Casings for heat exchangers and burner/recuperator assemblies incorporating such casings

Page 1 — bibliographic record

Page 2

Drawing sheet — no readable text.

Page 3

Drawing sheet — no readable text.

Page 4

ing said first inlet means, the said core space and the said

CASINGS FOR HEAT EXCHANGERS AND first outlet means for the passage of the said combustion BURNER/RECUPERATOR ASSEMBLES air;

NCORPORATING SUCH CASINGS the said first inlet opening also constituting an open ing through which the exchanger core is inserted into

CROSS REFERENCE TO RELATED and removed from the core space; APPLICATION the ceramic body having a second inlet opening This application is a division of my application Ser. thereto and a second outlet opening therefrom for hot No. 10,186 filed Feb. 7, 1979, now U.S. Pat. No. 10 flue gas from the furnace and having second passage 4,262,740 issued Apr. 21, 1981. means connecting the said second inlet, the said core

FIELD OF THE INVENTION

space and the said second outlet for the passage of the said hot flue gas;

The present invention is concerned with improve the enclosing means also comprising a metal casing ments in or relating to casings for heat exchangers, and 15 enclosing the ceramic body, connected directly to the in or relating to burner/recuperator assemblies incorpo said assembly mounting means to register with the flue rating such casings, and especially to such casings and tile aperture therein and having a removable cover assemblies enclosing a ceramic heat exchanger core of providing the said first inlet;

unitary structure. the metal casing having at the said first outlet there REVIEW OF THE PRIOR ART from mounting means for a burner body and the assem 20 bly also comprising:

A comparatively recent development in the heat a fuel burner having its body connected directly to exchanger field is the economical production of unitary the said first outlet mounting means and to the said heat exchanger cores made of ceramic material able to assembly mounting means, the burner inlet for combus withstand relatively high temperatures, e.g. of the order 25 tion air being connected directly to the first outlet of 1400° C. The resulting heat exchangers are particu mounting means to receive heated combustion air there larly suitable for use, for example, as heat recuperators from and having its outlet for combusted fuel connected or reclaimers for high temperature production furnaces, directly to the assembly mounting means in registry in which heat from the hot furnace flue gas in one flow with the burner tile aperture to deliver the combusted path is transferred to the furnace burner combustion air 30 gas thereto.

in another flow path to improve combustion and overall fuel efficiency. The core must be enclosed in a casing DESCRIPTION OF THE DRAWINGS which provides the necessary fluid inlets and outlets for Heat exchange casings and furnace burner recupera the paths, and in the prior art structures of which I am tor assemblies which are particular preferred embodi aware considerable difficulty has been experienced in ments of the invention sealing the core into the casing in a manner that will example, with referencewillto now 35 be described, by way of avoid leakage of fluid between the flow paths and con matic drawings wherein: the accompanying diagram sequent loss of efficiency. Even if the sealing is effective FIG. 1 is a view partly in transverse cross-section and when the device is new, it is found that in use leakage partly in side elevation of a first embodiment compris begins relatively quickly as it is subjected to the drasti ing a furnace cally changing temperatures encountered in service. the assembly burner/recuperator assembly and showing mounted in a furnace wall;

The problem is compounded by the difficulty of finding FIG. 2 is a view in transverse cross-section and end suitable construction materials with sufficiently close elevation of the embodiment of FIG. 1, the furnace wall coefficients of expansion to avoid the large changes in being omitted;

dimension that result from these drastic changes in tem perature. 45 FIG. 3 is a top plan view of part of a second embodi ment consisting of a heat exchanger adapted to be

DEFINITION OF THE INVENTION stacked with a plurality of similar units; It is therefore an object of the invention to provide a FIG. 4 is a transverse cross-section on the line 4-4 of new casing for heat exchanger cores permitting the FIG. 3; and production of integral burner/recuperator assemblies. 50 FIG. 5 is another transverse cross-section on the line In accordance with the invention there is provided a 5-5 of FIG. 3.

