US1870691A - Method of and apparatus for making and shaping solid carbon dioxide - Google Patents

Description

Aug. 9, 1932- R. R. Rus'T ETAL METBODJDF AND APPARATUS FORMAKING AND SHAPING SOLID CARBON DIOXIDE Filed Dec. 17, 1929 2 Sheets-Sheet 1 TO LIQLHFYING PLANT R 0 Y m} M m m ZS 3 4% M Ram Aug. 9, 1932. R. R. RUST ET AL METHOD,0F AND APPARATUS FOR MAKING AND SHAPING SOLID CARBON DIOXIDE Filed Dec. 17, 1929 Z'Sheets-Sheet 2 FROM I LIQUIFYING PLANT QC-If i ff TO LIQLHFYWG A PLANT INVENTOR Robert 12.221152 Charles -iivfanes.

ATTORNEY atentcd Aug. 9, 1932 U STATES sosna'r a. miss, or GARDEN CITY, m cmnnns L. Jenna, or rnnnm new You ASSIGNOBS .TO DRYICE CORPORATION OB AMERICA OI POBATION OF DELAWARE NEW YORK, N. Y A 003' EETEOD OF AND APPARATUS FOB MAKING SHAPING BOLD) CABBOH DIOXIDE Application filed December 17, 1929. Serial no. 414,675.

Our present invention relates to methods and apparatus tor evaporating liqu1d carbon dioxide to gasify part of it and freeze the remainder. Prior processes, so far as we are aware, involve intermittent operation either as to the evaporation of the liquid to, form solid or as to the compression of the solid into cakes or blocks. In particular,

certain prior methods that involve relatively i i fluctuation in the demand/made slow boiling or evaporation of the liquid against counterpressure maintained from and at the triple point, have required relatively long intermissions between charges of liquid into the container because of the no;

' cessity of removing the sclid product from the boiling chamber, either for compression in another chamber or after compression in v the boiling chamber itself.

Such intermittent operation involves wide upon the liquefying plant and correspondlng y large fluctuations in the rate at which the evaporated gas is returned to the system for recompression. Moreover, great losses result from all - lowering the pressure of the boiling chamber and exposing it to atmosphere, between each successive cycle of operations.

All the objectionable features above referred to are obviated by our present invention, which relates to method and apparatus whereby in a single progressive operation, liquid carbon dioxide can be continuously supplied; continuously evaporated to form solid; the solid progressively condensed to commercial density and toughness; and pro extrudedfrom the machine as a.-

' trained is utilized to slowly force extrusion of the outer or lower end of the column. The practical advantages of this will be obvious from consideration of the difiiculties that would-be involved in lubricating and maintaming moving parts at temperatures of 100 or more below zero F.

, While we sometimes employ mechanism to 5 retard or control the rate of extrusion of the column, it is not essential and when employed, isnaturally located where it can be kept warm and lubricated, if necessary.

It will be noted that our above described progrgssive method permits of intermitting the li uid supply, and also the extrusion of the co umn, without entailing the losses that occur where it is necessary to 0 en the evaporation chamber for removal 0 the solid.

While the prmcipleof our invention is a phcable to some extent for expansion of the? liquid where the liquid from the supply is abruptly expanded to pressures below the tripple point, thereby producing a solid, in snow form, precipitately, there are great advantages in aving the liquid discharged into the chamber against a counterpressure above the triple point so that a supplyof liquid'as such is maintained on the top of the columnof solid. In such a connection, an important feature of our invention consists in providin the pressure relief through which the boiled oil gas escapes, in the side wall of the passage thoughwhichthe column slides. In such case,

referably, the solidifying vention may be more fully understood from the following description in connection with the accompanying drawings, in which Fig. 1 represents more or less diagrammatically a vertical axial section through a solidifying apparatus, showing the characteristic parts and connections;

Figs. 2 and 3 illustrate a modified form of extrusion conduit, Fig. 2' being a longitudinal section on the line 2-2, Fig. 3, and Fig. 3 mo a cross section on the line 3-43, Fig. 2;

Fig. 4 is a view like Fig. 1, showing a mod- I ification in which the proportions and some of the details are difierent from those indicated in Fig.1;

' Fig. is an enlarged detail of the gas ofitakeshowninFig.1'

Figs. 6 and 7- are detail views of modified collecting grooves for'the gas ofi-take.

