US2585912A

US2585912A - Regenerator for the recovery of the cold content of gases

Info

Publication number: US2585912A
Application number: US783498A
Authority: US
Inventors: Herman F Buschow; Percival C Keith
Original assignee: Hydrocarbon Research Inc
Current assignee: Hydrocarbon Research Inc
Priority date: 1947-11-01
Filing date: 1947-11-01
Publication date: 1952-02-19
Anticipated expiration: 1969-02-19

Description

1952 H. F. BUSCHOW ET AL 85,9

REGENERATOR FOR THE RECOVERY OF THE COLD CONTENT OF GASES Filed Nov. 1, 1947 4 Sheets-Sheet l NVENTORS 170M411 Basdgwo BY Zeruzml [f Kai]:

! HTTORNEY 1952 H. F. BuscHow ETAL ,9 2

REGENERATOR FOR THE RECOVERY OF THE COLD CONTENT OF GASES Filed Nov. 1, 1947 4 Sheets-Sheet 2 a flTTU/EWE Y 1952 H. F. BuscHow ETAL 2,535,912

REGENERATOR FOR THE RECOVERY OF THE COLD CONTENT OF GASES Filed Nov. 1, 1947 4 Sheets-Sheet 3 MW M 56 4T70RNE) Feb. 19, 1952 ow ET 2,585,912

REGENERATOR F OR THE RECOVERY OF THE COLD CONTENT OF GASES Filed Nov. 1, 1947 '4 Sheets-Sheet 4 a HTTOPNE) Patented Feb. 19, 1952 REGENERATOR FOR THE RECOVERY OF THE COLD CONTENT OF GASES "'ljiflgerman F. Buschow, North Arlington, and Percival C. Keith, Peapack, N. J., assignors to Hydrocarbon Research, Inc., New York, N. Y., a corporation of New Jersey Application November 1, 1947 Serial No. 783,498

17 Claims.

The present invention relates to an improved regenerator for recovering the cold content of the outgoing oxygen and nitrogen products of rectification, which may be at a, temperature of about --280 F., in the production of oxygen by the liquefaction and rectification of air. More particularly it relates to the construction and design of the regenerators including the cold exchange surface areas therein so as to provide for high cold transfer efiiciency between the oxygen and nitrogen products of rectification on the one hand and the air on the other, and for efiicient purging of the regenerators upon each reversal of fiow therethrough to effect substantially complete removal from the regenerators of condensibles deposited from the air stream, thereby permitting continuous operation.

Cold regenerators are well known in which the relatively warm incoming air and the relatively cold outgoing oxygen and nitrogen products of rectification are passed with periodically reversed operation, so that streams of warm air are flowed through the same packing-filled spaces as the cold oxygen and nitrogen traversed during the preceding step of the process. In the operation of such regenerators the high boiling impurities deposited in the packing-filled spaces during the passage of the air therethrough are removed by sublimation during the subsequent flow therethrough of the products of rectification. In order to provide relatively high cold transfer efficiency such regenerators have involved the use of so-called pancakes of heat transfer material formed by winding successive convolutions of corrugated metal on a core to produce disks consisting of successive convolutions of corrugated metal, a multiplicity of which disks are inserted in the regenerator shell one on top of the other to provide the packing for the regenerator. The production of such packing is arduous and time consuming and greatly increases the cost of the regenerator.

Among the objects of this invention is to provide a cold regenerator having an exceptionally high area of cold exchanger surface per unit of volume, which can more readily be fabricated and assembled than heretofore known regenerators and in the operation of which unusually low pressure drop takes place in the fluid flowing therethrough.

Another object is to provide a regenerator packing member, which can readily be produced by a simple stamping operation, and which can readily be assembled within the regenerator 2 housing to produce longitudinally extending channels for turbulent flow of gaseous media therethrough.

Still another object is to provide such regenerator which is more efficient in operation in that the cold transfer rate is considerably greater than in prior known regenerators.

Other objects and advantages of this invention will be apparent from the following detailed description thereof.

In the accompanying drawings forming a part of this specification and showing for purposes of exemplification preferred forms of this invention with out limiting the claimed invention to such illustrative instances:

Figure l is a plan view of a preferred form of regenerator packing member on an enlarged scale and illustrates a preferred embodiment of this invention;

Figure 2 is a composite section taken in planes passing through lines 22 on Figure 1;

Figure 3 is a vertical section taken in a plane passing through line 3-3 on Figure 1;

Figure 4 is a perspective view of a regenerator packing unit showing the members of Figure 1 arranged in a stack on a supporting tube;

Figure 5 is a plan view of a modified form of a regenerator packing member on a smaller scale than the scale of Figure 1;

Figure 6 is a view partly in elevation and partly in section of a regenerator embodying this invention;

Figure '7 is a diagrammatic section through the regenerator of Figure 6 taken in a plane passing substantially midway between the ends of the regenerator packing units, one of which is shown in Figure 4;

Figure 8 is a diagrammatic elevational view of a regenerator assembly, the colder portion of one of the regenerators being broken away to show the interior construction; and

Figure 9 is a diagrammatic view of a regenerator assembly involving two sets of regenerators, each set consisting of two pairs of regenerators one of which pairs is broken away to show the interior construction thereof.

