of thermic equilibrium between its inner and the outer faces. But goin with this is a feature which is categorica ly indispensable to good condensation of zinc vapor into liquid zinc, namely: that the exterior of the cellular 5 septum must be surrounded by an atmosphere, as of air or gas, whose temperature or caloric receptiveness can effectively be held constant or varied at will between definite minimum and maximum limits.

Intimately connected with the foregoing is the element of fixed gases, which are driven off by the reaction and attain a temperature similar to that of the zinc vapor. The volume of such gases, relative to the zinc vapor, is highly variable, depending upon the character and quantity of the reagent which may be employed. But suflice it to say that such gases, not being condensible into a liquid, exercise a pernicious effect as to the metallic precipitation of zincvapor in that they act as containers of heat-units and, by their more or less maintained rate of movement from the entrance to the exit of the cellular system, mechanically entain the fumes. As a consequence, heat mus also be withdrawn from the pernicious gases and the extent and character of the cells should be such that the metallic vapor will be liquated, say like rain from mist, before reaching the terminus of the cell-system.

In general terms the invention is comprised in the disposal of a plurality of tubes or chambers connected in vertical or horizontal series or in combination of both forming a cellular structure in which the vapor and the condensed liquid metal flow, preferably in a common direction, while he ing subjected to a progressive cooling therein. This cellular structure is incased by brick work, of such character and thickness as to afford a high factor of insulation and is provided with means for definitely controlling an inflow of atmospheric air to the space exterior to the said cellular structure, as or when desired, and also with means for definitely controlling the efflux of heated air therefrom.

The requisite means being provided for carryin the foregoing project into effect, it will fie perceived that if the interior of the cellular structure is preliminarily heated to a temperature of, say, 1,100 degrees to the containing chamber and if the walls forming the said chamber are sufficiently non-conductive of heat, the rate of condensation will become progressively less and may entirely cease. Under such a condition no blue powder will be formed.

The condensing condition just described (that is, a temperature within the inlet por-v tion of the condensing cells well up to or even beyond that of the vaporization point of zinc and a temperature around the exterior of the cells somewhat above that of the freezing point of liquid zinc) can be definitely maintained, under a wide range in the rate of the reaction, by introducing atmospheric air into the cell-chamber from below in such manner as to progressively displace the contained heated air at a controlled rate of flow from above.

In the embodiment of the invention illustrated by the drawings, D is the cellular system whlch receives the zinc vapor from the reaction furnace and E is the refractory casing which forms the cellchamber F. As shown the cellular system is formed by the assemblage of a series of tubes, 6, jointed as at 7, into right angle connectors 8. A setof tubes is thus connected to form a unit, say in horizontal disposal as in Fig. 1, and this unit may then be vertically joined by a connector 9, to another similar unit beneath. The flow of the vapor through the system is indicated by the arrows 1. It will be clear that the horizontal extension of the unit and the number of units which may be stacked one over another may be indefinitely extended; hence any length of circuit may be provided which may be necessary to obtain such a period of time as will permit a complete precipitation of the vapor to liquid metal, by progressive cooling.

The preferable connection of the cellular system to the furnace is by the upper unit, as tube 10 joined by a connecting sleeve 12 on the exterior of the main caslng. This sleeve 12 may have a slidable valve 13 for throttling or entirely cutting off the flow of zinc to the condenser, as may be desired.

It has long been held by spelter specialists that the condensation of zinc vapor appears to proceed with greater regularity and to the maximum extent after the condensing chamber has acquired a bath of liquid zinc. This condition is utilized in .the present invcntion to the utmost extent, that is to such a maximum depth as will not objectionably diminish the interior capacity of the cells. Thus, the plugged hole 13, Figs. 1 and 2, is for the purpose of supplying the condenser with a preliminary bath of molten metal 14 which is maintained at a definite level within the tubes of the upper unit, or units, by dams, as 15. In the lower unit the liquid metal may be drawn 01f, as rapidly as it accumulates, arrow 8, Fig. 2, through a liquid sealed opening as 16, formed in the head 17, of the leading-out tube 18. This opening is arranged so as to retain a greater depth of bath in the lower unit than is retained in the upper unit or units by the dam or dams. In this wise a very large surface of molten zinc is afforded and its presumed aflinity for vaporized zinc may be availed of from the instant of starting an operation. The lower unit may be cleared of melted zinc at any time by means of the outlet 19, Fig. 2, formed in the bottom of the tube. The opening 17, in the head 17, is for the escape of CO and other gases entrained with or accompanying the zinc vapor, and this opening also provides egress for any residual vapor which may not have been fluidified, thereby indicating that the condenser has reached the limit of its capacity.

