US2517512A - Flexible circumferential seal for rotary heat exchangers - Google Patents

Description

Aug. 1, 1950 A. J. TIGGES ETAL FLEXIBLE CIRCUMFERENTIAL SEAL FOR ROTARY HEAT EXCHANGERS Filed July so, 1947 FROM FORCED DRA FJT FAN TO INDUCED DRAFT FAN ILQ.

AIR

HEATING 6A5 TTORMEY Patented Aug. 1, 1950 somer HEAT E Braddon, wellsville, N; Y assignors (to The'Air 1 Y 1;Breheater;Corporation, Nfiwt r e iiil a 1 s (cram-c A'regenerative air'prel'ieater has a rotormade up of a cylindrical shell joined to'a rotorpost by radial partitions which form compartments carrying heat transfer material thatis alternately contacted by heating gas and air or other fluid to be heated as the rotor turns about its axis toedispose the plates in a stream of"hea ting gas and then in a stream of air or otherfluid. The rotor is enclosed within a housing whichfis provided opposite the ends of therotor' with sector plates formed with apertures for the passage of the *fiuids 'to and from the rotor. It is customary to mount circumferential sealing strips" on the end ":edges o fthe shell to wipe againstfthe end or "sector plates so that the streams *of gas and air are detailed description of an illustrative embodis mentlof the invention when; read in conjunction with the accompanying drawings [in which: I

. lligurel is a sectional elevational viewin diagrammatic form of a rotary regenerativeair preheater embodying the present invention;

Figure 2 is a fragmentary sectional view on an enlarged scale showing the cooperative sealing means carried by the rotor shell and end plates of the housing in accordance with the present invention; and

Figure 3 is a fragmentary elevational view showing part of the sealing strip carried by the rotor shell.

The heat exchanger apparatus comprises a rotor mounted within a housing Hi to be driven at slow speed through its centrally located rotor post I I by a motor and reduction gearing I2. The rotor consists of a cylindrical shell l3 interiorly divided into a plurality of wedge or sector shaped compartments by radial partitions M of which one is shown in Figure 2, these partitions securing the shell to the rotor post. Circumferentially extending partitions or diaphragms mounted concentrically with the rotor post H subdivide the sector-shaped compartments into a number of sections, each of which contains a plurality of metallic heat transfer plates l6 maintained in spaced? relation to provide passages therebetween'for the flow o'fgas and air axially of-*thrrotor; it

Opposite each-end of the' rotor a stationary sectoriplate' ll closing the end of housing In is piovided withbpenings l8, IQ for theflowof gas and air. The airrand gas openings [8, Win the sector plate are separated by imperforate portions whichare at least as wide as the maximum width of the sector-shaped compartments of the fi dtorsofthat radial seals 20 (Figure 2) on the partitionsdd by wiping against the imperforate "parts of thesector plates I! prevent cross flow of-air and gas between their respective passages. *Hotgases from a boiler 01' other source of waste heat 'are admitted to'the rotor from a duct '23 and'passingover the heattransfer material :Ififlare discharged into' a duct 24 leading to an induced draft fan, not shown. Air or other fluid =to=be heatedis supplied under pressure by a forced draft fan,- notshown, through a duct 25 to th air side of the preheater and after being heated by contact with the plates [6 is conveyed through the duct 26 to the boiler furnace or other point of uses The construction described above isconventional v 1 l *EToassurex that the streams of gas and. air pass over the heat transfer material IS in the rotor and to minimize'leakage of gas and air, by-passing the rotor through the space 21 between the Triton 'she1l' l3" and housing 10 circumferential sealsrare customarily mounted on the end edges cf the rotor shell l3 to contact the opposing faces of the end or sector plates H.

