US2447252A - Heating apparatus with provision for utilizing combustion gases - Google Patents

Description

Aug. 1 1948. T R. c. JlMENEZ 2,447,252

A HEATING APPARATUS WITH PROVISION FOR UTILIZING COMBUSTION GASES Original Filed July 17, 1940 3 Sheets-Sheet 1 Inflenioz is I 27 Ramu L'asiz o Jimenez,

:20 flflldM/u Aug. 17, 1948- R. c. .nM'NEz 2,447,252

' HEATING APPARATUS WITH PROVISION N GASES FOR UTILIZING. COMBUSTIO Original Filed July 17, 1940 I5 Sheets-Sheet 2 I Invent)? Hamlin Cash '0 flmnez;

I Aug. 17, 1948. R. c. JIMENEZ 2,447,252

HEATING APPARATUS WITH PROVISION FOR UTILIZING COMBUSTION GASES Original Filed July 17, 1940 3 Sheets-Sheet 3 Inflenioz n azsiro 7M ,IMZJM M Patented Aug. 17, 1948 iJNiTED STATES PATENT OFFICE HEATING APPARATUS WITH PROVISION FOR UTILIZING COIVIBUSTION GASES Ramon Castro Jimenez, Winthrop, Mass.

Original application July 17, 1940, Serial No. 345,966. Divided and this application May-29, 1943, Serial No. 488,962

My present invention relates to th'e general class of heating and heat-exchange apparatus wherein the combustion of fluid fuel is accompanied by the giving off of exhaust gases of combustion, as for example in oil burner heating systems. More particularly theinvention aims to improve the combustion efliciency and to reduce the fuel consumption for a given result. This application is a division of my copending application Serial No. 345,966, filed July 17, 1940, now Patent No. 2,320,821 dated June 1, 1943.

In the drawings illustrating examples of means toward the left in said figure, showing a typical rotary oil burner unit and certain associated means according to the invention, including particularly that for delivering aspecially conditioned combustion gas mixture, also secondary air, to the burner;

Fig. l is a further view of the apparatus of Figs. 1 and 2, partly in plan and partly in horizontal section at a level just above the conditioning chest and with the upper portion of the boiler removed to expose the fire-pot and associated burner parts at the combustion locality;

Fig. is, a front end elevation of the conditioning chest, on the scale of Figs. 1, 2 and 4; and

Fig. 6, corresponding to Fig. 3, illustrates means of my invention including secondary air supplying means'in association with an oil burner of the so-called gun type.

Referring to the drawings in more detail, and first to Figs. 1 and 2, I have there represented a typical modern boiler or furnace [0 havin the usual provision for escape of the exhaust gases and products of combustion, including a breeching H and communicating stack 12 leading to a flue i3. While the invention is equally adaptable to heating or air-conditioning apparatus of any of the various types, including those wherein the circulating or heat-exchange medium may be steam, vapor, water or air, I have here chosen to illustrate it in connection with a hot-water radi- 8 Claims. (Cl. 158- 23) ation heating system such as commonly used for piping connections,

Theheated fiuid medium, such as water, passes V heating dwellings and other buildings.

The for the radiation system is heated in the boiler or furnace l0 through whichit is circulated in the usual coils, cores, boiler sections and internal not necessary here to show.

from the boiler through outlet piping It at the upper part thereof, see Figs. 1 and 2, communicating with one or more riser pipes such as ll leading to the radiation system. The heat-supplying water is returned for reheating as through f the return conduit l8, Fig, 4, communicating through branching return inlet pipes i9, l9a with v the above-mentioned heating coils and associated water compartments in the boiler It). An impeller or circulation-maintaining device may be disposed discharge members provided, as indicated at [8a, Fig. 4.

The heating source for the boiler is represented as an oil burner unit indicated as a whole by the reference letter B, seen separately in Fig. 3.

The invention is readily adaptable for use with any of the known types of the so-called gun type.

illustration I have here shown a so-called rotary burner installation, Figs. 1 to 5 and a gun type in Fig. 6. To avoid unnecessary detailed illustration and description of what may be standard equipment, it may be assumed that the boiler and the associated oil burner unit are of a standard commercial construction, for example, as represented by the Timken equipment known in the trade as model C.

As seen in Figs. 3 and 4, a combustion chamber is provided at the lower portion of the furnace or boiler assembly, said chamber including a flooring 20 of firebrick, clay or other suitable refractory or heat-resistant material. This flooring is disposed at a level above the cellar floor or other foundation adequate to provide a pit 2!; The base of theburner unit, including supports 22 and framing 23, is disposed in the pit, the burner power unit or motor 24- being hung on the burner with its rotoraxis disposed wardly above the combustion chamber floor 20.

