US3058723A - Regenerative heat exchangers - Google Patents

Description

Oct. 16, 1962 H. R. M55014 ETAL 3,058,723

REGENERATIVE HEAT EXCHANGERS Filed March 14, 1955 4 Sheets-Sheet 1 H. R. NILSSON ET Al.

REGENERATIVE HEAT EXCHANGERS Oct. 16, 1962 4 Sheets-Sheet 2 Filed March 14, 1955 Z11: y NTORJ Oct. 16, 1962 H. R. NILSSON ETAL 3,058,723

REGENERATIVE HEAT EXCHANGERS Filed March 14, 1955 4 Sheets-Sheet a 4K VNTORJ BY MA 1962 H. R. NILSSON EI'AL 3,05

REGENERATIVE HEAT EXCHANGERS Filed March 14, 1955 4 Sheets-Sheet 4 ENA 3,h58,723 Patented Get. 16, 1952 3,058,723 REGENERATIVE EAT EXCHANGERS Hans Robert Niisson, Eirtorp, and Per Walther Sigvard Persson, Johanneshov, Sweden, assignors to Svenska Rotor Maslriner Aktieholag, Nacka, Sweden, a co:-

poration of Sweden Filed Mar. 14, $55, Ser. No. arenas 22 Claims. (Cl. 257-270} The present invention relates to improvements in and relating to regenerative heat exchangers and particularly to the adaption thereof for operation under extreme high temperature conditions such as those prevailing in regenerators used where high temperature of air preheat is required to maintain high furnace temperature.

Illustrative examples of regenerators operating at high temperatures are those known from the open hearth furnaces and the coke ovens. They are usually constructed of firebrick and consist of two chambers completely filled with checker work. The flow of flue gases and that of air or gas to be heated are periodically reversed, so that the hot gases and cold gases alternately flow through the two sets of chambers. The cheekerwork retains the heat of the hot gases and gives it up to the cold gases with each reversal.

The saving effected by regenerators depends upon the temperature to which the incoming air or gas is preheated. With a gas temperature of 1600 F., the theoretical saving in fuel with 200 F. preheat of combustion air is about 4 percent; with 400 F., 11 percent; with 600 F., 15 percent; and with 800 F., 19 percent. a

In normal operating schedules, the two sets of regenerator chambers are generally reversed every half hour. Due to this the processes in the regenerators are periodically varying which is disadvantageous to the capacity of the oven.

The general object of the invention is to provide a regenerator which makes it possible to maintain constant operating temperatures whereby the capacity of the oven will be considerably increased.

As known per se this regenerative heat exchanger has a casing component providing passages therethrough for hot and cold gaseous media, respectively, and aligned inlet and outlet ducts connected to the ends of said passages as to provide for counterflow of the hot and cold gases through the exchanger in such a manner that the hot gas is admitted and the heated gas is discharged at one and the same end of the casing component and the cooled down gas and the cold gas is admitted at the other end of the casing component. According to the invention the heat exchanger has a rotor component which comprises two abutting portions, of which the portion nearest the inlet of the hot gas and the outlet of the heated gas is made up of refractory ceramic material and the portion nearest the outlet of the cooled down gas and the inlet of the cold gas is made up of metallic material.

Such a regenerative heat exchanger of the vertical type has the hot gas admitted and the heated gas discharged at the upper end of the casing component and the cooled down gas discharged and the cold gas admitted at the lower end of said casing component. The rotor component encircled by the casing component comprises two superimposed portions, the lower portion of which comprises a structural framework mounted to rotate, and the upper portion of which comprises a structure of refractory ceramic material which is supported by the lower portion and comprises refractory ceramic inner and outer shells and refractory ceramic elements disposed in the interspace between said refractory ceramic inner and outer shells.

The lower portion of the rotor component is advantageously provided also with heat absorbing elements, for instance such plate elements which are well known as the regenerative mass in the common air preheaters of the Ljungstrom type.