The regenerator packing member of Figures 1 to 3 is a substantially square shaped plate-like member defined by the sides II), II, top edge l2 and lower edge I3. It may be made of any relatively thin material of high heat conductivity, preferably aluminum or copper. Edges l2 and 13 are formed with narrow integral flanges l4 and I5. The packing member has a central 3 supporting opening i8 defined by an integral flange I'I.

Two series l8 and I8 of closely spaced passages 20 are formed in the face of the packing member. A narrow portion of the face of the packing member or rib 2| extends in a generally straight line direction from side In to the opening I and a like rib 22 extends from the other side of opening Ii to side Ii. Ribs 2|, 22 separate the two series of passages l8 and it. The sides of each passage 20 of the two series i8 and is are defined by a pair of vanes 23. Each of the vanes 28 extends in a plane at an angle, preferably a right angle, to the plane ,of the face of-the packing member and is integrally Joined at its ends with the packing member by the volutes or deflected portions 24. Each of the vanes 23 is produced by cutting through the plate-like member along lines of cuts which preferably but not necessarily are parallel and are spaced apart a distance equal to the width of passages 20, plus the thickness of the plate-like member, and deflecting the material. between each pair of cuts to the position shown most clearly in Figure 3, so that the material extends in a plane at an angle of from 60 to 90, preferably 90, to its original plane, 1. e., to the plane of the plate-like member. One-half of the material thus deflected extends above and the other half below its original plane, the flanges i4 and i3 extending beyond the vanes 23, as is clearly evident from Figures 2 and 3.

In the embodiment of the invention shown in Figures 1, 2 and 3 substantially the entire area of the plate, from which the packing member is formed, is deflected to produce the vanes 23, narrow area or rib 26 along the longitudinal median of the plane and the ribs 2|, 22 along the transverse median. Along the areas contiguous to the sides I and II half vanes 25 are formed by deflecting the material between these marginal areas and the cut contiguous thereto of the series 01' cuts hereinabove mentioned. Thus each quarter of the plate-like member is formed with a group of narrow passages 20 defined by the vanes 23, all of which passages are in heat transfer relationship with the passage deflned by the central opening it at one end through a path of heat conducting material consisting of the rib 2| or 22 and at the opposite end through a path of heat conducting material consisting of the flange I 4 or ii and the longitudinally extending rib 23. In other words,

ribs

2i, 22 and 26 serve as heat conducting bridges, between all of the passages leading into these ribs, including those most remote from central opening l6, and this opening [6.

While the packing member of Figure 1 is shown as of square shape it may be of any dcsired polygonal shape which permits ready nesting of stacks of the packing members with little or no space between contiguous stacks. Thus, for example, these packing members may be of other rectangular shape than the square shape shown, or they may be of hexagonal or triangular shape. Figure 5, for example, shows a hexagonal shaped packing member. In this figure a series 21 of closely spaced passages is formed in the upper half of the packing member and another series 28 of closely spaced passages is formed in the lower half. Each passage is produced by deflecting the material between parallel lines of cuts to form vanes defining the side walls of the passage as hereinabove fully described in connection with Figures 1, 2 and 3. In Figure 5, the two

series

21 and 28 are separated by a narrow portion or rib 28, which rib extends from the central supporting opening 16 to opposite corners of the hexagonal member. The two series of

passages

21 and 28 are surrounded by a narrow marginal portion 30 of the plate-like member. Spacer flanges corresponding to flanges i4, i8 01' Figure 2 are formed on all the marginal edges of the packing member of Figure 5, or, if desired, on only some of these edges, say on two opposite edges only.

In order to provide the large mass of high heat conducting material per unit of regenerator volume and high area of cold exchanger surface per unit of regenerator volume necessary for effectively recovering the cold content of the outgoing products of rectification, it is important the material of high heat conductivity of each of the packing members be relatively thin. Desirably each packing member is dimensioned so that its thickness does not exceed .040 inch, the spacing between contiguous vanes does not exceed .100 inch and the flanges are dimensioned so as to provide a clearance of .003 inch to .020 inch and preferably from .003 inch to .010 inch between the edges ofthe vanes of contiguous packing members when the flange of one member abuts the face of a contiguous member. Preferred dimensions for an aluminum packing member of the shape shown in Figures 1, 2 and 3 are as follows: thickness .032 inch, depth of flanges I4 and l5.105 inch, width of each passage 20.048 inch, depth of vane 23.08 inch, of which part extends above and part below the original plane of the material from which the vane is produced by deflection of the material as hereinabove described, diameter of central opening "-375 inch, width of ribs 2!, 22-1 of an inch.

It will be noted that each of the packing members may easily be fabricated by a simple stamping and cutting operation in which the cuts defining the-inner edge of flange i1 and the edges of the vanes 23 are first produced and then the material deflected to form the integral flanges H, II and I1, the half vanes 25, the vanes 23 defining the passages 20 therebetween, and the

ribs

2i, 22 and 26 providing a bridge of high heat conducting material between all of the passages and the central opening IS.