In Fig. 1 there is a chamber 1 in which the solid is formed. This chamber may be of any desired cross-section, either round, square, or rectangular, but must have the pro 1' taper and smoothness to permit the cargn dioxide formed to pass contiuously out the mouth of the chamber under the pressure of the gaseous carbon dioxide above it. In a practical trial we have used a slight flare of inch per foot, but it will be a parent that 's slo necessarily varies wit vthe size of the cham rs, and for la r machines the ta r may be dispensed wit or even re- Nozzles2 serve to introduce liquid carbon dioxide, referably precooled as low as practical and yet be safely above the triple pzint, from any suitable source. Pipe 4 may 4,

used to conduct gas to the compression system at any convement pressure above the triple point. In such case, screen 3 is placed in the top of chamber 1 to aid in the separation of any liquid or solid that might otherwise be entrained and carried back to the compression s stem. 7

The above eecribed elements are the pnmary essentials necessary to form sohd carbon. dioxide in accord with our invent on, and as a matter of fact even the screen 3 and pipe 4 ma be dispensed with, and carbon dionde soli "tied. in a very simple manner. If the chamber 1 is long enough and of proper taper, it is only necessary to close the mouth 7 of the chamber in starting with a porous l or in fact any kind of closure whataoe v e r that leaks, and introduce liquefied carbon dioxide above the triple point.

adjacent'to the leaks or pores in the plug, and build a cake progressively upwards from them, the gas formed esca ing downward and out through the. pores o the sohd already formed, and eventually out the bottom of the chamber. It will be understood that after.-

sary in a practical apparatus to provide of reclaiming the gas passing down through the block of solid, and for returning as it to the compression system, and-it me be desirable to have auxiliary means of con rol- 'Solid will then form inside the chamber;

'gle or other mechanical li the main portion of our invention, it is necesling the rate of withdrawal of the solid, for

' point. A perforated metal screen plate 8 serves to guide the block, but grooves and outlets as escribed below, maybe employed. The pipe 7 is preferably connected to back pressure regulating means as pressure gauge a and valve 76 or automatic means such as are wellkncwn in the art, to maintain a bal-. anced slightly positive pressure in the section 5, for the urpose of minimizing leakage and loss of car on dioxide gas through the lower portions of the a paratus. When it is so 0 erated, the need or. a gastight conduit at the bottom 18 obviated, but it will-be ap arent that we may operate the pipe 7 under su stantial pressure by providing a gastight closure at the bottom of the apparatus, in either case reclaiming the gaseouscarbon dioxide.

I For removin the column of carbon dioxide as forme we may provide means for controllably retarding the extrusion of the column and means for momentarily holding t fast above the portion to be removed, and means for sawing or otherwise cutting of! said portion.

The resistance of the column of solid to downward movement may be regulated by providing a downward extension of suitable length and taper and the taper may be made adjustable by providing V-slots 15 that may be more or less narrowed by screwing clamping screw 17 in clampin collar 16. 'Independently of this resistance regulatlon, we preferably employ the hydraulic cylinder 9 with platen 10, as a means or regu-. lating the rate of downward movement of the column and its extrusion from the apparatus. As means for stoppin such movement of the column, we may emp oy movable jaws 11, which may have serrated surfaces 12 to grip the block and may be actuated by hydraulic cylinders 13. It will be apparent that a togn age may be used in place of the cylinders without departing fromour invention.

' A saw 14 is provided for cutting of! blocks of solid.