The casing component encircling the rotor component comprises a lower structural framework forming the carrying portion of the heat exchanger and an upper portion held by said structural framework and built up of refractory ceramic material. The structural framework of the casing component includes an end plate comprising sector plates which extend from the central portion of said structural framework of the casing component, and the upper portion of refractory ceramic material of the casing component includes an arch of refractory ceramic material which bridges said upper portion of the casing component and provides sector means aligned with the sector plates of the lower structural framework of the casing component. Hereby is provided a first passage for flow through the heat exchanger of the hot gas and a second passage for flow through the heat exchanger of the cold gas to be heated.

A further object of the present invention is to provide an attachment for revolving the rotor component which will provide the carrying portion or the structural framework of the rotor component with a ball bearing assembly on which the rotor component is carried by its own weight and on which the same can be operated and wherein one of the races includes a pin rack or similar means while the other race serves as a support for connecting the assembly to the structural framework forming the lower portion of the casing component and wherein access can be readily had to the interior of the race members for the removal or changing of the ball bearings.

Other objects of the present invention are to provide a ball bearing assembly on which the weight of the rotor component is carried by means of peripherally spaced carrying means extending radially from the structural framework of the rotor component, means further being provided to distribute the rotor weight to so many balls as possible around each place of contact between each carrier of the rotor component and race upon which the carrier rests and to increase the places of contact of the forces from the weight of the rotor component along the circumference of the ball bearing assembly. Still other objects are to provide a selfcentering of the rotor upon the ball bearing assembly and to provide means for fixing the rotor component and the rotatable bearing race peripherally in relation to each other and to provide for relative radial movements between the rotor component and the respective races of the ball bearing assembly, coaxial relationship between the races and the rotor component and full registering between both the races still being maintained. Another object is to provide an attachment for the revolving rotor component which is inexpensive to manufacture, easy to install and remove and efiicient in operation.

For a better understanding of the more detailed nature of the invention, manner in which it may be carried out and the advantages to be derived from its use into practical effect, reference may best be had to the ensuing portion of this specification, taken in conjunction with the accompanying drawings illustrative by way of example but without limitation of different examples of constructions embodying the principles of the invention.

In the drawings:

FIG. 1 is a vertical central section of a rotary heat exchanger embodying the principles of the invention, said section being taken perpendicularly to a plane through the sector means of the heat exchanger.

FIG. 2 is a sectional view as viewed on lines 22 and 22', respectively, in FIG. 1 of part of the heat exchanger embracing several upper and lower compartments of the rotor components and shows disposition of the respective regenerative heat transfer materials in the upper and lower compartments.

, 3 FIG. 3 is a perspective View, partly broken, of the heat exchanger shown in FIGS. 1 and 2. a

FIG. 4 is a fragmentary vertical section on enlarged scale of a part of the structure shown in FIGS. 1 and 2. FIG. 5 is a fragmentary perspective view of a rotor component showing another form of rotor construction. Referring now more particularly to FIGS. 1 to 4 of the drawings, there is illustrated one suitable form of'preheater for carrying the invention into effect. The apparatus shown comprises a stationary outer casing structure, indicated generally at 10, comprising a lower structural frame- Work 12 forming a carrying portion of the heat exchanger and an upper portion 14 held by the structural framework and made of insulating refractories 16. The structural framework 12 of the casing is provided with an end plate 18 which has two sector shaped openings or ports 20 and 22' located generally on opposite sides of a diamet'ral plane through the heat exchanger and separated by the sectors 24 and26 of the end plate 18. The ports 20 and 22 are connected respectively with ducts 23 and 30 for conducting one of the heat exchanging fluids to the rotor and the other fluid from the rotor. The upper portion 14- of the casing structure is provided with a suspended arch 32 which bridges said upper portion and provides sector means34 and 36 aligned with the sector plates 24 and 26 of the structural framework 12 of the casing structure. The suspended arch 32 comprises two steel beams 38 and 40 supporting a number of suspended arch shapes 42 of insulating refiactory which are shaped with inclined side surfaces 44 to provide sector shaped ports 46 and 48, aligned respectively with the ports 20 and 22 in plate 18 and communicating respectively with ducts 5G and 52 of insulating refractoryfor conducting the first mentioned fluid from the rotor and said other fluid to the rotor.

