US3073384A

US3073384A - Rotor construction

Info

Publication number: US3073384A
Application number: US858975A
Authority: US
Inventors: Edward P Horn; Mary A Ballard
Original assignee: Combustion Engineering Inc
Current assignee: Combustion Engineering Inc
Priority date: 1959-12-11
Filing date: 1959-12-11
Publication date: 1963-01-15
Anticipated expiration: 1980-01-15

Description

E. P. HORN ETA. 3,073,384

Ro'roR' CONSTRUCTION Filed Dec. 11,. 1959 2 In 2@ V f/f/ 2K I T ill, i I1'l f l l lili M m l 24K IW INVIA/76,93:

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3,073,384 RTGR CONSTRUCTION Edward P. Horn, Wellsville, N.Y., and Clayton A. Ballard, deceased, late of Wellsville, NSY., by Mary A. Ballard, administratrix, Wellsville, N.Y., assignors, by mesne assignments, to Combustion Engineering, Inc., a corporation of Delaware Fiied Dec. 11, 1959, Ser. No. 858,975 2 Ciaims. (Cl. 165-9) The present invention relates to heat exchangers of the rotary regenerative type, and particularly to an improved structural arrangement that substntially eliminates the form of thermal deformation in the rotor of such heat exchangers known as turn-down.

In a rotary regenerative heat exchangers a cylindrical rotor has compartments carrying heat transfer plates which, as the rotor turns are tirst exposed to hot gases and are then disposed in an air passage to impart the absorbed heat to the air passing therethrough. The rotor is surrounded by a housing having end or sector plates formed with openings therein to provide for the passage of gas and air. To prevent mingling of gas and air, radial partitions or diaphragms forming the rotor compartments are provided with radial seals that wipe against the imperforate portions of the sector plates.

In heat exchangers of this type the radial partitions extend between the rotor post and the rotor shell in a plane parallel to the rotor axis in such a manner that they are subjected to the full temperature gradientthat exists in the lluids between their inlet and outlet openings. temperature gradient across a solid plate produces a differential of expansion causing distortion of the plate known as rotor turn-down. Since the radial seals are frequently attached to the axially spaced edges of each partition it is evident the clearance space between the partitions and the confronting sector plates may vary so that an efficient sealing relationship therebetween becomes extremely diilicult if not impossible to maintain.

Attempts have been made to overcome this difficulty by the development of flexible or otherwise adjustable sealing means that respond to the variable clearance space between the partitions and confronting sector plates, however such means have not proved entirely satisfactory and fluid leakage between the relatively rotatable parts of a rotary regenerative air preheater still comprises a major problem. With this in view, the present invention is directed to an improved structural arrangement of a radial partion for such a heat exchange device that substantially precludes detrimental thermal distortion of the rotor thereof.

This and other objects of our invention will be more apparent when read in conjunction with the drawing in which: l

FIGURE '1 is a side elevation in section showing the fabrication of our improved diaphragm.

FIGURE 2 is a sectional View of FIGURE 1 as seen from line 2 2.

In the drawings the numeral designates a cylindrical rotor housing for a rotary heat exchanger which is enclosed at opposite ends by ported sector or end plates 14. Centrally positioned within the housing is a pivotally mounted rotor post 16 supporting a rotor that is divided into sector shaped compartments by a series of radial partitions that extend out to a cylindrical rotor shell 22. The radial partitions are xedly attached at their respective ends to the rotor post 16and rotor shell 22 to provide an integral rotor structure. The rotor is turned on its axis by a motor" connected thereto through a suitable reduction gearing arrangement not here illustrated. Each rotor compartment carries regenerative heat ex- Such l Patented Jan. 15, `1963 change material in the form of metallic plates 20 'which rst absorb heat from the hot gases entering the preheater,

` and then as the rotor turns slowly about its axis, the heat exchange material is moved into the stream of cold air to transmit heat thereto. After passing over the heated heat exchange material and absorbing heat therefrom, the heated air is directed to a boiler combustion chamber or other point of usage.

In order that the streams of gas and air may not bypass the heat exchange material carried by the rotor by flowing thru the annular clearance space 19 between the rotor shell and the rotor housing a circumferential seal 24 is provided, and radial seals 26 are generally attached to the end edges of the radial partitions to engage the confronting surfaces of the end plate 14 to preclude fluid flow thru any clearance space therebetween.