The packing members hereinabove described are mounted on a supporting tube 3! to form a packing unit such as shown in Figure 4. The supporting tube 3| desirably is a hollow tube of high heat conducting material, for example, aluminum or copper, having relatively thin walls,

. e. g., about .12 inch thick, and having integral interior fins 32 extending from the inner wall in a radial direction towards the center of the tube to improve the efllciency of the heat exchange between the gaseous medium passing through tube 3] and that flowing through the channels 20 in the packing member. The outside diameter of the tubes is substantially the same as the diameter of the central supporting opening it in each of the packing members so that the packing members fit snugly on the tube. The packing members may readily be mounted on the supporting tube 3i by passing the tube through the central opening it of a stack of the members suitably grouped to form the desired regenerator unit; preferably the individual packing members are arranged in alternate groups 33, 34. All the packing members in the groups 34 in the embodiment of the invention shown in Figure 4 have the passages 28 therein extending in a generally vertical direction, while all of the packing members of each of the groups 33 have the passages 26 therein extending in a generally horizontal direction. Such grouping of the packing members of each stack results in a turbulent flow of the gaseous stream through the regenerator and im-- proves the heat transfer efliciency of the regenerator.

The individual packing members desirably have the flange I1 brazed to the supporting tube 3| and thus bonded thereto. Also either the corner portions of flanges I4 and |5, or the entire longitudinal extent of these flanges, may be brazed to the abutting portion of the face of the contiguous member. The ends 35, 36 of the supporting tube 3| of each packing unit extend beyond the stack of packing members mounted thereon for the purpose hereinafter described.

Each of the packing units before assembly with other like units to form the regenerator packing, as shown in Figure 6, has bearing

members

31, 38 positioned at the opposite ends of the stack of plate-like packing members. Desirably one or more such bearing members 39 are positioned at an intermediate point of the stack of packing members of each packing unit. These bearing members may be formed, for example, by winding one or more layers of a foil-like material, for example, aluminum foil, about each packing unit. Preferably two layers of aluminum foil 3 inches wide are wound or wrapped about each packing unit to form the bearing

members

31, 38, 39. When the packing units are assembled the bearing members of contiguous units are in contact with each other maintaining a small clearance 48 between individual packing units, thereby preventing the packing members of one unit from rubbing against the packing members of another unit, and thus minimizing damage to the packing members of each unit.

Ends 35 of the tubes 3| pass through collars 4|, 42 which are welded or otherwise fastened to beams 43 extending transversely through the upper part of shell or housing 44. The ends of beams 43 are suitably fastened to the housing 44, for example, by welding. Two

rows

45, 46 of packing units are suspended from the opposite sides of each beam. The packing units of each row are disposed, as hereinabove described, with the bearing

members

31, 38, 39 on each of the packing units in abutting relationship. The packing units of each pair of

rows

45, 46 are mounted on opposite sides of each beam 43 and have their bearing

members

31, 38 and 39 in abutting relationship, as clearly appears from Figure 6. These bearing members on each of the packing units of each row 45 suspended from one beam 43 are disposed in abutting relation-' ship with the bearing members on the packing units of row 46 suspended from an adjacent supporting beam 43. As shown in Figure 7 the packing units of one row 45 may be offset relative to the position of the packing units of the contiguous row 46. The space between the outer packing units and the inner wall of shell 44 is filled with aluminum foil 41, or may otherwise be blocked ofi to avoid flow through this space. Alternatively, the exterior of shell 44 may be accurately dimensioned so as to fit the contour of the arrangement of individual packing units formed by grouping these packing units in closely spaced relationship with the bearing members in contact, as shown, for example, in Figures 6 and 7. The regenerator should contain not less than or individual packing units the exact number 6 depending on the volume of oxygen, nitrogen and air to be handled.

A header 48 is disposed at one end of regenerator housin 44 and a second header 43 positioned at the other end of this housing. Extending across each of these headers and suitably secured thereto as by welding is a series of manifolds 50, there being one such manifold connected with each of the headers 48, 49- for each pair of

rows

45, 46 of packing units. Ends 35 of the tubes 3| of each pair of rows of packing units are connected with manifold 58 communicating with header 48 and the opposite ends of these tubes are connected with manifold 58 communicating with header 49. Thus all of the tubes 3| of the packing units are communicably connected at their opposite ends with the

headers

48 and 49. A port 5| provided with an expansion joint 52 leads into header 48 and a port 53 provided with an expansion joint 54 leads into header 49.

Housing 44 is formed with a top port 55 and a base port 56. A stand 51 is provided for supporting the regenerator in the upright position shown in Figure 6. If desired, however, the regenerator may be constructed for placing in a horizontal position on a suitable support,

In Figure 8 a regenerator assembly is shown involving two regenerator pairs 58 and 59. Regenerator pair 58 consists of regenerators 68, 6| each structurally substantially the same as the regenerator of Figure 6. Regenerator pair 59 consists of regenerators 62, 63 each structurally substantially the same as the regenerator of Figure 6. Parts of the regenerators 60, 6|, 62 and 63, the same as those of the regenerator of Figure 6, are indicated by the same reference characters. Regenerators 68, 6| and 62, 63 have the

ports

56, 55 interconnected for flow from one regenerator to another. as shown in Figure 8.