' Countercurrent flow of the two fluids provides for most eflicient heat transfer and in accordance with that practice the apparatus illustrated is connected so that for example cold air to be heated enters through duct23 and port 29 to. flow upwardly through the rotor and be discharged in the direction of arrow 54 through port 46 and dnct52', while the hot gas to be cooled is admitted through duct 52 and port 43, to the, top of the rotor and after having given up heat is discharged therefrom through port 22 and duct 30, as. indicated by arrow 56. 7 With such connections it will be evident that the upper end of the apparatus will be hotter than the lower end when in use and for convenience the upper end of the apparatus to which hot fluidis admitted and from which heated fluid is dis-, charged will be referred to as the hot end, the lower end being referred to as the coldf end. The upper portion of the casing, made of insulating refractory which according tothe invention forms the hot end of the 'apparatus is held by the structural framework and does not rest on thebase- V V V n In accordance withthe principle underlying the construction of the casing structure the rotor component, indi catedgenerally at 58, also comprises two superimposed portions, of which the lower portion comprises astructural plate framework 60 mounted to rotate, and of which the upper portion comprises a structure 62 of refractory ceramic material. i

In order to simplify the construction of the. rotor componentthe lower portion thereof is formed from sector shaped baskets 64. so that anybasket may be readily replaced with a minimum of inconvenience and labor.

In the embodiment shown in'FIG S 1 to 3 the rotor 58 is intheform of a cylinder and the baskets 64, of which the lower portion 60 of the rotor is made up, are assembled about the centre of the rotor with. their radial sides 66 inabutment so that theplurality of the baskets, forms a complete annulus'aroundzthe. centre of the rotor. Each basket 64 comprises radial side walls 68 and inner and outer ' arenateiend walls 70 and 72 and each of said walls is composed of double walled plate sections closed at their tops and bottoms. The abutting radial plate sides, 66

provide radially and axially disposed marginal extensions 74 and 76, respectively, which abutting marginal portions are bolted or riveted together in order to obtain a coherent unit serving as the carrying portion of the rotor component. lThe arcuate and circumferentially abutting double walled inner and outer end sections and 72 of the baskets 64 create complete circular walls providing the inner and outer shells of the carrying portion of the rotor and the radially abutting double walled sections 68 of the baskets 64 form partitions which extend radially outward from the inner shell 70 to the outer shell 72 of the carrying portion 60 of the rotor and divide the annular space between the shells of said carrying portion, into a number of sector shaped compartments 78. Each of said compartments '78 is further subdivided by ohordlike sections of the same double walled plate nature as the wall sections of the baskets 64 into a larger number of compartments 82. The chordlike sections'are provided at or near their bottoms with means 84 into which suitable supports as bars 36am anchored for supporting regenerative heat exchanging plate elements 88 in accordance with well known practice. 7

The upper portion 62 of the rotor 58 comprises radial partition wall sections 90 as well as arcuate inner and outer shell wail sections 92 and 94, all consisting of refractory ceramic material and each .of said wall sections registering with the radial partitions and the inner and outer shell sections, respectively, of the structural framework 69 of the rotor and carried thereby. The sector shaped compartments 96 into which the upperrotor portion is divided are further subdivided into a number of compartments 98 by chordlike wall sections 100 of refractory registering with the chordlike plate sections 80 in the structural framework 60' and carried thereby. The

width of each hollow double-walled section 7% and 72, respectively, which form the inner and outer shells of thelower portion of the rotor, corresponds in width to the width of the inner and outer shells 92 and 94, respectively, of refractory in the upper portion of the rotor. The total width of each pair of abutting radialJpartitions of the lower portion of the rotor corresponds to the width of the radial partitions 90 of refractory in the upper rotor portion. The width of the hollow doublewalled transverse'sections 80 of the lower rotor portion is likewise equal to the width of the transverse sections of refractory of the upper rotor portion. Further,-

the longitudinal walls of the lower hollow double-walled sections which accordingly register with the longitudinal surfaces of the upper refractory wall sections areprovided with upward extensions 102, 104 and 1% which serve as flanges between which the bases of the refractory wall sections are located. The upper portion is filled with heat. exchanging material in the form of refractory ceramic'elements which can consist of tubes Hi3 packed edgewise or of other packed refractory shapes. In order to support the regenerative refractory material 108 in the compartments 98 of. the refractory portion 62 of the 7 rotor the compartments 82 of the structural framework portion 6430f the rotor are celled with gratings 110. V

