US2373767A - Liquid heater - Google Patents

Description

April 17,1945.. H. J. D N. Mc'cLLuM LIQUID-HEATER Filed July 27,' '1942 :s sheets-sheet 1 wk. ww .NW %N wm..

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, fauci@ April 17 1945 H. J; DE N; MccoLLUM LIQUID HEATER Filed July 2'7, Y 1942 5 Sheets-Sheet 2 April 17,1945'. Y H. J.' DE N. MccoLLuM 2.5373767 LIQUID HEATER Filed July 27,' 1942 5 Sheets-lSheet/S A I Patented Apr. 17,1945

" Henry J. De N. McCollum, Chicago, Ill.; Thelma lMcliollum executrix or said Henry J. De N.

McCollum, deceased e Appiiontion Jniy'zi, 1942,'serini No. 45ans e I 5 claims. (ci. zas- 32) The present invention 'relates to liquid. heaters andis more particularly directed to liquidheaters of the internall combustion type adapted for use in aircraft or other vehicles in which maximum heat production is desired from a. heater of minimum size and weight;

A typical use for'a heater of this type is toptovide a source of'hot water for use on large airplanes of the type which vmust remain' away from their bases for extended periods.r This hot water may be needed for washing, shaving and other purposes. Another typical purpose for which a heater vof 'this type may be used is forheating a liquid which is then circulated through radiators `in the space occupied by the crew; For this purpose glycol is'the liquid frequently used as a. heat exchange medium. VThese uses are merely illustratlve and others will be apparent fromthe following description.

It is an object of my invention to provide an other liquids.

A' further object is to provide an improved internalcombustion liquid heater which maintains Fig. is a back view of a portion of the mechanism illustrated in Fig. 4; and

Fig. 6 is a front elevational View of ,a portion or the mechanism illustrated in Figs. 4 and 5.

Heaters of the' type to which the present invention relates are supplied with a combustible mixture of air and fuel, such asgasoline from a carburetor or, --when utilized on a vehicle having an internal combustion engine superchar'ger, the combustible mixture can b e drawn from the outlet of the supercharger. Normally, ilow of combustible mixture through the heater is produced improved heater of the internalv combustion type i particularly adaptedfor lheating water, glycol or the temperature of the liquidsubstantially constent regardless of the quantity' of liquid passed through .the heater.

A further object is to provide an improved internal combustion type liquid heater which can` `be economically' constructed, which will be high- 1 ly eilicient, which will operate 'satisfactorily under varying conditions, which -will be small in size and weight,y and which will have along, useful life.

" Other objects will appear from the following description of a preferred embodiment of my invention. i

In the drawings in which similar characters of reference refer to similar parts throughout theseveral views:

Fig. 1 is a side elevation of a heater embodyshown in longitudinal section;

Fig. 2 is a transverse sectional view takenjn by a pressure diierential brought about either by connecting the exhaust outlet of the heater to a suction producing apparatus, or by connecting the'combustible mixture inlet to a source of com- For instance,

bustible mixture under pressure. when the heater is used in conjunction with a vehicle having anon-supercharged internal combustion engine, flow can be produced' through thev heaterv by connecting the exhaust heater iltting to the intake manifold of the vehicles internal combustion engine. If the vehicle engine is supercharged, combustible mixture can be fed' under pressure from the'supercharger in which case no suction producing means is needed at the exhaust fitting.

In Figi of the diawingssvalve iitting'` in has its inletend I2 internally threaded for attachment to. a.' conduit through whichv combustible mixture is supplied to the heater.o Within the tting l0 is located a throttle valve of the butteriiy type. This' valve is not shown but the rotatable shaft on which it is mounted is indicated by lthe numeral I4. This throttle valve by its position controls the rate of flow of combustible mixture through the heaterapparatus.

ing thepresent invention with la portion thereof y its the direction indicated by theallows' along the Fig.l 3 is a transverse sectional view takenin i theev direction of the arrows along the `line -3-34 i is o. freetionei side elevation of .uo-

per left hand fraction of Fig. l'drawn to largerl The lower end oi? the fitting I0 is tubularand contains a bundle of small diameter tubes' I6 formed of a metal having good heat conducting properties, such as copper, for'instance. 'I'he sum of the bores through these tubes together with the spaces between the tubes provides a passagethat oil'ers little resistance to the ilow of com- A- -bustible mixture therethrough'. 'I'he `tubes, however, prevent flame from ashing .back into the Avalve Ill-in a well known manner.

