US3314472A - Element basket for heat exchanger - Google Patents

Description

April 18, 1967 KRUMM ET AL ELEMENT BASKET FOR HEAT EXCHANGER Original Filed Aug., 25, 1964 United States Patent 3,314,472 ELEMENT BASKET F OR HEAT EXCHAN GER Eugene D. Krurnm and Norman Casagrande, Wellsville, N.Y., assignors to The Air Preheater Company Inc., a corporation of Delaware Continuation of application Ser. No. 391,841, Aug. 25, 1964. This application Apr. 6, 1966, Ser. No. 540,778 7 Claims. (Cl. 16510) ABSTRACT OF THE DISCLOSURE A matrix for a rotary regenerative heat exchanger in which a series of laterally adjacent plates are biased together by a laterally acting spring means in a manner that precludes their relative movement and thus prema ture failure from abrasion or vibratory strain.

This is a continuation of application Ser. No. 391,841, filed Aug. 25, 1964, and now abandoned.

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

The apparatus is usually disposed about a vertical axis such that there is imparted to each element plate substantial stability whereby detrimental movement or vibration of each element plate is possible only when a blast of high pressure cleaning air or steam is blown through the spacing between 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 to be agitated an amount which is dependent upon the tightness with which they are packed in the apparatus.

Consequently, a serious condition resolves around the fracture of element plates by failure from fatigue thatis caused by their nearly continuous agitation. To alleviate the problems associated with this condition, bundles of element plates are frequently packed tightly in open ended bundles before being assembled according to a preconceived plan into the heat exchange apparatus. Although packed tightly when assembled, corrosion and erosion of the element plates during operation of the apparatus tends to weaken and loosen them until the normal rotation of the rotor agitates them suflicient to bring about their destruction.

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

The invention may be more readily understood when reviewed in conjunction with the accompanying drawings in which:

FIGURE 1 is a sectional view of a rotary regenerative heat exchanger embodying the invention,

FIGURE 2 is a view of the invention as seen from line 22 of FIGURE 1,

FIGURE 3 is a perspective view of a basket having a single curved loading plate,

FIGURE 4 is an enlarged sectional view of an element basket having loading plates at opposite ends thereof.

As illustrated in the drawing the heat exchange apparatus comprises essentially a housing enclosing a rotor 12 containing a mass of heat exchange material 14 that is contacted by a stream of hot gases entering the housing through an inlet duct 16 and exhausted through an outlet duct 18 after having traversed the heat exchange material in the compartments therebetween. Cool air or other cool gas entering the housing through an inlet 22 is exhausted through an outlet duct 24- after having traversed the heat exchange material lying in the compartment therebetween. While the gases are being directed through their respective passageways the rotor 12 is being rotated about its axis by drive means 20 in order that each portion of heat exchange element contained therein may be alternately subjected to the hot and cool gas.

The heat exchange material carried by the rotor comprises a mass of heat absorbent plates 26 formed with projections that provide flow passageways therebetween for the flow of hot and cool gas. The plates are assembled in an orderly array and positioned in a metallic basket that firmly holds the plates in a predetermined relationship in order that they may be easily handled as an integral element mass when arranged in the rotor of a heat exchanger.

Each basket essentially comprises a pair of spaced end. plates held together by side or tension straps. More particularly the end plates comprise a pair of curved spring plates 28 and 29, or a single curved spring plate 28 and a plane plate 27 between which are packed the heat absorbent plates 26. The end plates are held together tightly by tension straps 32 in order that the element plates 26 are similarly held in a tight relation. The tension straps 32 are preferably flanged along the longitudinal edge lying at the edge of a basket assembly to provide a retaining surface for the heat absorbent plates 26 carried within the basket.

In making a basket assembly a plane plate 27 or a formed plate 2 is first positioned on a suitable working surface. If a formed plate 29 is to be used it is placed on the working surface with its convex surface facing upward. Straps 32 are then secured to a pair'of opposing straight edges of said plate to provide in efiect an openended rack onto which may be stacked a quantity of formed plates 26. When a predetermined quantity of plates has been thus assembled on the open rack, a second convex spring plate is positioned upon the stacked plates 26 with its convex side facing downward and in abutment with the topmost plate of the assembly. A compressive force is then applied to the entire bundle assembly sufficient to cause the spring plates to flex and the undulations or other formations of the plates 26 to be compressed sufiicient to enable them to lie in a tightly abutting relationship.

A compressive force of from 8 to 12 pounds per square inch applied normal to the plane of the assembled plates is usually considered adequate to bring all plates into abutment as desired when applied to a type of undulated element plates as illustrated. However, more or less force may readily be applied to plate assemblies of various stiffness to produce the desired degree of element packing.

While the compressive force is still being applied to the plate assembly, side straps 32 are welded to the straight edges of the upper spring plates 28. After the side straps have been bonded integrally to the sides of the plate 28, the compressive force is released to permit the normal expansive force of the corrugated element plates in combination with the normal expansive force of the somewhat compressed spring plates 28 and 29 to hold the element plates 26 in a permanently tight relationship.