It is important to here observe that the directiofl of flow of the liquid zinc is the same, throughout the system, as that of the vapor; the hotter metal from above constantly moving along to and displacing the cooler metal below; consequently there are no dead pockets and little, if any, opportunity for the reevaporation of zinc even in the hottest part of the system.

As shown, the aforesaid dams, 15, are preferably insertible whereby, as stated, the depth of the retained bath may be increased or decreased. Moreover, should the vapor reach the upper series of cells at so high a temperature as to produce more or less reevaporation of the retained metal then the dam may advantageously be entirely removed.

The abrupt and numerous deflections of the vapor in its passage through the connectors is an element of advantage, the effect of which is to cause a constant commingling of the lighter and denser portions of the vapor; to retard the velocityand to bring, at one time or another, all of the flowing volume into direct physical contact with the surfaces of the cells. These sharp deflections are also of the first importance with respect to the fixed gases which enter with the vapor; as it is quite as essential to with draw heat-units from the pernicious gases as the metallic fumes. Again, these impingements assist materially in the me chanical disassociatio n of the vapor from the gases, as the velocity-head is impeded at each of such collisions and new internal currents, or swirls, are produced, thus bringing about a greater extent of surface contact. It should be borne in mind that in flowing through the series of cells the fixed gases suffer in themselves a much lesser diminution in their volume than does the vapor. Consequently, the fixed gases become more aggressive and the vapors less resistive, so to speak, hence to obtain a complete precipitation of the fumes into a fluid involves, as primarily stated, the elements of time, velocity and area as well as the thermic elements have 'to be considered in carrying out the condensing operation.

The cover 20, of the main casing, and each of the four side walls thereof, 21, 22, 23, 24, are preferably constructed of fire bricks, interlocked as 25, and clamped together end-wise by steel channels, as 26, and tie-rods, as 28. By this construction, not only can the cover be lifted off or replaced at will but by breaking the coupling sleeves 28, 28, all of the side walls may also be swung out of place, entirely exposing the condenser and its joints for inspection, repair or replacement.

The bottom of the cell chamber is formed of one or several series of bricks, as 29, which rest upon a grille of steel I-beams, as

30, these in turn being finally supported. upon a series of rollers 31. The object of this construction will be referred to later on.

Upon the brick bottom, 29 (see Figs. 2 and 3,) a considerable number of bricks 32, are set, checker-board fashion, affording wide spaces, as 33, between them and upon these are placed another series of bricks, preferably splits each out of side-contact with the other, so as to form a considerable number of narrow slits, as 35. Then a series of flues, as 36, are formed along the lower footings of the side walls. These openings may be closed or opened from the outside by any suitable means, as by the damper-block 37, Fig. 2. In the cover several tubes or flues, as 38, are inserted and these are also to be provided with suitable means (not shown) for closing or opening them from the outside. This construction affords the means for definitely controlling the temperature of the cell chamber F; for, with the tubes in the cover closed and the flues in the side-walls also closed, there will be no exit or displacement of air within the said chamber, whereas with the tubes and flues partially or wholly opened, in various combinations and areas, the circulation of the contained heated atmosphere, from below up,may be at any velocity desired. The arrows w denote the inflow of air from without and clearly indicate how the jets m, through the numerous inlet slits must necessarily act to impart motion to the entire volume of contained air, forcing the more highly heated air from above out through the cover openings, .as arrows n. In this manner there are no dead spaces and the upper portion of the chamber can readily be maintained at a higher temperature than the lower; which is precisely in accord with the desired or ideal condition.

The tubes 6 and connectors 8 and 9 are preferably formed of a compound of graphite and clay, such as is ordinarily known as retort graphite, which material is an excellent conductor of heat and has a low coefficient of expansion and contraction. It is of the first importance that the jointing of these members shall be of the most perfect and enduring character. To this end, first, the cell-structure is supported by light brick columns 40 and is everywhere entirely free of the main casing except only in the instance of the in and out tubes where they rest in the brick wall of the main casing. This avoids imposing any strain upon the tubes other than that due to their own Weight and to temperature stresses; then, second, the joint, as see Fig. 4, is of such design that whatever may be the tendency of the strains the effect is to maintain the utmost intimacy of contact between the cement and the molded parts. Thus, the ends of the tubes are formed to a taper 41, and