'I'he valve fitting I0 is suitably secured to an elbow-shaped casting i8 having a hollow portion H2li whichr serves as 'a combustion chamber, the

combustible mixture entering this chamber 1 through .radial ports 22 located below the ame scale with portions thereof broken away toillustrete the nieehenism interiorly thereof;

arrester I6. I'he radial ports .22 are formed by striking out vanes from acylindrical member and 50, for instance.

therefore the ycombustible mixture enters the `combustion chamber 20 with a swirling motion.

' Within the combustion chamber, the combustible mixture is ignited by an igniter-plug 24 of the hot wire type, which is threaded through a boss 28 formed as a portion of the casting I8. Inasmuch as it may be desirable in diierent installations to have the igniter plug 24 on'diilerent sides of the heater, two threaded bosses 28 are provided opposite each other. The igniter is screwed into either one of these bosses, While the other is closed by a plug 28. If desired, two igniters may be used in some installations. The igniter 24 is of the hot wire type in which the .wire resistance element is electrically heated to a temperature suiilcient to initiate combustion of the mixture flowing into the combustion chamber. Once the combustion has been initiated, the igniter 24 can be deenergized either manually or thermostatically, inasmuch as a reigniter .i8 serves to re-kindle the combustible mixture if for any reason combustion should be temporarily interrupted.. The reigniter 30 comprisesv a spirally wound sheet of inconel or other heat and vcorrosion resistant metal which is quickly heated by the combustion within the combustion chamber to a temperature suilicient to kindle the combustible mixture. This reigniter is, more fully disclosed in my copending application Serial No. 410,039 iiled September 8, 1941. For convenience. the reigniter 38 is secured to the end of a plug 82 threaded into'a boss 34 formed at the end of the casting I8.

From the combustion chamber within which the combustible mixture is burned, rthe hot products of combustion pass through a heat exchange tube 38, the inlet end of which is provided with a ilange 38 secured to the combustion chamber casting |8 by means of cap screws 40, the joint between the members being sealed by a gasket 42.

Within the heat exchange tube 38 the hot products of combustion pass around a cylindrical muler structure 44 spaced from the side wall of the tube 38 by a plurality of `longitudinally extending ribs 48, the structure thereby providing a. plurality of longitudinally extending channels which straighten out the eddies in the hot products of combustion so as to produce a smooth llow. The side Wall of the cylindrical structure 44 is provided with a multiplicity of perforations-48 while the interior is packedA with sound damping material, such as stainless steel wool The arrangement thus provided damps out pulsations in the hot products of combustion, and serves as a muiller to quiet the operation oi' the heater as well as preventing periodic pulsations of the type known as motor boating.

The hot products of combustion leaving the heat exchange tube 38 are collected inan L- shaped'end cap 52 and are passed outwardly` through an exhaust fitting 54 threaded for at-v tachment to an exhaust conduit to be connected to a space of lower pressure than that of the fuel l' mixture supply. At its inner end the exhaust iltting 54 is threaded into the end cap 82 and has a Venturi shaped restricting tube 58 which serves to stabilize the rate. of' ilow of combustible mixture through the system by compensating for f The heater so mdesoribed operates to hoot the heat exchange tube 38 and this heat is transferred to a tube 58 of copper or other good heat conducting material wound therearound in closely formed turns, .the inlet end of this tube being wound back upon itself and connected to an inlet fitting threaded into the casting AI8 where it communicates with a bore 82 leading t0 a cored out liquid jacketing space 84. 4This liquid jacketing space 84 formed in the casing I8 substantially completely surrounds the combustion chamber, and at alow point on the casting I8 is connected by means of an internally threaded spud 68 to a liquid inlet tting 88, this ilttng in turn being connected to an inlet pipe 1I).