.Therotary elements of the burner unit are concentrically disposed at the upper end of said motor shaft 25, the latter rotating in the coun:

terclockwise direction as viewed in Fig. 4. Said elements include an annular cup 25 to which the incoming fluid fuel or oil is supplied from the fuel line 3lla,,a top plate 27, aseries of radially water or other fl 'd circulating medium oil burners, including For the purposes of 23 for the atomized,

or vaporized fuel, and a circumferential series of vanes or fan elements 29. These latter in accordance with the invention are specially shaped and arranged for a purpose to be described. The combustion chamber floor 28 is provided with one or more through apertures of customary size, one of which is seen at Zllain Figs-3 and 4, for admitting atmospheric air to the combustion chamber.

In addition I desirably provide in accordance with the invention a supplementalgorsecondary; air inlet 3| comprising an upright-tubularmem-z her or short section of pipe of suitable heatresistant metal or other material. lhis-supplemental air inlet is mounted in a through aperture in the combustion chamber fioon and-is extended above the latter to or adjacent the combustion level so as to discharge in calculated relation to the rotary burner mechanism and to-- the discharge outlet 10 for the returning gaseous admixture to-be morefully described. :In this manner an adequate supply of oxygento ':sup-- port--combustion is assured in-the region-of the fuel delivery and combustion.-

The =oil;-feed--lin'e; leadihg-iromeny suitable fuel oil suppl-y (not-shownb is indicated at 36;

This" fuel-supply conduit 3B, generally--a copper tubing of about diameter has formedin or in' 'communication with it, ata point adjacent the bu-rner -B,-a coil 33:- The end-of this coil remote-fromthe; oil-supply I (with reference to the-direction of flow) is contin-uedas or connected to the pre-heated-oil-delivery line a already mentioned a in connection with Fig-. 3.

The coil 334s disposed-in-a closed-chamber or jacket--35 shown as of cylind-rical form;seeifiig.

5, having end walls orheads iifi or 31,. through which the inlet and outlet :connections -f or the coil with the-fuel lines "39 and wag-respectively,

are=extended insealed condition.

The -spaceWithin suchohambenor jacket 35,-

externally of and surrounding the oil -heating coil-33, is herein adapted-to receiveand circulate through-it a portion of the :heat-exchange medium of the radiation system. associated --with theboiler---or--furnace [fi -such medium,' as v already noted; being of -an'y-- ofthe -'various types,--hot-= water--being assumed in the example selectedmerely-forthe purposes of illustration. Aceordingly; as best seen 'in Figswl and-2, I provide a conduit for conducting -such hot Water-=01 other medium from H the boil-e1 to the compartment -35- of ==the conditioning device, chestor retort, the

latter as a whole being indicated-by-therefer ence character C. Such conduit may extend from-=an-yconvenient pointin'a hot water circulation--jacket or other compartmentof the boiler-or indeed may be comprised in -a circuit separate from that of the radiation system, sub

jectto he'ating in any convenient manner; asbythe' oil burner unit]; of the furnace 19 or other-- wise. As here shown an oif-take'conduitor-pipe 38'-' -is-provided-incommunication with the outlet cent-the furnace or boiler Ill and-it is contemplated that-in many instarices, particularly in cases of initial equipment, as whena furnace is first installedxina newly' constructed dwelling,

thatthisconditioning --unit C Willi be enclosed in-or form a part of the:furnace:orboilerinstallae.

tion, -soas to be enclosed in anyqexterior. decora A tive orinsulating casing for-- the" heating or airconditioning apparatus as a Whole. In other instances, such as where my system and apparatus are to be employed in conjunction with a previously installed burner and heating mechanism, the conditioning unit C will be disposed at the most conveniently available location adjacent the boiler, as upon the cellar flooring, substantially as represented in Figs. 1 and 2. In the illustrated example the hot Water conduit 38 accordingly has an extension 39 in this instance directed downwardly and disposed to communicate-withraninletmlon a wall of the inner compartment 35, herein the rear end wall 31.