Header 49 of regenerator 68 is connected with header 4-8 of regenerator 6| by a main 64. A main 65 connects header 49 of regenerator 62 with header 48 of regenerator 63. The two mains 64, 65 are connected by a main 66.

The top headers 48 of

regenerators

60 and 62 are connected by a main 61. The bottom headers 49 of the regenerators 6|, 63 are interconnected by a main 68.

In the apparatus of Figure 8 streams of nitrogen rectification product and air flow alternately over the packing units disposed within the regenerator pairs 58, 59, the nitrogen imparting its cold content to the packing members and the air recovering this cold when it flows thereover during the succeeding step of the process. Oxygen rectification product fiows through main 61, headers 48, tubes 3| giving up its cold content to the packing members, which cold content is recovered by the air passing over the packing members. The oxygen leaves regenerators 6|, 63 through main 68. A portion of the oxygen flowing through mains 64, 65 is withdrawn through line 66 by blower 69 which recirculates the portion thus withdrawn through non-reversing heat exchanges 18 and 1| into the oxygen line 12 leading from the rectification system, which may be of any well-known type, to the main 6! communicating with the headers 48. In line 12 the recirculated oxygen mixes with the stream of oxygen flowing from the rectification system, the resultant oxygen stream flowing through main 61, headers 48, tubes 3| within regenerators 68, 62, mains 64, 65, a portion being withdrawn through main 66 and the remainder passing 7 through headers 48 in regenerators 6|. 63. tubes 8| in regenerators 6|, 63 and exiting through main 68. The recirculated oxygen passing through heat exchanger 18 flows in heat exchange relation with a minor portion or the air leaving one or the other of the regenerator pairs 58, 59, this minor portion of the air being thus warmed to a temperature such that when introduced into an expander 13 liquefaction or air within this expander does not take place. From the expander 13 the expanded air may be supplied to the low pressure stage of the rectification system.

In exchanger 1| the recirculated oxygen flows in indirect heat exchange relation with nitrogen which flows from the rectification system through exchanger 1| and thence through line 14 leading to the regenerators. Thus the nitrogen enters the regenerator pairs 58, 59 at a higher temperature than would otherwise be the case. This nitrogen flows through one of the regenerator pairs 58, 59 and removes therefrom carbon dioxide and other condensibles deposited therein during the preceding step of the process. The

efllciency of the purging action of the nitrogen is materially improved by its entering the regenerator pairs 58, 59 at such higher temperature as hereinabove described, since the preheating of the nitrogen in this manner results in temperature conditions within the regenerator optimum for the removal of carbon dioxide.

Reversal of flow of nitrogen and air through regenerator pairs 58, 59 is accomplished by a pair of reversing

valves

15, 16. Reversing valve 15 is provided with an air inlet line 11, a pair of

lines

18, 19 leading to ports 56 of the regenerators 6|, 63 and a nitrogen exit line 88. The other reversing valve 16 is provided with a pair of lines 8|, 82 leading to the ports of

regenerators

60, 62, nitrogen line 14 leading from the non-reversing exchangers 1| and an air exit line 83 leading to the rectification system and having a branch 84 through which a minor portion of the air, as hereinabove described, flows through exchanger 18 to the expander 13.

In the operation of the apparatus of Figure 8, air at a pressure of 60 to 100 pounds and a temperature of from to 110 F. is supplied through line 11, and, as indicated by full line valve settings, flows through valve 15, line 19 into and through regenerators 63, 62 where it is cooled to a temperature close to its dew point at the pressure prevailing in this regenerator. The thus cooled air exits through line 82 into valve 16 from which the air flows through line 83, a major portion passing to the rectification system and the remaining minor portion flowing through line 84, heat exchanger 10 to expander 13. From this expander the expanded air at a pressure of 5 to 12 pounds passes to the low pressure stage of the rectification system. Simultaneously nitrogen flows through line 14 into valve 16, line 8| into and through regenerators 66, 6| giving up its cold to the packing units in these regenerators. The thus warmed nitrogen exits through line 18, valve 15 and nitrogen exit line 80.

Oxygen from the rectification system flows through line 12, main 61, headers 48, tubes 3| within the regenerators 68, 62, headers 49, connecting mains 64, 65. A portion of this oxygen is withdrawn as product through main 68 after its flow through headers 48, tubes 3| in regenerators 6|, 63. The remainder is recirculated by blower 69 through exchangers 10, 1| into line 8 12 where the recirculated oxygen augmented by oxygen from the rectification system flows through main 61, headers 48, tubes 3| in regenerator pairs 58, 59, a portion being recirculated n as hereinabove described.

