US3010704A - Circumferential seal - Google Patents

Description

Nov. 28, 1961 J. T. EGBRT CIRCUMFERENTIAL SEAL.

Filed Feb. 9, 1959 United States Patent 3,010,704 CIRCUMFERENTIAL SEAL John T. Egbert, Wellsville, N.Y., assignor to The Air Preheater Corporation, New York, N.Y., a corporation of New York Filed Feb. 9, 1959, Ser. No. 791,959 7 Claims. (Cl. 257-269) The present invention relates -to rotary regenerative heat exchange apparatus or the like land particularly to improved circumferential seals adapted for use between the rotor and its enclosing housing.

In a rotary regenerative heat exchanger a cylindrical rotor has compartments that carry metallic heat transfer plates alternately between a low lpressure heating fluid and a high pressure fluid to be heated. The rotor is surrounded by a housing having end or sector plates formed with openings that provide for the ow of the heating fluid and the uid to be heated. In orderto preclude the flow of uids through the clearance space between the rotor and housing in a way to bypass the heat transfer material carried by the rotor it is customary to provide the rotor with circumferential seals that bear against the sector plates or other stationary parts of the housing.

Since the end plates and other stationary parts of the housing are subjected to constant extremes of temperature they tend to distort more than the enclosed rotor that is constantly turning between the heating uid and the uid to be heated whereby the rotor is never permitted to attain the extreme temperatures of either fluid and it is therefore not subject to the same extremes of thermal deformation as is the housing.

In such view the presen-t invention contemplates an improved circumferential sealing means of novel form that seals against -a portion'of a rotary heat exchanger which is subject to a of distortion.

Moreover, the present invention contemplates a sealing means that utilizes available iluid pressure to maintain abutting parts thereof in a fluid-tight relationship. These and other improvements will be better understood upon consideration of the following detailed description when read in conjunction with the drawings in which:

FIGURE l is `a sectional elevation in digrammatic form of a rotary regenerative yheat exchanger embodying the present invention.

FIGURE 2 is -a fragmentary `sectional elevation showing the detailed vconstruction of an improved sealing de vice.

FIGURE 3 is a fragmentary sectional elevation showing the detailed construction of a slightly varied form of sealing device.

In the drawings the numeral Y designates the cylindrical shell of a rotor that is divided into sector shaped compartments by radial partitions connecting it to a rotor post 12 which is driven by a motor and reduction gear not illustrated. 'I'he rotor compartments contain regenerative heat exchange material usually in the form of heat absorbent plates that are spaced apart to permit flo-w there through of the heating iluid and the fluid to be heated.

The heating uid enters the heat exchanger through a duct 13 `connected to a boiler or other source of heat and is dischmged, after passing over the heat absorbent material, through an outlet duct 15 to which an induced draft fan (not shown) is usually attached. As the rotor turns slowly about its axis, the heated heat exchange material is ymoved into the stream of air or other uid to be heated that is admitted through a duct 17. After passing over the hot heat absorbent material and absorbing heat therefrom the stream of air is conveyed to a boiler furnace or other place of use through a duct 19.

3,010,704 Patented Nov. 28, 1961 ICC A housing 14 enclosing the rotor 10 is provided at either end with end or sector plates 16 that are apertured tov In,

permit the various tluids to ilow through the rotor. order that the fluid streams will not bypass the rotor and cumterential seals that bridge the space therebetween.

In accordance with this invention therefore, the oircumferential seals comprise an 'annular base member 20 that is mounted on the end or sector plate 16 in axial alignment with the end edge of the cylindrical shell of rotor 10. An annular sealing means 22 is positioned in the space between the end edge of the rotor shell 10 and the annular base member and is `adapted to be moved axially into engagement with the edge of the rotor by compression `springs 24. To provide for a tuid tight expansion wall between the annular base member 20 and the annular sealing means 22, a pair of concentric backing rings 26 are rst secured to opposite sides of the base member to provide therewith an annular U-sfhaped channel. Then, to enclose completely the annular space between the sealing member 22 and the base memberY 20, a pair of concentric walls 32 are secured to opposite sides of the sealing member 22 `and adapted to extend axially into lateral abutment with the inner walls of rings 26. The backing rings 26 are constructed of material having suicient body tand strength to be substantially inflexible while the cooperating rings 32 are comparably thin and ilexible\in order that they may be laterally flexed into abutment with the adjacent surface of the backing rings 26 by -a slight excess of pressure within the enclosure. Such an excess of pressure within the annular enclosure 28 is obtained by :admitting high pressure iiuid through an opening 34 in that portion of the inner wall of the env ber 22 and the wear surface 25 prevents relative rota-- Itional movement therebetween. Similarlyya series` of driving pins y42 secured circumferentially around thev backing plate 26 4in alignment with slots l4'3 in the ad jacent flexible wall 32 preclude relative rotational movementrtherebetween while permitting a limited degree of axialV movement to compensate-for axildistortion Iofv the rotor or housingrstructure and abrasion ofthe seal-y ing surface. v j,

ATo compensate for excessive wear, the sealing member 22 isV provided with a wear surface Y25 having-pre-. determined characteristics that'enhance its wear resist' ance "and sealing ability. When conditions warrant; the

thickness of the surface may be greatly increased as at 25A of FIGURE 3 to permit long periods of service without the necessity of suspending operation for the renewal of the wear surface. A further modification illustrated in FIGURE 3 relates to mounting the biasing spring 24A for the annular sealing member outside the housing on a bracket 27 whereby the force of an externally mounted spring 24A may be directed Vagainst the axially disposed rod 29 and the edge of the annular sealing member 22A.

