US2766970A

US2766970A - High pressure circumferential seal

Info

Publication number: US2766970A
Application number: US381437A
Authority: US
Inventors: Edward P Horn
Original assignee: Air Preheater Co Inc
Current assignee: Alstom Power Inc
Priority date: 1953-09-21
Filing date: 1953-09-21
Publication date: 1956-10-16
Anticipated expiration: 1973-10-16

Description

Oct. 16, 1956 E. P. HORN HIGH PRESSURE CIRCUMFERENTIAL SEAL 3 INVENTOR.

'. Ecro/a Fwy/d FAQ/p BY? Q E United States Patent F HIGH PRESSURE CIRCUMFERENTIAL SEAL Edward P. Horn, Weilsville, N. Y., assignor to The Air Preheater Corporation, New York, N. Y., a corporation of New York Application September 21, 1953, Serial No. 381,437

6 Claims. (Cl. 257-6) The present invention relates to heat exchangers and particularly to an improved circumferential seal for use between a rotor and an enclosing housing of a rotary regenerative preheater or like apparatus.

In a rotary regenerative heater a cylindrical rotor has compartments carrying metallic heat transfer plates which as the rotor turns are first exposed to the heating gases and then disposed in the air passage to impart the absorbed heat to the incoming air. The rotor is surrounded by a housing having end plates formed with openings to provide for the flow of gas and air over the heat transfer plates. In order to preclude the flow of gas or air through the clearance space between the rotor and the housing Without passing over the heat transfer material, it is customary to provide the rotor with circumferential seals that bear against the sector plates or other stationary parts.

The present invention contemplates improved circumferential sealing devices of novel form and will best be nnderstood upon consideration of the following detailed description of several illustrative embodiments thereof when read in conjunction with the accompanying drawings in which:

Figure 1 is a sectional elevation showing the flexible circumferential seal of this invention as attached to the annular rotor shell.

Figure 2 is a sectional elevation of a modified seal mounting shown with reference to the housing and end plate flange.

Figure 3 is a perspective drawing of the corrugated seal of this invention showing a splice plate used to join abutting sections of the corrugated sealing element.

In the drawings the numeral designates the cylindrical shell of a rotor which, as it rotates, carries a mass of heat exchange material 12 from hot to cold sides of the heat exchanger in well known fashion. Surrounding the rotor is the housing 20, having an annular flange 24 secured to its circumferential edge and lying in engagement with the annular flange 26 of the connecting plate which forms one end plate for the housing and to which the gas and air ducts are connected. Extending circumferentially with respect to the peripheral edge of the rotor shell 10 and bridging the space between said peripheral edge and the flange 26 of the connecting plate is the circumferential seal 30 which embodies this invention.

Seal 30 is a contact seal mounted on and firmly attached to the rotor shell 10 by means such as pins 32 (Figure 1) or bolts 34 (Figure 2). The seal rotates with the rotor and presses against the inner surface of flange 26 of the connecting plate to preclude leakage of gas or air through the annular space 35 between the rotor shell 10 and the housing 20.

The sealing member 36 comprises a plurality of armately formed sectorial sections forming a complete circle around the peripheral edge of the rotor shell. Each section is formed from a metallic sheet corrugated longitudinally in order to provide a member compressible in a 2,766,970 Patented Oct; 16, 1956 ice v 2 direction axial of the rotor in its location between the rotor shell and the connecting plate flange.

In order to provide a circumferential sealing member that reduces leakage to a minimum between adjacent or contiguous sections thereof, a splice plate 38 (Figure 3) having corrugations mating with those of each corrugated seal section may be fitted at each joint. A splice plate 38 is preferably tack welded to one end of each corrugated sealing section prior to its final assembly with other similar sections into a composite annular sealing member on the edge of the rotor shell 10. Besides serving as a barrier to the passing gases, the corrugated splice plates 38 serve as st'iifeners to assist bracing the edge of the sealing members 39 against the inner face of the connecting plate flange. That portion of the sealing member which is held against the inner face of the end plate flange 26 is reinforced at 36 with a material of such hardness that it will not cause excessive wear of the connecting plate flange but will itself take the wear.