Upon reversal, which may take place every three minutes, as indicated by the dotted line valve settings, air flows through valve 15, line 18, regenerators 6|, 68 and is refrigerated close to its dew point in its flow through these regenerators. The air exits through line 8| and flows through valve 16 and thence through the same flow path as hereinabove described. Simultaneously nitrogen flows through line 14, valve 16, line 82, regenerators 62, 63, exiting through line 19, valve 15 and nitrogen exit line 80. Oxygen flows through the same paths as during the preceding step of the process, namely, through the tubes 3| in the regenerator pairs 58, 59, cocurrently with the stream of nitrogen flowing through regenerators 62, 63 and countercurrent to the stream of air 'flowing through regenerators 6|, 66 in indirect heat exchange relation therewith. The nitrogen which alternately, flows through one or the other of the regenerator pairs 58, 58 removes therefrom carbon dioxide and other condensibles deposited therein from the air during the preceding step of the process.

The regenerator assembly of Figure 9 diiIers from that of Figure 8 chiefly in that (1) it involves two sets of regenerators, one for the reversal of air and nitrogen and the other for the reversal of air and oxygen instead of the single set of Figure 8; and (2) the supporting tubes in certain of the regenerators are sealed or pinched off, or are in the form of solid supporting rods since no flow therethrough takes place.

In Figure 9, 86, 81 are the pairs of regenerators forming the set through which the flow of air and nitrogen takes place alternately and 88, 88 are the pairs of regenerators forming the set through which the flow of oxygen and air takes place alternately, the regenerators of the pairs 88, 68 being approximately one-fourth the volumetric capacity of the regenerators of the pairs 86, 81. Regenerator pair 86 comprises regenerators 90, 9| having the

ports

56, 55 interconnected for flow from one regenerator to the other. Regenerator pair 81 comprises regenera tors 92, 93 having the

ports

56, 55 interconnected; regenerator pair 88 comprises regenerators 94, having the

ports

56, 55 interconnected; and regenerator pair 89 comprises regenerators 96, 81 having the

ports

56, 55 interconnected. Each of the

regenerators

98, 92, 94, 96 structurally is substantially the same as the regenerator of Figure 6 and like parts have been indicated by like reference characters. In the case of the regenerators 9|, 93, 95 and 91 the tubes 3| on which the individual packing members are stacked, as hereinabove described, are pinched oil? or otherwise sealed, since no flow therethrough takes place. Inlieu of hollow tubes solid supporting rods having a diameter equal to that of opening I6 0! the packing member may be used.

Reversal of flow of nitrogen and air through regenerator pairs 86, 81 is accomplished by a pair of reversing

valves

98, 89. Valve 88 is connected with ports 56 of regenerators 8|, 83 through lines I06, |0|, respectively, and has a nitrogen exit line 82 and a branch air inlet line I03 leading from a main air line I64. Reversing valve 89 is connected with the ports 55 of regenerators 90, 92 by means of lines I65, I86, respectively, and has a nitrogen inlet line I81 and an air exit line I08 connected with the air line I09 leading to the rectification system.

Reversal of flow of oxygen and air through the regenerator pairs 88, 89 is accomplished by a pair of reversing valves H0, III. Reversing valve H is connected with the ports 56 of

regenerators

95, 91, respectively. by lines H2 and H3, and has an oxygen exit line H4 and a branch air inlet line I I5 leading from the main air line I04. Reversing valve I I I is connected to regenerators 94, 96 by a pair of lines H6, H1, respectively, and is provided with an oxygen inlet line H8 and an air exit line H9 communicating with the main air line I09.

Oxygen line H8 has a valve I20 therein and is provided with a branch I2I. Valve I20 regulates the amount of oxygen flowing through branch line I2I and line H8. Lines I22, I23, I24 and I25 lead from the branch line I2I to the inlet ports 5| communicating with the headers 48 in each of the

regenerators

96, 94, 92 and 90. The outlet ports 53 leading from the headers 49 disposed in each of the regenerator-

s

96, 94, 92 and 90 communicate with lines I26, I21, I28 and I29 which lead into a recirculating main I30 communicating with the oxygen line H8 at a point between valve I20 and reversing valve III.

Recirculating line I30 may pass through nonreversing heat exchangers corresponding to exchangers 10, 'II, as in the modification of Figure 8. Instead of recirculating oxygen through the circulating system consisting of lines I2I, I22, I23, I24, I25, ports 5|, headers 48, tubes 3|, headers 49 and main I30, other rectification products, such as nitrogen, argon, neon, etc., or an extraneous gas may be recirculated through this system, in which case the circulation system is designed so that it is independent of the oxygen air line H8.

In the operation of the apparatus of Figure 9 air at a pressure of 60 to 100 pounds and a temperature of from 70 to 110 F. is supplied from main air line I04 to the branches I03, H5, and flows through valves 98, H0, lines IOI, H3, regenerator pairs 81, 89, exiting through lines I08, HI, valves 99, III and lines I08, H9, respectively, into the main air line I09 which leads to the rectification system. Simultaneously nitrogen is supplied from the rectification system through line I01, flows through valve 99, line I05,

regenerator pair 86 and exits through line I00,

valve 98 and nitrogen exit line I02. Oxygen is supplied through line I I8 and flows through valve III, line H6, regenerator pair 88 and exits through line I I2, valve H0 through the oxygen exit line H4. The nitrogen and the oxygen give up their cold content to the packing units in the regenerator pairs 86, 88. The air in flowing over the packing units in the regenerator pairs 81 and 89 is cooled to a temperature close to its dew point at the pressure prevailing in these regenerators. Any carbon dioxide or other condensibles contained in the air is deposited in the regenerators.