While this invention has been described with reference to the embodiments illustrated in the drawing it is evident that numerous changes may be made without departing from the spirit of the invention, and it is in-y tended that allrnatter contained in the accompanying drawings shall be interpreted as illustrative only and not in a limiting sense. j

Y .Y 3 What I claim is:

1. Regenerative heat exchange apparatus o r the like including a rotor having a cylindrical rotor shell; a housing surrounding the rotorl provided at opposite ends with sectorl plates having spaced apertures that direct high and low pressure fluids through spaced portions of fthe rotor; circumferential sealing means at opposite ends of therotor; adapted to preclude fluid iiow between the rotor and rotor housing, said sealing means comprising an annular. base member aligned with the rotor shell and xed to the sector plate; an annular sealing shoe intermediate the annular base member and rotor shell; means adapted to bias the annular sealing shoe into contacting relationship with'l the Vend edge of the rotor shell, concentric backingrings xed to opposite sides of the annular base to provide an annular channel therebteween; concentric exible Walls secured to opposite sides of the sealing shoeV adapted to laterally abut the inner walls of the annular channel to provide an annular enclosure, saidV enclosure having `an opening in one Wall thereof adapted to admit high pressure fluid to the enclosure to actuate the exible Walls into continuous contact with the backing members.

2. Regenerative heat exchangeapparatus or the .like including a rotor having a cylindrical rotor shell; a housing surrounding the rotor provided at-opposite ends with sector plates having spaced apertures to direct high and low pressure llluids through spaced portions of the rotor;

circumferential sealing means at opposite ends of the rotor adapted to preclude iluid flow between the rotor Y and rotor housing, said sealing means comprising an annular base aligned with the rotor shell and secured to the sector plate; an annular sealing member intermedi- -ate the annular base and the rotor shell; concentric backing rings iixed to opposite sides of the annular base toY provide an annular channel therebetween; concentric 1 Vwalls xed to opposite sidesof said annular sealing memher ,adapted to extend axially `thereof into lateral abutment with the inner sides of said channel Vto form therewith an annular enclosure; springmeans adapted to bias the annular sealing member into axial abutment with the end edge of the rotor shell; and means in an inner Wall of said enclosure admitting high pressure iluid thereto l to effect Ylateral contact betweenrthe concentric walls and low pressure uids through spaced portions of the rotor;V

circumferential sealing `means at opposite ends,V of the rotor adapted to preclude uid ilow between the rotorY and rotor housing,v saidsealing means comprising an annular base aligned with the rotor shell and secured to the sector plate; an -annular sealing member intermediate theannular base and the rotor shell; concentric backing rings xedto opposite sides ofthe annular base to vform therewith an annular channel; concentric walls xed to opposite sides of the annular sealing member adapted to extend axially thereof into lateral abutment with the inner walls Vof the annular channel to form therewith an annular enclosure, the Walls of said annular enclosure having an opening therethrough permitting the ingress of high pressure fluid to effect a lateral contact the concentric walls and the backing rings; spring means arranged to bias the annular sealing member into axial abutment with the end edge of the rotor shell and driving means extending between laterally abutting walls adapted to permit relative axial movement therebetween while precluding relative rotational movement about the rotor axis.

Y 4. Regenerative heat exchange apparatus or the like including a rotor having a cylindrical rotor shell; a housing surrounding the rotor provided at opposite ends with spaced apertures that direct high and low pressure fluids through spaced portions of the rotor; circumferential sealing means at opposite ends of the rotor adapted to preclude fluid ow between the rotor and rotor housing, said sealing means comprising an annular base aligned with the rotor shell and secured to the sector plate; an annular sealing shoe intermediate the annular base and the end edge of the rotor shell; concentric backing rings xed to opposite sides of the annular base to form therewith an annular channel; concentric walls xed to opposite sides of said annular sealing shoe and adapted to extend axially thereon.c into lateral abutment with the annular channel to form a completely enclosed annular enclosure, one of said walls having an opening to permit the flow of high pressure into the enclosure; driving means extending betwn laterally vabutting walls adapted to permit relative axial movement therebetween while precluding relative rotational movement about the rotor axis; and spring means arranged tobias the annular sealing member into axial abutment with the end edge of said rotor shell.

5. Regenerative heat exchangeV apparatus 'as defined in Y claim 4 wherein the spring means biasing the sealing shoe into contact with thefend edge of the rotor is positioned Within the contines of said annular enclousre. 6. Regenerative heat exchange apparatus as defined in claim 4 Whereinvthe axial force of the spring means is transmitted to the sealing shoe by a driving rod slidably mounted in the annular base. y

7. Regenerative heat exchange apparatus as'deiined in claim 4 wherein the backing rings are laterally rigid and the adjacent concentric Walls are .relatively ilexible to permit their lateral conformity.

References Cited in theifile of this patent UNITED STATES PATENTS i [2,692,760 Flurschutz l Oct. 26,1954 2,740,614 Hammond et al. Apr. 3, 1956 FOREIGN PATENTS 665,187 Great Britain Jan. 16, 1952

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