Desirably-- Y temperature-responsive control ;mean.s1 is provided-inassociation with the hot sive= means may also serve as-the control form-1.- the heatingof such hGtIWEttBIYSUDPIYJLACGOI'dmingly, as best seen in Figs. 1 and2, the-.hotwaterwconduit 35% is operatively associatedwitha water'w supply heater unit 41; This maybe of the known type such as commonly installedif-or examplewithi the Timkenequipmentpreviously referred to;.. Cool Water from the main is supplied .toi-thisunitr... asthough the supp y pipe 4 theheated-water::-

being carried by'a piping connection such-ras 4312::

to thevarious points of usein the dwelling or other building. Such unit ha's incorporatedt'with K it a thermostatic switch 44, for examplel'askn'own.

by the trade nameaqua-therm, disposed i-nJth electric'circuitof the burner unitB and adjusted: .1

to switch off-theburner whenever the water-passa-i. ing from the boiler through-the pipe. 39ir-reaches.

a predetermined maximum temperature, say-in the vicinity of F. Inany eVEHtthethGI'mO- l static control setting is such, under my invention; that the oil in the pre-heatercoil 33- generally v does not acquire a temperature above 5160 11 1 orwhatever is the vaporization pointof the par: ticular-fuel.

Leadingfrom a portion of the oil-heatinghot-J water compartment or chamber 35 remote from-.1 the inletilw hereinat -the front or endgwalli'l'fifi is a returnwater conduit or pipe 4'5,Z wherehy-. the' Water after passing about the C0il33111's rev. conveyed to the boiler iii, as by connection-With? one of the returnpipes ii! of the radiation system previously mentioned; seeiparticularly Fig- 4.

The invention further contemplates condition-. a

ing,-including pre-heating, of :the air or -.ti1ead.+ mixture of air Iandother gaseous matterwhich" is supplied. to the atomized or .volatilize'd pre heated fiuid f-uel and commingled with the latter'to support and increase the efiiciencyi-of-comabustion at the burner.

Accordingly,'=as bestseen in Fig's.-l and 1a, Iv provideflmeans fortrapping and" taking-wit a quantity of the gases of combustion-#from-the burner. and which otherwise vwoul-dlpasyofi through thei breeching' II and-stackl2 to=the=- 1111843. Such means herein comprises collect-.: ing-idevice orgas trap 5e disposed lll-bhdStQiCk-I l2 :"at ia position calculated toaifor'dadequate draft maintenance. In thefiillustratedsexample said trap 55 isspaced somewhat above the breechen ingJ'l and directly inith-epath of theigaseousa combustion product travelling. from thelatterin v;-

thel stack t2: The gas trap 50 .iis locatedxin cala culated relation to a thermostatic'switch l2t:dis1-:.; posed in the stack 12 "and connected to shutoff As here illustrated, see particularly Fig. 1, the

gas trap 50 is set in the stack beyond said thermoswitch l2t, that is, between the latter and the flue l3. I have foundin actual practice that reliable control and otherwise efficient operation are had when the trap is arranged with its mouth approximately four to six inches vertically above this thermostatic control device l2t.

Desirably, as shown, said gas-trapping device 50 isof adjustable capacity, so that thequantity or proportionof gases to be caught and diverted to the conditioning unit C may be variably controlled and set to suit the conditions at any given installation. As represented this device as comprises a main element or receiver 5| open at its lower and larger end 52 and decreasingin size toward its upper end 53, in the manner of an inverted cone or funnel. Its reduced upper end 53 is in closed communication with a laterally extending outlet or pipe 54 projecting through the wall of the stack l2 and herein affording support thereon for the trap device.

The receiver or collecting element proper 5! of this gas trap 59 is so constructed and disposed that sufficient draft to the flue is readily afforded. Its downwardly open mouth 52 is spaced from contact with the surrounding wall of the stack, to extents calculated and adjusted to the draft conditions of the particular installation, as for example an all-round spacing of approximately one inch; that is, in a ten-inch stack, the trap is adjusted to a maximum intake area of about eight inches in diameter. Further, said receiver or .cone 5| is made perforate, .over a substantial area of its lower portion, as by the series of perforations 55 of a size and total area calculated to preserve adequate draftage while accumulating and diverting the desired proportion of the combustion gases. In practice I have found that a multiplicity of perforations of approximately one-sixteenth to three-sixteenths of an inch in diamthe skirt or main 7 portion .of the receiver 51 well serves the purpose.

eter and distributed around A spacing of about one inch between adjacent apertures is found suitable for most installations, as affording an appropriate ratio of draft-maintaining aperturing in combination with the peripheral spacing between the trap and the stack wall.