, According to one method of operation, the platen 10 is raised into the mouth of the chamber, and the apparatus is filled with snow by maintaining the pressure throughout the apparatus below the triple point by connecting both 4 and 7 to a suitable point in the compressor system. Pipe 4 is then throttled to build up a pressure above the triple point in chamber 1, while pipe 7 continues below the triple point, causing solidification to take place between these points. Once the block is started, plat- 21 inches long and ing it while the pressure of the platen 10 'is' relieved and a block sawed OE and removed. Platen 10 is then raised until it touches the bottom of the column of solid carbon dioxide, when the jaws 11 may be released, and the performance repeated.

In Figs. 2 and 3, we have shown a modified arrangement whereby the cross section and taper of the extrusion outlet 54:? may be varied either to predetermine any normal operating resistance of. the column to extrusion or to momentarily stop the column. The advan. tage of this arrangement is that it dispenses with the grippers and theuV-slot. As indicated, particularly in Fig. 3, the walls are of spring metal, preferably steel, and are formed or provided with wedges 17a: near the middle or springiest portion of each side The cross-section is decreased, at will by forcing down the rigid collar 162: a distance which will force the wedges inward and s ring the walls to the desired extent.

In ig. 4, we have shown a simplified ar; rangement which can be employed for continuous operation without the use of any gripper jaws and without the necessity for usin the hydraulic cylinder, except possibly %or the preliminary operation of pluggingmpthe end of the extrusion. ipe to a desired height, in the manner aho scribed.

of an apparatus used for quite small scale production. The upper section 21 was about of 3% inches at the' bottom, COnverging t Ward the p bout of an inch.

The gas vent section 25 was about 8 inches long and practically uniform 3% inch'di ameter.

The converging terminal section 25a was a simple cone 6 inches long, converging downward from 3% inch diameter to ap-' proximatel 3f; inch diameter. It was found 1 that this re atively great len h as compared with diameter imposed a s cient resistance I 1 to downward movement of the column of frozen carbon dioxide so that the extrusion at the bottom was fairly 'uniformfwithout any special adjustable controlling means.

A preferred operation was substantially the same as that described in connection with Fig.1, except that after the apparatus was once started and in normal operation, the liquid input of gas and solid outputs were substantially constant, this, as explained 7 above, being highly desirable for steady operation of a liquefying and recompreming plant. 1 e

ve do ad an internal diameter In normal operation, after the column of solid has beenbuilt up a sufficient distance above the gas outlet 26, the valve 24 can be closed and valve 27 of the off-take opened. Liquid may be then supplied through pipe 22 at a pressure of, say, 300 pounds and correlatively low temperature. Valve 27 will then be. regulated to maintain an outlet pressure of 1 to 2 inches mercury above atmosphere on gauge 2740, or, if preferred, a suction pump could'be applied to establish a vacuum of 2 to 10 inches of mercury. The outlet pressure being thus predetermined, theoperating pressure in 21, above the column, can be coning to radial exit ducts-26b, discharging into the collecting annulus 260, which may be a casting welded to 25 as indicated.

Figs. 6 and 7 show difierent forms of collecting grooves. In Fig. '6 the lower surface 26m 0 the groove 26a'is sloped downward in the direction of movement of the columnof solid carbon dioxide for the urpose of guid;

ing the column or particles t erefrom down ward.

cept that the downward" angle is steeper.

I a Furthermore, the-correspondmg upper sur- In the Fig. 4, the proportions are".those face 262 is undercut, the latter tendingto' preserve t'he outlet ducts 266 from clogging. g r In Figs. 1 and 4, we have indicated how taps t may be arranged as strategic levels, particu- I larly in the upper'part of the apparatus for testing the presence .or absence of liquid at' the level of the tap. In ordinary preferred operation, it is desirable to have pressure a ove the triple point inthe upper part of the evaporating 'dow'n'wardthrou hthe solid for exit through the lateral 0 -take section.

its

apparatus and perfectly dry solid in the gas .ofi-take section 5, with an intermediate zone The taps make it possible to determine maximum and minimum hei' hts for the liquid, because a tap at the li uid levelwill blow on snow, whereas a tap :1 ve or below the liquid zone will blow mostly gas with only mimmum solid particles such as may be accldently entrained.

