US3246686A - Regenerative preheater including heat transfer mass and floating sealing plates - Google Patents

Description

April 19, 1966 G. KALBFLEISCH ETAL 3,246,686

REGENERATIVE PREHEATER INCLUDING HEAT TRANSFER MASS AND FLOATING SEALING PLATES Filed March 5, 1962 5 Sheets-Sheet 1 P" 1966 G. KALBFLEISCH ETAL 3,246,586

REGENERATIVE PREHEATER INCLUDING HEAT TRANSFER MASS AND FLOATING SEALING PLATES Filed March 5, 1962 :3 Sheets-Sheet 2 IIIIIIIIIIIA A ril 19,. 1966 G. KALBFLEISCH ETAL 3,246,636

REGENERATIVE PREHEATER INCLUDING HEAT TRANSFER MASS AND FLOATING SEALING PLATES Filed March 5, 1962 5 Sheets-Sheet 3 Fig.5

11. 43 1.1, 42 15 l 2 E; U 16 40 J l 12 m United States Patent REGENERATIVE PREHEATER INCLUDING HEAT TRANSFER MASS AND FLOATING SEALING PLATES Georg Kalbtieisch, Eppelheim, near Heidelberg, and ()tto Ludt, Leimen, near Heidelberg, Germany, assignors to fivenska Rotor Maskiner Aktieholag, Stockholm, Sweden, :1 company of Siweden Filed Mar. 5, 1962, Ser. No. 177,582 14 Qlaims. (Cl. 165-9) This invention relates to rotary regenerative preheaters of the kind including a rotor surrounded -by a stationary housing provided opposite the rotor ends and having end walls formed with circumferentially spaced apertures between imperforate portions and permitting the flow of heated gases and gases to be heated to and through the rotor, and floating sealing plates confronting the imperforate portions of the housing end walls to preclude flow of gas between the circumferentially spaced apertures.

Maintaining the clearance as slight as possible between these floating sealing plates and the axial end faces of the rotor, which is necessary for a good sealing effect, is difficult due to the thermal distortions occurring during the operation. Accordingly several proposals have been made to secure a good sealing. Many of these proposals are based on the idea of supporting the floating sealing plates on the rotor by means of rolling elements. The present invention also starts from this idea but constitutes a further development in which each of the floating sealing plates individually and independently of other floating sealing plates is biassed by a force urging it towards the rotor and is supported on the latter in rolling frictional engagement therewith. The drawback still remains that the life of the supporting arrangement is substantially injured as a result of the great stress caused by the hot flue gases as well as by the mechanically abrading dust particles.

The regenerative preheater according to the present invention avoids the disadvantages of the previous devices in that according to the present invention the rolling elements are each mounted independently of the other rolling elements so that each element may respond directly and independently of the others to the thermal distortions occurring in the rotor at the precise place adjacent a particular rolling element. Further in order to avoid injury to the rolling elements caused by the stress of hot flue gases and by mechanically abrasive dust particles each rolling element is firmly attached to its shaft while the bearings of the said rolling element shafts are located outside of the housing wall, away from the flowing media.

In order to better understand the invention, a number of embodiments are shown in the drawings by way of example.

FIG. 1 is an axial section of an air preheater rotating on a vertical shaft.

FIGS. 2 to 4 each show a specific roller bearing construction as applied to the floating sealing plates.

FIGS. and 6 illustrate in section and top view the application of the invention to a peripheral seal.

FIG. 7 shows a sealed off protrusion of the shaft of the rolling element.

In the construction shown in FIG. 1 the axial end faces of the rotor 1 are covered by the two sealing, or sector plates 2 and 2'. The means for suspending the ends of both plates adjacent the rotor axis are of known construction and therefore not specifically shown. They permit the plates to swing up and down and thus to adapt themselves to any distortion of the rotor. The stationary end walls of the housing 3 are denoted 4 and 4 respectively. At the outer end of the movable sector, or sealing plate 2 is a roller 5 which bears against an annular flange 6 3,246,686 Patented Apr. 19, 1966 ice which forms a radially directed extension of the axial end face of the rotor and is in rolling engagement with the flange 6 as the rotor revolves. The roller 5 is firmly attached to a shaft 7 which is journalled in the bearing device 8 outside the housing 3.