For variably adjusting the capacity of the trap 50 I have by way of example shown the skirt element 5] as split longitudinally upward from its mouth, as at 59, and said element is formed of a flexible metal or other heat-resistant sheet'material such that the edges of the conical skirt along such split may be brought together into more or less overlapped relation or may be moved laterally out of such overlapping relation or even be spread and opened apart to adjustable extents, thereby in effect correspondingly changing the area of the trap mouth to the desired extent. Such adjustment may be performed by means such as an adjusting screw or rod 51' journalled on the stack l2 and having one or more threaded portions 58 operatively engaging a like number of lugs 59 on the split skirt 5|. Turning of said adjusting rod, as by means of the manual adjusting knob filo accordingly serves to move the split portions of the skirt toward or from each other and to hold them in adjusted position, to provide the appropriate area for the mouth of thetrap, tion to the stack wall and in relation to the total area of perforation of the trap for draft mainin spaced relaculating about the tenance as stated, 'theJfact-or ofldraftoutput of? the particular 'burner'also being taken into consideration in the adjustment ofth'e gas andheat trapping means described.

The gastrapoif-take orv outlet 54 is connected at its outer. end to a downwardly extendingpipe or gas conduit .60 through piping connectionsfil,

6| etc. of a non-abrupt-angularcharacter, usu-g. ally avoiding reverse bends, andv ofrsuch direccompartment 62 of the conditioning unit ,0.

Within the latter thegas supply conductor ,60" inwardly.v

terminates in an admission port 63, set from the compartment wall and spaced abovelin a vertical plane with :the associated and herein. inner chamber 35. Thus the gaseous combustion v;

products, including any condensate-thay may be formed in the gas conduit 60 are conveyed, and

admitted to the main gas and herein outer chamcompartment 62 of the conditioning unit C. Such moisture of condensation developingat the discharge outlet 63 of the gas conduit falls to and accumulates at thelower portion of the main chamberfiZ where it maybuild up to the level of or somewhat above the bottom of the inner chamber'til, under ditions, and in part is vaporized or revaporized her or as below further explained. Desirably a gauge of the liquid level, as indicated at 62a in Figs. 1 we and 2, is provided, in communication with the, lower portion of the main compartment 62, as is I also a temperature gauge or thermometer 62b for readily determining the In the operation of the system, vaporization of moisture in the main chamber 62 normally takes accumulating and also from the depositing condensation moisture from the incoming gases, at the admission port 63. Suchincoming moisture falls. onto the thenheated wall of the inner compartment 35, some portion thereof being vaporized or revapore ized, to commingle with the original air content and with the gaseous main compartment 62, while theremaining portion thereof collects into the body or accumulation of moisture at the lower portion of the main chamber 62 as already above indicated. Thus the gaseous product conducted. from the trap 59 to the conditioning unit C is. there mixed with initial air in the tank, and with moisture or water vapor, with some degree of cooling by transfer to the usually relatively cooler water-circulatingand oil-pre-heating chamber 35. In some instances such latter chamber may omitted, together with the water or other heating medium circuit, the fuel line then being directly rather than indirectly in heat-subject relation to the conserved combustion gases.

The described gaseous admixture thereafter is the main chamber of the conditioning unit C and is delivered to the combustion region H led from of the oil burner unit B, at the discharge outlet lepreviously, referred to in connection with Fig; to the action of the" Said admixture, still pro-heat the air for:

3, adjacent and subject burner fan or air impeller. heated, serves in effect to At its lower, B0 is extended inwardly through a wall, herein'one end wall of the outer,

usual atmospheric, contemperature conditions within said main compartment or outer chest v62.

combustion products cirin heat-subject relation to the recirculated supporting combustion. and 1 otherwise improves:

the efliciencysof the :combustive. action. Referring to Figsnl to Age. conduit. 1.] forjsaidl.

humidified and otherwise-:conditioned gaseous admixture leads outxfrom-themain. compartment 62,:at-a point remote. fromutheradmission-.port.

63 iforcthe combustion -gases, herein .in.the .op-.

posite end wallof saidmaincompartment, .Such;

piping-or conduit H includesappropriate.connec-.. tions 'or unions [2, 1'2,ipreferably.of. a:non.-.abrupt=.

angular characterras referred to .in connection with the gasconduit fifi.i zThe conduitll is con-J.

tinued through an opening 13 at .the; base of thee furnace -.andv admitting '.-below; the combustion;

chamber ulcer-20 to the. pit..:2l at any convenient. point, saidaconduitgincluding;a. riser .pipe :14 ':ex. tendingaup z through the combustion. chamber. flooring-1Z0 and:having;at its upper .end..the :.direc..-. tive'w'outletoor discharge :element 10 .previously mentionedcand:locatedand. ldirectedain students..."

subjectarelation: to .the: burner primary. air, in-.

take;': As best seen :in Figs.;.3 and :4...said element comprises: anelbow. which may. be angularly. adjusteduponrthelriserild so as .to directtheheated gaseous-discharge at the. most efiicient. anglerelativea-vto the: vanes 4.29 :of :the. rotary air; impeller. 2 1-?49 of the burner: unit.

