US1518377A - Method and apparatus for separating liquid gases - Google Patents

Description

Dec. 9,1924. 1,518,377 R. VUILLEUMIER METHOD AND APPARATUS FOR 'SEPERATING LIQUID GASES Filed Nov. 5, 1916 I $31 tto'cnev w Lu. M, X

Patented Dec, 9,1924...

PATENT OFFICE;

RUDOLPH VUILLEUMIER, OF NEW ROCHELLE, NEW YORK, ASSIGNOR TO THE SAFETY CAR HEATING & LIGHTING (30., A CORPORATION OF NEW'JERSEY.

METHOD AND APPARATUS FOR SETARATING LIQUID GASES Application filed November 3, 1916. Serial'No. 129,271.

To all whom it may concem:

Be it known that I, RUDOLPH VUILLEU- MIER, a citizen of the United States, and a "resident of New Rochelle, in the countyof U 'Westchester and State of New York, have invented an Improvement in Methods and Apparatus for Separating Liquid Gases, of which the following is a specification.

This invention relates to the separation of liquefied gases, and with regard to certain more specific features, to a paratus and method for separating liquefie gases by rectification. One of the objects of the presentv invention is to provide a compact apparatus and method wherein the steps or stages are so arranged as .to minimize the external losses, which. in the case oflow-temperature work take the form of so-called heat gains. 1

Another object is to provide simple and reliable apparatus for facilitating'the transfer of heat from one fluidto another and for accelerating the separation of the several constituents of .the fluid. 7

Another. object is to provide a'method of the above general type 1n which there is an I effective interchange of latent heat between the incomin gas being liquefied and the evaporatingdiquid that is undergoing rectification.

Another object is to provide an apparatus and method for obtalnin'g gases of high purity, at reduced cost for installation and.

' attendance. Another object is to provide a rectifying column with a high pressure direct heating means, which is susceptible to close temperature regulation and which comprises an efli cient separator in compact form.

Other "objects will be in part obvious and in part pointed out hereinafter.

The invention accordingly comprises the features of construction and operation, combinations of elements, arrangements of arts 4 and sequences of steps which are exemp 'fied in the structure hereinafter described and vthe scope of the apfplication of which 'will i be indicated in the ollowing' claims.

In the accompanying drawin s, in which is shown one of various possi le embodiments of this invention, Figure 1 is a sectional elevation of a preferred form of rectifying column, with some of,the auxiliary apparatus 5 and Figure 2 is a transverse section on the'line 2-2 of Figure 1.

Similar reference characters indicate similar parts throughout both views of the drawings.

The present invention, generally speaking, relates 'to an improved apparatus and method for low-temperature work, and particularly for obtaining oxygen and nitrogen from air by liquefaction'and subsequent rectification, the heat energy required for distillation being obtained primarily byltransfer of heat from the gas undergoing lique-' faction at a higher pressure. Other fea tures, such as the employment of a highpressure \direct heating device and the provision of automatic means for maintaining at a proper value the pressure in the heating device, will be clear from the following description.

Referrin now to' the accompanying drawings, there is illustrated a rectifying column, preferably in the form of a vertical cylinder 21 whose external connections comprise an intake pipe 22. for the pre-cooled, purified and partly expanded incoming air; a delivery pipe 24 for the nitrogen or other lowboiling constituents; and a delivery pipe 26 for the oxygen or other high-boiling constituents. vention, as well as the functions of the various parts and the sequence and purpose of the several steps of the process, will prob- The structural features of the inably-be most readily understood by considering the path of the fluid from the time the air is first utilized at room temperature and atmospheric pressure until the nitrogen and oxygen, again at normal temperature, are conveyed through ;measuring' devices and stored in suitable receptacles.

Of the ten stages which comprise the preferred form of the process of the resent invention, the first, second, third, ourth and tenth are omitted from the drawings. The

' ten stages may be listed somewhat categorically as follows; first, compressing; second,

pre-cooling; third, purifying; fourth, cooling in a temperature interchanger; fifth,

cooling by expansion; sixth, scrubbing; seventh, liquefying'; eighth, cooling by pressure release; ninth, heating and rectification of the constituents, and tenth, heatin of the separate gases evolved during the mnth stage. Obviously, many of these stages may vention.

During the first stage, air at room temperature and atmosphericpressure is compressed. This causes a rise of temperature. In the second stage, the compressed air is passed through a preliminary cooling device, where it resumes normal temperature and preferably'is cooled to a temperature somewhat belownormal, but is maintained at the ressure attained in the first stage.