recuperative burner assembly for use with a heat ex DESCRIPTION OF THE PREFERRED changer core comprising a rectangular parallelopiped EMBODIMENTS of ceramic material and having within itself separate first and second flow paths which are in heat exchange 55 The casings of the invention are employed with a relation with one another and at right angles to one heat exchanger core 10 which is of rectangular parallel another, the assembly comprising: epiped shape, more particularly of cubical shape, of assembly mounting means for mounting the assembly ceramic material, so that it is readily able to withstand to a furnace wall, the means having therein two spaced fluid temperatures of up to 1400 C., such as are encoun apertures for registry respectively with a burner tile tered with the flue gases of a high temperature produc delivering combusted gases to the furnace and a fluetile tion furnace. The core provides a first flow path consti receiving hot flue gases from the furnace; tuted by a respective plurality of parallel passages ex enclosing means for the said core comprising a body tending from an inlet face 12 to an outlet face 14, the of ceramic material having therein a parallelopiped path being intended for the passage of combustion air shaped core space receiving the said core and mounting 65 for a furnace hot air burner 16. The core also provides it therein, the ceramic body having a first inlet opening a second flow path constituted by a respective plurality thereto and a first outlet opening therefrom for burner of parallel passages extending at right angles to the first combustion air and having first passage means connect path passages and in heat exchange relation thereto, this

Page 5

second path extending from an inlet face 18 to an outlet other embodiments they could be other materials, such face 20. The second path receives hot flue gases from as cast iron.

the furnace chamber fed by the burner 16. Such a uni The gasket compressor member is located at the inlet tary ceramic core is sold for example by GTE Sylvania. for incoming air so that it is at the coolest part of the Referring now specifically to FIGS. 1 and 2, illustrat- 5 assembly and will be least affected by temperature ing a burner/recuperator assembly, the casing for this changes. The casing 36 is provided with a flange 68 by embodiment consists of a hollow refractory body 22 which it is fastened to a common mounting plate 70, as surrounding the core 10 and having inlet 24 and outlet by bolts 72, and with studs 73 by which the recuperator 26 for the first path, and inlet 28 and outlet 30 for the can be connected to a flue leading the cooled gases to second path. The first path inlet 24 is the only one big 10 atmosphere. The burner 16 is provided with a respec enough for the core to pass through, and this is there tive flange 74 by which it also is fastened to the plate 70, fore the only opening by which the core can be inserted as by bolts 76. The flange 68 also serves as a base mem in the casing. The body 22 provides around the edges of ber receiving fasteners 78 by which a refractory flue tile the core face 14, between that face and the outlet 26 a 80 is secured to the recuperator to receive hot flue gas square circumference shoulder 32 on which rests a 15 from sists the furnace working chamber. The burner 16 con of a body 82 and burner block or tile 84, and the square-circumference first gasket 34 of a suitable high temperature ceramic fibre composition. The gasket 34 two tiles 80 and 84 are of about the same length as the receives the edges of the face 14 and seals the first flow thicknessThe of a furnace wall 86 in which they are in path outlet against leakage of fluid into the other path 20 serted.

gether form a burner and the recuperator thereby to compact unitary structure that accommo and consequent loss of efficiency and control of fluid dates the right-angled flow. In this embodiment the body 22 is surrounded by passages of the ceramicconfiguration core. This of the cross flow compact structure a metal casing 36 providing a flange 38 to which a may be contrasted with the known prior arrangements flange 40 of the burner 16 is connected by bolts 42. The in which the recuperator is mounted apart from the casing provides an upstanding square circumference perimeter wall 44 surrounding the inlet 24 and receiving 25 burner and the gases are conveyed through heavily a square-shaped gasket 46 that extends around the edges relatively conduits, insulated high heat with the consequent problems of loss and expansion of materials.

