US3166119A

US3166119A - Radial seal for rotary regenerative heat exchanger

Info

Publication number: US3166119A
Application number: US102725A
Authority: US
Inventors: Richard W Bellows
Original assignee: Combustion Engineering Inc
Current assignee: Combustion Engineering Inc
Priority date: 1961-04-13
Filing date: 1961-04-13
Publication date: 1965-01-19
Anticipated expiration: 1982-01-19
Also published as: GB1007559A

Description

Jan. 19, 1965 R. w. BELLOWS RADIAL SEAL FOR ROTARY REGENERATIVE HEAT EXCHANGER Filed April 13. 1961 Jilin INV EN TOR.

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IIIIIII main 3,166,119 RADIALSEAL FOR ROTARYVREGENERATHVE HEAT EXCHANGER "Richard W. Bellows, Weilsvilie, N.'Y., assignor, by mesne assignments, to Combustion Engineering, Inc, a stock corporation of Delaware Filed Apr. 13, 1961, 'Ser. No. 182,725 2 Claims. (Cl. 165-?) The presentinvention relates generally to heat exchange apparatus and particularly to an improved radial sealing V arrangement for use between relatively rotatable parts of a rotary regenerative heat exchanger.

In rotary regenerative heat exchange apparatus of the type herein defined, a cylindrical rotor has compartments carrying heat transfer material which is first exposed to a stream of heating fluid and then, as the rotor is turned about its axis, the compartments of heat transfer material are exposed to air or other fluid to be heated passing through a spaced passage where-the heated heat transfermaterial impartsabsorbed heat to the air. The rotor is surrounded by a housing having end or sector plates formed with openings that provide for the flow of heating gases and air therethrough. To prevent mingling of the two fluids, radial partitions that form the, rotor compartments are provided with radial sealing members adapted to wipe against the imperforate portions of the sector plate.

Conventionally a rotor for a heat exchanger assumes a dished configuration during operation dueto the differential of expansion between the hot end-"that lies adjacent the inlet for the heating fluid and the cold end that lies adjacent the inlet for the cooler fluid to be heated. Since the radial sealing members are usually secured to the end edges 'of the radial partitions insuch a manner that they are forced to conform to the, thermal deformation of the radial partitions to which they are attached, the sealing relationship between the sealing members and the adjacent end plate is easily disturbed to permit extensive leakage of fluid therebetween.

Thus it maybe seen that sealing means must be readily, adaptable to varying clearance conditions if .they are to serve their intended function to eifectivelylimit' the leakage of fluids between relatively movable surfaces. Motivated by this information, radial sealing means have else they have been pivoted to the partitions in order that they might be biased into a sealing arrangement with the confronting surface of an adjacent end plate. Such an fecting a practical arrangement for transforming a thermal change into an actuating force of a magnitude sufficient to move the sealing means towards or away from a cooperating sealing surface.

. The chief object of this invention therefore is to pro- -vide an arrangement .of sealing means that moves to accommodate a shifting in the sealing relationship between a rotor and its surrounding housing. 7

A further object of the invention is to utilize as the actuating force for an adjustable sealing means the same thermal force that causes the initial distortion of the rotor.

This invention therefore provides for a specific arrange- 28 in order that itmay be rotated slowly about its axis 1 by the motor and reducing 'gear arrangement. The'rotor been mounted independent from the radial partitions or ment that uses an available change of temperature in a rotary regenerative heat exchanger to .rna'intain sealing means inga predetermined sealing relationship a wide range of temperature variation.