As -above=stated-, said gaseous. mixture-nutletflo is located in such proximity to theaair im eller, whether of the rotaryt-ype of burner of Fig. Ber

the gun'type'of Fig. 6, as-to be subject to the impel-ling pr draft action Desirably a150, as here: shownazin Figs- 3 and -a, theair moflngbladesor vanes 29 ar -of sucharea, generally somewhat 2 larger'than customary 'vfOI' the -particular burner without -myinstallationy andthe-blade construetion-and' arrangement; particularly as to angular positiorr'with relation to the outlet TEL are made such as to insure a su-bstantial-or augmented impel'l-in'g'or-draft-action atsaid discharge outlet-10 Such'e'fiect-is made adequate, in consideration-of andin proportionto the entire apparatus of my-- systemyto createadraft action back through thegas conduit ilk-the conditioning-unit-C and the downleadinggas' conduit 60 continuously to the gas trap" "'within the" stack, whereby during operation of theburn-er a--continuous flow of the trapped gases of combustion is maintained fromthe-'stackxto the combustion region."

Preferably I provide'means for controlling-"the force of this draft action. Herein; as best seen in Fig." 1', I have 'installedin the gas conduit 7| a" manually adjustable va1ve'15jc1osing :of which to a greater or lesser extent 'serves'to vary and set the force'of draft as appropriate to the particular in stallation and conditions. Or if at any time the exhaust-gasrutflizing and air-pre-heating 'portion '01 my apparatus should be desired to be tem-' poraril'y not employed, this. may be accomplished by shutting, off .said' valve l5completely and desirably also.another.valve, not shown, adjacent the stack.

The gas supply line ll may also'convenientlyibe providedwith. aninspection and regulating .port. such-for example as the cup-or trap 1.6 connected. in the conduit H and having a removableclosure or cap 11; see particularly Fig. 1. By loosening or removing the cap I! the character and forceuof the gaseous-flow through .theconduit H may. be examined, for test =andsregulatorypurposes. Said receptacle 16 may. also serve to retain possible condensate produced within-the relatively short length of conduit 1| between -theboiler and the conditioning: unit-C, -as may occasionally take place under conditions of extreme atmospheric humidityrrAny' excessaccu mulation of such con-w densate-may-lbe ireliev'ed'as by :means of a' bleeder aperture. 1.8at allow pointrin the conduit.ll,also

as bestseemin Fig; 11. 1

Such bleeder. apertureserves also. for. the ad-' mission. and admixture with the gaseous flowto theaburner :of .an additional amount. of atmoszpheric air-as may :beafound desirable for increasing the oxygen content. .For the same-purpose, one orlnore other. 'air-zinlets may also .be .pro-

vided in the conduit H eitheradjacent the bleeder aperture 18 or elsewhere, for example as indi-'.

cated at 19 in FigSLl, 2 and 4. Such air inletaperturesgenerally have adiameter of about- A inch, depending somewhat upon the draft conditions at 1 the-particular installation, the si-ze bei-ngreduced to approximately r e inch-under exceptionally draftybasement conditions.

In a similarconnection itis also here noted-that i the secondary or supplemental airinletducts adjacentthe combustion point; such for example as represented at 20a and'particularly'at SI in Fig. 3 are of calculated'size, generally about-%= inch diameter, again dependent in some measureon-the given circumstances. It will be seen that in either the rotary type of Fig.3 or the'gunt'ype of Fig. 6 that one or more such secondaryair supply ductswithin the fire box .areprovided; preferably at lower and upper levels respectively, onesupply- "ing air adjacent the lower portion of the'flame' and thecther to theupperportion'of the'flame and combustion region. Fo'rexample, the upper air inlet 3! of Figs..1 to 5 has a length 'abovethe'" floor 28 of the combustion chamber of approx imately five inches,.thereby extending it to and. delivering theair at the desired level in connecapparatus,.may be a somewhatheavierand more.

heat resistant insulation for the burner electrodes.

,As in any instance, it is recommended, that the burner nozzle be inspected periodically.