Whilc'we have specified dimensions actually em loyed in a specific apparatus according to ig. 4,it will'be understood that this is merely by way of illustration since dimensions are of importance only as concerns the relative proportioning of the various parts.

7 In g- 7 there is asimilar surface, 263/ ex 'i I of the apparatus to insure operation in accordance with the methods described. In this connection, we may note briefly that the frictional resistances to flow oi.- solid and pressin esca e of as, with reference to the pressure avai able or forcing such flow, are significant factors. As to the frictional opposition to flow of the solid, it will be noted thatthis varies primarily with the surface area of the inner walls of the apparatus and that this factor varies in direct proportion to the diameter and length. On the other hand, for any given internal gas pressure, the ressure available for forcing movement of t e solid increases as the square of the diameter. Consequently, for increasing cross section of the apparatus mentioned in connection with Fig. 4, the flow resistance of the solid will decrease if the len '11s of the respective sections and the angles 0 divergence and convergence are preserved. On the other hand, the increase of effective pressure area may be compensated either by increasing the lengths of the sections, increasing the convergence of the exit section 25a, or decreasin the divergence of section 21, or in a specia case, makin 21 converging.

ile we prefer to have the extruded column dense enough to be-used directly as a commercial product without further compression it is possible and may be desirable to break up or recompress the product in a press mold such as is commonly employed for comcarbon dioxide snow.

Furt ermore, while it is preferred to operate the apparatus continuously and uniformly with a pressure above the triple point, insuring liquid at all times, in the upper part of the pressure chamber, it is possible and may be desirable to lower this pressure below the triple point, in which case there will be instantaneous jet evaporation and formation of the solid, as the liquid is discharged into this space. Such jet formation of the solid naturally occurs when the apparatus is first started up and the primary column of solid being formed, to p ug the outlet passage. By proper regulation of the pressure, such jet operation may be made continuous, the column in such case naturally being relatively light and porous; and in such case the roduct would naturally be recompressed if intended for ordinary commercial transportation and use.

The means for limiting and controlling the rate of extrusion of the solid column, such as cylinder 9 and platen 10, for the lower end of the column, may be useful in various ways. It may be used to make the rate of extrusion more or less independent of the primary fluid ressure at the to of the column and of the ow-resistance a orded by the interior walls of the down-flow passage. In a particular case, the pressure may be made greater and the opposing resistance less than required for accumulating normal balanced operation, as described in connection with Fi 4. ThlS would ermit a hi her rate of pro uction of the solid.

oreover, in normal balanced operation of the apgiaratus, the formation of solid at the top 0 or the extrusion of the column, even' though continuous, may tend to develop non-uniformities, due to special conditions, such as variations in the supply pressure from the liquefying plant, or in the back pressure on the gas line leadin back to the compressors, or irregular Slip 0 the column in overcoming the resistance to its down-flow or extrusion. While these may be corrected by more perfect design of the apparatus and regulation of the supply and'vent pressures, it will be evident that irregularities of operation may be controlled directly by the above described expedient of slightly increasing the driving pressure at the to of the column or decreasing the opposing ow resistance and then opposing extrusion and rendering uniform its rate, b meas of the platen and cylinder, retreat 0 which is controlled at a perfectly uniform rate.

We claim:

1. A method which includes making and solid carbon dioxide by evaporatin liqui carbon dioxide in a pressure chamber; afiording an outlet for extrusion of the accumulated solid while opposing substantial resistance to such extrusion; and utilizin the internal pressure of gas in the cham er to compress the solid, and force extrusion thereof through said outlet against said resistance.