of the core face 12 to seal the first flow path inlet against Referring now to FIGS. 3 to 5, the embodiment illus leakage. The casing 36 is completed by a separate re trated therein has a body 22 of refractory material but movable portion 48 having a flange 50 to which is con no external metal casing, the devices being intended to nected by bolts 52 flange 54 of a flexible air inlet conduit be stacked so that their respective flow paths are in 56. This casing portion 48 in this embodiment also con parallel or in series with one another, as may be re stitutes a gasket compressor member, and the face of the quired for the particular installation. Similar parts are gasket 46 opposite to that engaged by the edges of the given the same reference number as the embodiment of core face 12 is engaged by a square circumference face 35 FIGS. 1 and 2. Since there is no external metal casing of the member 58. In this embodiment the casing parts the studs are replaced by bolts 82 which extend com 36 and 48 are of sheet metal and the face 58 is the bot pletely through bores in the body 22 and have their tom wall of a square-circumference channel so as to heads accomodated by counterbores. Other embodi provide the necessary rigidity, the channel being ments of the invention will be apparent to those skilled formed by turning and returning the part of the member 40 in the art within the scope of the appended claims. 48 adjacent the face 58. The channel is closed to further I claim:

increase its rigidity by an outwardly extending member 1. A recuperative burner assembly for use with a heat 60 that is stiffened by having its edges turned at right exchanger core comprising a rectangular parallelopiped angles to the plane of the member. The resulting gasket of ceramic material and having within itself separate compressor member is in this embodiment urged into 45 first and second flow paths which are in heat exchange engagement with the gasket 46 by resilient means con relation with one another and at right angles to one stituted by four strong compression coil springs 62 another, the assembly comprising:

mounted around studs 64 that are rigidly fastened to the assembly mounting means for mounting the assembly casing part 36 and extend freely through holes in mem to a furnace wall, the means having therein two ber 60. Other forms of resilient means, e.g. Belleville 50 spaced apertures for registry respectively with a springs are apparent to those skilled in the art. The burner tile delivering combusted gases to the fur gaskets 32 and 36 are thereby constantly urged into nace and a flue tile receiving hot flue gases from sealing engagement with the edges of the core faces, the furnace;

despite any dimensional changes that can occur with enclosing means for the said core comprising a body change in temperature of the assembly, or with changes 55 of ceramic material having therein a parallelopiped resulting from creep of the materials of the assembly shaped core space receiving the said core and with time. The conduit 56 is sufficiently flexible not to mounting it therein, the ceramic body having a first interfere with these arrangements. inlet opening thereto and a first outlet opening The core is readily removed at any time very simply therefrom for burner combustion air and having and easily by removing nuts 66 from the studs 64 and 60 first passage means connecting said first inlet then removing springs 62. The member 48 can now be means, the said core space and the said first outlet lifted off the studs and the core withdrawn through means for the passage of the said combustion air; opening 24. It will be seen therefore that at any time the the said first inlet opening also constituting an open core can be replaced by one of different characteristics, ing through which the exchanger core is inserted such as flow or heat transfer ability, and the new core 65 into and removed from the core space; sealed without difficulty into the casing and without the the ceramic body having a second inlet opening danger of subsequent leakage. Although in this embodi thereto and a second outlet opening therefrom for ment the casing parts 36 and 48 are of sheet metal, in hot flue gas from the furnace and having second

Page 6

passage means connecting the said second inlet, the mounting means in registry with the burner tile said core space and the said second outlet for the aperture to deliver the combusted gas thereto. passage of the said hot flue gas; 2. A burner assembly as claimed in claim 1, and in the enclosing means also comprising a metal casing 5 cluding first gasket means mounted within the core enclosing the ceramic body, connected directly to space between the exchanger core and the ceramic the said assembly mounting means to register with body, second gasket means mounted between the exchanger the flue tile aperture therein and having a remov core and a removable cover for the said first inlet able cover providing the said first inlet; opening, the metal casing having at the said first outlet there 10 the said first and second gasket means both surround from mounting means for a burner body and the ing the first passage means to seal it from the sec assembly also comprising: ond passage means, a fuel burner having its body connected directly to and spring means connected between the metal cas the said first outlet mounting means and to the said ing and the removable cover and urging the re assembly mounting means, the burner inlet for 15 movable cover toward the casing to thereby com combustion air being connected directly to the first press the first and second gasket means for the said outlet mounting means to receive heated combus sealing of the first passage means from the second tion air therefrom and having its outlet for com passage means.

busted fuel connected directly to the assembly