After a set of element plates has been in service for some time there may be a tendency for the plates to corrode and erode away due to their being in continuous contact with corrosive dust laden gas. When such conditions obtain and the plates thus begin to occupy less space within their particular basket assembly, the spring plates 23 and 29 expand to occupy more space in order that the element plates 26 may be held at substantially the same degree of tightness throughout long periods of operation.

Accordingly, the element plates will be held continuously tight and rotation of the rotor about its axis, even if disposed horizontally, will not cause the element plates to shift or move relative one to another. Moreover steam or air blown into the open ends of an assembled mass of plates to remove deposits of dust therefrom will not induce any perceptible vibrational effect upon them and the destruction of plates due to fatigue failure is substantially eliminated.

Thus, While the 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 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. Rotary regenerative heat exchange apparatus having a rotor including a central rotor post and a concentric rotor shell joined by radial partitions to provide a series of sectorial compartments therebetween, a plurality of heat absorbent element bundles carried in the compart ments of the rotor, said element bundles each comprising a plurality of stacked element plates, a spring loading means laterally abutting each bundle of stacked plates, and means combining the loading means with the element bundles to permit the spring action of said loading means to maintain the plates in a continuously compressed relation.

2. Rotary regenerative heat exchange apparatus having a rotor including a central rotor post and a concentric rotor shell joined by a series of radial partitions to provide a series of sectorial compartments therebetween, a housing surrounding the rotor having inlet and outlet ports adjacent spaced ends of the rotor adapted to simultaneously direct a heating fluid and a fluid to be heated through spaced compartments of the rotor, means for rotating the rotor about its axis, bundles of heat absorbent element packed in the compartments of the rotor, said bundles each comprising a plurality of stacked plates having flow passageways therethrough for the flow of the heating fluid and the fluid to be heated, a spring loading means adjacent each element bundle, and tension means combining each spring loading means with the element plates of each element bundle whereby the plates are held continuously tight in their predetermined relationship.

3. Rotary regenerative heat exchange apparatus having a rotor including a central rotor post and a concentric rotor shell joined by a series of radial partitions to provide a series of sectorial compartments therebetween, a 6

housing surrounding the rotor having inlet and outlet ports adjacent spaced ends of the rotor adapted to simultaneously direct a heating fluid and a fluid to be heated through spaced compartments of the rotor, means for rotating the rotor about its axis, bundles of heat absorbent element packed in the compartments of the rotor each comprising a plurality of stacked element plateshaving flow passageways therethrough for the flow of the heating fluid and the fluid to be heated, a curved. loading plate adjacent each end of the element bundle, and means joining the curved loading plates at spaced ends of the element bundle whereby intervening element plates are held in a continuously tight relationship.

4. Rotary regenerative heat exchange apparatus having a rotor including a central rotor post and a concentric rotor shell joined by a series of radial partitions to provide a series of sectorial compartments therebetween, a housing surrounding the rotor having inlet and outlet ports adjacent spaced ends of the rotor adapted to simultaneously direct a heating fluid and a fluid to be heated through spaced compartments of the rotor, means for rotating the rotor about its axis, bundles of heat :absorbent element packed in the compartments of the rotor comprising stacked element plates having passageways therebetween for the flow of the heating fluid and the fluid to be heated, spring loading means at the ends of each bundle, and a strap means affixed at opposite ends thereof to said spring loading means to provide an enclosure for the stacked element plates.

5. Rotary regenerative heat exchange apparatus as defined in claim 4 wherein said strap means lying adjacent the ends of said bundles of heat absorbent element are provided with lateral flanges that overlap the end edges of said element plates to preclude their longitudinal movement within the bundle.

6. An element bundle for a heat exchanger comprising a plurality of stacked element plates, curved loading means abutting each bundle of stacked element plates, and means combining the spring loading means with the ele ment bundle to permit the spring action of said loading means to maintain the element plates in a continuously compressed relation.

7. An element bundle for a heat exchanger comprising stacked element plates having passageways therebetween for the flow of a heating fluid and a fluid to be heated, curved spring loading means laterally abutting said bundle, and means aflixed to said spring loading means to provide an enclosure substantially normal to said passageways for the stacked element plates that maintains the element plates in a continuously compressed relation.

References Cited by the Examiner UNITED STATES PATENTS 2,579,212 12/1951 Stevens et al. 10 3,191,666 6/1965 Brandt 165-9 X ROBERT A. OLEARY, Primary Examiner.

M. A. ANTONAKAS, Assistant Examiner.

Claims (1)

1. 6. AN ELEMENT BUNDLE FOR A HEAT EXCHANGER COMPRISING A PLURALITY OF STACKED ELEMENT PLATES, CURVED LOADING MEANS ABUTTING EACH BUNDLE OF STACKED ELEMENT PLATES, AND MEANS COMBINING THE SPRING LOADING MEANS WITH THE ELEMENT BUNDLE TO PERMIT THE SPRING ACTION OF SAID LOADING MEANS TO MAINTAIN THE ELEMENT PLATES IN A CONTINUOUSLY COMPRESSED RELATION.

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