US2433434A - Chilling cone - Google Patents

Description

ec. 30, i947.

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H. CHURCH CHILLING GONE Filed Aug. 29, 1945 2 Sheets-Sheet 2 /N VEN TOR B H0 WARD CIL/Ue 0H Patented Dec. 30, 1947 UNITED STATES PATENT OFFC anni CHLLING GONE Howard Church, Los Gatos, Calif., assgnor to The Permanente Metals Corporation, Oakland,

a corporationv of Delaware Application August 29, 1945, Serial No. 613,367

According to the carbothermic process a mixu ture of magnesium oxide .and carbon is introduced to a furnace operating at a temperature between approximately 1850 and 2000 C. At these temperatures the carbon reduces the magnesium oxide to form magnesium and carbon monoxide according to the following reaction:

This reaction .is reversible at temperatures above 200 C. so that it is necessary to rapidly cool, i. e, shock-chill, the magnesium vapors and carbon monoxide gases, as theyemerge from the furnace, to a point below 200 C., or where they are stable in the presence of Yeach other. The chilling medium employed may be hydrogen, natural gas, hydrocarbon liquids, and helium and the other noble gases. Obviously, this shock-chilling step is of prime importance in carrying out the carbotherrnic process for if too long a period is required to traverse the range of .instability the iinal product recovered after the chilling step will include large quantities of MgO and C and thereby render the process .inelicient This invention is concerned with the apparatus for use in carrying out the shock-chilling operation, and particularly where an .inert gas is employed as the chilling medium.

The apparatus which the art has employed in the shock-chilling operation has comprised a generally cone-shaped structure adapted to be located with its narrow end at a point adjacent the passage in the .furnace wall provided for the escape of the :furnace vapors and gases. The opposite dared end of the cone is connected to a condenser or settling chamber wherein the solid products -of the chilling step are collected. At

the tip of the cone or nozzle, means are provided for injecting the cooling medium, to contact the furnace vapors and gases. The vapors and gasesleaving the furnaceare chilled instantly by theinert cooling gas or chilling medium as they are intimately mixed within the cone. lt is impor tant that large quantities of the chilling medium be injected into the mixture of furnace vapors. and gases since the amount of chilling mediumv employed directly affects the eiliciency of the chilling step. However, due. to the proximity of 3 Claims. (Cl. 26.6-15) L the cone to the heat of the furnace, the prior art'- has always resorted to circulating cooling oil with-l in the cone and along the length rof its walls for the purpose of protecting its walls from thermal'v stresses.

This has considerably reduced the area between the walls of the cone for the passage of the cooling gas or other cooling medium and 115; cause of the various passages that have to bel eter.

it has been necessary to employ for that purpose a number of pipes of relatively small inside diam- As a result the quantities of cooling medium that can be passed through the nozzle are relatively small in view of its overall dimensions and friction losses are great. Furthermore, the cone itself is diiiicult and costly to fabricate beprovided for the circulation of the cooling oil for the cone walls themselves, and for the *pashl sage of thecooling medium for the furnace products to the constricted end of the nozzle. A typical example of the complex structure under discussion may be noted by reference to U. S. Patent No. 2,109,841 to Hansgirg- It is among the objects of the present invention to provide a chilling cone which is character ized by simplicity 'of construction and low cost of manufacture. Another object is lto provide a chilling cone capable of handling greater quan-4 tities of the cooling medium employed in shockchilling magnesium vapors than chilling cones of the prior art having the same overall dimensions. A further object is to eliminate the necessity forv cooling the nozzle with oil or the like throughout itsv entire length. These and other objects will be apparent from the description of the invention herein. v

According to the invention, a pair of inner and outer conical wall sections cooperating to form a generally cone shaped structure having a closed annularpassage is provided at points adjacent the base of the cone with means for the introfl duction of a cooling liquid .and a shock-chilling gas.4 The cooling liquid is adapted to continuously iiow through a series of pipes within the annular passage to an area-adjacent the tip oi the nozzle where it serves to cool the tip and prevent the harmful elects of the furnace heat. rThe cooling liquid passes from the tip through anotherseries of pipes also located within the annular i passage oi the cone and opening out at a point chilling medium is provided within the cone. The shock-chilling gases pass from the cone through a series of slots in the inner wall at the tip of the nozzle and contact the vapors and gases emerging from the furnace.

The preferred embodiment of the invention is shown on the accompanying drawings, on which Fig. 1 is an axial section thiereof; Fig. 2 is an elevation looking at the larger end; Fig. 3 is an enlargement of a, detail showing the cooling gas inlets to the gases to be shock-chilled; Fig. 4 is a development view of such detail, broken away; Fig. 5 is a sectional view, broken away, on the line 5-5 on Fig. 1.

The chilling cone, generally designated as II, is shown on Fig. 1 as conventionally connected to the furnace wall I2 and to the wall I3 of the collecting chamber, with an interposed heat and gas resistant sleeve |4 having `an axially extending flange or neck I5 to protect the adjacent end of the chilling cone, similar to that set forth in the Jameson Patent No. 2,367,029.

The cone comprises an outside Wall IG and an inner wall l1 terminating short of the outside wall adjacent the smaller end, these walls forming between them a comparatively large unobstructed and frictionless passageway |8 having the form of an annular truncated cone closed at its larger end by an annular end wall I9. A housing 2| having a longitudinal wall 22 and radial walls 23 is located directly on and about the cone adjacent the base thereof, there being a plurality of openings 24 through the cone wall I'| about the periphery thereof to afford connection between the interior of the housing and the passageway I8. The housing serves as a manifold to supply gas, and is provided with a suitable number of gas inlets 26 to admit diluting and chilling gas thereto; and it is also provided at the bottom thereof with a drain pipe 21 having a valve 28 therein, to drain off any liquid that accumulates therein. The passage- Way I8 has a similar drain 23 at its lowest point for a similar purpose.

