US2462395A - Concentric shell hot-air heater - Google Patents

Description

Feb. 2, i949. s. .1. HEIMAN CONCENTRIC SHELL HOT-AIR HEATER Fletl Filed April 11, 1945 Patented Feb. 22, 1949 UNITED STATES TENT OFFICE 1 Claim.

will be directed and guided in a predetermined path from intake to discharge, absorbing a maximum of heat from its contact with the heated parts of the combustion chamber, with high efi'lciency.

Another object of my invention is to so construct a device of the kind aforesaid, that said air will be guided in a plurality of consecutively reversed directions while contacting the initially heated surfaces of th-e structure during such travel, and thence be discharged as the room- 2-'- heating medium.

An added object of this invention is to construct a heater of the kind described, wherein the combustion. chamber will consist of a doublewalled shell, with the inner wall being reentrant and depending from the top of the chamber to a point above the bottom of the outer wall, said inner wall having its bottom sealed, and said shells closed across their upper ends, together with means to direct the ow of air in successively reversed directions to engage substantially the full surface exteriorly of the combustion chamber.

Further objects of this invention are to so construct a heater of the kind described, that :i1

there will be a maximum of radiation surface in contact with the air circulated therethrough, and within a very small cubic amount of heater body, and wherein the hottest part of the flame in the combustion chamber will be substantially at the sealed bottom of the reentrant inner shell of the combustion. chamber.

A still further object of this invention is to so yconstruct a heater' of the kind aforesaid, that the greatest advantage is had from the radiation space of the same, by transferring said heat directly from the points where it exists in the radiation surface of the heater, by passing a current of air over the same to thereby become heated,

prior to discharging said air into the room to be heated.

An additional object of my invention is to provide a heater construction wherein there will be little tendency of overheating or burning out of the walls of the combustion chamber, inasmuch 2 as the heat is extracted therefrom rapidly, evenly and continuously, by a current of air passed in contact with the heated surfaces of the heater.

Other objects of this invention are to so construct a heater ofthe kind described, that will be simple and easy to make and use, not likely to get out of ord-er, will keep clean over long periods of time, will eliminate indirect heating surfaces in favor of direct or radiant heating surfaces, wherein there will be a fairly direct iiow of combustion gases from their generation t0 their discharge, will operate with comparatively low drafts and thereby enhance the safety of operation inasmuch as the said gases travel substantially continuously upwardly to and through the flue.

Many other objects and advantages of the construction herein shown and described will be obvious to those skilled in the art to which this invention appertains, as will be apparent from the disclosures herein given.

To this end, my invention consists in the novel arrangement, construction and combination of parts and the uses mentioned, as will be more clearly pointed out in the following specifications.

In the drawings, wherein like ref-erence characters represent like or corresponding parts throughout the views,

Figure 1 is a substantially horizontal crosssectional view taken through the structure; and

Figure 2 is substantially a Vertical cross-sectional view taken through the same.

Referring more particularly to the drawings, wherein I have illustrated a preferred embodiment of my invention with as few parts as possible, in order to show the invention more clearly, there is shown a space heater generally, with its combustion chamber I formed between a pair of radially spaced inner and outer shells or walls 2 and 3, respectively, said inner wall being reentrant or depending into the outer shell, somewhat as shown. l

A top Wall c is provided across the space between the tops of the pair of cooperating shells i and Sto form the top end closure thereat, and the bottom end of the inner shell 2 is provided with a transverse wall 5 to seal thereacross.

Any suitable source of heat, as for instance the pot of an oil burnerl, may be interposed within the combustion chamber, below the sealed bottom of the inner shell of the said chamber, and a flue 'l may be provided to lead outwardly from the upper end of said chamber in the usual manner. In order to slow down the flow of combustion gases upwardly of the chamber, a transverse baille 8 may be positioned between said pair of shells forming said chamber, preferably adjacent the upper end of the chamber, this baille sealing off passage of said gases of combustion, except at a point preferably remote lfrom said ue. Although said gases move constantly up to the flue, they move somewhat slower than without sucha baleandlthis, ow'or gases'rnakes for safety inoperation with a low draft'.

An innermostJ shell or wall 9 extends vertically from its open lower end I to a point spaced.'

above the top wall 4 of the combustion. chamber and is spaced radially from the adjacent surface of the shell member 2 to provide arr air'passage'.- way between said shells in a manner about to be described.

An outermost shell or tube l I encloses-rthe outer periphery of the shell member 3 to provide an air passage between the: two, and a topr closure l2 i bridges across the tops ofthe members 9 and l! to seal the same against other than the predetermined path of travel of air as indicated by the arrows, said. top wallA element l2A being spaced Vabove the top wall of. the. combustion chamber.

Openings i3 may be providedthrough. the. lower end of theoutermost shell wall H, for discharge oi"A heated airtherethrough into the room or other space to-be heated, and in that case, an air intake chamber I4` is=y formed above the top wall I2, by placement of a wall l5v spaced above the wall. I2'` toV form said intake' chamber together with, saidI last-mentioned wall IZ, the inlet ports beingvindicatedfat I6.