In accordance with the present invention the circumferential sealing means includes annular or ringlike members 30 approximating the rotor in diameter and mounted on the sector plates l1 opposite both ends of the rotor. Each annular seal 30 is formed with a U-shaped groove 3| racing and alined with the adjacent end edge of the rotor shell l3. To cooperate with the channellike seals 30 the rotor shell l3 carries sealing strips 32 projecting from the end edges of the rotor shell into the grooves 3| of the sealing members so that they may be maintained in contact with one of the sealing surfaces 33 or 34 of the latter by pressure diiferential across the seal strip. The part of a seal strip 3| traversing the gas passage with the rotor would be drawn by the suction of the induced draft fan to bear against the inner wear surface 34 of the seal while on the air side of the exchanger the seal strips would bear against the outer wear surfaces 33 of the rings 30, being forced against the latter by the positive air pressure produced by the forced draft fan. The seal strips 3| thus act as curtains alternately in contact with one or the other wear surfaces 33, 34 of the annular members 30 to positively close off the gas and air passages from the space 21 between the rotor shell l3 and the surrounding housing 110.

The seal strips 32 are of a pliable material such as glass fabric or other suitable material which is flexible enough to permit free movement. across. the space between the sealing surfaces 3'3 and '34; This space is wide enough to allow for any eccentricity of the rotor without causing undue rubbing of the seal strips. The seal strips 32 are prefer ably made in two layers a, and b and the portions of each layer projecting from the edge-of rotor shell [3 are provided at intervals with slots 35 to improve the flexibility; these slots are staggered in the two layers as appears in Figure 3 to'avold leakage. 4

The wearing surfaces 33 and it on the annular channel members 31! are preferably of simianterial as will resist corrosion and wear. A heavy chromium plated surface on these seals is considered preferable. These rings are also preferaibly made in segments so that portions may readi- 13/ be replaced when necessary.

What is claimed is.

1. In a regenerative air pre'hea-ter or the like transfer material, and a housing surrounding the rotor and provided opposite the ends of the latter with sector plates formed with apertures for the flow or heating gases and air to and through the rotor under the action of induced and iorceddrait fans; annular channel shaped sealing members mounted on the inner races of said sector plates oppositeithe rotor in .alinement with the endedscs ol the cylindrical shell of the rotor; and flexible sealing strips mounted on the end edges of said rotor shell and projecting from the end edgesof said shell into contact with one wall of said channel when traversing the gas passage and-with the opposite wall of said channel when traversing-the air passage when swung into contact therewith by the differential pressure existing across said 1 strips. In a regenerative air preheater or the like having passages for a heating gas and :air or other gaseous fluid to be heated, a rotor-made up or a cylindrical shell joined to a rotor post by radial partitions forming compartments that carry. heat transfer material, and a housing surrounding the rotor and provided opposite the endsofthe latter with sector plates formed with apertures for the flow of heating gases and air tdfand through the rotor under the action of induced. and forced draft fans; annular channel shaped sealing members mounted on the inner races of said sector plates opposite the rotor and formed with generally U-shaped grooves facing andin alinement with the end edges of the cylindricalshell of the rotor; and sealing strips of pliablematerial adapted to flex when subjected toj-fluidpressure mounted on the end edges of said shell and projecting from the end edges of aid shell into the grooves of said annular ch nnels for cooperation with one wall of said groove-when traversing the gas passage and with thejj opposite wall of said groove when traversing theairpassage and brought into contact there- I H by-the differential pressure existing across saidf'strips.

iii In a} regenerative air preheater or the like having passages for a heating gas .and air or other gasegos fluid to bev heated, a rotor made up of a cylindrical shell joined to a rotor post by radial partitions forming compartments that carry heat transiemnaterial, and a housing surrounding the rotorzandprovidedopposite the ends of the latter with; ctor. plates formed with apertures for the flower-heating gases and air to and through the rotor under the action of induced and forced drait 'lgans; annular sealing members of a diamete approximating that of the rotor mounted on the casing in positions confronting the end edges'of'the rotor shell; and flexible sealing strips carried by the ends of the rotor and maintained in contact-with said annular sealing members by the nressure differential produced across said sealing-strips by said tans.

.1; i ALEXANDER J. TIGGES.

D. BRADDON.

REFERENCES CITED The -iollowing references are of record in the file ofthis patent:

STATES PATENTS Number; Name Date 1493.38,. Lansdell a Mar. 31, 1874 2;0.55,0Il .1. Eriksson Sept. 22. 1936 1347,8511 Waitkus May .2, 1944

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