Projecting from the end of the inner wall I'I is a wall 3| having a conical, that is, truncated cone shape and being at a wider angle to the cone axis than the wall I1. Such angle of the wall 3| is preferably about 30. The joint between these two walls may be of any suitable type, but it is preferred to be an expansion joint with the end of the wall 3| within the end of the wall I1. Extending from the other end of the wall 3| is a wall 32 of conical, that is, truncated cone shape and at an angle to the cone axis slightly less than that of the wall IT and preferably about '1l/2. These three cones are coaxial, as are all of the truncated cone-shaped parts of the novel chilling cone whether mentioned previously or later herein. Extending from the end of the Wall I6 is the outer walls 36 of an annular truncated cone-shaped jacket 3'! having a wider angle with the cone axis than the wall 3|, and

preferably of about 35. The inner wall 38 of the jacket is at an angle to the cone axis which is between that of the walls 3| and 36, and preferably about 32 50. The jacket, and the gas space between the Walls 3| and 38, are thus slightly and gradually constricted in the direction of the furnace. The walls 36 and 38 are joined at their furnace ends by an annular end wall 3B having an annular bulge 4| of smaller diameter than the adjacent end of the wall 32, such bulge forming an indented portion or concavity 42 in which the end of the wan 32 is locats- 'The other end of the jacket 31 is closed by an annular wall 43.

As shown on Figs. 3 and 4, the wall 32 has rows of peripheral gas passages 44 therethrough which are inclined to give the gas a direction of travel at an angle to but in the direction of movement of the gases to be shocked chilled, this angle being preferably about 45 to the cone axis. The wall 3| has similar but less rows of gas passages 4E which are inclined to impart to the gas a direction of movement more in the direction of movement of the gases to be chilled than the passages 44. Adjacent rows of passages 44 are staggered with respect to each other, and adjacent rows of passages 46 are likewise staggered. The rows 44 and 45 extend all around the periphery and each passage is close to adjacent passages of the same and adjacent rows. The passages are preferably rectangular, narrow axial y of the wall, and long peripherially thereof, with only short parts of the walls left unperforated between the ends of adjacent passages of a row as seen at 48, and with only narrow portions 49 left unperforated between adjacent rows.

A pipe 5| serving as a manifold to supply cooling oil or other suitable fluid, extends around within the passageway I8, preferably adjacent the base of the cones, connected to which is a pipe 52 to feed the cooling fluid thereto. A series' of pipes 53 which are arranged annularly about the cone and spaced from each other are connected to the pipe 5|, and extend through the gas passage-way I8 and into the jacket 31 to just short of the furnace end thereof. The pipes 53 have oblique open ends all facing in the same peripheral direction to impart to the oil a movement of rotation about the jacket 3T. The oil is carried away by a series of pipes 54 extending through the annular wall 43 and leading into a common oil outlet manifold 56 having a suitable number of exit pipes 51.

` In operation, the gases and vapors formed 1n the furnace I2 pass through the outlet opening in a wall thereof, or through the protecting sleeve I4, through the novel chilling coneand into the collecting apparatus I3. The chilling gas passes through the passageway IB and through the openings 44 and 46 to mix with, dilute, and shockchill the furnace gases which then pass on. The novel chilling cone affords very much less friction or resistance to the ow of shock-chilling gas, due to the free and unobstructed path ther fore andV to its greater cross section, and thus permits a larger and faster supply of such gas to the gases emanating from the furnace. This is of prime importance due to the exceedingly great volume of chilling gas required in the production of magnesium metal, and of other materials as well. In the case of magnesium the feed of chilling gas is raised from about 750,000 cubic feet per hour to about 1,200,000 cubic feet per hour with the novel chilling cone of the saine size as those conventionally used and with the chilling gas atthe same pressure. This is important because it is then possible to increase the rate of magnesium oxide and carbon fed to the furnace by about 800 to 1000 lbs/hr. over that possible with the old cone. Not only is the novel chilling cone more effective, but it is simpler in construction and easier and less expensive to fabricate than those'conventionally used.

understood that it may also be employed in the 5 production of other materials wherein it may have application.

What is claimed is:

1. In apparatus for recovering metals from their vapors, a chilling cone comprising outer and inner conical walls spaced from each other to form a rconical annular passage; cooling iiuid inlet and outlet pipes Within said passage adjacent said outer wall, said inlet pipes extending substantially to the furnace end of said cone, said outlet pipes extending short of said inlet pipes, and a jacket Comprising that part of said outer wall between the outlet pipes and the furnace end of the cone.

2. In apparatus for recovering metals from their vapors, a chilling cone comprising conical outer and inner walls forming a conical annular passage between them, the outer Wall bending to form a greater angle with the cone axis adjacent the furnace end, the inner wall bending to form a greater and then a lesser angle with the cone axis adjacent said end.

/3. In apparatus for recovering metals from their vapors, a chilling cone comprising conical outer and inner Walls forming a conical annular passage between them, the outer wall bending toward the cone axis to form an obtuse angle therewith as it approaches the furnace end, the inner wall bending toward the cone axis behind the bend in the outer Wall and then bending to form a lesser angle with the cone axis ahead of the bend in the outer wall.

HOWARD CHURCH.

` REFERENCES critici)A The following references are of record in the ille of this patent:

UNITED STATES PATENTS Name Date I-Iansgirg Mar. 1, 1938 Number

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