In t e third stage the air is purified by suitable means known in the art. a

In the fourth stage, this -cooled compresseed and purified air has its temperature further lowered by being passed through a heat-interchanging, device, preferably of the type illustrated, described and claimed in my co-pendin application, Serial No. 125,534, filed ctober 14, 1916, for apparatus and method for transferring heat. At the-end of the fourth stage, the air is delivered in an upward direction through the pipe 27 as indicated by the arrow 3, Figure 1. x

-From the pipe-27 the cooled and comressed air passes upwardly through the fth stage, as indicated by the arrow 5, through the expansion valve 29, controlled by the hand wheel 30 through the valve stem 32, a suitable heat-insulating sleeve 33 being provided to .preventconduction of heat from the acking box 35 to the air passing through t e valve It is of course to be understood in this connection that this type of expansion device is merely illustrative and that other and more eflicient expansion means may be used if desired. In this stage, the air is cooled to the point of liquefaction and is preferably partly liquefied, to an extent sufiicient so that the latent heat of evaporation of the liquefied portion may approximately equal the heat gains in succeedingparts of the apparatus.

From the valve 29 the air-passes through its sixth stage, which has been referred to as scrubbing. The air first travels upwardly, as indicated by the arrow 6, through the intake pipe 22, to a point adjacent the upper end of the column '21, whence it is directed downwardly by a cap 36, as indicated by the arrows 6", through a long vertical cylinder 38 surrounding the intake pipe 22. Within this cylinder 38' is scrubbing material comprising preferably beads 39 of graduated size larger on top and The air travels downwa diminishing in size toward the bottom of the cylinder. The cylinder withits contentsthus acts as a separator in which frost particles and other solid impurities are re-' moved fromthe air and retained until a convenient time for cleaning the apparatus. r ly, as indicated by the arrows 6, until it reaches the bottom of the cylinder 38, and is then divided into a plurality of streams for the seventh stage of the process.

*or the seventh stage, the cold and purified air, still under pressure, is divided into a plurality of streams travelin substantially radially outward through the distributing pipes 41, as indicated by the arrows 7 whence it is delivered to the several sets of heat-interchainging coils 42, through which the air travels in a generally upward direction to the collecting ring 44 adjacent .the top of the rectifying column 21. From through the pipe 45. In order that the several streams of air may travel through approximately the same distance in their passage upwardly from the distributing pipes 41 to the collecting ring 44, the length of the several coils 42 is made approximately equal. This may be done by making the coils of larger diameter of greater pitch. than the coils of smaller diameter; and in order further to subdivide the air into streams and to make the most efiicient use of the available space, the coils of larger diameter and of greater pitch are wound in multiple sets so that there will be more individualcoilsof' a given larger diameter than there are coils of a given smaller diameter. Thus, for example, the innermost coil. or the coil of smallest diameter, consists of a single coil having a given pitch while the coil of the next larger diameter may be woundwith a greater pitch and may be duplicated so as to bear a relation to the first or inner coil similar to the relation between a double thread and a single thread. In this manner all the individual coils or convolutions may be made to have approximately the sametotal length and may furthermore be made to have the same rise in a vertical direction per foot of travel therethrough of the streams of air. This feature of construction provides a uniform flow of fluid through each coil and results in a substantially uniform heat distribution. Packed around and between the coils 42, are beads or particles 46 of copper or other material having a high thermal conductivity. This structure, as described and claimed ger se in my co-pending application, Serial 1 0. 125,534, above mentioned, accelerates the transfer of heat between the fluid within the coils and the fluid outside the coils, first by breaking up' the outer fluid into a large number of minute streams, all in intimate thermal contact with the beads or particles 46, and second, by providin through contacting beads, a series of paths of low thermal resistance between the container for the first fluid and all 'ortions of the second or outer fluid. Suita le packing {not shown) Oil is provided around the outside of the cylinder 21 to protect'the fluids from external losses. As above noted, this compactness with a corresponding reduction of superficial area is'of the highest value as the greatestv losses incurred in this entire process are due to the inward leakage of heat which is "roughly proportional, other things being portions of the column from one another,v

equal, to the total external or superficial area. Aside fromthis loss, the process is carried on substantially by an interchange of energy without the necessity for drawing upon an external source. It may also be noted at this point that the method by which the fluid is passed downwardly in this apparatus with a consequent breaking up into numerous minute streams, not only conduces to an eflicient and effective heat interchange but thoroughly intermingles all portions of the fluid and accelerates the interchange of constituents of rectification. This breaking up o-f'the streams with the above effects applies notonly to the descending liquid but to the ascending gases, and both are in intimate thermal contact with the beads 46.

