US3372736A - Rotary regenerative heat exchangers - Google Patents

Description

March 12, 1968 BRANDT ETAL ROTARY REGENERATIVE HEAT EXCHANGERS 3 Sheets-Sheet 1 Filed Sept. 29, 1965 IA/VE/VToKS HERBERT BRANDT Mn GERHARD KRITZLEK March 12, 1968 B N T ET AL 3,372,736

ROTARY REGENERATIVE HEAT EXCHANGERS Filed Sept. 29, 1965 3 Sheets-Sheet 2 if 50 I 15 ll Illlll |lll ll TIHH 'IIILLII Ill l-Z8 may F35 280 2 4 /zaa ll ITHH Hill] ||1F|| n llll [11 12 M. INVENTORS HERBEKT BRA T /v9 GEKHARD FEITZLEK ROTARY REGENERATIVE HEAT EXCHANGERS Filed Sept. 29, 1965 3 $heets-5heet 5 JlN EA TOES HEKBEKT BRfim/DT GERHARD KRITzLEg United States Pate'nt hhce 3,372,736 Patented Mar. 12, 1968 6 Claims. cl. 1ss

ABSTRACT OF THE DISCLOSURE The number of gas-tight joints between the walls and plates in each sector of the regenerator of rotary regenerative heat exchangers is reduced by constructing at least some of the arcuately disposed partitions of smaller axial length than the regenerator. The structure also reduces the total length of sealing edges at the ends of the regenerator.

This invention relates to rotary regenerative heat exchangers of the kind in which a substantially cylindrical regenerative heat exchange member, hereinafter referred to as a regenerator, is disposed between gas inlet means, gas outlet means, air inlet means, and air outlet means whereby hot gas may be led to the regenerator and passed in an axial direction through passages in the regenerators so as to give up heat from the hot gas to a mass of plates or tubes which form the passages, and upon relative rotation between the regenerator and some or all of the gas and air inlet and outlet means, air may be led to the regenerator and passed in an axial direction through the said passages in the regenerator so as to pick up heat from the mass.

The regenerator may be stationary or it may rotate. In either event, it is desirable that the ends of the regenerator which are swept over by the ends of some or all of the gas and air inlet and outlet means should do so in such manner that there is a minimum amount of leakage of air or gas between the various means, and usually this is effected by sealing members, sometimes spring-pressed, disposed around the edges of the openings of some or all of the means so as to be pressed into contact with end surfaces of the relatively rotative regenerator.

Usually, the regenerator comprises outer and inner cylindrical and co-axial walls providing an annular chamber between the walls, and radial walls which divide the annular chamber into a plurality of sectors. Each sector is divided by arcuate partitions, substantially concentric with the outer and inner cylindrical walls, so as to divide the sector into a plurality of concentric arcuate ring chambers. Each ring chamber is subdivided by one or more radial partitions to provide a series of sub-chambers each of which is substantially trapezoidal in shape when viewed along the axis of the regenerator; in some cases, dependent upon the size of the regenerator, the innermost ring chambers (that is, the ring chambers immediately adjacent and outwardly of the central axial chamber through which a driving shaft extends) may not be subdivded by radial partitions, being themselves substantially of the same shape and size as the trapezoidal subchambers. The arrangement of the arcuate and radial partitions in a sector may be such that all of the sub-chambers formed therein are substantially of similar shape and size to each other so that each sub-chamber may be filled with a pack of plates or tubes, to form the mass, all of the packs of plates or tubes being of similar shape and size to each other.

The sealing members slide over the end edges of the (ill radial and arcuate walls and partitions of each sector, and said sealing members may have a width not less than the arcuate width of a sub-charnber so as to ensure that no subchamber is at any one time open to both an air inlet or outlet means and a hot gas outlet or inlet means.

In regenerators as hitherto used, all of the arcuate and radial walls and partitions of a sector are of the same axial length as the regenerator, so that when the sealing means sweep over the ends of the regenerator they make contact with the end edges of all of the walls and partitions. This results in a large total length of sealing edges at the ends of the regenerator (the sealing edges being provided by the end edges of the arcuate and radial walls and partitions of the sectors), and this in turn necessitates that all of the joints between the walls and the partitions should be made gas-tight, usually by the contiguous edges and faces being close welded or seam welded to each other.

The object of the present invention is to so form each sector of the regenerator that the amount of gas-tight joints between the walls and plates may be reduced, and so that the total length of sealing edges at the ends of the regenerator may be reduced.