Figure 1 shows the seal mounting as including an annular angle member 40 that is welded to the end edge of the rotor shell, preferably through its extent. The vertical portion 44 of the angle member 40 provides a supporting backing for seal 30, while the horizontal portion 46 thereof provides a base for mounting a plurality of circumferentially spaced driving pins 44. The pins 44 are spaced apart at intervals which provide a minimum of two spaced driving pins for each corrugated sealing section 30. Each section 30 of the corrugated sealing member has openings 48 in its lower corrugation spaced to coincide with the intervals of pins 44 in the base 46 of angle member 40.

In assembling a seal of this type, individual sections thereof are inserted into the preheater housing through the air or gas openings in the connecting plate. Prior to its insertion, each corrugated sealing section is laterally compressed suflicient to enable it to enter the space between the pins 44 and the end plate flange 26, and on clearing the pins in a position above the latter with the apertures 48 alined with the pins 32, the sealing members are permitted to expand, thereby forcing the apertured corrugation into engagement with the pins 44 and the extreme corrugation at the opposite end against the inner face of the end plate flange 26. Corrugated sealing sections are placed in continuing arrangement until they collectively form a composite circular sealing ring around the peripheral edge of the rotor shell 10.

In assembling the individual arcuate sealing section 30 into an annular seal around the edge of the rotor shell, each section is inserted through the gas or air opening in the connecting plate, then placed in position on the rotor shell and fixed thereto by bolts. The sealing segments are sized so that they must be slightly compressed before fitting into the space between the end edge of the rotor shell and the connecting plate flange, whereby each seal will be capable of expanding, as well as contracting, to compensate for variations in spacing between said members as may be caused by thermal distortion of the rotor and its surrounding housing.

When it is deemed desirable to remove a single corrugated sealing section which appears to have worn, one follows the reverse of the assembly procedure described in the preceding paragraphs.

The annular circumferential seals of the type herein disclosed find application at either end of the rotor shell, since the spring action inherent in each corrugated member maintains a corrugated fold thereof at all times in contact with its adjacent end plate flange, whether standing in an upright position on the upper edge of the rotor shell 10 or in an inverted or dependent position from its lower edge.

The novel sealing arrangement herein described pro- 1 3 vides an efficient sealing'device forruse'between rotors and rotor housings of apparatus subject to substantial amounts of thermal distortion. Because the flexible sealing sectors 30 are not fixed together but overlap freely they are at all times-free to enlarge or contract to or compress with axialvm'ovement ofthe rotor, both types of change in the rotor being due to thermal expansion and contraction when the rotor is in service. The sealing sections are self-adjusting and automatically attain the positionin which they effect the best seal. The sealing sections may be readily removed and replaced through the air and gas openings in'the end plates, and replaceaccommodate changes in rotor-diameter, and to-expand ment of a single sealing section 'Will in no way afiect:

the continuity of the composite j sealing memb'er.-

What I claim is: V I V 1'. Asealing means for precluding fluid flow between relatively'rotatable members of an apparatus, said sealing means comprising a series of longitudinally corrugated segments of arcuate form collectively comprising an annular sealing member bridging the space between said relatively I rotatable members.

2. Ac ircumferential sealas defined in claim 1 wherein each corrugated sealing segment has fixed to an end portion thereof a corrugated reinforcing member extending beyond said end portion tooverlap the adjacent end portion of an adjoining corrugated sealing segment.

3. A circumferential seal as definedin claim 1 wherein each corrugated sealing segment has fixed to its radially outer face-adjacent an end portion thereof a corrugated reinforcing'member extending beyond said endportion to overlap the adjacent end portion of an adjoining corrugated sealing segment. V 1 4. Circumferential sealing apparatus as defined in claim 1 wherein each sealing "segment'is engaged by axially disposed pins located. in the peripheral end edge;

of one of the relatively rotatable members.

5. Circumferential sealing apparatus as defined in claim 1 wherein each sealing 'segment is positioned on axially disposed pins located in the peripheral end edge of one of the relatively rotatable members.

s. Sealing 'meansmd'apted to preclude' fiuid' new be: tween axially spaced fixed 'andir'elatively' rotatable housing members comprising an annular angle member fixed to the rotatable niember and disposed axially thereof 7 in the space between said-housing members with a leg 1 portion of said angle member extending toward said fixed housing member; a plurality of pin-like protuberances integral with the other leg'of saidangle member in axial alignment with said rotatable member; and a compressible sealing member .apertured to fit 'over the pins: andarrangedto bridge the space between the base of said angle member and said fixed member.

References Cited in the file of this'pa tent 500.682 Great Britain Feb. 14,