US3379240A

US3379240A - Element basket for regenerative heat exchangers

Info

Publication number: US3379240A
Application number: US630132A
Authority: US
Inventors: Thomas L Woolard; Kenneth O Bellows
Original assignee: Air Preheater Co Inc
Current assignee: Alstom Power Inc
Priority date: 1967-04-11
Filing date: 1967-04-11
Publication date: 1968-04-23
Anticipated expiration: 1985-04-23
Also published as: NL6804238A; DE1751034A1; ES352638A1; IE31823L; NL152976B; FR1559525A; BE713578A; GB1174513A; IE31823B1

Description

April 23, 1958 T. 1 WOOLARD ETAL ELEMENT BASKET FOR REGENERATIVE HEAT EXCHANGERS Filed April ll, 1967 United States Patent O ABSTRACT OF THE DISCLOSURE A heat storage segment for a rotor of a rotary regenerator is formed of a U-shaped basket, a rigid arcuate pressure member, and resilient heat sto-rage plates. The platesr are placed in the basket and compressed using the pressure member which is then welded to the basket thus formin-g a unitary segment for the rotor,

An element arrangement for rotary regenerative heat exchange apparatus in which resilient plate type elements are collectively deformed sufficiently to make available the spring action of the deformed elements to maintain the elements continuously tight within the heat exchanger or component thereof so as to preclude lateral movement or Shu-cking thereof during normal operation.

In rotary regenerative heat exchange apparatus a mass of. heat exchange material is commonly comprised of a packed series of element plates which are positioned in a hot gas passageway to absorb heat from a stream of hot gases passing therethrough. As the plates become heated they are moved into a spaced passageway for cooler air where the heated plates then transmit 4their heat to the cooler air or other gases passing therethrough.

The apparatus of a rotary regenerative heat exchanger is usually disposed in a disk-like manner on a vertical axis such that normally there is imparted to each of the element plates a degree of natural stability whereby movement or vibration of each element plate is apparent only when a blast of high pressure cleaning air or steam is blown into Ithe space between the element plates to remove objectionable deposits therefrom. If however the apparatus is disposed about a horizontal axis each increment in the rotation of the rotor causes the element plates thereof to be agitated or move anamount which is dependent upon the tightness with which they are originally packed in the apparatus. Inasmuch as continuous agitation of the plates elects their premature breakage or failure, a serious condition resolves around the fracture of element plates by nearly continuous exing from their continuous agitation. To alleviate the problems associated with this condition, a plurality of element plates are frequently packed tightly in open-ended bundles before being assembled according to plan into the rotor of heat exchange apparatus. Although they may be packed tightly when assembled, corrosion and erosion of the element plates during operation of the apparatus tends to weaken and loosen them until normal rotation of the rotor agitates them increasingly in an amount suicient to bring about their ultimate failure and destruction.

The present invention therefore contemplates an arran-gement whereby the bundles of element plates are held in continuously tight relationship by the spring action of the element plates themselves, even after they have been seriously worn away by the forces of corrosion and erosion, so as to substantially preclude their destruction by failure from fatigue.

The invention may be more readily understood when viewed in conjunction with the accompanying drawing in which:

FIGURE 1 is a sectional view of a rotary regenerative heat exchanger in accordance with the invention.

ICC

FIGURE 2 is a sectional elevation of the heat exchanger as seen from line 2 2 of FIGURE 1.

FIGURE 3 is a perspective View of basketed element plates assembled according to the invention.

FIGURE'4 is a sectional view of the plane basketed element plates before being subjected to compression.

As illustrated in the drawin-g, a housing 10 enclosing a rotor 12 containing a mass of heat exchange material is contacted by a stream of hot air or other gases entering the housing through an inlet duct 16 and is exhausted to an outlet duct 18 after having traversed the heat exchange material in the compartments therebetween. Cool air or other" gas entering the housing through an inlet 22 is also exhausted to an outlet -duct 24 after having traversed the heat exchange material lying in the compartment therebetween. While the gas is being directed through its passageway the rotor is continuously being rotated about its horizontal axis Iby a drive means 20 in order that each part of the heat exchange element contained in the rotor is alternately subjected to the hot gases and cooler air. The heat exchange material carried by the rotor comprises essentially a mass of heat absorbent plates 26 formed with projections or spacers that provide uid ow passageways therebetween for the ow of hot and cool gas. The plates are asembled in an orderly array and positioned in a U shaped basket 27 or the like that firmly holds the plates in .predetermined relationship in order that they may be easily handled as an integral heat exchange mass when arranged in the rotor of a rotary heat exchanger.