The rotor 53 is rotatably supported at its periphery by a hearing which is generally indicated at 112 .and has a lower bearing member 114 secured to the end plate 18 factor but also relative ease of repair and replacement when wear does occur. i

As has already been pointed out it. is the str c ural framework 50 of the rotor which carries the refractory upper portion 58 of the rotor and it is the peripheral bearing 112 which supports the structural framework of the rotor so that the rotor is carried by the structural framework 12 of the casing structure at or adjacent the cold end of the preheater.

The lower bearing member 114, which may be a continuous ring or made up of a number of segments, is provided with an annular recess 118 in the corners of which are located arcuate lengths of wire 129 providing lower rails upon which a multiplicity of balls 122- may roll. The number of lengths or sections of wire in each circumference may vary and if desired each rail may consist of only one piece. The joints between adjacent ends of wire should, however, be staggered.

, The upper bearing member 116 may comprise a rigid ring but in the construction shown the same is comprised of a plurality of arcuate elements 124 each providing a segmental section of an annular recess 126 forming the upper raceway for the balls 122 registering with the lower raceway 118. The arcuate elements 124 carry pins 123 which form the teeth of a peripheral rack with which a driving gear (not shown) for turning the rotor meshes. Additional arcuate lengths of wire 126 in the corners of recess 1126 provide upper rails engaged in rolling contact by balls 122, the latter being held in evenly spaced relation peripherally by the retainer 136 which is also advantageously in the form of a series of separate segmental elements.

As in the case of the lower rails, the joints in the upper rails should be staggered both with respect to each other but also with respect to the joints in the lower rails, so that no ball passes over more than one joint at a time.

The abutting radial sides 66 of the baskets 64 forming the carrying portion of the rotor provide radial extensions 132 and by means of said extensions serving as brackets or lugs which rest directly on the upper rotatable bearing member 116 the rotor 58 may be carried by means of said rotatable bearing member. As the weight of the rotor 58 may be considerable in several cases no further means are necessary to attach the rotor to the rotatable bearing member 116 but the rotor simply rotating with the rotatable bearing member at the turning of the latter on account of the frictional engagement between the carrying lugs 132 and the rotatable bearing member 115.

in the present embodiment the rotor during the operation becomes hot and expands radially relatively to the housing. The brackets or lugs 132 of the structural framework 60 of the rotor and carrying the same are free to slide upon the upper rotatable bearing member 116 but particularly in rotor constructions of very large diameter due to heat conducted to the upper bearing member the same will increase considerably in width so that the exact registering between the races in the upper and the lower bearing members would be affected. In order to avoid the difierential expansion between the upper and the lower bearing members due to temperature diiference it is advisable to make as stated above the rotatable bearing member of the relatively movable segments 124 permitting radial enlargement and contraction of the rotatable bearing member while still retaining the coaxial alignment of the upper .and lower bearing tracks.

The plurality of ring segments 124 are independently movable in radial direction relative to the rotor brackets or lugs 132 and individually guided thereto in a manner which will be described below. Generally at least one carrying bracket 132 is brought to register with each ring segment 124, the latter being brought to fix peripherally in relation to the rotor and said mutually fixed peripheral relationship is effected by means of the carrying brackets or lugs 132.