2. A method which includes making and accumulating solid carbon dioxide by evaporating liquid carbon dioxide in a pressure chamber; affording an outlet for extrusion of the accumulated solid while opposing substantial resistance to such extrusion; and utilizing the internal ressure of as in the chamber to compress t e solid, an force extrusion thereof through said outlet against said resistance, the internal gas ressure and the outflow counter resistance being correlated to force extrusion at a rate corresponding approximately to the rate of thev forma tion of the solid in the pressure chamber.

3. A method of makin and compressing solid carbon dioxide, whic includes forming and laterally confining a column of said solid; evaporating liquid carbon dioxide to add solid at one end of said column and utilizing the pressure of the evaporated gas to compress and force extrusion of the other end of said column.

4. A method for continuous production of compressed solid carbon, dioxide, which in cludes forming a column of said solid by discharging and evaporating liquid carbon dioxide in a pressure chamber, and controlling outlet of the gas and solid thus prothe column or the downward flow,

, afiording duced;'utilizingone end of said column as a: high resistance flow path, afiording back pressure sufiicient to maintain said liquid carbon dioxide above triple point pressure; relatively low resistance outlet for .escapeo evaporating gas, at and'near triple point pressure, at an intermediate point in said column and utilizing the internal pressure of said liquid and evaporating gas'to 1 compress and force .outward movement ofthe column.- 1

.5. A method for continuous production of compressed solid carbon dioxide, which ineludes formin a column of said solid by discarbon dioxide, permitting vent of through an intermediate ortion of said colum and extruding the ower end of said column by the as pressure on the up r end thereof and ref pa ucing the rate of extrusion to uniform ty by upward pressure applied on the lower end of said column.

' 1 9. A method which includes" forming a confined column of solid carbon dioxide; applying pressureand adding solid at the upper end of said column'by evaporation of liquid carbon"dioxide, permitting vent of gas through an intermediate rtion of said col umn and extruding the ower end of said column by'the gas pressure onthe upper end thereof, and controllin rate of extrusion of the column by controlling the movement of the lower portion thereof. 1 1 10. A method which includes forming a confined column of solid carbon dioxide; ap? plying pressure and adding solid at the upper 'endof said column, by evaporation of liquid carbon dioxide; permitting vent of evaporated gas through an intermediate portion of said column while extruding the lower i en dhf charging an evaporating liquid carbon dioxide in a pressure chamber, and controlling outlet' 0 the gas and solid thus produced; utilizing one end of said column as a high resistance flow path, affording back pressure suilicient to maintain said liquid carbon dioxide above triple point pressure; affording relatively low resistance outlet for escape o evaporating gas, at and near triple point pressure, at an mtermediate point in said column and utilizing the internal pression.

sure of said liquid and evaporating gas to compress and force outward movement of the column through an outlet passage afiording substantial flow resistance to such extru- 6. A method for continuous production of compressed solid carbon dioxide, which includes forming a'column of said solid by discharging and evaporating liquid carbon dioxide in a pressure chamber, and controlling outlet of the gas and solid thus produced;

utilizing one end of said column as a high resistance flow path, afi'ording back pressure sufiicient to maintain said liquid carbon di- 40 oxide above triple point pressure; afiording relatively low resistance outlet for escape of evaporating gas, at and near triple point pressure, at an intermediate point in said column and utilizing the internal pressure of said liquid and evaporating gas to compress and force outwar movement of the column through a remote outlet of decreasing cross section, predetermined to oppose substantial flow resistance to such extrusion and to laterally compress said column.

7 A method of making and compressing solid carbon diozu'de, which includes forming a column of said solid and-confining it laterally; maintaining liquid carbon dioxide at 15:5 the triple point pressure at one end of said column and there evaporating it to form solid additions to said end of said column and utilizing the internal pressure of the li uid and evaporating gas to force extrusion o the to column through'an outlet passage at a desired rate.

8. A method which includes forming a confined column of solid carbon dioxide; applying pressure and adding solid at the upper end ofsaid column by evaporation of liquid said column by thegas pressure on the upper end thereof.