In order to minimize or prevent the travel of heat energy lengthwise or vertically of the column 41, horizontal layers of heat-insulating beads or particles 47 such as coke, clinkers, charcoal, and the like, broken up into particles of suitable size, may be arranged at intervals vertically ofthe column. These beads-47 of low thermal conductivity in no wise detract from the rapid conduction of heat in a generally horizontal direc-' tion, but by insulating adjacent vertical thebeads 47 divide the column intowhat may be termed a plurality of horizontal thermal layers, and make it possible to maintain at different heights of the column progressively increasing or decreasing temperatures. In this way the temperature best suited for one operation, such as theevaporation of a high percentage of the low-boiling constituent, may be maintained at and near the top of the column, while another temperature best adapted for another operation, such as the evaporation of a high percentage of the high-boiling constituent, may be maintained at and near the bottom of the column, without in any way impairing the effectiveness or rate of heat transfer between fluids in any of the thermal layers of the column. i The rectifying column is thus provided with a largenu'mber of heating coils 42, affording a large surface for the rapid conduction of heat to the fluid undergoing rectification, and the'eifectiv'e heating surface is further increased by'the beads 46. each of which is in intimate contact with the fluid to be evaporated. 'And this intimate 'relationbetween the fluids and the heating surface makes possible an accurate control of the temperature throughout the column by regulating the pressure in the seventh stage, hereinafter described.

The cold air passing upwardly through the coils 42, as indicated by the arrows 7., is progressivlcy liquefied by coming into intimate thermal ,contact with progressively colder fluid that is traveling in a downward direction outside the'coils, and this causes the upwardly traveling fluid to be liquefied, the liquefaction becoming complete by the time the fluid reaches the collecting ring 44, where it is forced into the pipe 45, as indicated by the arrow 7. There is sufficient velocity to the upwardly traveling-fluid so that the liquefied particles thereof are readily carried alongtoward the pipe 45 over the slightly ascending pitch of the coils 42. The latent heat ylelded during liquefaction 'of the fluid is readily absorbed by the fluid traveling downwardly in the spaces out-side and between tlie'coils 42. This second fluid, as will be hereinafter described, is the liquefied air undergoing progressive rectification during the ninth stage of the process. The

seventh stage is completed when the liquefied air reaches the pipe 45. .1

During the eighth'stage, the liquid air, delivered under some pressure through the pipe 45, is forced through the expansion valve 50, as indicated by the arrow 8, whence it flows downwardly for the ninth stage,

hereinafter described, as shown by the-arrow 9. The reduction of pressure during the eighth stage and accompanying lowering of boilingepoint causes a partial evapora tion of nitrogen together with a small percentage of oxygen and absorption of latent heat, which causes a cooling of the portion of the fluid that remains in a liquid condition.

One object of this invention is to have the pressure and boiling point during liquefaction accurately maintained at a value heat given up atthe higher temperature by the fluid that is being liquefied at the higher pressure. Accurate evaporation results under proper conditions to give the desired result rather than an undesirable result. Thus, for example, conditions as to temperature, pressure, rate of flow and such factors, must be in the proper relation to each other to result in evaporation at the proper and desired rate and to result also in the production of a product of apurity requisite for commercial success. By the means tion if the pressure falls below normal. And

provided by this invention, the pressure and hence the boiling points. during liquefaction are accurately main'tainedat avalue higher than the pressure and hence boiling points existent during evaporation. The evaporation takes .place preferably at approximately atmospheric pressure. It thus becomes possible to rectify the'fiuid ,constitutents of the varying composition in the. ninth stage hereinafter described, in direct thermal contact with the constituents of liquefaction in the seventh stage and at temperatures best suited for efiicient rectification. The maintenance of proper temperatures, particularly during rectification, is a matter of great moment. The descending liquid undergoing'rectification in the ninth stage, to be hereinafter described, retains the maximum amount of high boiling constituents, and carries them well toward the base of the rectifying column, while the ascending vapors undergoing rectification in this ninth stage retain and carry the maximum amount of low boiling constituents well toward the top of the column. It is thus possible to rectify efficiently, (in the ninth stage) at a lower temperature than the temperature of liquefaction (in the seventh stage) and the latent heat required for rectification is obtained by transferring directly to the fi-uidsin the ninth stage the latent heat given up by the fluids in the seventh stage. In this way, both liquefaction and evapora-' tion may be efiected with a high degree of precision. The liquefaction above mentioned occurs during the seventh stage; The evaporation is effected in the ninth stage, hereinafter described.

In order to make the apparatus automatic in its operation, the expansion valve is provided with a heat-insulating sleeve 52 connected 'to a pressure-regulating device 54. The latter is preferably of the spring-loaded diaphragm type and is so constructed that the liquid (from the seventh stage) which communicates through sleeve 52, exerts itspressure upon the bottom of the diaphragm 53, raising the dia-,

phragm to open the valve slightly through stem 55, as the pressure exceeds a predetermined amount, and lowering the diaphragmto move the valve 50 toward its closed posisince the valve communicates directly with r the bottom of the diaphragm 53, without intervening packing, a free movement of the valve stem and consequent accurate pressure regulation is attained. The regulator 54* is maintained as nearly as possible at normal temperature conditions since the sleeve 52 is substantiall non-conductive of heat as above describe, and since the active fluid passing, through the sleeve and acting upon the diaphragm 53 is mainly gaseous and is acted upon by the pressure of the liquid in the system with which the sleeve 52 is in connection. A tube 57 communicates with a gage 58 to indicate the pressure prevailin in the seventh stage of theapparatus. 'I%ehand wheel 60serves for the adjustment of the regulator 54, so that the standard of pressure maintained may be under manual control.