However, as it is not possible in practice to manufacture the preheater with sufficient precision to bring all the carrying lugs 132 to make contact with the rotat- 6 able bearing member 116, in the construction shown resilient means in the form of arcuately upward bent plate springs 13- are provided between each bracket or lug 13-2 and the rotatable bearing member 116. Such a plate spring is designed for instance so that the same permits a springing form 1 to 2 mm. Besides the advantage of a more even force distribution on the rotatable bearing member 116 these resilient means 134 resting at both their ends on the rotatable bearing member 116 procures twice as many contacts of force upon the rotatable bearing member. The rotatable bearing member which may be made in for instance six or more segmental sections dependent upon the size of the preheater can for reasons of costs only be made of limited thickness While the weight of the rotor is distributed only upon a relatively small number of balls 122 along the bearing ring reckoned from the place of force contact. An increase in the number of force contact points results in that a larger number of balls are carrying the weight of the rotor.

The general arrangement of the brackets or lugs 132 and the segmental sections 124- of the bearing ring 116 is preferably such that a symmetrical distribution of the parts is obtained and the load also is evenly distributed. The resilient means can be utilized to bridge the joints 136 between the segmental sections 124 of the bearing ring 116 in which case the number of segmental sections 124 corresponds to the number of baskets 64 or, possibly, is a whole number fraction thereof. With the plate springs located in this manner as bridging means between the ends of the segmental sections 124 the weight of the rotor is transferred via the brackets 132 to each segmental section still in two places, viz. at or adjacent the ends thereof.

The arched spring plates 134 engages the rotor brackets 132 at the apex of the arch and in order to maintain the registering between said parts the plate springs are provided with guide means in the form of projections 13% registering with the corresponding rotor brackets 132 and said guide means serve on one hand as driving means for the rotatable bearing member and on the other hand as means to center the rotor at the radial expansion and constraction thereof due to heating and cooling respectively. Owing to its design the plate spring is easily removable and it can for instance be drawn out by means of a suitable tool and a segmental section 124 of the upper bearing member may then be removed Without lifting of the rotor. After mounting of the segmental section of the upper bearing ring the plate spring is thrust into position.

The plate springs 134 are fixed in peripheral direction to the segmental sections 124 of the rotatable bearing member 116 by means of stop pins 140 fastened to the segmental sections and keying with holes or receses 142 adjacent the ends of the plate springs.

The structure just described provides numerous important advantages with respect to both initial cost and upkeep. As to the former, the use of the wire elements to provide the tracks for the balls eliminates the need for providing finely finished surfaces forming the recesses 118 and 126. The wire elements themselves are very inexpensive advantageously being made of piano wire or other high carbon or steel like metal or similar elastic nature. Balls 122 are advantageously of the kind used in standard ball bearings and also may be relatively inexpensive since the action of the bearing is such that a high degree of precision in the parts is not required and balls rejected for us ein ordinary ball bearings because of failure to meet dimensional tolerances may readily be used. The reason for this is that the number of balls employed in relation to the weight carried is such that the balls deform the wire rails sufficiently to create narrow tracks on the rails, and the elasticity of the metal of the rails and of the ball themselves is sufficient to compensate for minor dimensional variations.

The elastic deformation that is possible with the construc: tion described also insures even distribution of the weight carried by the bearing. Such construction is made practically possible because of the fact that in apparatus of the kind under consideration the speed of rotation of the rotors is only a very few revolutions per minute, so that even in the case of relatively very large diameter rotors the linear speed of operation 'of the bearing. is very low as compared with usual anti-friction bearing applications. Wear is thus very slow particularly since temperature conditions may be controlled so that the bearing may readily be grease lubricated. Because of the anti-friction nature of the bearing, power consumption is very low.

By. virtue of the manner in which the tracks or rails are formed on the rails by the action of the bearing itself, sections or segments of the rails and also individual balls that become unduly worn or otherwise defective .can readilybe replaced and this is easily accomplished because the structural framework 12 of the casing is pro vided with a removable door 144, giving access from the exterior of the casing to the balls and rails. In the construction shown, balls and rail segments can be removed while the bearing is under load. Even complete baskets 64 may be replaced in a similar manner provided that the opening of the door 144 is made sufiiciently large.

I It will be evident that the bearing construction is such that not only is the lower bearing member 114 fixed 'both radially and axially with respect to the end plate 18, but also the upper bearing member 116 which is radially. fixed. by the balls 122. The rack 123 is thus 'fixed with respect to the stationary structure carrying the driving gear which enables simple and inexpensive forms of gearing to be used and also makes the apparatus adaptable for friction drive.