Similarly the lower sector plate 2 has a roller 5' which rolls on an annular flange 6 which forms a radially directed extension of the other axial end face of the rotor. The roller 5' is firmly attached to the shaft 7 which is journalled in the bearing device 3.

It will be clear that by using the necessary contact pressures and the rolling engagement, the correct positioning of the floating sealing plates 2 and 2' relative to the rotor end faces which they are adjacent is ensured. Irrespective of any distortions of the rotor itself the small clearance between the sector, or sealing plates and the end faces of the rotor 1 will be maintained at the values determined by the supporting means. Jamming, such as may occur when the two plates 2 and 2' are interconnected by coupling rods, is definitely excluded.

FIG. 2 shows only the edge portion of the rotor containing the heat transfer mass, that is, the upper part of the shell 11 of the rotor and the annular flange 12 attached thereto as well as the outermost end of one of the floating sealing plates 13. In a manner known per se the supporting is brought about by means of a wheel 14 rolling on the annular flange 12. However, it is important that this wheel is not rotatably mounted on its shaft 15 but firmly attached thereto. This rotary shaft protrudes from within the housing through the circumferential wall 16 of the housing. The protrusion can be tightly secured by mounting it in a pivotally mounted ball member 17. The bearing housing 18 of the rotary shaft 15 is in this manner provided outside of the housing. In this case the bearing is formed as a ball bearing mounted in bearing housing 18. A reliable seal is provided by means of a folding bellows 19. Hereby the necessary security is gained that in spite of the fact that the protrusion ex. tends through the wall of the housing no dust or other harmful particles can enter into the bearing housing 18. In order to keep the high temperatures away from the bearing a cooling disk 20 is provided on the shaft.

The roller supporting structure described above swings around the ball member 17; and it is biassed by a draw spring 21 in a clockwise direction urging the supporting wheel 14 firmly against the flange 12 of the rotor.

The bearing housing 18 is connected to the sector plate 13 by means of the rod system 22, 23, 24 in which a turnbuckle 25 allows optional change of the length of the connecting rod 22 and thus precise adjustment of the distance of the sector or sealing plate 13 from the end face of the rotor, viz. the width of the sealing clearance to a desired measure. It can be seen that as a deformation of the rotor is sensed by the roller 14 the sector plate 13 will also be adjusted in accordance therewith via the rod system 22, 23, 24. This second protrusion through the housing of the preheater, viz. through the wall 26 of the channel duct, is also provided with a gas tight seal by means of a folding bellows 27.

In the illustrated preheater the floating sealing plate 13 and the peripheral seal 28 connected therewith serve as sealing elements. The necessary sealing along the peripheral housing wall 26 of the channel duct is effected by a slot guide 29 and by spring strips 30. Alternatively, a bellows of heat resisting fabrics may be utilized.

In the embodiment according to FIG. 3 the bearing housing 31 of the roller 14 is rigidly mounted to a sector plate 13 rather than the housing 16 of the preheater as in the embodiment of FIG. 2. For this purpose the sector plate has an elongated arm 32 firmly attached thereto and protruding outwards through the circumferential wall of housing 16 of the preheater to the bearing housing 31. The shaft 15 is firmly attached to the roller 14 and extends through the wall 16 of the preheater. Since the elongated arm 32 serves as the carrier for the shaft 15 which is subjected to changes of position corresponding to the deformations of the rotor, a passage of predetermined size between plate 13 and the end face of the rotor is provided. Sealing is established by means of a folding bellows 19.

Also in this embodiment the possibility of precise adjustment is provided by connecting the bearing housing 31 with the carrier 32 by a movable holder 33. The roller 14 follows'the deformations of the flange 12 of the rotor and thereby causes the bearing housing 31 to follow in the same manner. This movement in turn acts through carrier 32 to cause the sector plate 13 to move upwards and downwards in the same manner.