From the eighth stage, the cooled and partly evaporated liquid flows downwardly, as indicated by the arrow 9, to the distributing head 62, whence the fluid is divided into a plurality of divergent streams passing outwardly through the distributing pipes 63, as indicated by the arrows 9 whence the fluid travels in a generally downward direction through the spaces bet-ween and outside the coils 42 containing the upwardly traveling fluid of the seventh stage. The ninth stage comprises the downward travel of the liquid and may be considered as divided into a large number of sub-stages, re resenting evaporation and rectification of progressively higher ratios of oxygen to nitro en in pro ressively lower situated thermal layers of t 1e rectifying column 21; during the first sub-stage, at the uppermost thermal layer of the column, the conditions of temperature and pressure are maintained at such a value that evaporation of a portion of the lowboiling constituent, such as nitrogen, takes place, together with a minimum percentage of oxygen or other high-boiling constituent, the remainder of the nitrogen and oxygen remaining in liquid form until it reaches the next sub-stage of the process, at the next lower thermal layer of the rectifying column, where the evaporation and rectification is maintained at a slightly higher ratio of oxygen to nitrogen.

In progressively lower thermal layers of the column, the temperature standard is progressively higher owing to the fact that the And as a consequence, the percentage of oxygen increases toward the bottom of the column. The evaporated oxygen travels upwardly to the adjacent thermal layers, where it is checked by rectification because of the lower heat standards maintained and lower percentage of oxygen "maintained at the upper thermal layers. So that the gas rising upwardly from the uppermost thermal layer has a fairly constant oxygen content, equal to the minimum value maintained in the rectifier. This gas travels upwardly, as indicated by the arrows N, through the vapor scrubber 65,- and thence outwardly through the delivery pipe 24. The scrubber serves to separate from the gas the small entrained vapor particles or mist of liquid air, which are carried ofi by'the boiling as. The gas is caused to travel in a genera y downward direction through the scrubber, and thence upwardly, whilethe liquid particles gravitate toward the funnel-shaped bottom 66 and re-enter the rectifying column through the liquid seal 67. The scrubbing material, preferably comprises small beads 69 carried on a 4 screen 70. The gas, mainly nitrogen, that is delivered to the pipe 28 is at the low pressure prevailing in the ninth stage and its temperature is that of the boiling point of .the liquid as it issucs in the valve at the pressure prevailing at that point. In this condition, the cold nitrogen gas is used in a temperature intercl'langer (not shown) during the tenth stage for the purpose of coolingthe incoming air, and at the same, time ralsmg the temperature of the outgoing gas, as hereinafter described.

In the lower thermal layers of the ninth stage of'the apparatus, the descending liq-,

uid, mainly oxygen, is further heated by the ascending air within the coils 42 (seventh stage) toapproximately the boiling point of oxygen for the prevailing low pressure. in this ninth stage. At this temperature, the nitrogen has of course been practically all rectified and evaporated. The oxygen is now partly or entirely evaporated, the latent heat needed for this purpose being taken from the ascending liquefying gas within the coils 42 (seventh stage) which as above described liquefies at a higher temperature than the evaporating temperature for the oxygen because of the higher pressure prevailing 1n the seventh stage.

off through the lower delivery pipe 26, as indicated by the arrow 0, whence it passes to the tenth stage. v A feature of this process which should be especially noted is the effective and. thorough interchange of latent as well as sensible heat.- The amount of heat absorbed in evaporation and given off I in liquefaction is of a high value and corresponding importance, and it is to be noted here that this heat. as well as the sensible till tween which the rectification as hereinbefore described talres'place and to maintain also automatically a proper and desired distribution of temperature between these limits.

The. oxygen gas,-which may be partly liquid, is taken For most efiicient operation the temperature distribution should be such that the temperature at the top of the rectifying column ing point of the low boiling constituent, namely the nitrogen, and such umn' corresponds substantially to that of the boiling point of the high boiling constituent, namely oxygen. The intervenm zones in the rectifying column, in which uring the ninth stage hereinbefore described the pro-- gressive evaporation and' rectification takes that the tem- .perature at the'bottom of the rectifying colcorresponds substantially to that of the boilplace, are thus by the maintenance of the temperature limits maintained at temperatures intermediate of these limits so that the plurality of sub-stages of the ninth stage take place throughout a uniform temperature gradient automatically maintained.

