US2911202A - heater sealing device - Google Patents

Description

Nov. 3, 1959 c. E. TREWILER 2,911,202

AIR HEATER SEALING DEVICE Filed May '7, 1957 I,./ rwt' 1] l 0 13 1 (6 f 23. I 22 A F 1. l T 4 re H United States Patent AIR HEATER SEALING DEVICE Carl E. Trewiler, Niagara Falls, N.Y., asm'gnor to The Air Preheater Corporation, New York, N.Y., a corporation of New York Application May 7, 1957, Serial No. 657,583

4 Claims. (Cl. 257-269) The present invention relates to rotary regenerative air preheaters and more specifically to improved sealing means adapted to preclude the flow of fluid between rotary and stationary parts thereof.

A rotary regenerative air preheater has a rotor including a cylindrical shell joined to a rotor post by radial partitions that form compartments carrying heat transfer material that is alternately contacted by heating gas and air or other fluid to be heated. The rotor is surrounded by a rotor housing having end or sector plates formed with openings to provide passage for the gas and air. To prevent the mingling of the two fluids the partitions forming the rotor compartments are provided with radial seals and the rotor shell is provided with a circumferential seal that cooperates with stationary parts of the rotor housing to preclude fluid flow therebetween.

The invention is directed to an improved form of sealing arrangement for use in rotary regenerative preheaters which will be best understood upon consideration of the following detailed description of an illustrative embodiment of the invention when read in conjunction with the accompanying drawings in which:

Figure l is a sectional elevational view in diagrammatic form of a rotary regenerative air preheater embodying the present invention.

Figure 2 is an enlarged fragmentary view in section showing the relationship between the sealing members and the relatively rotatable members.

In the drawings the numeral designates the cylindrical shell of a rotor divided into sector shaped compartments by radial partitions 11 which connect it to a rotor post 12 that is in turn driven about its axis by a motor and reduction gearing 13. The rotor compartments contain regenerative heat transfer material in the form of closely spaced metallic plates 14 which first absorb heat from hot gases entering the preheater through a duct 15 from a boiler or other source to be discharged after passing over the heat transfer plates 14 through an outlet duct 16 to which an induced draft fan (not illustrated) is connected. As the rotor turns slowly about its axis the heated plates 14 are moved into the stream of air admitted through the duct 17. After passing over the plates 14 and absorbing heat therefrom the stream of air is conveyed to the boiler furnace or other place of use through an outlet duct 18.

A housing 20 enclosing the rotor 10 is provided at either end with end or sector plates 21 which are apertured at 22 and 23 to admit and discharge streams of air and gas flowing through the preheater in countercurrent relationship.

In order that the streams of gas and air may not intermix, radial seals 25 are provided along the end edges of the diaphragms and circumferential seals 27 and 29 are provided at the end edges of the rotor shell to wipe against confronting parts of the end plates so as to seal off the annular space 24 surrounding the rotor.

In accordance with the present invention therefore, the circumferential seal 27 comprises an upright annular channel member 26 positioned in the annular space 24 and fixed to the stationary housing member to provide a trough adapted to receive a cylindrical sealing member 28 extending completely around the rotor. The sealing member 28 is adjustably fastened to an annular wear member 32 by a series of circumferentially spaced bolts 33, while the wear member 32 is in turn spaced from the end edge of the rotor by an annular support means 34 which is flexible or extensible so that substantial deformation of the rotor shell may occur without forcibly displacing the wear member 32. One edge of the annular support means 34 is secured to the wear member 32 by bolts 33 while its axially opposite edge is secured to the end edge of the rotor shell 10. The wear member 32 serves also to link the circumferential sealing member 28 to the radial sealing member 25 so the edge thereof adjacent the end plate extends in unbroken continuity from the rotor post to the sealing member 28. A flange 35 at the outboard end of radial sealing member 25 permits joining the radial sealing member to the wear member 32 and sealing member 28 by means of the bolt 33. The inboard end of sealing member 25 comprises a radial projection 38 contacting a cylindrical camming means 42 which maintains the inboard end of the sealing member 25 closely adjacent the end plate.

The radial sealing member 25 may itself comprise a single leaf on one side of the diaphragm 11 or spaced leaves slidably abutting opposite sides of the diaphragm in accordance with standard sealing procedure. Driving means 44 fixed to the diaphragm 11 is adapted to preclude separation of sealing member 25 from the diaphragm while permitting limited axial movement.