A portion of the oxygen flows through line I2 I, branches I22, I23, I24, I25, ports 5I, headers 48, tubes 3| in each of the

regenerator sections

96, 94, 92, 90, this portion exiting through headers 49, ports 53 and main I30 from which the oxygen fiows with the oxygen stream flowing through line H8 into the reversing valve III. The resultant oxygen stream, as hereinabove described, passes over the packing units in regenerator pair 88.

Upon reversal, which may take place every three minutes, as indicated by the dotted line valve settings, air flows through valves 98, H0, lines I00, H2, through the regenerator pairs 86, 88,1ines I05, H6, valves 99, III, lines I08, H9, respectively, to the air line I09. Nitrogen flows through valve 99, line I06, regenerator pair 81, exiting through line IOI, valve 98 and thence through the nitrogen exit line I02. A portion of the oxygen from the rectification system is recirculated through the tubes 3| in each of the

regenerators

90, 92, 94', 96, as hereinabove described, and mixes with the oxygen stream flowing through line I I8 into the reversing valve I I I. This mixed oxygen stream fiows through line I I1, regenerator pair 89, exiting through line H3, valve H0 and oxygen exit line H4. The nitrogen which alternately fiows through one of the regenerator pairs 86, 81 and the oxygen which alternately flows through one of the regenerator pairs 88, 89 removes therefrom carbon dioxide and other condensibles deposited therein during the preceding step of the Process.

It will be noted the regenerator of this invention has an exceptionally high surface area of cold exchanger surface per unit of volume of regenerator. With the design of packing units hereinabove described involving packing members approximately 3 inches square made of aluminum having a thickness of .032 inch and otherwise dimensioned as hereinabove described, the regenerator may have about 365 square feet of cold exchanger surface per cubic foot of regenerator volume. The turbulent flow caused by the grouping of the individual packin members within each unit, as hereinabove described, further improves the cold transfer efliciency of the regenerator. The regenerator is there ore of exceptionally high cold transfer effic ency. This makes it possible to have the volumetric space through which the nitrogen and oxygen on the one hand and air on the other flows relative y small thereby minimizing reversal losses. In the modification of Figure 8 in which no reversal of oxygen flow takes place, such reversal losses are still further minimized.

The construction and design of the par-k ng members perm t their ready assembv on t e s porting tubes 3|. Hence, the re enerato is s mple to form and assemble. Moreover, t e flow through the channels in the packin u its and the tubes 3I is in a general longitudinal d re ion with consequent min m m ressure drop of fluid flowing throu h each regenerator.

The regenerators sho n in Figu es 6. 8 and 9 are in a vertical position and in the case of Figures 8 and 9 the air enters at the lower end and the products of rectificat on at the upper end. If desired, the air could instead be introduced at the upper end and the products of rectification at the lower end. Preferably the ports and associated headers at the warmer end of the regenerators are larger than the corresponding parts at the cooler end to compensate for volume changes occurring in the gaseous fluids flowing therethrough.

In Figures 1, 2, 4 and 5, the packing members embodying this invention are shown associated with the cylindrical tubes or supporting rods which are generally preferred. However, these packing members may be made for use with hexagonal, square or other shaped tubes or supporting rods; hence, the terms tube and supporting rod are used in a broad sense and are intended to include all such polygonal tubes and supporting rods.

It will be understood different embodiments of the invention can be made without departing from the scope of this invention. Thus, while each regenerator pair of Figures 8 and 9 has been shown as consisting of two regenerators, regenerator assemblies may be constructed containing any desired number of regenerators placed in series and/or parallel. Accordingly, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

1. A regenerator packing member comprising a thin plate-like polygonal member of high heat conducting material, a flanged mounting opening therein, narrow integral flanges on at least two opposite peripheral ed es thereof and having in the face thereof a multiplicity of closely spaced passages formed by cutting the plate-like member along closely spaced lines and deflecting substantially all of the material between contiguous lines to provide vanes defining said passages. the said vanes each extending substantially equidistantly above and below the plane of the face of the plate-like member and lying in a plane at an angle to the plane of the face of the platellke member, said member when assembled with other like members with the flanges of one member disposed in substantially abutting relationship with the face of a contiguous member providin an exceptionally large mass of high heat conducting material per unit of regenerator volume permeated by a multiplicity of said passages for flow of a fluid medium therethrough in surface contact with said high heat conducting material.

2. A regenerator packing member as deflned in claim 1. in which the high heat conducting material is aluminum and the thickness of said material does not exceed .040 inch.

3. A regenerator packing member as defined in claim 1, in which the high heat conducting material is copper and the thickness of said material does not exceed .040 inch.