As above stated, thewsupplying of the recirculated combustion gasesand pro-heated air may temporarily be shut off when desired, as by means .of the valve 75. Ats'uch-time, that is, when gases 4 are not bein taken from the stack, that" portion of. the pre-heating;of the .fiuid-fuel effected directly-by the hot'water or other heating fluid may be continued, or it also may temporarily be made ,nonoperative,--merely. by closing the shut-off valve provided at any-convenient. point in the hotwater conduit 38;.3see Figs. :1 and'2. :A similar valvemay. be disposed in the'jextension 35 of said hotwater conduit, below the/domestic water supply-heater'uniti l l in association with a yalvecom. trolled by-pass- (not shown communicating betweensaid conduit 39 and thewater return piping leer; -Thus-when-desired the water heating unit 4! may be operated without either or both the fuel and the air'pre-condltioning means of the invention;

It will be understood that the ."degree' of preheatingof theoilor fiuidfuel .is regulated for maximum -efliciency. .of combustion. The proper oil temperature in the delivery line 30 generally is found to lie in the range of about 120 to 145 F., depending somewhat on the particular circumstances of any given installation. The construction and arrangement of the preconditioning system as a whole and the incorporated control means are such that in no case will the temperature of the oil exceed about 150 F., leaving a safety factor of at least below the critical temperature of approximately 160 F. As noted, the oil temperature may be variably controlled by means of the automatic temperature-responsive switch devices, including the thermoswitch 44 responsive to the temperature of the water en route to the unit C and the stack thermoswitch [215 subject to the temperature conditions adjacent the gas trap 50. Said stack thermoswitch [2t operates in the known manner, preferably in series with the relay coil of the motor switch device 300, to stop the burner quickly in the event of a predetermined drop in stack temperature such as due to flame failure, also to cut off the burner in the event of undue continued rise in stack temperature above a selected degree. This device l2t desirably is of the type such as marketed under the name Protectorelay which is adapted to recycle in the event of flame failure, automatically giving the burner one chance to restart if other conditions are proper, but which does not permit the burner to deliver oil into a hot fire box until after a determined scavenger period for any accumulated gases and which period may be adjusted to suit the particular installation. If desired, means may be provided for readily visually determining the temperature in the outer compartment 62 of the conditioning unit C, such as the thermometer 62b, Figs. 1 and 2, mounted on said unit and subject to the heat condition in said compartment. It will also be understood that any and all of the controls or safety devices usual in an oil burner installation may be em-.

ployed, including for example an automatic magnetic or other switch, relay or like device such as indicated at 30c at the lower left portion of Fig. 1 whereby the burner is completely shutoff in the event of failure of the fuel supply.

From the foregoing it will be apparent that the method and system involved, as fully disclosed and claimed broadly in my copending parent application utilize in combination the pre-heating of the oil or other fluid fuel and a pre-heating of the air supplied to the region of combustion together with an admixture with that air of a calculated portion of the combustion gases, conditioned by conduction, condensation, circulation in a confined space, some cooling by useful heat transfer and by subjection to moisture in liquid and vapor form, some of which may be admixed with the gases, which also receive a proportion of atmospheric air. Such trapped combustion gases are thus conditioned, circulated and recirculated to and from the burner. The outer compartment of the conditioning unit C and the received gases serve at the same time to maintain the desired heated condition adjacent the fuel coil. In cases where the pre-heating of the fuel in such coil 33 is directly effected by the hot water or other heating medium circulating from the boiler, there is also a mutual balancing and heat transferring or retransferring cooperation between the contents of the outer and inner compartments, including at times 'a booster effect upon the hot water or other fluid medium returning to the boiler.

In apparatus of my invention, there is attained under normal operation a materially closer apair supply ducts has proach to complete combustion of the fuel than in any commercial burner of which I am aware. Incidentally, it may here be noted that when initially starting from a completely cool status the burner system as here disclosed normally reaches its operating stage of maximum efiiciency within a period of not more than about three minutes.

The remarkably improved combustion results are due to the combined effect of pre-heating not only the fuel but also the air for combustion while also mixing with it gases from the stack, conditioned as disclosed. And since a considerable part of the gaseous combustion product is returned for circulation and recirculation through the system, any unburned residue is constantly reduced. The total result is that even after an entire heating season little or no trace of soot is discernible in the boiler or stack. The flame at the burner is of the desired bluish-orange or sun-like character to which the term turnasoline is sometimes applied; In Fig. 6 I have. sufficiently illustrated an installation of my apparatus in connection with an oil burner B of the so-called gun type. The apparatus in general may be the same as in the preceding figures, and parts not otherwise mentioned may be as previously described. In Fig. 6

' corresponding parts have similar reference numerals as in Figs. 1 to 5 with the addition of a prime mark.