Since the radial outboard end of the radial sealing means 25 is integral with the circumferential sealing member 28 the entire sealing apparatus is adapted to act as a unit. The circumferential member 28 and its integrally connected radial sealing members 25 are carried by a series of circumferentially spaced rollers 44 in brackets 46 which are supported upon the bottom of trough 26. By this arrangement should the rotor 10 become distorted or otherwise drawn away from the adjacent end plate the support means 34 would distend as required to permit the separation while the sealing means 25 would maintain a predetermined spacing from the end plate 21.

After assembly in the disclosed manner a quantity of liquid sealant is supplied to the channel 26 suflicient to submerge the end of sealing means to thereby preclude the flow of gaseous fluid between opposite sides thereof.

The type of sealant supplied to the channel 26 is not deemed critical since its required characteristics are dependent upon the operating conditions of the preheater. However, where substantial pressure differentials are involved liquid metals with a high specific gravity are preferred. By the use of auxiliary heating means 48 adjacent trough 26 metals such as lead which are solid at normal temperatures may be used. The heating means would be activated prior to rotation of the heat exchanger to reduce the sealant to a liquid state, while during normal operation heat from the hot gas passing through the heat exchanger would in most instances be sufficient to maintain the sealant in a liquid state so that supplementary heating may be discontinued.

Sealing means 29 adjacent the lower edge of the rotor 10 would not necessarily bear against the bottom of the liquid containing trough but would need be merely submerged in the liquid sealant to prevent fluid flow between opposite sides thereof, since the force of gravity would alone be suflicient to maintain a sealing relationship between the radial sealing member and its adjacent end plate. l s l While this invention has been described with reference to the embodiment illustrated in the drawing, it is evident that numerous changes may be made without departing from the spirit of the invention and 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 I claim is:

l. Regenerative heat exchange means or the like having a rotor including a cylindrical shell joined to a rotor post by radial partitions forming compartments that carry heat transfer material, and a housing surrounding the rotor in spaced relationship to provide an annular space therebetween, and end plates provided at opposite sides of the rotor housing with circumferentially spaced apertures to direct the flow of heating gases and air to and through the heat transfer material carried by the rotor; sealing means adapted to preclude the flow of fluid through .the space between the rotor and the rotor housing comprising an annular member fixed to said housing to provide an upright trough in said annular space; an annular sealing member extending axially into the trough formed by said annular means and supported thereby; a liquid sealant carried in said trough adapted to submerge the end edge of the annular'sealing member; radial sealing means adjacent each radial partition arranged to extend axially thereof into sealing relationship with the adjacent end plate; means integrally connecting the radial outboard end of the radial sealing means and the annular sealing member; and extensible means adapted to bridge the space between an end edge of the rotor shell and said annular sealing means to permit relative movement therebetween.

2. Apparatus having a rotor including a cylindrical shell joined to a rotor post by radial partitions forming compartments that carry material for contact by gaseous fluids and a housing surrounding the rotor to provide an annular space therebetween and end plates at either end opposite said rotor formed with circumferentially spaced openings defining passages for the flow of gaseous fluids to and through the rotor; radial sealing means adjacent the radial partitions adapted to contact imperforate portions of said end plates to preclude fluid flow therebetween; circumferential sealing means intermediate the rotor and rotor housing including an annular member fixed to said housing to provide an upright trough in said annular space; an annular sealing member extending axially into the upright trough and supported by the bottom thereof; a liquid sealant carried by said trough adapted to submerge the end of the annular sealing member supported on the bottom thereof; and means interconnecting the top of said annular member and the radial outboard ends of the radial sealing members whereby said radial sealing members are positioned in sealing relation with the imperforate portion of the end plate by the support provided the annular sealing member on the bottom of said trough.

3. Apparatus as defined in claim 2 having extensible means bridging the space between the rotor shell and edge of the annular sealing member adapted to permit relative movement therebetween.

4. Apparatus as defined in claim 2 including antifriction means intermediate the annular sealing member and the bottom of said trough.

References Cited in the file of this patent UNITED STATES PATENTS 2,744,731 Brandt May 8, 1956

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