The fixed position of the bearing member 116 axially relative to the end plate 128 is highly important from the standpoint of eifective sealing, since it maintains the end of the outer rotor shell located in substantially fixed relation axially with respect to the adjacent end plate, re-

gardless of dishing or other distortions of the rotor caused by temperature "differentials. Since freedom of lateral expansion and contraction of the rotor is permitted by the sliding connection between the rotor bracket supports 132 and the upper bearing member 116, no stresses arising from rotor distortion are transmitted to the latter. With the end of the rotor thus axially fixed at its periphery, effective sealing between the end plate 18 and the outer perimeter of the rotor is readily obtainable with a very simple and inexpensive form of seal. In the apparatus shown the peripheral seal 146 is carried by the rotor ad-' vantageously being of known form consisting of a multiplicity of leaves of relatively soft and malleable metal clamped to the outer shell 72 of the lower portion 60 of the rotor by ring elements 143. The sealing between the inner perimeter of the lower rotor portion 60 and the end plate 18 is obtained by a similar seal 150 and the outer top rim of the outer shell 72 of same rotor portion 60 seals against adjacent part 152 of the structural framework by a similar peripheral seal 154. Seals of the kind mentioned result in very little wear or power consumption due; to drag, since theyare substantially free from pressure contact, but obviously can be very effective only between parts having a substantially constant clearance, such as is produced by the present invention. Radial seals extending from the partitions 66, 68 in the lower section of the rotor are indicated at 156. In order to aid in maintaining the most constant clearance possible between the rotor shell and the end plate, difierential expansion in the axial direction between the bearing structure adjacent the heated rotor and the outer casing ring 12 exposed to the cooler ambient atmosphere should be kept to a minimum. To this end it is desirable to place the bearing at or adjacent to the cold end of the rotor where there is the. least radiation from the shell and where the heat that can be tranmitted by conduction from the rotor is the least.

In order to cool the steel beams 38 and 40 which support the suspended arch 32 the upper portions of the beams may be disposed in channels i158 and 160 provided in the wall 162 of refractory shapes which separates the fluid passage at the hot end of the preheater and through which a cooling medium such as air is circulated. V

A rotary type heat exchanger according to the invention for coke oven applications would have to meet the following requirements:

Air and gas quantities, respectively, at 60 F.900 cu. ft./

sec. Temperature of gas entering regenerator2750 to 2550" Temperature of gas leaving regenerator-600" F. overage.

Temperature of air leaving regenerator2000= F.

Pressure drop through regenerator-3 to 4 mm. WG.

The use of a rotary regenerator according to the invention makes it possible to maintain constant operating temperatures which will increase the capacity of the oven about 15% and which, for an oven of the capacity mentioned, would evaluate to $1,500,000 capitalization. The

invention has solved the problem of design of a low presform the hub and rim portions, respectively, and the radii the spokes'of the Wheel and all of them are made.

of plate section raised edgewise and provided on their upper edges with U-irons 174 welded thereto. The U- irons provide channels into which the bases of the inner and outer shell sections 178 and the radial portion wall sections 189 are seated. Said wall sections are built up refractory of tiles 182 joined by'rabbets 184. In order to avoid repetition the showing and description of the transverse wall sections and the refractory ceramic heat exchange filling are omitted. The spokes 172 provide radial extension 186 which are carried on the upper rotatable bearing member 116 of the same construction as shown in FIGS. 1 to 4. In order to reduce the span of the suspended arch.32 which in larger preheater units can be considerable themiddle of the arch is supported by a post 188 located in the centre of the rotor.

It is obvious that the invention also simplifies the construction of the heat exchanger so that the same can be made up in sections and baskets at the plant which are shipped as units of which the heat exchanger is built up on the site of use of the same.

From the foregoing it will be obvious that the principles of the invention may be carried into effect by means of a wide variety of specific structural embodiments, that various features may be combined in different ways and that certain features may be employed to the inclusion of others. The invention is accordingly to the understood as embracing all forms of apparatus falling within the scope of the appended claims.