the recess 42, in the connector is correspond ingly tapered. The diameter of the wider portion of the tube-taper, as 43, should be about the same or somewhat less than that of the lesser diameter, as 44, of the recess in the connector; the object thereof being to permit the end of the tube to be readily introduced within the recess. Then in the face 45 of the tube a groove, 46, is formed, and a corresponding groove 47, is formed in the face 48, of the connector. These grooves are connected by the annular recess 49, with the tapered recess 50. The relative position of the parts is limited by the contact of the faces 51. When thus assembled, cement is introduced and tamped, forcing it to flow inwardly and entirely fill the spaces. Now, when the cement is hardened by preliminary heating, any tendency on the part of the tube to withdraw from the socket will tend to tighten the cement in the tapered portion of the recess; any tendency to force the tube and connector together will tend to tighten the cement in the annular section 49, of the recess; any tendency of the cement to expand to a greater extent than the material which it joins, will obviously tend to tighten and finally, any tendency of the cement to shrink Within itself will also tend to tighten by tension between the grooves 46, 47 and the tapered reeess 50.

The longest possible endurance of the condenser will be obtained by operating it continuously, as this will avoid any excessive changes in the temperature of the cell system. Therefore, as has already been briefly pointed out, the condenser as a Wholeisqbuilt upon a grille of I-beams 30, which rest upon a plurality of rollers 31, Figs. 2 and 3. Due to this construction as can be seen in the diagrammatic plan View, Fig. 5, one condenser can be utilized to serve at least two furnaces. As shown, when furnace number one is in operation, delivering its evolved zinc vapor to the condenser, reserve furnace number two is free to be put in working condition, and when furnace number one fails, it is only necessary to disconnect the vapor tube, roll the condenser along to the position indicated in broken lines, re-connect with furnace number two, proceeding as before, and vice versa.

It is obvious that various modifications may be made in carrying out our invention without departing from the spirit and scope thereof.

We claim as our invention:

1. A zinc condenser comprising chambers connected in series so that all substances entering one chamber will pass therefrom to another chamber, a heat insulating casing inclosing said chambers, said casing having means to permit the inlet and outlet of air thereto and therefrom to regulate the heat conditions.

2. A cellular structure for condensing zinc comprising chambers connected in a manner to have liquid therein pass from one chamher to the other, a casing surrounding the chambers in series and constructed to permit the inlet and outlet of air.

3. A cellular structure for condensing zinc comprising chambers connected in a manner to have liquid therein flow by gravity from one chamber to the other, a casing surrounding the chamber in series and constructed to permit the inlet and outlet of air.

4. Accellular structure for condensing zinc comprising chambers connected in serles in a manner to permit gaseous and liquid fluids to flow from one to the other, a casing for the chambers having heat insulating Walls and constructed to permit the inlet and outlet of air thereto and therefrom.

5. A cellular structure for condensing zinc comprising chambers connected in a manner which Will permit gaseous and liquid fluids to flow simultaneously therebetvveen, a casing for the chambers having heat insulating Walls and constructed to permit the inlet and outlet of air thereto and therefrom.

6. A zinc condenser consisting of a cellular structure comprising chambers connected in series for containing liquid metal, and a heat insulating casing forming a chamber for the cellular structure, and means for regulating and maintaining the heat conditions Within the chambers at different points of the travel of the substances therethrough.

7. A zinc condenser consisting of a cellular structure comprising chambers, for containing liquid metal, connected in series and in a manner, to pass the liquid successively through the chambers, a heat insulating casing forming a chamber for the cellular structure the Walls thereof being constructed to permit the inlet and outlet of air to and from the said chamber, and means for regulating and maintaining the heat conditions Within the chambers at different points of the travel of the substances therethrough.

8. A zinc condenser consisting of a cellular structure formed by a plurality of tubes and connectors disposed horizontally for containing the vapor and liquid metal, said cellular structure being surrounded by heat insulating Walls provided With a plurality of air inlets and outlets for controlling the temperature of the space exterior to the cellular structure for regulating the heat conditions at different points.

9. A zinc condenser consisting of a cellular structure formed by a plurality of tubes and connectors disposed horizontally constituting the upper unit said upper unit being connected in series With an additional lower unit or units containing the vapor and liquid metal, and an exterior heat insulated chamber in Which the temperature is controlled by the inlet and outlet of air.

10. A zinc condenser consisting of a cellular structure formed by a plurality of tubes and connectors connected in series, to form a cell unit or a stack of such units, suitably mounted in a chamber said tubes being so arranged and connected that the vapor and the liquid metal as it is condensed will flow along Within the said cellular structure in a common direction.

11. A ZlIlC condenser consisting of a cellular structure comprising chambers connected in series mounted in an inclosing chamber in Which the vapor will be forced through the cells by pressure and the liquid metal as it is condensed will flow by gravity, the two movements being in a similar direction.