The burner B is installed at the base of the furnace or boiler I0 in the usual manner, with the delivery or combustion end of the gun or burner casing extending inwardly through an appropriate aperture in the front wall; The particular burner illustrated, merely by way of example, is of the type such'as shown in U. S. Patents Nos. D. 98,726, 2,066,651, 2,084,709 and others of that general class. Such burner is equipped with a rotary air impeller, the shaft of which is indicated at 25. The supply line for the preheated liquid fuel or oil is seen at 30a, the oil flow being had in the usual manner, generally under the action of an oil pump operated by the burner motor and not seen in Fig. 6, being behind the impeller casing. The reclaimed and conditioned combustion gases coming from the chest or conditioning unit C such as that of Figs. 1 to 5, with the admixed pre-heated air, are conducted through the conduit II and delivered directly adjacent and within the influence of the impeller, the return outlet or delivery end of the conduit being indicated at 10'. As in the preceding figures such outlet 10' is angularly disposed for maximum efficiency of pick up of the gases, insuring their delivery to the combustion point in admixture with the air ordinarily supplied by the impeller. Y

Within the fire box and above a flooring 20' desirably provided for the combustion chamber, I provide one or more special or secondary air admission ducts, for generally similar purposes as the elements 20a and 31 of Figs. 1 to 5. Such air supply inlets are indicated in Fig. 6'at and 8| respectively. Each has its outer end open to. atmosphere at any convenient point outside the boiler or furnace I0, bein here shown as extending inwardly through the front wall. One of said its inner or air delivery end 86a disposed adjacent and below the flame or combustion point, said duct extending first through the heated space 2 l below the combustion chamber floor 20. The delivery end 81a of the other duct 8| also is adjacent the combustion region but herein above the flame of the burner. Thus damages i: .11 .:an adequate supply of; oxygen to support combustion is assured.

' The gas trap such as here. shown isadaptedfor .use otherwise than with the. general. class of burner installations, in conjunction with. the conduct'or utilization of. combustion gases, as for example in my said parent application, now Pat- .ent No. 2,320,821.

It Will be understood that myinvention is not limited to the exemplary embodiments herein il-f jlustrated orv described, and I set forth its scope in my following claims.

I claim: 1. In combustion apparatus having means forming a combustion chamber and communicat .ing means providing a path for heated gaseous combustion products from the combustion region, a gascan-d heat interceptor device'adapted'for positioning in the path of such-combustion products, said'interceptor device comprising a cup-like body; having an open mouth for entrance of such combustion products and an enclosing Wall provided with a relatively smaller-outlet aperture-spaced from said mouth, a. conduit in closed communication with saidoutlet aperture, the interceptor wall'having therein a multiplicity of perforations ,for through passage of a portion of the gaseous products intercepted, and said interceptor body including means for adjustably varying the area of its mouth relative to the cross-sectional area;- of the 'path of gaseous combustion products in which it is to be positioned.

22. In combustion apparatus, in combination, means forming a combustion chamber having a communicating stack for gaseous products of; "combustion, a gas and heat baflie and collecting device disposed in the stack across the path of said combustion products, said device comprising a skirt element having a relatively large'open end 1: providing a mouth and a reduced opposite outlet i -for'intercepted combustion products, the open end of theskirt element being'laterally expansible and contractible.variably to adjust the area ofthe "T mouth; the sln'rt element being disposed in spaced "relation to the surrounding stack Wall and having a multiplicity of relatively small perforations of ia'total area to'preserve draftage in the stack While accumulating and diverting a portion of the com- :bustion products; and :means for variably adjusting the mouth area thereby to regulate the rdraftage.

' 3-. For combustion apparatus having means a forming a combustion chamber and acommuni- I :cating'st'ack, a heat-and gas baths and interceptor device'adapted foriinstallation in such stack, said device comprising :an inverted cup-like element having a relativelylarge open mouth and having lateral and end wall means defining such mouth and providing a heat an'digas receiving enclosure to which the mouth airorcls entrance, said-wall, means having therein a'zmultiplicity of perforations for draft maintenance purposes, conduit means having closed communication with said cup-like element at a point spaced from its open mouth and adapted for supporting said element" within and in spaced relation to such stack, and means for adjustably regulating the area of the open mouth of said element.