4. A regenerator packing member comprising a plate-like polygonal member of a thickness not exceeding .040 inch of high heat conducting material having a central mounting opening therein, narrow integral flanges on at least two opposite peripheral edges thereof and having in the face thereof two series of closely spaced passages separated by a narrow face portion of said plate-like member, each of said series of said closely spaced passages being formed by cutting the plate-like member along closely spaced lines extending in a substantially straight line direction from said narrow portion to near the periphery of said plate-like member, and deflecting the material between contiguous lines to provide vanes deflning said passages, said vanes each extending in a plane at an angle of from 60 to 90 to the plane of the face of the plate-like member and being dimensioned so that they do not extend beyond said flanges, said member when assembled with other like members on a support passing through said central opening with the flanges of one member disposed in substantially abutting relation.

with the face of a contiguous member providing an exceptionally large mass of high heat conducting material per unit of regenerator volume permeated by a multiplicity of said passages for flow of a fluid medium therethrough in surface contact with said high heat conducting material.

5. A regenerator packing member comprising a substantially square aluminum plate of a thickness not exceeding .040 inch having a central supporting opening therein, integral spacer flanges on said plate, said plate having in the face thereof two series of closely spaced passages formed by cutting the plate along closely spaced lines extending in a generally longitudinal direction from near the medium line of said plate to the peripheral edges containing said flanges, said lines being substantially perpendicular to said peripheral edges, and deflecting the material between contiguous lines to provide vanes defining said passages, said vanes each being disposed in a plane at substantially right angles to the plane of the plate, the two series of closely spaced passages being separated by a portion of the plate extending thereacross in a substantially straight line direction which when extended intersects the said central opening, said' plate when placed with other like plates on a support passing through said central opening with the flanges of one plate in substantially abutting relation with the face of a contiguous plate providing an exceptionally large mass of aluminum per unit of exchanger volume permeated by a multiplicity of said passages for flow of a fluid medium therethrough in surface contact with the aluminum.

6. A regenerator packing unit comprising a supporting rod, a plurality of thin polygonal plate-like members of high heat conducting material, each having a central opening of a cross section area substantially equal to that of said supporting rod and mounted thereon with the rod passing through the central openings of the platelike members, each plate-like member having narrow integral spacer flanges on at least two peripheral edges thereof and having in the face thereof a multiplicity of closely spaced passages formed by cutting the plate-like member along closely spaced lines and deflecting the material between contiguous lines to provide vanes defining said passages, said plate-like members being disposed on said supporting rod with the flanges of each plate-like member except a terminal member in substantially abutting relation with the face of a contiguous plate-like member.

'7. A regenerator packing unit as defined in claim 6, in which each plate-like member is of aluminum of a thickness not exceeding .040 inch, and the flanges have a depth such that they provide a clearance of .003 inch to .020 inch between the edges of the vanes of contiguous plate-like members mounted on said supporting rod with the flanges of one plate-like member abutting the face of a contiguous member.

8. A regenerator packing unit as defined in claim 6, in which each plate-like member is of copper of a thickness not exceeding .040 inch, the flanges have a depth such that they provide a clearance of .003 inch to .020 inch between the edges of the vanes of contiguous plate-like members mounted on said supporting rod with the flanges of one plate-like member abutting the face of a contiguous member.

9. A regenerator packing unit comprising a supporting rod, a plurality of thin polygonal platelike members of high heat conductivity each having a central opening of a cross sectional area substantially equal to that of said supporting rod stacked thereon with the rod passing through said central opening, each plate-like member having integral spacer flanges extending from the plane of said plate-like member on two opposite peripheral edges and having in the face thereof two groups of closely spaced passages formed by cutting the plate-like member along closely spaced lines extending in a general longitudinal direction from near the median line of said platelike member to but short of the peripheral edges containing said flanges and deflecting the material between contiguous lines to provide vanes defining said passages, said vanes each extending in a plane at substantially right angles to the plane of the plate-like member and being dimensioned so that they do not extend beyond said flanges, said plate-like members being stacked on said supporting rod so that the flanges of each member of the stack, except a terminal member, are in substantially abutting relationship with the face of a contiguous member of the stack and the said stack provides an exceptionally large mass of high heat conducting material per unit of regenerator volume permeated by a multiplicity of said passages for flow of the fluid medium therethrough in surface contact with said hi h heat conductin material.

10. A regenerator packing unit as defined in claim 9, in which the plate-like members have a thickness not exceeding .040 inch are are of aluminum.

11. A regenerator packing unit as defined in claim 9, in which the plate-like members are substantially square and are arranged in groups on said supporting rod with the plate-like members in each group having the passages therein extending in substantially the same direction and the passages in the plate-like members of alternate groups extending in a direction at substantially right angles to the direction of the passages in the plate-like members of the remaining groups.