According to this invention, a regenerator for a rotary regenerative heat exchanger comprising a series of subchambers each containing heat exchange material, said sub-chambers being formed by metal walls and partitions disposed radially and arcuately of the regenerator, the said radially disposed walls and partitions having a length, extending in the axial direction of the regenerator, which is equal to the axial length of the regenerator whereby the end edges of said radial walls and partitions lie in the planes of the axial ends of the regenerator, is characterised in that at least some of the arcuately disposed partitions have a length, extending in the axial direction of the regenerator, which is less than the axial length of the regenerator whereby the end edges of said arcuate partitions lie within the boundaries of the regenerator and are spaced, axially of the regenerator, from the planes of the axial ends of the regenerator.

Thereby the arcuate partitions are of less axial length than the regenerator.

Some or all of the arcuate partitions may be discontinuous between their axial ends.

Thereby, the necessity to attach the edges of the arcuate partitions to the adjacent faces of the radial walls and partitions in a gas'tight manner is eliminated, and the fastening of said edges and faces to each other may be eliected by spaced or intermittent welding.

In practice, some or all of the so-called arcuate partitions may, in fact, be planar, but for the purposes of this specification all of such partitions, whether arcuate or planar in fact, Will be referred to as being arcuate.

Referring to the accompanying drawings:

FIG. 1 is a diagrammatic end elevation, looking in the direction axially of the regenerator, of a sector of a regenerator of the kind described, and constructed in a manner known hitherto; and

FIG. 2 is a diagrammatic sectional elevation taken on line II-ll in FIG. 1.

FIGS. 3, 4 and 5 are diagrammatic end elevations of a sector of a regenerator, embodying separate forms of the present invention.

FIG. 6 is a diagrammatic sectional elevation taken on line VI-VI in FIG. 3.

FIGS. 7 and 8 are enlarged detail views of parts of FIG. 3.

FIG. 9 is an enlarged detail view of part of FIG. 4.

FIG. 10 is an enlarged detail View of part of FIG. 5.

'FIG. 11 is a diagrammatic sectional elevation showing the attachment of arcuate partitions to a radial partition in the forms of the invention shown in FIGS. 3, 4 and 5.

Referring to FIGS. 1 and 2, a regenerator comprises a series of sectors 11 disposed adjacent each other circumferentially to .form a cylindrical regenerator bounded by an outer cylindrical wall 12 (only part of which is shown), and provided with an inner cylindrical wall 13 (only part of which is shown) which is concentric with the outer wall 12.

Each sector 11 is bounded by radial walls 14, which also separate adjacent sectors from each other. Within the sectors are arcuate partitions 15, 16, 17 and 18 which, being concentric with the walls 12 and 13, are circular in the complete regenerator; thereby a series of ring chambers 19, 24 21, 22 and 23 are formed within the sector.

Each ring chamber 1943 is provided with a series of radial partitions 24, 25, 26, 27 and 28, respectively, so as to divide the ring chambers into sub-chambers 29, 3t), 31, 32 and 33 respectively. The sub-chambers 29-33 are all substantially of the same trapezoidal shape and size in end elevation (as seen in FIG. 1), having the same radial lengths and nearly the same widths in the circumferential direction, but with the radial partitions 24-28 making slightly different angles with the circumferential walls and partitions 12, 13, 1548.

All of the walls 12, 13, 14 and partitions -18 and 2428 are of the same axial length (h in FIG. 2) as the regenerator, so that their end edges, at an axial end of the regenerator, are all in the same plane.

One embodiment of the present invention is shown in FIGS. 3 and 6, enlarged details of parts of the said fig- 'ures being shown in FIGS. 7 and 8.

The arcuate walls 12 and 13, and the radial walls 14 of the sector 34 shown in FIGS. 3 and 6 are all similar to the same elements shown in FIGS. 1 and 2, that is they all have the same length, axially of the regenerator, as the axial length h of the regenerator, and the end edges thereof are all swept by the sealing means of the heat exchanger.

However, the arcuate partitions 35, 37 and 38 each have a length which is less than I: so that their end edges terminate short of the end faces 3% 40 of the regenerator, as shown in FIG. 6.

The short arcuate partitions 35, 37 and 38 may not be continuous throughout their axially directed length, being formed as shown in FIG. 6, of two or more spaced apart partition portions 35 and 35a, 37 and 37a, and 38 and 38a.

The packs of heat exchange material which are disposed in the sub-chambers 29-33 to provide the heat exchange mass are located in said chambers by, inter alia, the arcuate partitions and portions thereof 3538a. The ends of the sub-chambers may accommodate grids 41 which have outer faces which are co-planar with the ends 3? and 40 of the regenerator, and which operate to retain the packs of heat exchange material against axiallydirected movement in the sub-chambers.

Furthermore, the outer faces of the grids 41, being coplanar with the end edges of the radial walls and partitions of the regenerator sectors, ensure smooth gliding of the sealing means over the ends of the regenerator, by leading the sealing means smoothly between circumferentially adjacent radial walls or partitions without allowing sudden impact of the relatively movable sealing means with the ends of the radial walls and partitions.