What we claim is:

1. Rotary heat exchanger of the vertical type for gaseous media having a casing component providing passages therethrough for hot and cold gases, respectively, aligned inlet and outlet ducts so connected to the ends of said passages as to provide for counterflow of the hot and cold gases through said exchanger in such a manner that the hot gas is admitted and the heated gas is discharged at the upper end of the casing component and the cooled down gas is discharged and the cold gas is admitted at the lower end of the casing component, and a rotor component encircled by the casing component and comprising two superimposed portions, the lower portion of which comprises a structural plate framework mounted to rotate, and the upper portion of which comprises a structure of refractory ceramic material supported by the lower portion and comprising refractory ceramic inner and outer shells and regenerative refractory ceramic elements disposed in the interspace between said refractory ceramic inner and outer shells.

2. Rotary heat exchanger as claimed in claim 1, in which the structural plate framework comprises a spoke wheel, the hub and rim portions of which register with the inner and outer shells, respectively, of the upper portion of the rotor component.

3. Rotary heat exchanger as claimed in claim 2, in which the upper portion of the rotor component is provided with radial partitions dividing the interspace between the inner and outer shells of said upper portion in a plurality of sector shaped compartments, said partitions being made up of refractory ceramic material and registering each with :1 spoke of the structural framework.

4. Rotary heat exchanger as claimed in claim 3, in which transverse wall sections of plate and of refractory ceramic material in the lower and upper portions of the rotor component, respectively, divide the respective circumferentially disposed compartments of the rotor component into a plurality of radially disposed subcompartmerits, each transverse wall of refractory ceramic material in the upper portion of the rotor component registering with a corresponding transverse plate wall in the lower portion of the rotor component and being supported thereby.

5. Rotary heat exchanger as claimed in claim 3, in which grating means are provided in the structural framework of the rotor component to support the regenerative heat exchange material mounted in the compartments of the upper portion of the rotor component.

6. A rotary heat exchanger as claimed in claim 5, in which the regenerative heat exchange material mounted in the compartments of the upper portion of the rotor component comprises refractory ceramic tubes packed edgewise in the upper portion of the rotor component.

7. Rotary heat exchanger as claimed in claim 6, in which the hub and rim portions as well as the spokes and transverse wall sections of the structural framework of the rotor component provide upward extensions serving as flanges between which the bases of the wall sections of refractory ceramic material are seated.

8. Rotary heat exchanger as claimed in claim 1, in which regenerative elements are disposed in the interspace between the plate shells of the structural plate framework of the rotor component.

9. Rotary heat exchanger as claimed in claim 8, in which the regenerative elements disposed in the structural plate framework of the rotor component comprise plate elements.

10. Rotary heat exchanger of the vertical type having a casing component, a rotor component comprising two superimposed portions, the lower portion of which comprises a plurality of sector shaped plate baskets positioned in abutting relationship around the centre of the heat exchanger so that the radial sides of contiguous baskets define partitions extending radially from the inner to the outer periphery of the lower rotor portion and the inner and outer walls of the lower rotor portion comprise abutting transverse end sections of abutting baskets, and the upper portion of which comprises radial partitions and inner and outer wall sections of refractory ceramic material registering with the radial partitions and the inner and outer end sections, respectively, of the lower rotor portion and being supported thereby; regenerative heat exchange material mounted in the circumferentially disposed compartments into which the rotor is divided by means of the radial portions therein, the regenerative heat exchange material in the lower rotor portion comprising metal elements and the regenerative heat exchange material in the upper rotor portion comprising refiaotory ceramic elements; and bearing means for rotatably supporting the rotor component at the outer periphery of the lower portion thereof with respect to the casing component.

ll. Rotary heat exchanger as claimed in claim 10, in which transverse wall sections of plate and of refractory ceramic material in the lower and upper portions of the rotor, respectively, divide the respective circumferentially disposed compartments of the rotor into a plurality of radially disposed sub-compartments, each transverse wall of refractory ceramic material in the upper portion of the rotor component registering with a corresponding transverse plate wall in the lower portion of the rotor component and being supported thereby.

l2. Rotary heat exchanger as claimed in claim 11, in which the abutting radial sides of the baskets forming the lower portion of the rotor component are fastened together, a coherent rotor supporting unit being formed solely thereby.