12. A regenerator for the recovery of the cold content of the rectification products produced in the rectification of air to produce oxygen, in combination, a housing having at one end an inlet for one of said rectification products and at the other end an exit therefor, a header in said housing at the said first-mentioned end thereof, a plurality of hollow tubes leading from said header. a stack of polygonal plate-like members on each tube with the sides of said plate-like members disposed close to the sides of the platelike members on the contiguous tubes, each platelike member having a thickness not exceeding .040 inch, being of high heat conducting material, having narrow integral spacer flanges on at least two peripheral edges thereof and having in the face thereof a multiplicity of closely spaced passages formed by cutting the plate-like member along closely spaced lines and deflecting the material between contiguous lines to provide vanes defining said passages, said vanes being dimensioned so that they do not extend beyond said flanges, said plate-like members being stacked so that the flanges of each member in the stack, except a terminal member, are disposed in substantially abutting relationship with the face of a contiguous member. thereby providing an exceptionally large mass of high heat conducting material per unit of regenerator volume permeated by a multiplicity of said passages for flow of the first-mentioned rectification product therethrough in surface contact with the high heat conducting material, a header in said housing at the said other end thereof with which the said hollow tubes communicate, an air: inlet disposed at the said other end of said housing, and an air exit disposed at the said first-mentioned end.

13. A regenerator as defined in claim 12, in which the plate-like members are of aluminum.

14. A regenerator for the recovery of the cold content of the rectification products produced in the rectification of air to produce oxygen, comprising. in combination, a longitudinally extending housing having at one end an inlet for one of said rectification products and at the other end an outlet, a header in said housing at the said first-mentioned end thereof, a plurality of hollow tubes leading from said header for flow therethrough, said tubes being substantially equally spaced throughout the cross sectional area of the portion of said housing through which they extend, a second header in said housing into which said tubes extend, a stack of thin polygonal plate-like members of high heat conducting material mounted on each tube with the tube passing through the central openings of the plate-like members of the stack, each plate-like member having a central opening of a cross sectional area substantially equal to that of the overall cross sectional area of the tube passing therethrough, each plate-like member having narrow integral spacer flanges on two opposite peripheral edges thereof and having on the face thereof two series of closely spaced passages separated by a narrow portion of said plate-like member, each of said series of said closely spaced passages being formed by cutting the plate-like member along closely spaced lines extending in a substantially straight line direction from said narrow portion to near the periphery of said platelike member and deflecting the material between contiguous lines to provide vanes defining said passages, said vanes each extending in a plane at substantially right angles to the plane of the plate-like member and being dimensioned so that their depth does not exceed that of said flanges, each of said stacks of said plate-like members having the flanges of each plate-like member, except a terminal plate-like member, in substantially abutting relationship with the face of a contiguous plate-like member, said tubes with said plate-like members thereon substantially completely occupying the cross sectional extent of said housing and providing an exceptionally large mass of high heat conducting material per unit of cold regenerator volume permeated by a multiplicity of said passages for alternate flow of air and rectification product therethrough in surface contact with said platelike members of high heat conducting material.

15. A regenerator as defined in claim 14, in which the plate-like members are substantially square, of a thickness not exceeding .040 inch and the plate-like members of each stack are arranged in groups with the plate-like members in each group having the passages therein extending in substantially the same direction and the passages in the plate-like members of alternate groups extending at substantially right angles to the direction of the passages in the remaining groups.

16. A regenerator assembly for use in the recovery of the cold content of the rectification products produced in the liquefaction and rectification of air to produce oxygen, comprising, in combination, two pairs of regenerators, means for passing air through one pair of regenerators while concurrently passing a rectification product through the other pair of regenerators, valve means for effecting reversal of flow so that air flows through the regenerator pair through which the rectification product had previously passed and the rectification product flows through the regenerator pair through which the air had preprising a colder and warmer regenerator, headersdisposed at the opposite ends of each colder regenerator, tubes connecting the headers and disposed within each of said colder regenerators, regenerator packing within each regenerator, and means for passing a fluid through said headers and the connecting tubes within each of said colder regenerators.

17. A regenerator assembly for use in the recovery of the cold content of the rectification products produced in the liquefaction and rectification of air to produce oxygen, comprising, in combination, a set of regenerators comprising two pairs of regenerators, one pair for the flow of nitrogen rectification product therethrough while air flows through the other pair and upon reversal air flows through the pair through which had previously passed the nitrogen and the nitrogen through the pair through which had previously passed the air, a second set of regenerators comprising two pairs of regenerators, one pair for the flow of oxygen rectification product while air flows through the other pair and upon reversal air flows through the pair through which had previously passed the oxygen and the oxygen through the pair through which had previously passed the air, each pair of regenerators comprising a colder and warmer regenerator, headers disposed at the opposite ends of each colder regenerator, tubes connecting the headers and disposed substantially equally spaced throughout the cross sectional area of each of said colder regenerators, supporting rods substantially equally spaced throughout the cross sectional area of each said warmer regenerators, a stack of regenerator packing members on each tube and supporting rod, and means for passing a fluid through said headers and connecting tubes in each of said colder regenerators.

HERMAN F. BUSCHOW.

PERCIVAL C. KEITH.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,148,865 Shipman Aug. 3, 1915 2,016,164 Williams Oct. 1, 1935 2,097,434 DeBaufre Nov. 2, 1937