Each bundle of element plates comprises a pair of arcuately contoured substantially

rigid pressure members

28 and 30 arranged in essentially concentric aligrunent within the U shaped rotor basket 27 and compressed against the spring action of the intermediate sheets 26. When the

arcuate pressure members

28 and 30 are urged together to the extent that the plates 26 therebetween are bent substantially concentric therewith, the plates are held in their bent positions by welding or otherwise bonding the member 30 to the rotor or basket structure 27. For example, the

arcuate plates

28 and 30 may =be compressed together against the spring action of the plane yresilient element sheets 26 therebetween whereby the sheets 26 are forced into an arcuate -form and held permanently so by welding along the joints 34 that connect the pressure members to the basket structure.

Additionalsupport bars 36 may be used to securely hold togetherin fixed relation the

pressure plates

28 and 30 at locations which are suitably selected; The support bars 36 may be streamlined or otherwise contoured to provide a minimum of resistance to gases owing through the element basket in contacting arrangement therewith. Weldments at 37 attaching each support bar 36 to the basket structure provide a suitable arrangement for permanently securing the members 28v and 30 together with the element plates 26 therebetween continuously bent or otherwise deformed so as to present a constant spring action against the pressure members 28 and 30' tending to move them further apart and thus permit the curved resilient plates 26 to lie in a plane, uniiexed position.

Care must be taken so that the plates 26 when bent or deformed between pressure mem-

bers

28 and 30 are not forced to exceed their limit of elasticity commonly termed the elastic limit whereby the element plates will not then expand against adjacent plates and thus produce a tightening elfect on other plates adjacent thereto.

When properly compressed between the two arcuate or otherwise deformed

pressure plates

28 and 30, the resilient sheets 26 will be forced into a similar configuration so that each sheet 26 will become, in effect, a spring means abutting adjacent sheets tending to hold them in a vise-like grip so there can be no agitation or shucking of the element plates effecting their early destruction.

In preparing a bundle of regenerative type element sheets for a basket in agreement with the heretofore disclosed description, that part of the closure comprised of the rotor structure or basket with curved plate 28 is rst assembled either vertically or horizontally on a satisfactory loading table or the like. The support bars are preferably located at this time at the edge of the curved plate 28 to provide an intermediate space into which the element plates 26 `are placed.

The outer arcuate pressure member 30 is then placed loosely upon the assembly in concentric alignment with arcuate plate 28 and compressive forces are applied to one or both of the

pressure members

28 and 30 compressing the element sheets 26 therebetween and forcing them to take the curvature of concentric arcs similar to the

pressure members

28 and 30.

At such time the outer plate is permanently xed by welding at 34 before the external forces are removed therefrom.

While this invention has been deined 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. It is accordingly 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.

We claim:

1. The method of making an element bundle for a heat 30 exchanger which comprises the steps of placing in lateral abutment a plurality of resilient element sheets, compressing said plurality of resilient element sheets Ibetween a pair of similarly disposed curved pressure members until the resilient sheets assume a curved form similar to that of said pressure members, and connecting together said pressure members while the resilientsheets are similarly curved whereby the resilient element sheets serve as a composite spring means effecting continuous contact with said pressure members.

2. The method of making an element bundle for a heat exchanger as defined in claim 1j wherein the elemen sheets are curved within their elastic limit. -v

3. The method of making an element bundle for a heat exchangeras dened in claim 1`wherein the element sheets are curved to an arcuate shape substantially concentric with said pressure members.V

4. An element bundle for a heat exchanger comprising a plurality of resilient element sheets in lateral abutment, curved pressure members at opposite ends of said bundle of element sheets essentially in concentric alignment one with another and means compressing the resilient element sheets between the concentric pressure members to impart to the resilient element sheets acurvature similar to that of said pressure members whereby each element sheet acts as a spring which resists deformation.

5. An element bundle for -a heat exchanger as defined in claim 4 wherein the pressure members at opposite ends of said bundle of element sheets are substantially rigid with respect to the resilient element sheets therebetween.

References Cited UNITED STATES PATENTS 6/1965 Brandt 165-9 X 4/1967 Krumm et al. 165--10