These and other objects or" my invention more readily apparent when read in conjunction with the drawing in which:

FIGURE 1 is a sectional elevation of a rotary.regenerative heat exchanger involving the inventidnyand FIGURE 2 is an;en1argedsectionalelevation showing the upper and lower radial seals thatcomprisefthe invention.

ing a cylindrical shell 12 divided into sector shaped compartments by radial partitions14 that .are connected'to a central rotor post16 which is turned about its axis by means such as, amotor and reduction gearing arrangement shown at 18. The rotor compartments contain a mass of heat absorbent material, usually in the form of spaced metallic plates, which first absorb heat from the heating fluid entering the heat exchanger through a duct 22 that is connected to a boiler or other source of heat. After passing over the heat absorbentmaterial and transmitting heat-thereto, the hot gases aredischarged through an outlet duct 24 to which an induced draft fan (not illustrated) is usually attached. As the rotor turns slowly about its. axis, the heated plates "are moved into a stream of air'or other fluid to be heated entering the heat exchanger through a duct 26 where their heat to the air. J 1

The rotor is rotatably'mounted on a support bearing is supported for rotation within a cylindrical housing 34 that is provided at opposite ends with end or sector plates 36 which are apertured at circurnferentially spaced locations 38 and. 40 to admit and discharge the heating fluid and'the fluid tobe heated. In .order that thefluid traversing the heat exchanger. do not intermix, the endplates have i'rnperforate portions between apertures 38land 4t) that are at least as great in circumferential extent'as one rotor compartment. Radial seals 44 which are 'mourited on the end edge of radial partitions 14 are adapted to rub against or in closely spaced relation with the com fronting surface of the adjacent sector plate to eflective ly isolate acomplete 'sectorial compartment between apertures and thus preclude the by-passing of the radial partitions. Other sealing means 46 known as circumferential seals extend around the end edge of the rotor to prevent.

fluid by-passing the rotorby flowing through the annular clearance space 48 between the rotorand housing.

In accordance with the present invention, the radial seals 44 comprise plane metallic leaves that are pivotally secured at their inner ends by-a pivot pin 52 to an end mit movement toward or away from the con-fronting face of the adjacent end plate in accordance with the relai tive distortion of the rotor andfthe rotor housing' A thermal actuatingbar 54 is positioned substantially parallel to each sealing leaf with its radial inner end secured to the rotor structure at a point 56 adjacent the pivot pin 52 in order that its outboard end may be free to expand or contract radially in' accordance with normal variations in temperature. A bell-crank 58 is pivotally secured to the radial partition at a-point intermediate the outboard ends of the radial seal 44 and the actuating bar 5410 permit linking one arm of the bell crank to the expansion Patented. J at. 19;, 19.6 5 throughout will become 7 In the drawings the numeralltl designates a rotor hav the plates give up bar 54 while an angularly displaced arm of the bell crank is linked'to the adjacent end ot'thesealing means 44.

The exact configuration of the bell crank 58 is not deemed critical inasmuch as the angular displacement or the relative length" of its arms may be varied to best comply with existing conditions to providea predetermined axial movement of the sealing means when the length of the expansion bar 54 isaltered by a thermal variation. Similarly, an additional linkage means as illustrated by numeral 60 may be used at either end of the rotor when necessary to translate a radial movement of bar 54 to an axial movement of the adjacent seal44.

To provide a suitable actuating force to the sealing 'means,.the thermally responsive actuating bars 54 are necess'arilyformed of material having a coeflicient 'of'exa pansion different from that of the radial partitions to which they are secured. For the application illustrated in the drawing wherein the upper end of the rotor lies adjacent the inlet :for the heating fluid or at the hot end of the rotor, the thermal expansion bars must have a coefficient of expansion greaterthan' that of the :radial partition to which they are attached in" order that the seals will move upward when the rotor turns downward in response to a differential of expansion. With a reversal of flow conditions wherein the hot end of the rotorv matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative only and not in a limiting sense.