As hereinbefore described, there takes place in the various zones in the rectifying column .during the ninth'stage simultaneous partial evaporation and partial condensa' tion; that is, the descending liquid constant- 1y undergoes partial evaporation while ,the resultant vapors which rise therefrom and are moved in an upward direction constantly undergo partial condensation. The liquid resulting fromthis partial condensation is again partially evaporated after reaching a lower, warmer zone in the column and these steps are repeated throughout the various zones of the rectifying column, provided these zones are maintained at the requisite temperatures as above described. For efli cient rectification therefore it is highly desirable to maintain the necessary temperature gradient ,within the rectifying column. To determine one of the temperature limits, for example thatexisting at the bottom or warmer region of the rectifying column, the fluid is introduced into the distributing pipes 41 to. the coils 42 preferably in vapor form so that the corresponding temperature in the rectifying column at the lower region may, correspond substantially to the boiling point of the oxygen or constituent of higher boiling point of the fluid thus introduced and at the pressure prevailing in the coils,

and which at the upper region in the rectifying column corresponds substantially to the temperature of the nitrogen or constituent of lower boiling point of the liquefied fluid discharged into the rectifying column and at the pressure prevailing therein. The

intermediate regions in the rectifying col-.

umn will assume temperatures intermediate of these two limits and will thus represent a predetermined temperature gradient in passing from the coldest to the warmest regions in the rectifying column.

From these. considerations itmay further be noted that should, for example, the pressure of the fluid entering the coils 42 at the lift llti

base thereof be greater than that correspondzones in-thecolumn will be detrimentally affected. Moreover, the higher pressure in the coils 42 as thus assumed will cause an unduly rapid condensation of the fluid. in the lower portions of the coils 42 and will thus permit the fluid therein to leave these lower portions in liquid form rather than partial liquid form. As the flow of the thus liquefied fluid continues upwardly through the coils- 42 under the above-assumed conditions, the fluid in the coils 42 will thus be deprived of the necessary latent heat required to 'supplyefliciently the liquid traveling downward in the rectifying column with the necessary heat of vaporization.

4 Hence evaporation in the upper regions of the rectifymg column fails to take place and the liquid in the rectifying column must therefore penetrate the lower zones of the rectifying column in order to receive the necessary heat of vaporization and in so doing act further to lower the temperature 'in the lower portions of the coils 42.

Assuming now" that the pressure during the seventh stage, or in other words the pressure of the fluid under oing liquefaction inthe coils 42, is maintained below that at which its temperature corresponds to that. of the boiling'point of oxygen or of the constituent of higher boiling point, the temperature in thelower regions of the rec tifymgcolumn will be maintained corre-' spondmgly too lowand a reversal of the detrimental effects above set forth will take place. Hence, efiicient rectification in the rectifyin column maybe seriously impaired by undesirable effects which tend to disturb the temperature limits between which-the rectifyin column is intended to operate and to distur also the temperature gradient existing between these two limits.

- durin In providing the automatic valve 50, however, for maintaining automatically, a constant pressure during the seventh stage or the stage at which the fluid in the heat interchanging coils 42 is undergoing liquefaction, the temperature limit at the lower regions-of the rectifying column is automatically maintained constant and the -pressure is preferably maintained at such nvaluethat thls limit will correspond to the i'pressure 'revailing in the rectifying boiling)L point of the oxygen or constituent of Mg oiling point of the fluid. This boilmg point 'is of course dependent upon the col- 1mm and 'ence it will be seen that the auto- .matic valve after being once set serves fiacomaucal yewith i Pressure ,eflicient action of rectification in sense.

ing in the rectifying column, to maintain the proper relation between the pressure in the heat interchanging coils 42' and the pressure in the rectifying column which, as hereinbefore noted, is preferably atmospheric pressure. The automatic valve therefore controls automatically the distribution of liquefaction of the fluid uniformly througln out the coils 42; and hence, as will be read ily seen from the foregoing considerations of assumed abnormal. conditions, controls automatically the uniform distribution of the latent heat of liquefaction throughout the'coils available for the uniform and progressive rectification and evaporation of the constituents that takeplace in the rectifying column. The automatic valve thus serves to preserve a temperature gradient throughout the rectifying column and insures a highly the rectify ing column.

In the tenth stage, the cold nitrogen gas with small oxygen content and the cold oxygen gas from the ninthstage, are con veyed in separate channels through the heatinterchan or above described in connection purity of the products.

1 From the above, it will be clear that with the apparatus and process herein provided, the several objects of the invention are realized and other advantageous results obtained As various possible embodiments might be made of the above invention and as various changes might be made in the embodiments above set forth, it is to be understood that all matter herein set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting Having thus revealed my invention, I claim and desire to secure by Letters Patent of the United States: 1. The method of rectifying gases WhlCll consists in liqiiefyinga gaseous fluid by causing atransfer of heat therefrom to finely divided particles of high heat conductivlty maintained at progressively lower heat standards, expanding the li uefied fluid,