4; In fluidluel combustionapparatus, means forming a chamber defining a region of combos tion for a fluid fuel burner, rotary vane means for'directing air admixed With fuel to the combustion region, a stack for the gaseous products of combustion extending from said-chamber, in-

terceptormeans in the'stack' adapted to trap and 12 .ldivert a selected portion of: the gaseous combustion: products i-while permitting draftage to be maintained, and a conduit leadin from the interceptor means toand opening at a location directly 5: subjeot to the'infiuence of such rotary vane means a in 'a' manner toxpromote return flow and delivery of the diverted/gaseous products to the com zbustionregion.

5: In' fluid; fuel combustion apparatus, means ;;forming 'a-chamber defining a region of combus- -m'tion for aizfluid fuel burner, rotary vane means :for directing-.airiadmixed with fuel to the comxbustion region, a :stack for the gaseous products of combustionrextending from said chamber, in- 5jterceptor means in the stack adapted to trap and divertaselected portion of the gaseous combus- 1 171011" products :while permitting draftage to be maintained, a conduitleading from the interi ciceptopm'eans to and opening at a location directly 1 subject to the influence or" such rotary vane means 1 in atmanner to promote return flow and delivery 'of the diverted gaseous products to the comi; bust-ion region-and. means for adjusting the in- -zterceptor means to insure a selected draft action pastathe'int'erceptor means.

6;;In fluid-fuel combustion apparatus, means forming a chamber defining a region of combus- '---tionfor aafluida'fuelburner, rotary vane means -;,'for.- directing air'adinixed'with fuel to the com- '0nbli-Stl01'li1f63l0l'l, astaclrfor the gaseous products of ,Combusti0n"eXtendin'g.from said chamber, in- -rterceptor means in the stack adapted to trap and -i'divert aselected portion of the gaseous combusztion products :While permitting draftage to be ;-maintained; a conduit leading from the interceptor. means to andopening at a location directly subject to the influence of such rotary vane means in a manner to. promote return flow and delivery of 'thei-diverted 1 gaseous products to the com- -bustioniregion, and secondary air duct means :a leading from atmosphere to the combustion re ion andthereihaving a delivery opening also subject tO thSafillflUGl'lCS of such rotary vane means.

'Z.;In:,fiuid fuel combustion apparatus, means forming a chamber defining a region of combusuitiOlIfOI a 'fiuidffuel burner, rotary vane means 5wfor zdirecting 'airadmixed with fuel to the combustion-region; ast'ack for the gaseous products 2: ofrpombustionextendin'g from said chamber, interoeptor means in the stack adapted to trap and a-divert 'aselected' portion'of the gaseous combustion products- While permitting draftage to be maintained, a conduit leading from the interceptor means toiandopening at a location directly 55 subj ect'to the influence of such rotary vane means in 'a manner to promote return flow and delivery ofw-the; diverted gaseous products to the combustionregion, secondary air duct means leadi ng --from atmosphere to the combustion region arrd 'there:having a delivery opening also subject zto, the-influence of such rotary vane means, and means-for variably adjusting the interceptor mmeans toeregulatethe proportion of the total 5' gaseouscombustion products to be trapped and diverted.

8. A gas and heat interceptor and deflecting device-for installation in the stack of a combustionapparatus, said device comprising an inverted -:-:hood-like body' of non-combustible wall-forming material open at the lower end to provide an inlet of" relatively large area, the Wall of said body above the inlet having a multiplicity of relatively small perforations affording through flow for a portion of-stack gases entering at said inlet, said bodyhavinganoutlet of an area relatively smaller 14 than and spaced oppositely to its inlet, an off-take Number Name Date conduit in closed communication with said outlet, 823,962 McLeod. June 19, 1906 and means for adjusting the open area of the 854,156 Eldred May 21, 1907 inlet. 884,945 Nix .Apr. 14, 1908 RAMON CASTRO JIMENEZ. 5 1,014,573 Davis Jan. 9, 1912 1,447,385 Hardinge Mar. 6, 1923 REFERENCES CITED 1,510,391 Feely Sept. 30, 1924 1,702,936 Frenler Feb. 19, 1929 The following references are of record in the 1,743,205 F i 14, 1930 fil f h patent: 10 1,756,663 Sabol Apr, 29, 1930 1,831,529 Frenier Nov. 10, 1931 UNITED STATES PATENTS 1,856,720 Meikle May 3, 1932 1,879,011 Appel Sept. 27, 1932 Number Name Date 1,943,053 Boisset Jan. 9, 1934 225,625 McNeil Mar-16, 15 1,979,465 Heath Nov, 6, 1934, 5 Carter 1335 2,086,812 Luty July 1-3, 1937 361,133 Carter p 188? 2,174,663 Ken Oct 9 365,342 I-Iubber June 21, 1887

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