11'. A method which includes forming a confined column of solid carbon dioxide; applyin pressure andaddingsolid at the upper end 0 said column, by evaporation of liquid carbon dioxide; permitting 'vent' of evaporated gas. laterally through 'anintermediate. portion of'saidcolumn while extruding the ower end of said column by the gas ressure on the upper end thereof; and contro ling the pressure and rate of column formation at the upper end with respect to the rate of. column extrusion at the lower end, so as to maintain a desired length of column between the top of the column and the intermediate vent.

12. A paratus for production, compresevaporating liquid carbon dioxide to make-"- solid, a column retaining outlet passage adapted to aflord resistance to escape of the solid; means for venting the evaporated gas laterally through said column, intermediate the ends of said passage.

14. Apparatus for production, compres-. sion and discharge of a column of solid carbon dioxide, which includes a column forming tubular structure having a pressure of e a of .eeielh-ee the solid I on the upper chamber and means 'for discharging liquid carbon dioxide in the up r ortion thereof;

an intermediate, lower ere hlateral outlet of the as through the solid.

15. e aratus for production, compression. and ischarge of a column of solid carbon dioxide, which includes a column forming tubular structure having an up r pres sure chamber with downwardly iverging walls, and means for dischargin liquidecarbon dioxide therein;an interme ate ortion of ap roximately uniform section a ording lateral'ohtlet for escape of evaporating gasand alower section having open lower en and convergingwalls to laterally compress the solid, to e pose resistance to extrusion of thesolid an to endwise escape of the gas through said open lower end. 16. Apparatus for production, compression and discharge of a column of solid carbon dioxide, which includes a column forming tubular structure having an upper pressure chamber and means for discharging liquid carbon dioxide therein; an intermediate portion afl'ording lateral, low pressureto cause czagration of the liquid and permit escape o e gas' and a. lower qfening for extrusion of a column of the soli by the fluid pressure on the upper portion thereof, in combination with means for moving the walls adjacent said lower opening, to mcr'ease or decrease section of the extruded column.

17. Apparatus for production, compression and discharge dioxide, which includes a. column forming tubular structure having an upper pressure chamber'and means for discharging liquid carbon dioxide therein; an intermediate portion aflording lateral, low pressure to cause eva ration of the liquid and permit escape of t e and a lower 0 ning for extrusion of a co umn of the solid y the fluid resure on the upper portion thereof, in com ination with laterally movable means engaging the lower portion of said column for retard' or stopping downward movement thereof.

18. Apparatus for production, com ression and dischar of a column of soli carbon dioxide, which includes a column forming .chambe lower end of said column and means their convergence and vary the cross the sto moves downward at a regulated rate.

19. p tus for production, com ression and di arge of a column of solie carbon dioxide, which includes a column forming tubular structure havingan upper pressure r and means for discharging. liquid carbon dioxide therein; an intermediate portion affording lateral, low pressure tocause evtfioration of the liquid and permit escape of e as; and slower o ning for extrusion of a co umn of the solid y the fluid ressure on the upper portion thereof, in com ination with a move le stop element engaging the whereby the sto moves downward at a re lated rate, which re less than the rate at w ich the column would be extruded by said fluid pressure.

20. A method which includes supplying. liquid carbon dioxide to a compression chamber above triple point pressure, at an a roximately uniform rate; evaporatin said iquid at triple point to form solid an gas, and returning the gas for reliquefying at approximately uniform rate; and utilizing the approximately uniform pressure of the fluid to extrude the solidat approximately uniform rate. l

Signed at New York, in the county of New York and State of New York, this 14th day of December, A. D. 1929.

ROBERT R'. RUST. CHARLES. L. JONES.

of 'a column of solid carbon tubular structure having an upper pressure i ,chamber and means for discharging liquid carbon dioxide therein an intermediate portion afl'ording lateral,.low pressure to cause an ration of the liquid and permit escape and a lower 0 ing for extrusion y the fluid ressure EOYHOD thereof, in com ination with a move le stop element engaging the lower end of said column and means whereby

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