Preferably, the grids 41 are formed of bars which are disposed at angles which are not normal to a radius of the regenerator, for example as shown in FIG. 8, so that it is ensured that no point on the sealing means, during its arcuate travel across a sub-chamber, remains in contact with a grid bar during the whole of such travel; thereby, the grid bars will not saw into the sealing means to create excessive wear of the sealing means.

The arcuate partition, or partition portions, 35-38a need only be secured, for example by welding, to the adjacent radial walls 14 or partitions 59 at intermittent points; for instance, as shown at 42 in FIG. 11.

As it is not necessary to prevent leakage of gas or air between radially adjacent sub-chambers, because said sub-chambers will both be receiving hot gas, or cold air, at any one moment of time (at no period of time will hot gas be passing through one sub-chamber and cold air be passing through a radially adjacent sub-chamber), there is no need for the arcuate partitions to be arranged, or secured in gas-tight manner to the radial walls or partitions, to prevent such leakage, with the exception of the arcuate partition 35.

FIG. 4 shows another embodiment of the invention in a sector of a regenerator. Therein, some of the radial partitions are bent substantially at right angles at one end thereof so that a single sheet of metal may form the radial partition, for example 43 and the whole or part of an arcuate partition, as at 4 4.

FIG. 5 shows a further embodiment of the invention, which substantially is a modification of the embodiment shown in PEG. 4. A radial partition 45 is bent near to one end, at an abtuse angle to provide a portion 46 of a transverse partition. The partition portion 46 not being disposed normal to a radius of the regenerator, its end edges will not saw into the sealing means as the latter moves, relatively, thereover.

In order that plates of metal which may vary in length (radially of the regenerator) may be used in the assembly of the regenerator sectors, the various methods shown in FIGS. 7, 9 and 10 may be adopted to enable such plates to be so used as radial partitions.

FIG. 7 is an enlargement of a portion of FIG. 3, and shows a bar 47 of short length (radially of the regenerator) secured to the outer circumferential wall 12 of the regenerator, and to that bar 47 there is secured the outer edge portion of a radial partition 48.

FIG. 9 is an enlargement of a portion of FIG. 4, and shows the outermost edge portion 49 of a radial partition 59 extending between and outwardly beyond, and secured to bent end portions 44, forming an arcuate partition, of two adjacent radial partitions 43.

FIG. 10 is substantially similar to FIG. 9, being an enlargement of a portion of FIG. 5, and shows the outermost edge portion 49 of a radial partition 50 extending between and outwardly beyond, and secured to the bent end portions 45 of two adjacent radial partitions 46, and also between and beyond the adjacent edges of portions of an arcuate partition 51.

What we claim and desire to secure by Letters Patent 1. In a rotary regenerative heat exchanger having a durable radial seal and substantially free from dead sectors, which comprises a cylindrical regenerator chamber divided into sectors through which a heated gas and a gas to be heated flow, gas inlet and gas outlet means, means for causing relative rotation of said regenerator chamber with respect to said inlet and outlet means, sealing means between adjoining cross-sections of the regenerator chamber and adjacent inlet and outlet means, said regenerator chamber being formed out of an outer cylindrical casing wall and an inner coaxial casing wall, radial sector walls rigidly connecting said walls with each other and thereby radially dividing the cross-section of the regenerator chamber into sectors, in which further intermediate radial walls are arranged in combination with intermediate circumferential partitions, in equal distances to each other and to the inner and outer casing wall, subdividing the sector chambers into narrow cells by means of said further intermediate radial walls, the edges of which lie in the same plane as that formed by the radial sector walls, and serving as sealing edges against comparatively narrow radial sealing strips provided between the inlet and outlet means for the gas to be heated and the gas providing the heat and the surfaces of the regenerator chamber, thereby substantially eliminating the dead sectors, the improvement which comprises constructing at least some of the intermediate circumferential walls such that they have different heights all of which are less the;

the total height of the regenerator chamber, whereby their edges terminate short of the end faces of the regenerator.

2. The improvement according to claim 1, which comprises constructing said at least some of the intermediate circumferential Walls in at least two spaced apart portions.

3. The improvement according to claim 1, which comprises grids disposed in said sector-chambers, said grids having outer faces co-planar with the ends of the regenerator.

4. The improvement according to claim 1, which comprises disposing some radial partitions so that they extend from the outer casing wall to a position short of the inner casing wall and others from the inner casing wall to a position interposed between said radial partitions.

5. The improvement according to claim 1, which comprises affixing a short bar to the outer circumferential wall and securing the outer edge portion of a radial partition to said bar.

6. The improvement according to claim 1, which comprises disposing some radial partitions in a paired arrangement and others in a single arrangement so that the end of a single partition is received between the ends of paired arranged partitions.

References Cited ROBERT A. OLEARY, Primary Examiner. T. W. STREULE, Assistant Examiner.

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