12. A zinc condenser consisting of a cellular structure comprising chambers connected in series, as a cell unit or a plurality of such units, mounted in an inclosing chamber, the cellular structure being arranged to receive and retain a bath of liquid metal over which the vapor flows, the chambers connected in a manner to permit liquid metal to flow therebetween.

13. A zinc condenser consisting of a cellular structure comprising chambers connected in series mounted in an inclosing chamber the terminal of the series being provided with an opening for the egress of gas,

a liquid sealed openmg for the egress of liquid metal at a comparatively constant rate of flow from the interior of the chambers connected in series, and a tap opening for emptying the system.

1 1. In a zinc condenser having a cellular structure formed by a plurality of tubes and connectors in Which the vapor and liquid metal is contained the combination between a tube and its connector of a joint-space for receiving cementing material, said space having in cross section a tapered, a lateral and a vertical recess connected With each other whereby expansion or contraction of the tube, the connector or the cement will act to maintain the tightness of the joint.

15. In a zinc condenser the combination of a cellular structure into Which the vapor is introduced and a heat insulating chamber arranged and constructed to receive external air through openings in its bottom and to permit of the efilux of the heated air through flues in the cover to regulate the heat conditions at different points of the structure.

16. In a zinc condenser the combination with a cellular structure contained Within the inclosing chamber of an external tube for connecting the cells with a reaction furnace, a steel grille upon which the chamber is built and a series of movable rollers supporting the grille.

17 The combination of a plurality of furnaces and a zinc condenser composed of a cellular structure contained within a casing and having an external connecting tube to connect the condenser to any one of the furnaces without affecting the working conditions of the condenser; the zinc condenser being provided with a suitable system of supporting rollers the arrangement and construction thereof being such that the con denser can be moved back and forth between the furnaces.

18. In the metallurgy of zinc the con densing of zinc fumes in the resence of liquid zinc progressively decreasing in temperature.

19. In the metallurgy of zinc, the condensing of zinc fumes in the presence of liquid zinc, the temperature of the liquid zinc and the temperature of the zinc vapors decreasing as the liquid and fumes traverse the condensing system.

20. In the metallurgy of zinc, the condensing of zinc fumes in the presence of liquid zinc, the temperature of liquid Zinc and also of the zinc fumes decreasing according to conditions in the condensing system.

21. In the metallurgy of zinc, the condensing of zinc fumes in the presence of liquid zinc, the temperature of the liquid zinc and also of the zinc fumes decreasing correspondingly, as the process proceeds, with the decrease of the temperature in the condensing means.

22. The condensing of zinc vapor to liquid by passing it through a condensing cham her in the presence of liquid zinc of successive cooler temperatures and progressively and gradually cooling the vapor as it passes into the presence of the liquid zinc.

23. In the metallurgy of zinc the passin of zinc fumes through a condenser and maintaining a gradual and progressive cool ing of the fumes until they change to liquid zinc by controlling the cooling effect of the condenser according to changes in the volume and temperature of the fumes delivered to the cdndenser.

24. A zinc condenser comprising chambers connected in series and also comprising travel 0f the vapor passing through the chambers, the temperature in each chamber being below the volatilizing point of zinc.

25. A zinc condenser consisting of a cellular structure comprising chambers connected in series having portions for holding liquid metal therein and means for regulating the cooling effect of the chambers on fumes Within the same, the temperature in each chamber being below the volatilizing point of zinc.

26. A zinc condenser consisting of a cellular structure surrounded by heat insulated walls provided with a plurality of air inlets and exits for controlling the tempera-- ture of the space exterior to the cellular structure.

27. In the manufacture of zinc the passing of the fumes from a furnace to a condenser and then while the condenser is in normal working condition sending the fumes from another furnace when the supply from the first furnace is cut oil.

28. In the metallurgical process for the manufacture of Zinc a condense-r, two furnaces, and means for connecting the condenser to either furnace without affecting the working condition of the condenser.

29. In the metallurgical process for recovering zine. as a vapor and precipitating it as a liquid, a movable condenser disconnectible from one reaction furnace and then shift'able and connectible to another reaction furnace, all of said elements being maintained at or about the proper operating temperatures. This specification signed and witnessed the iiOth day of June, A. D. 1910, in the city of Paris, in the Republic of France.

CHARLES THIERRY. Signed in the presence of- PAUL CoULoMB,

H. C. Coxn.

This specification signed and witnessed the 20th day of June, A. D. 1910, in the city of New York in the State of New York.

JOHN THOMSON.

Signed in the presence of E. E. KIRGHER, H. C. Onoss.

Gopies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. 0.

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