I claim: I 1 A I p 1. Regenerative heat exchange'apparatus having a rotor that includes a cylindrical'rotor shell joined to a rotor post by radial partitions to form'sectorial compartments that carry a mass of heat absorbent material, and I a cylindrical housing. surrounding the rotor provided at opposite ends thereof -withend plates including imperforate portions located between circumferentially' spaced apertures that direct the flow of heating fluid and" fluid to be heated through the heat absorbent material carried by the rotor; radial sealing means bridging the space between an end edge of each radial partition and the confronting face of an adjacent end plate adapted to preclude fluid flow therebetween, said sealing means comprising a leaf member laterally abutting an endedge 0f the radial partitions and having one end pivotally at- V tached thereto to permit movement of a free end toward and away from the adjacent end plate; a bell crank pi-votally attached to the radial partition adjacent the free. end of the leaf member; thermal expansion means having one endafiixed to said partition and anopposite end piv- Y otally attached to an arm of said bell crank; and a pivotal linkage between a spacedarmof said bell crank and said free end of the leaf memberv arranged to transform radial movement of said thermal expansion means into an axial force moving the sealing leaf relativeto its adjacentend plate.

2 Regenerative heat exchange apparatus having a rotor that includes a cylindrical rotor shell joined to a rotor post by radial. partitions to form sectorial compartments that carry a mass of heat absorbent material, and a cylindrical housing surrounding the rotor provided at op posite ends thereof with end plates including imperforate portions located between circumferentially spaced apertures that direct the flow of heating fluid and fluid tobe heated through the heat exchange material carried by the rotor, radial sealing means bridging the space between an end edge of each r adial partition and the confronting face of an adjacent end plate to preclude fluid flow therebeto said radial partition adjacent the rotor post and its outboard end pivotally secured to an arm of the bell crank, and a pivoted linkage connecting a spaced arm of said bell crank and the outboard end of said radial sealing leaf whereby radial movement of said thermal expansion means moves the sealing means axially with respect to its adjacent end plate.

References Cited inthe file of this patent I UNITED sTATEs PATENTS 2,650,074 Ballard Aug. 15,1953 2,873,952 -Mudersback A Feb. 17, 1959 3,088,518 Rayburn May 7, 1963 FOREIGN PATENTS 500,682 Great Britain .Feb. 14, 1939

Claims

1. REGENERATIVE HEAT EXCHANGE APPARATUS HAVING A ROTOR THAT INCLUDES A CYLINDRICAL ROTOR SHELL JOINED TO A ROTOR POST BY RADIAL PARTITIONS TO FORM SECTORIAL COMPARTMENTS THAT CARRY A MASS OF HEAT ABSORBENT MATERIAL, AND A CYLINDRICAL HOUSING SURROUNDING THE ROTOR PROVIDED AT OPPOSITE ENDS THEREOF WITH END PLATES INCLUDING IMPERFORATE PORTIONS LOCATED BETWEEN CIRCUMFERENTIALLY SPACED APERTURES THAT DIRECT THE FLOW OF HEATING FLUID AND FLUID TO BE HEATED THROUGH THE HEAT ABSORBENT MATERIAL CARRIED BY THE ROTOR; RADIAL SEALING MEANS BRIDGING THE SPACE BETWEEN AN END EDGE OF EACH RADIAL PARTITION AND THE CONFRONTING FACE OF AN ADJACENT END PLATE ADAPTED TO PRECLUDE FLUID FLOW THEREBETWEEN, SAID SEALING MEANS COMPRISING A LEAF MEMBER LATERALLY ABUTTING AN END EDGE OF THE RADIAL PARTITIONS AND HAVING ONE END PIVOTALLY ATTACHED THERETO TO PERMIT MOVEMENT OF A FREE END TOWARD AND AWAY FROM THE ADJACENT END PLATE; A BELL CRANK PIVOTALLY ATTACHED TO THE RADIAL PARTITION ADJACENT THE FREE END OF THE LEAF MEMBER; THERNAL EXPANSION MEANS HAVING ONE END AFFIXED TO SAID PARTITION AND AN OPPOSITE END PIVOTALLY ATTACHED TO AN ARM OF SAID BELL CRANK; AND A PIVOTAL LINKAGE BETWEEN A SPACED ARM OF SAID BELL CRANK AND SAID FREE END OF THE LEAF MEMBER ARRANGED TO TRANSFORM RADIAL MOVEMENT OF SAID THERMAL EXPANSION MEANS INTO AN AXIAL FORCE MOVING THE SEALING LEAF RELATIVE TO ITS ADJACENT END PLATE.