In accordance with the present invention the radial partitions each comprise two support members 1S at axially spaced ends of the rotor post 16 attached thereto and adapted to extend radially outward to the rotor shell 22. These support members are imperforate and may be formed from a plain metallic sheet or they may be variously stiifen'ed to provide the strength lnecessary to support the heat exchange element Z0 and the rotor shell 22. Each support member 18 extends axially a distance d that is but a small portion of the total height h of the rotor; it being necessary that sucient structural strength and rigidity be imparted to the several support members that they be capable of supporting the mass of heat exchange elements carried in the rotor compartments.

Each pair of axially spaced members 18 is joined by a sealing member to preclude fluid flow between compartments on opposite sides of each radial partition. This sealing member may take the form of a thin membrane 28 extending from the rotor post to the rotor shell and bonded to or in other sealing relationship along each radial edge with one of the support members 1S. If the membrane 28 is bonded integrally to the structural members 18 it is of major importance that the membrane have insufcient rigidity to provide any resistance to the relative thermal deformation of the axially spaced support members 18.

In packing the several rotor compartments with heat exchange material a clearance space 32 is provided around each support member 18 whereby the fluid flowing past each of said members is permitted to assume a substantially constant temperature. By this arrangement the temperature imparted to each support member is similarly constant across its depth d so that any temperature variation in the members 18 will result only in their deformation in a radial direction and freedom from undesirable turn-down.

In operation tluid owing through therotor tends to v impart heat carried thereby to the heat exchange element 20 and also to the rotor parts including the spaced support members 18 and the intermediate membrane 28. Since each member 18 is subjected to a nearly constant fluid temperature the thermal gradient across d of each element is substantially eliminated and any temperature variation thereof will result only in its harmless deformation in a radial direction. By limiting the deformation of the radial partition to expansion in a radial direction the sealing relationship between

seals

24 and 26 and the adjacent face of sector plate 14 will be maintainedconstant Aand uid leakage therebetween will be maintained at a minimum level.

This is a continuation in part of application Serial No.

post, a mass of heat transfer material, rigid radial partitions extending between the rotor post and rotor shell to form a series of sectorial compartments for the support of the heat transfer material, each of said radial partitions formed to include a pair of axially spaced. rigid radial support members xedly attached at their respective ends to the rotor post and cylindrical rotor shell, and a nen-rigid sealing membrane yieldingly carried between said radial support members to preclude the flow of uid between opposite sides of said radial partitions.

2. Regenerative heat exchange apparatus having a rotor including a rotor shell and a central rotor post, a mass of heat transfer material, axially spaced rigid radial support members xedly attached at opposite ends thereof to the rotor post and rotor shell to form a series of sec- References Cited in the le of this patent UNITED STATES PATENTS 1,843,252 Toensfeldt Feb. 2, 1932 2,287,777 Boestad June 30, 1942 2,818,934 Pennington Jan. 7, 1958

Claims

1. REGENERATIVE HEAT EXCHANGE APPARATUS HAVING A ROTOR INCLUDING A CYLINDRICAL ROTOR SHELL AND A CENTRAL ROTOR POST, A MASS OF HEAT TRANSFER MATERIAL, RIGID RADIAL PARTITIONS EXTENDING BETWEEN THE ROTOR POST AND ROTOR SHELL TO FORM A SERIES OF SECTORIAL COMPARTMENTS FOR THE SUPPORT OF THE HEAT TRANSFER MATERIAL, EACH OF SAID RADIAL PARTITIONS FORMED TO INCLUDE A PAIR OF AXIALLY SPACED RIGID RADIAL SUPPORT MEMBERS FIXEDLY ATTACHED AT THEIR RESPECTIVE ENDS TO THE ROTOR POST AND CYLINDRICAL ROTOR SHELL, AND A NON-RIGID SEALING MEMBRANE YIELDINGLY CARRIED BETWEEN SAID RADIAL SUPPORT MEMBERS TO PRECLUDE THE FLOW OF FLUID BETWEEN OPPOSITE SIDES OF SAID RADIAL PARTITIONS.