evaporating and rectifying t e expanded fluid by passing it over progressively warmer sections of said particles of high heat conductivity, the heat yielded to said articles by said incoming gaseous fluid durmg liquefaction being transferred to the streams through finely divided particles of high heat conductivity maintained at progressively lower heat standards, whereby heat is transferred from said fluid to said particles, expanding the liquefied fluid, and evaporating and rectifying the expanded fluid bypassing it over progressively warmer sections of said particles of high heat conductivity, the heat yielded to said particles by said incoming gaseous fluid being transferred to the ex--- panded liquefied fluid to evaporate and recfithe latter and to liquefy the gaseous flui 3. The method of separating fluids which comprises partially liquefying a gaseous fluid by expansion, passing the partially liquefied fluid 'ina'plurality of subdivided streams through a heat transferring device to extract heat therefrom to complete the liquefaction thereof; subjecting the liquefied fluid to evaporation and rectification by passing said liquefied fluid in reverse direction and in a plurality of subdivided streams through progressively warmer portions of said heat transferring device to withdraw heat from said subdivided fluid undergoing liquefaction to complete the liquefaction thereof, and maintaining constant automatically the pressure of the fluid undergoing complete liquefaction.

f. The method of separating fluids which comprises partially liquefying a gaseous fluid by expansion, completing the liquefaction thereof by passing said partially lique fied fluid through a heat transferring device maintained at progressively lowerv heat standards, subjecting the liquefied fluid to. evaporation and rectification by passing it through progressively warmer portions of said device to withdraw heat from said fluid undergoing liquefaction to com lete the liquefaction thereof, and maintaining automatically the temperature limits between the highest heat standard and the lowest heat standard in said device obtains its latent heat of evaporation from to thermo-contact with progressivel portions of a. heat transferring device.

the latent heat of liquefaction of thein coining fluid in said plurality of separate streams, .and separating the progressively evaporated constituents.

6. The method of rectifying fluids, which comprises c ooling a fluid, expanding the fluid, passing the fluid through successively colder-portions of a heat transferring device to liquefy the fluid, maintaining constant automatically the pressure of the fluid duringliquefaction, to maintain the temperature limits between which said device operates substantially constant, recti fying the fluid and heating the constituents of rectification by causing them to absorb heat from the initial fluid which is being cooled. I Y

7. The method of handling fluids which comprises partially liquefying a gaseous fluid by expansion, scrubbing or cleansing the partially liquefied flui'd to remove solid I particles therefrom, and completin the liquefaction of said fluid by subjecting it co der 8. vThe method of handling ases which comprises cooling a gas, partia ly liquefyingthe gas by expansion, scrubbing or clean-sing thepart-ially liquefied gas to remove solid particles therefrom completing the liquefaction of the gas by subjecting it 'to progressively colder portions of a heat transferring device, evaporating and rectifying the liquefied gas through successively warmer portions of said 'devlce by causing the evaporating gas to absorb its latent heat of evaporation from the latent heat of liquefaction of the incoming gas, and maintaining constant automatically the pressure during the liquefaction of said gas. 7

"9. The method of handling fluids. which comprises cooling a gaseous fluid under pressure, reducing the pressure torreduce the temperature, scrubbing or cleansing the fluid to remove solid particles therefrom, and liquefying the fluid by subjecting it tothermal contact with progressively colder portions of a heat-transferring device.

10. The method of handling fluids, which comprises cooling a gaseous fluid under pressure, reducing the. pressure to reduce the temperature, scrubbing or cleansing the fluid to remove solid particles therefrom, and liquefying the fluid by subjecting it to progressively colder portions of a heattrausferring device and rectifying the fluid at a pressure automatically maintained constant. v i 11. The method of rectifying a fluid having a high boiling and a low boiling constituent which consists in expanding the fluid. passing the fluid through successive- 1v colder portions of a heat-transferring device to hquefy the fluid. mamtainmg automatically a range of temperature in said Bi l evaporated later in warmer portions of said devlce and withdrawn separately from said first constituent.

12. The'method of handling fluids, which comprises cooling a gaseous fluid in a heattransferring device. liquefying the? fluid in a second heat-transferring device, maintain ing constant automatically the-temperature limits between which said second device operates, lowering the pressure of the fluid to reduce its boiling point and evaporating and rectifying at progressively higher heat standards the several constituents of the fluid by passing the fluid through said second device in reverse direction to the incoming fluid, and heating one of the products o the entering fluid in said first device.

13. The method of separating fluids which consists in liquefying a gaseous fluid by pas'sing'it through successively colder portions of a heat transferring device, preventing interchange'of heat between adjacent portions of sald fluid, respectively, in said successively colder portions of said heat transferring device by insulating said portions from one another, expanding the fluid to reduce the boiling points of its several constituents, and evaporating and rectifying the fluid through progressively warmer in-' 'sulated portions of said device by causing the evaporating fluid to obtain its latent heat of evaporation from the latent heat of liquefaction of the incoming fluid, and separating the progressively evaporated constituents.