A variation of the embodiment of FIG. 3 is shown in FIG. 4 where the parts corresponding to similar parts in FIG. 3 carry the same reference numerals. The difference lies in the means for adjustment and, more precisely, to the carrier 32 and carrier plate 33' on which the bearing means 31 are fastened. The carrier plate 33' can be moved upward and downward by means of an adjusting screw 33" to adjust the distance between the sector plate and the end face of the rotor. The passage openings in the housing wall for the carrier 32 and the shaft 15 are sealed off by means of a movable plate 19.

FIGS. and 6 illustrate that the principle of construction according to the invention is also applicable to the peripheral seal. For this purpose annular segments 40 are hinged by links on the sector plates 13 and also mutually to each other as shown in FIG. 6. The construction of the rollers can be designed according to FIGS. 2 to 4 so that those details are not illustrated here again. The sealing off of the sector plates and the segments, respectively, against the outer housing wall 16 can be effected by a lead asbestos cloth 41 or another flexible material of sufficient heat resisting properties.

Due to their linked joints connecting the separate annular segments, the segments can participate in all the movements of the rotor. However, since the external bearings produce a tilting moment the separate annular segments 40 are connected by means of rods 42, which are firmly attached thereto, to the inner section 43 by means of links 44. These rods 42, which may, for instance, consist of fiat iron bars, are attached to the annular segments 40. They both prevent the tilting and assure that the segments 40 are kept concentrical with the rotor axis.

In the first embodiment as in FIG. 2, springs 21 were chosen as an example of one means for urging the rollers towards the rotor. The use of such springs may be contemplated in any preheater having either a horizontal or a vertical axis. However, even in the vertical axis type weighting means may be employed.

Roller means at the inner section are generally not necessary since the adjustment may be performed easily by means of an external lever. Moreover the fluctuations at the inner circumference of the rotor are small. However, it is to be noted that inner sector bearing means with rollers corresponding to the principle of invention are possible.

FIG. 7 illustrates a seal that can be contemplated in all the cases heretofore elucidated. The purpose of this seal is to pass the shaft of the supporting roller 14 through the wall 16 of the housing while maintaining best possible sealing effect. For this purpose the shaft 15 is enclosed within a tube 50 that is welded to the wall 16. The free space between said tube 50 and the shaft 15, viz. the free flow section, is to be as small as possible. The roller 14 is formed with an annular groove into which the free end of the tube 50 projects somewhat and provides a labyrinth seal therein. In the same way a manifold labyrinth sealing is possible. The wheel is provided with deflector vanes 51, known per se, in order to drive off the gaseous medium from the free passage space and thereby prevent the entrance of dust mingled air. Finally a still further sealing 52 may be provided in the passage opening of the wall 16 and also a sealing disk 53. All the different sealing means may be employed in combination with each other to prevent all disturbing influences on the bearings.

The separate forms of sealing means contemplated above have only been treated in order to show that several possibilities of construction exist for obtaining a satisfying sealing; but obviously they need not all be utilized together.

The embodiments show that it is possible by use of the principles of construction herein described to apply the advantageous support by means of independently mounted roller elements within the space filled by the aggressive media, while removing the delicate bearing means from the perilous zone. As a result the life of the roller bearings is increased to an extent not possible in roller bearings of preheaters as heretofore disclosed.

We claim:

1. In a rotary regenerative heat exchanger of the type comprising a stationary housing structure providing a space enclosed between a peripheral wall and two axially spaced end walls, each end wall having spaced ports providing two separate flow paths for heat exchanging fluids to and from said space, a rotor containing regenerative material between two opposite end faces mounted to rotate in said space about a central axis between said housing end walls so that said regenerative material passes alternately through the two said flow paths, and a nonrotatable axially movable sector plate extending transversely of said space between each of said end walls and the adjacent confronting end face of said rotor, the combination with said rotor and said sector plates of separate means for independently regulating the position of each of said sector plates axially with respect to the adjacent end of the rotor as the ends of the rotor are caused to move axially due to distortion of the rotor caused by temperature differentials, each of said separate means comprising a sensing element in rolling contact with a different one of the opposite end faces of said rotor within said space and axially movable in accordance with the axial movement of the end portion with which the sensing element is in contact, yieldable biasing means for maintaining each of said sensing elements in contact with said rotor, a shaft element rigidly connected to each sensing element to rotate therewith, said shaft elements each extending radially with respect to the axis of the rotor, through an opening in the peripheral wall of said housing at a point axially adjacent the respective end of the rotor, said openings providing clearance for movement of said shaft elements axially with respect to the rotor axis, bearing means rotatably supporting each said shaft element outside said peripheral wall, each said bearing means mounted in bearing housing means movably mounted outside of the peripheral wall of said housing, connecting means for connecting each said bearing housing means with the radially outer portion of the sector plate which is located at the same end of the rotor, in predetermined fixed relationship, thereby causing each of the sector plates to move in relation to the said stationary housing structure in accordance with the movement of the axially adjacent sensing element to maintain substantially constant clearance between each sector plate and the respective confronting end face of the rotor.

2. Apparatus as defined in claim 1 in which sealing means is provided around each said shaft element for preventing flow of fluid through the openings in said peripheral wall.

3. Apparatus as defined in claim 1 in which a pivotal bearing carried by said stationary housing structure supports each said shaft element and said connecting means comprises an articulated linkage.

4. Apparatus as defined in claim 3 in which said linkage includes an element passing through a second opening in said stationary structure and a second seal is provided for sealing said opening.

5. Apparatus as defined in claim 3 in which said linkage includes means for adjusting the value of the clearance maintained by said linkage between each said sector plate and the respective confronting end of the rotor.

6. Apparatus as defined in claim 3 in which each end portion of the rotor confronting a sector plate is provided with an annular flange projecting radially from the circumference of the rotor, each sensing element being located and biased to bear against the side of the respective flange remote from said sector plate and said linkage is connected to said sector plate on the side thereof remote from said sensing element.

7. Apparatus as defined in claim 1 in which each sector plate is provided with an extension rigidly secured thereto and projecting through said stationary structure, the respective bearing means being rigidly secured to said extension and constraining the shaft carrying the sensing element to move axially relative to the axis of the said rotor in accordance with the movements of the sensing element.

8. Apparatus as defined in claim 7 in which the respective end portion of said rotor confronting a sector plate is provided with an annular flange extending radially from the periphery of the rotor, the confronting sector plate being provided with an aperture registering with said flange and said sensing element being carried by said shaft element on the side of said sector plate remote from the end of the rotor and projecting through said aperture to engage said flange.

9. Apparatus as defined in claim 7 in which said extension includes adjusting means for adjusting the clearance between the sector plate and the rotor.

10. Apparatus as defined in claim 7 in which a bellows type seal is provided for preventing leakage of fluid around said extension.

11. Apparatus as defined in claim 7 in which a sliding plate seal engaging said stationary structure is provided for preventing leakage around said extension.

12. Apparatus as defined in claim 1 in which at least one of the sealing means for preventing leakage through the openings in said stationary structure comprises a tube rigidly secured to the wall of said stationary structure and extending inwardly therefrom in spaced relation around said shaft, and a labyrinth type space seal between the inner end of said tube and said sensing element.

13. Apparatus as defined in claim 1 in which additional separately articulated and interconnected sector elements provide a peripheral seal at each end of the rotor.

14. Apparatus as defined in claim 13 in which flexible diaphragm-like sealing means is provided between the last mentioned elements and the wall of said stationary structure.

References Cited by the Examiner UNITED STATES PATENTS 1,930,586 10/1933 Delaval-Crow 306--36.1 2,055,071 9/1936 Eriksson -9 2,188,510 1/1940 Lapsley 308- 72 2,678,194 5/1954 Horney et al. 165-9 2,873,952 2/1959 Mudersbach et al. 1659 3,010,703 11/1961 Bellows et al 1659 3,053,586 9/1962 Osborne 30836.1

JAMES W. WESTHAVER, Primary Examiner.

CHARLES SUKALO, Examiner.