The opposite end of thetube 58 passes outwardly through a sheet metal shell 12 .which encloses the combustion chamber and heat exchange portions of the apparatus and is connected to a fitting 14 threaded into a longitudinally extending header tank 18. This tank extends. from a position adjacent the outlet fitting 54 nearly to the inlet tting I2 and near its forward end is connected on the opposite side to an outlet pipe 18.

At its forward end the tank 18 is ilanged and is secured by screws 88 to a similar ilange on a cap 82, this cap having a forwardly extending vertical web-like member 84 secured byscrews 88 to the inlet fitting I8, thereby forming a solid structure. The inner face of the cap 82 is formed to provide a threaded cylindrical recess into which one end of a thermostatic tube 88 is thread'- ed. This tube contains a themostatic bellows 90 closed at its inner end bya plug 92 sealed to `the inner end of the tube 88. 'I'he opposite or forward end of the bellows is attached to a plunger 94 which extends through an opening 88 in the cap 82'with its outer end in a position subjecting through the cap 82 so that liquid within the header tank 18 can circulate through the tube 98, thus bringing the liquid within thetank into intimate heat transfer relation with the liquid within the bellows 80.

The outer end of the plunger 94 is seated in a slotted socket |08 formed in the edge of a lever |02 pivoted at its lower end upon a transversely extending pin |84 secured to the inlet member III. The upper end of theqlever |82, therefore, is free to move backwardly and forwardly under the influence of similar movement of the plunger 84. This lever is biased against the end of the plunger by a grasshopper sprlng |08 coiled about the pin |04 with its uppzer end resting against the face of the lever opposite the-plunger 94, while its lower end rests in a slot in an abutment |08 formed as a projection on the web 84 of the cap 82. The upper end of the lever arm ||i2l is .of thinner vsection than the lower portionI so as to provide an upstanding thin nnger IIIl transversely slotted as indicated at H2, This miser is located within a longitudinally extending slot I I4 formed in a downwardly extending arm I|8 clamped'at its upper end to the bottoms-'valve smit u. 'A

asvavcr slot ||2 in the upper end of the lower lever lill and is secured at its ends in the upper lever H6. Thus, fore and aft movement of the upper end oi' the lower lever |02 will be transmitted to the upper arm I I6 through the pin ||8 so as to cause similar fore and aft movement of the lower end obtained by lthe use `of substantially the same `or euuivalentmeans.4 e

Iclaim:

of this upper arm. This angular motion is in turn. i

transferred to the shaft I4, thereby causing the buttery valve partially to .be closed upon expansion of the'bellows 90.

In order to prevent rattles and to take up any lost motion which may exist, the arm ||6 and the lever |02 are connected to opposite ends of a light weight floating grasshopper spring |20.

The motion of the arm IIB and hence the rotationv of the shaft |4 is limited by a .stop member |22 clamped to the shaft ||4 by screw |24. This stop member has an outwardly radiating'iinger.

|26 which moves back and forth with rotation of the shaft |4 in a slot |28 formed in the edge of a cup-shaped member |32 press-fitted over a cylindrical surface |34 formed as a portion of the inlet fitting casting I0.. Thus the shaft |4 is free to rotate back and forth upon contraction v and expansion ofthe bellows-90 until the finger |26 is brought against either the forward or back` ward end of the slot |28, beyond which no motion can take place. l

Assuming that with a heater of the above type properly installed, it is desired to supply hot 1iq` uid,v such as water or glycol, the heater is started, that is, a iiow of combustible mixture is produced .through the device and the igniter 24 is energized. This initiates combustion of the combustible mixture, soon after which the igniter can be deenergized, inasmuch as the reigniter 30 will immediately re-kindle the combustible mixture if combustion for any reason momentarilyfails. The hot products of combustion pass through the heat exchange portion of the apparatus and transfer the .heat therein to the heat exchange.

l. In a liquid heater, the combination of -an internal combustion type heater having means forming a combustion chambenand a heat ex' change conduit connected to said combustion chamber and adapted toreceive the'hot products y l of combustion therefrom, an inlet connection adapted to be connected to a source of combustible mixture, a throttle valve in said inlet connection, conduit means for conveying combustible mixture from said throttle valve to said combustion chamber, liquid conducting means in heat exchange relation with said heat exchange conduit, a headerl connected to one end of `said liquid conducting means and adapted to receive and s tore the liquid after it has been circulated through said liquid conductingA means, lthermostatic bellows means arranged in heat exchange relation to the liquid in said header, and means,