.will become heated, with the greatest degree of heat being. adjacent the bottom. wall 5, and the gases of combustion will travel. upwardly continuously andpastr the baie. and. outwardly Ythrough the liuc, the air entrained in: the plenum chamber will:V be. propelled. downwardly through the innermost.- shell. wall S- to strike the said wall 5.-, andireverse its vertical direction. and travel-up iwardlyfbetweenthe. opposed surfaces-of the shells 2. andY 9.- tothe top-of1 said. combustion chamber,

where it travels radially outwardly and then. in a? verticaldirection.v reversed from. its. last reversal, downwardly inthe-space between the shell walls 3: and Il., atfthe. lower. endof. said. space beinggdschargedoutwardly into.the. room or spa-ce taba he ated, throughtheoutlets. i3..

Thus-'it is seen that there.is.a-very.- lor-lgM Hath ofi travel. of. ain in.. contacawiththe. .radiation surfaces. of. theheater,r said. air being, out.A ocom- -iminicatilzvn with thef gases or; combustion however, and;that substantially all.. of. the wall surface oi thacombustion chamber is. thus wiped by said; entrained air, to. obtain a direct transfer- A enceoheat to the latter and'get the` greatest advantage ofjsnch radiation surface.

Indirect heating surfaces are. thus avoided, in

- Lavor. of. the, director. radiating heatingsurfaces of..the. combustion chamber. There is a. moving face of the combustion chamber.

, body-of.' air. irncircul'ation. with allor the Wallsur- Of course it is to be understood that the natural flow of air through the path just described, may be employed, where it is desired to discharge the heated air through the ports I=6 and use the openings IS as inlets, and in which case the fan may either be dispensed with or its air-propelling d1- rection reversed, the air still traveling in a series of consecutively reversed directions and in close contact` withathe combustion chamber wall surfaces. during. such movement.l A

Although the combustion chamber is hottest adjacent the bottom of the reentrant shell, there is. little or no danger of the same burning out thereat, inasmuchas substantially the coldest air contacts with said hottest region to immediately absorb the radiated heat of the latter.

In ordery togetl an even more eflicient transfer of. heat from the combustion chamber wall, a sheet of good heat-conducting material, as of metal for example, may be interposed to extend vertically in the space between. the walls 2' and 9) and preferably. made sinuous or corrugatedi as at. 41B, said sheet being, either integral'. with said wall or. welded' or otherwise well bonded theretdso as to act as an extension of said radiating surface, this element I8` preferably terminating somewhat above the open bottom of the wall 9, so that there is no undue interference with the upward reversal of the air after' ithas; made its downward movement' through the' last-mentioned shell 9; The element |8 thus multiplies the effective radiation surface of. the wall' 2 and more efliciently transfers its heat' Ito the air passing along either side .of the corrugations..

A covering or insulating wall I9 may -be used to enclose the entireA structure; and in. order to avoiding building up of. un'desirablyY high wall temperatures, vents 20 may be provided leading from the exterior into the space between said covering and the shell l l.

It may be. stressed. here, that the inner or reentrantA shellv wall of' the combustion chamber terminates at the sealed bottom 5 at the :height of the hottest zone of the flameV from the pot or burner` 6, or other source'- of'l combustion. Hence, thereA is an almost immediate transferrence of heat. from. the zone of'. maximumv temperature within thecombustion chamber, to the shell elements 6 and 2, and; from the' latter portions of the. shell insert to the air circulated as hereinbefore shown and described, thereby resulting in maximum efficiency of heat transferrence from said hottest part of the furnace..

A heater constructed as herein described will be exceptionally safe in its operation, inasmuch as it will work eiciently under-fairly low drafts, and the ow of the combustion gaseswill be progressively and constantly upwardly tothelevel of the flue.

Having. thus. describedv my inyention, itis. obvious that various immaterialgmodications may be made. in the. sama without. departing from the spiritofmy invention; hence Ii do not wish to be understood. as limiting myself to the. exact form, arrangement, construction and combination of parts herein shown and described, except as limited by the state of the art', to. which this invention appertains, and. the claim hereunto appended.

What I' claim as new and desire to secure by Letters Patent is:

In a heater construction for discharging heated air. into a room at' substantially oor level, concentrically spacedupright inner and outer, walls,

a closure across the tops of said walls, and a closure across the bottom of said inner upright wall to thereby provide a combustion chamber enclosed by said upright walls and top and bottom closures, a pair of shells concentrically positioned relative to said upright walls, one of said shells being exteriorly of and spaced from said outer upright wall and the other shell being interiorly of the inner uprightwall, said last-mentioned shell vhaving an open lower end terminating above said bottom closure, said outer shell having a cold air inlet thereinto, and the space within said outer upright wall havin-g a hot air outlet therefrom, means for entraining air from said one shell downwardly into said inner shell so that the same will travel in reversed directions in sequence along the inner and outer side of the innermost shell and in a direction then reversed from the last-mentioned of said reversed directions along the outer Wall of said outer upright wall, and an upright heat-conducting corrugated element arranged between said innermost shell and the adjacent Wall surface of the inner of the upright Walls and carried by the latter and entirely spaced from the innermost shell and having passages through which said air is guided there- 6 past, said corrugated element engaging only said adjacent wall entirely above the bottom of the innermost shell toconduct heat directly to the air flowing in contact therewith.

. SIDNEY J. HEIMAN.

REFERENCES CITED The following references are of record in the file of this patent:

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