Claims (1)

1. IN A ROTARY REGENERATIVE HEAT EXCHANGER OF THE TYPE COMPRISING A STATIONARY HOUSING STRUCTURE PROVIDING A SPACE ENCLOSED BETWEEN A PERIPHERAL WALL AND TWO AXIALLY SPACED END WALLS, EACH END WALL HAVING SPACED PORTS PROVIDING TWO SEPARATE FLOW PATHS FOR HEAT EXCHANGING FLUIDS TO AND FROM SAID SPACE, A ROTOR CONTAINING REGENERATIVE MATERIAL BETWEEN TWO OPPOSITE END FACES MOUNTED TO ROTATE IN SAID SPACE ABOUT A CENTRAL AXIS BETWEEN SAID HOUSING END WALLS SO THAT SAID REGENERATIVE MATERIAL PASSES ALTERNATELY THROUGH THE TWO SAID FLOW PATHS, AND A NONROTATABLE AXIALLY MOVABLE SECTOR PLATE EXTENDING TRANSVERSELY OF SAID SPACE BETWEEN EACH OF SAID END WALLS AND THE ADJACENT CONFRONTING END FACE OF SAID ROTOR, THE COMBINATION WITH SAID ROTOR AND SAID SECTOR PLATES OF SEPARATE MEANS FOR INDEPENDENTLY REGULATING THE POSITION OF EACH OF SAID SECTOR PLATES AXIALLY WITH RESPECT TO THE ADJACENT END OF THE ROTOR AS THE ENDS OF THE ROTOR ARE CAUSED TO MOVE AXIALLY DUE DISTORTION OF THE ROTOR CAUSED BY TEMPERATURE DIFFERENTIALS, EACH OF SAID SEPARATE MEANS COMPRISING A SENSING ELEMENT IN ROLLING CONTACT WITH A DIFFERENT ONE OF THE OPPOSITE END FACES OF SAID ROTOR WITHIN SAID SPACE AND AXIALLY MOVABLE IN ACCORDANCE WITH THE AXIAL MOVEMENT OF THE END PORTION WITH WHICH THE SENSING ELEMENT IS IN CONTACT, YIELDABLE BIASING MEANS FOR MAINTAINING EACH OF SAID SENSING ELEMENTS IN CONTACT WITH SAID ROTOR, A SHAFT ELEMENT RIGIDLY CONNECTED TO EACH SENSING ELEMENT TO ROTATE THEREWITH, SAID SHAFT ELEMENTS EACH EXTENDING RADIALLY WITH RESPECT TO THE AXIS OF THE ROTOR, THROUGH AN OPENING IN THE PERIPHERAL WALL OF SAID HOUSING AT A POINT AXIALLY ADJACENT THE RESPECTIVE END OF THE ROTOR, SAID OPENINGS PROVIDING CLEARANCE FOR MOVEMENT OF SAID SHAFT ELEMENTS AXIALLY WITH RESPECT TO THE ROTOR AXIS, BEARING MEANS ROTATABLY SUPPORTING EACH SAID SHAFT ELEMENT OUTSIDE SAID PERIPHERAL WALL, EACH SAID BEARING MEANS MOUNTED IN BEARING HOUSING MEANS MOVABLY MOUNTED OUTSIDE OF THE PERIPHERAL WALL OF SAID HOUSING, CONNECTING MEANS FOR CONNECTING EACH SAID BEARING HOUSING MEANS WITH THE RADIALLY OUTER PORTION OF THE SECTOR PLATE WHICH IS LOCATED AT THE SAME END OF THE ROTOR, IN PREDETERMINED FIXED RELATIONSHIP, THEREBY CAUSING EACH OF THE SECTOR PLATES TO MOVE IN RELATION TO THE SAID STATIONARY HOUSING STRUCTURE IN ACCORDANCE WITH THE MOVEMENT OF THE AXIALLY ADJACENT SENSING ELEMENT TO MAINTAIN SUBSTANTIALLY CONSTANT CLEARANCE BETWEEN EACH SECTOR PLATE AND THE RESPECTIVE CONFRONTING END FACE OF THE ROTOR.

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