13. Rotary heat exchanger as claimed in claim 12, in which the abutting radial sides of the baskets are fastened together along the margins thereof.

14. Rotary heat exchanger as claimed in claim 10, in which the radial sides and the transverse end sections of the baskets forming the lower portion of the rotor component comprise hollow double-walled plate sections, the width of each hollow double-walled section forming the inner and outer shells of the lower portion of the rotor component corresponding in width to the width of the inner and outer shells, respectively, of refractory ceramic material in the upper portion of the rotor component and the total width of each pair of abutting hollow doublewalled sections forming the radial partitions of the lower portion of the rotor component corresponding to the width of the radial partition of refractory ceramic material registering therewith in the upper portion of the rotor component.

15. Rotary heat exchanger as claimed in claim 14, in which transverse wall sections divide the compartments in radially disposed sub-compartments, each transverse wall section comprising a hollow double-walled plate section in the lower portion of the rotor component corresponding in width to the width of a transverse wall of refractory ceramic material registering therewith in the upper portion of the rotor component.

16. Rotary heat exchanger as claimed in claim 15, in which the longitudinal walls of the lower hollow doublewalled sections registering with the longitudinal surfaces of the upper wall sections of refractory ceramic material provide upward extensions serving as fianges between which the bases of the wall sections of refractory ceramic material are seated.

17. Rotary regenerative heat exchanger of the vertical type for gaseous media having a rotor component comprising two superimposed portions, the lower portion of which comprises a structural plate framework, mounted to rotate, and the upper portion of which comprises a structure of refractory ceramic material supported by the lower portion and comprising refractory ceramic inner and outer shells and refractory ceramic elements disposed in the interspace between said latter shell; and a casing component encircling the rotor component and comprising a lower structural framework forming a carrying portion of said heat exchanger and an upper portion held by said lower structural framework of the casing component and built up of refractory ceramic material, said lower structural framework of the casing component including an end plate comprising sector plates extending from the central portion of said structural framework of the casing component and said upper portion of the casing component including an arch of refractory ceramic material bridging said upper portion of the casing com ponent "and providing sector means aligned with the sector-plates of the lower structural framework of said casing component, whereby to provide a first passage for flow through said heat exchanger of a first gaseous heating medium and a second passage'for flow through said heat exchanger of a second gaseous'medium to be heated.

.18. Regenerative heat exchanger as claimed in claim 17, in which a suspended arch bridges the upper portion of. refractory ceramic of the casing component, said suspended arch comprising at least one 2beam support and refractory shapes suspended thereon. I

19. Regenerative heat exchanger as claimed in claim 18, in which the upper portion of the beam support is surrounded by a heat insulating refractory wall in which a channel is provided for circulation of a cooling medium along the beam support. I i I A .20. Regenerative heat exchanger as claimed in claim 18, in which the middle of the suspended arch is supported by a post located in the centreof the rotor component,

21. Regenerative heat exchanger as claimed in claim 17, in which inlet and outlet ducts are connected to the ends of said passages as to" provide for counterflow'of the hot and cold gases through said heat exchanger in such a manner that the hot gas .is'admitted and the heated gas is discharged at the upper end of the casing component and the cooled down gas is discharged and the cold gas is admitted at the lowerend of the casing component, the ducts connected to the upper ends of said passages comprising walls of refractory ceramic material and the ducts connected to the lower ends of said passages comprising walls of plate material. I

22. Regenerative heat exchanger as claimedin claim 17, in which the structural framework forming the lower portion of the casing component is provided :with door means to permit access to the rotor component.

References Cited in the file or" this patent UNITED STATES PATENTS 2,432,198 Karlsson et al. Dec. 9, 1947 FOREIGN PATENTS 291,402 Great Britain Dec. 13, 1928' 1,082,683 France Dec. 31, 1954

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