14. The method of handling fluids, which comprises compressing a gaseous fluid, co0l ing the compressed fluidin a heat-transferring device,- e'xpanding the cooled fluid,

' cleansing orscrubbing the fluid, liquefying the purified fluid by passing it through successively colder portions of a second heattransferring device, reducing the pressure of the liquefiedfluid through a valve'operated automatically to maintain at constant t to pressure the fluid on the high pressure side of the valve', "passing'the fluid. in the opposite direction throughsaid second deviceto effect evaporation and rectification at progressively higher temperatures in different parts of said second device, separatingthe constituents of rectification, and

separation by heat transferred from.

passing said constituents through said first device to heat said constituents and simultaneously cool the incoming fluid therein.

15. The method of separating air into oxygen and nitrogen, which comprises compressing the air cooling thecompresscd air in a heat-transferring device, expanding the cooled air, cleansing or scrubbing the air, liquefying the purified air by passing it through successively colder portions of a second heat-transferring device, reducing the pressure of the liquefied air through a valve operated automaticallyv to maintain at constant pressure the air on the highpressure side of the valve, passing the air in the opposite direction through said second device to effect evaporation and rec tification at progressively higher tem eratures in different parts of said secon device, separating the nitrogen and oxygen thus evolved,and.passing said nitrogen and oxygen in se arate channels through said first device to eat said nitrogen and oxygen and simultaneously to cool the incoming air therein. r

16. In apparatus of theclass described, in combination, a heat-transferring device comprising successive portions maintained at progressively increasing heat standards, insulating means interposed between adjacent portions of said device for preventing heat interchange between said adjacent portions, and means for passin through said device a liquefied fluid, and or evaporating and rectifying in successive portions of the device the several constituents of progressively higher boiling point.

' 17. In apparatus of the class described, in combination, a heat-transferring device comprising successive portions maintained at progressively increasing temperatures, insulating means interposed between adjacent ortions of said device for preventing heat interchange between said adjacent portions, means for passing through said device a liquefied fluid, and for evaporating and rectifying, in said successive insulated portions of the device, the several constituents of progressively higherboiling point, and means said fluid after evaporation, means for couducting said evaporated fluid through said device, and sdeparate conducting means constituting a iquid seal for returning entrained non-gaseous matter from said device to said evaporating fluid.

19. In apparatus of theclass described, in combination, expansion means for cooling a gaseous fluid, a cleansing device comprising beads of progressively smaller size, means for passing the expanded fluid through said device, and a heat transferring device for liquefying the purified fluid.

20. In apparatus of the class described, in combination, expansion means for cooling a gaseous fluid, a cleansing device comprising beads of progressively smaller size, means for passing the expanded fluid through said device to remove solidparticles therefrom,

and a heat-transferring device for liquefyliquefied fluid of lower boiling point'than.

the first fluid through said second device in opposite direction to the flow of the first fluid to evaporate and rectify aconstituentof the second fluid, a cleansing device, and means for withdrawing the evaporated constituent through said cleansing device.

22. In apparatus of the class described, in combination, a heat-transferrin "device for cooling a gaseous fluid, means for cleansing the fluid, a second heat-transferring device for liquefying the fluid, the latter device comprising progressively colder portions, means for passing a liquefied fluid of lower boiling point than the first fluid through said second device in opposite direction the flow of the first fluid to evaporate a constituent of the second fluid, a cleansing device comprising beads or particles, and a supporting screen therefor, and a li uid seal for returning entrained fluid to sai second fluid, and means for Withdrawing the evaporated constituent through said cleansing device.

23. In apparatus of the class described in combination, means for. liquefying a fluid, an, expansion device for reducing the pressure thereof after liquefaction, means for automatically regulating the pressure duringliquefaction, means for evaporating and rectifying the fluid at progressively higher heat standards by absorbing heat from progressively warmer portions of the incoming fluid being liquefied, and means for withdrawing separately the evolved constituents. 24. In apparatus of the class described, in combination, coils adapted for the passage therethrough of a fluid, a container surrounding the coils and providing a channel for the passage of a second fluid within the container and outside the coils and in thermal contact with the coils and said first fluid, means for insulating the coils and container in a plurality of thermal layers,

and means within said container for purifying the fluid.

25. In apparatus of the class'describcd, in combination, coils adapted for the passage therethrough of a fluid, a container surrounding the coils and providing a channel for the passage of a second fluid within the container and outside the coils and in thermal contact with the coils and said first fluid, means for insulating the coils and container in a plurality of thermal layers, and means within said container for purifying the fluid prior to its passage through said coils, said means comprising beads or particles arranged in the path of said fluid and of pro ressively smaller size.