I ,operated .by expansion and contraction of said bellows means for partially opening and closing said throttle valve. g

2. vIn a liquid heater, the combination of an internal combustion .type heater having means forming a combustion chamber, and heat ex'- -change means connected to said combustion chamber and adapted to receive the hot'products;

of combustion therefrom, conduit means adapted to convey combustible mixture to said combustion chamber, throttle valve means in said conduit tube B8. 'I'he liquid passing through the liquid jacket space 64 and through the tube 58 is, therei'ore, heated, and passes into the header tank 16 from which it is withdrawn through `the pine 18. After the liquid within the header tank 16 has reached the desired operating temperature. the ether or other substance within the bellows 90 will be vaporized. thus causing the bellows to expand somewhat. This movement of the bellows is transferredthrough the plunger 94 to the lower lever |02 and rocks the upper end of this lever forwardly, the motion being transferred by the pin ||8 to the upper arm H6. This motion in turn produces rotation of the butterfly valve I4.

thus restricting the opening through the inlet .fitting I0, thereby decreasing the rate of flow of combustible mixture through the heater. With this system it will be seen that the higher the ications and variations' may be made Awithout l departing from the underlying principles' of the invention.` I therefore desire, by the following claims, to include within -the scope of the .invention all such modications and variations by which substantially the results thereof may be i 4.In afliquid heater, the

internal combustion type vheater having means means, liquid conducting means in heat exchange relation with s aid heat exchange means to interchange heat from the hot products of combustion to the liquid in said liquid conducting means, a header for receiving the4 heated liquid from said lliquid conducting means, thermostatic means connected to operate said throttle valve and adapted to alter the setting of said throttle valve upon an increase or decrease in temperature of the liquid in said header, and means to interchange heat between the liquid in said header and said thermostatic means. A

3. In a liquid beaten4 the combination of an interna] .combustion type heater having means e forming` a combustion chamber, and a heat exchanger connected to said combustion chamber and adaptedto receive the hot products of cornbustion therefrom, an inlet connection. adapted to be connected to a source of combustible mixture, a throttle valve in said inlet connection, conduit means for conveying combustible mixture from said'throttle valve to said combustion chamber, liquid conducting means inheat exchange relation with said heat exchanger to interchange heat .from the hot products of combustion to the liquid in said liquid conducting means, a header for receiving the heated liquid from said liquid con.- ducting means, .thermostatic means arranged in heat vexchange relation to the liquid in said header,`

means operated by expansion andv contractionof said thermostatic means for partially opening and closing said throttle valve, and stop means to. limit the movement of said, throttle valve to less than the full range of movement provided by said g thermostatic means, whereby the amount of heat produced by the internal vcombustion heater will vary inversely with the temperature of the liquid in said header. 5

combination of an forming a combustion chamber, and a heat exchanger connected to said combustion chamber bustion therefrom. an inlet connection adapted to be connected to a source of combustible mixture, a throttle valve in said inlet connection, conduit means for conveying combustible mixture from said throttle valve to said combustion chamber, liquid conducting means -in heat `exchange, relation with said heat exchanger to interchange heat from the hot products of combustion to the liquid in said liquid conducting means, thermostatic means arranged in heat exchange relation to the liquid issuing from said liquid conducting means and responsive solely to the temperature thereof, and means operated by expansion and contraction of said thermostatic means for partially opening and closing said throttle valve.

5. In a liquid heater, the combination of an internal combustion type heater having means forming a combustion chamber and heat exchange change relation with said heat exchange means to interchange heat from the hot products of combustion to the liquid in said liquid conducting means, a header connected to said liquid conducting means for receiving the heated liquid, a'

thermostatic element in heat exchange relation to th'e liquid in said header a throttle valve operated by said thermostatio element, said throttle valve being located in said conduitl means, and a housing enclosing the internal combustion type 'heater and said liquid conducting means and separating them from said header and said thermostatic element,

HENRY J. DE N. McCOLLUM;

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