26. In apparatus 0? the class described, in combination, a heat-transferring device for liquefying a gaseous fluid, heat insulating means subdivlding said device into a plurality of successive portions for preventing heat interchange between adjacent portions and for maintaining said portions at-progressively lower heat standards, means for expanding'the liquefied fluid, and means for subjecting the fluid to progressive distillation and rectification of its several constituents bypassing said fluid through portions of said device of sticcessively higher heat standards, the heat yielded by the incomingfluid during liquefaction being transferred to the expanded fluid to evaporate the latter. j

27. In apparatus of the class described, in

combination, means for compressing a gasescrubbing the fluid to remove solid particles, a second heat-transferring device for,

liquefying the purified fluid, the latter dcvicecomprising portions maintained at progressively lower heat standards, means for reducing the pressure of the liquefied fluid, said last-named means being operated automatically to regulate the pressure of the fluid on the high-pressure side thereof, means for passin the fluid through said second heat-trans erring device in the opposite direction to the incoming fluid to effect evaporation and rectification at progressively higher temperatures in said second device, means for separating and purifying the products of distillation, and means for passing said products through said first heat-transferring device to heat said producjzs and simultaneously cool the incoming fluid therein.

v28. Apparatus for separating air intooxgen and nitrogen, comprising means for compressing the air, a heat-transferring device for cooling the compressed air, means for expanding the cooled air, means for cleansing or scrubbing the air to remove solid particles, a heat transferring device 60 from for liquefying the purified air, said latter device comprising portions maintained at progressively lower heat standards, a valve for reducing the pressure of the liquefied air, meansfor passing the air through said secondheat-transferring device in the opposite direction to the incoming fluid to effect evaporation and rectification at progressively higher temperatures in different parts of said second device, said valve being operated automatically to regulate. the pressure .of the'liquefying air, means for separating the products of rectification, and means for passing said products through said first heat-transferring device to heat said products and simultaneously cool the incoming air therein.

29. The method of separating fluids, which comprises sub-dividing a fluid into a 3'0 plurality. of separate streams and passing such sub-divided fluid through successively colder portions of a heat transferring device to liquefy it, preventing interchange of heat between the portions of said fluid respectively in adjacent portions of said successively colder portions of said heat transferring device by insulating said portions from one another, expanding the fluid to reduce the boiling points of its several constituents, sub-dividing said expanded fluid into a plurality of small streams, and evaporating and rectifying the fluid throu h progressively warmer portions of said evice by causing the evaporating fluid to 0btain its latent heat of evaporation from the latent heat of liquefaction of the incoming fluid, and separating the progressively evaporated constituents.

30. The method of separating fluids, which*comprises sub-dividing a fluid into a plurality of separate streams and passing each of said separate streams through substantially equal distances through successively colder'portions of a heat transferring device to liquefy it, preventing interchange of heat between the portions of said fluid respectively in adjacent portions of said sucicessively colder portions of said heat transferring device by insulating said portions one another, expanding the fluid to reduce the boiling. points of its several constituents, breaking the fluid up into a plurality of minute streams by means of particles of high thermaLco-nductivity, and evaporating. and rectifying the fluid at progressively higher temperatures by passing thefluid' through said device in thermal contact with said particles by causing the evaporating fluid to obtain its latent heat of evaporation from the latent heat of liquefaction of the incoming fluid, and separating' the progressively evaporated constituen-ts.

31. The method of separating fluids,

, r'ality which comprises passing a fluid through successively colder portions of a heat transferring device to liquefy it, expanding the fluid to reduce the boiling points of its several constituents, sub-dividing the fluid into a plurality of minute streams by means of particles of high thermal-conductivity forming part of said device, and evaporating and rectifying the fluid at progressively higher temperatures by passing the fluid through said device in contact with said particles in turn in thermal contact with the incoming fluid, and separating the several evaporated constituents.

32. In apparatus of the class described, in combination, aplurality ofi concentric coils for a fluid arranged in multiple and of varying diameters so that said, coils are arranged one within the other, the coils of a diameter greater than the innermost coil bein wound in multiple. sets to provide substantially the same length for all the coils and to provide substantially the same rise per foot of travel therethrough of said fluid, a container surrounding the coils and providin a channel for the passage of a second fiui outside of said coils and Within the container, and means including particles of'high thermal conductivity disposed within said container and about said coils for breaking up said second fluid into a large number of small streams and for afl'ording intimate thermal contact between the two fluids.

38. In apparatus of the class described, in combination, a plurality of concentric coils for a fluid arranged in multiple and of varying diameters so that said coils are arranged one within the other, the coils of a diameter greater than the innermost coil being wound in multiple sets to provide substantially the same length for all the coils and to provide substantially the same rise per foot of travel therethrough of said fluid, a container surrounding the coils and providing a channel for the passage of a second fluid outside of said coils and within the container, means including particles of high thermal conductivity within said container and about said coils and disposed in a pluof layers spaced along the axis of said coils for breaking up said second fluid into a large number f small streams and for insuring intimate thermal conductivity in a direction substantially transversely of the axis of said coils, and means of low thermal conductivity interposed between adjacent layers of said particles of high thermal conductivity for preventing the flow of heat between adjacent layers.

In testimony whereof, I have signed my name to this specification this first day of November, 1916.

RUDOLPH VUILLEUMIER.

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