US2335918A - Water heater - Google Patents

Description

c. w. DAVIS ET AL 2,335,918

WATER HEATER Filed March 3, 1941 2 Sheets-Sheet 1 Z 1 Mm y W M 4 7 NAG .R

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Dec. 7, 1943.

Dec. 7, 1943. c. w. DAVIS ETAL 2,335,918

WATER HEATER Filed March 3, 1941 Z SheetS-Sheet 2 I INVENTORS COETLHND W04 v/s.

WHLTEQB ENGH.

A TTOENEY Patented Dec. 7, 1943 UNITED, STATES PATENT OFFICE WATER HEATER tion of Illinois Application March a, 1941, Serial No. 381,422

8 Claims. (Cl. 122-16) The invention pertains to heaters and particularly to water heaters of the class in whicha tank holding the water to be heated is provided with connections extending to a heated pipe or .coil through which the water circulates during the heating operation, heating means being provided to. heat the coil or pipe and to thereby heat the ically pertains to water heaters of the general class referred to, in which a heating flue or flues' extend through the tank and each preferably contains a water heating pipe, the invention providing a construction of flue or fiues and heating pipe or pipes such that the flue or flues may serve as a chimney for a burner or means used to heat the water heating pipe or pipes, special devices being employed in the flue or flues to secure prolonged and efficient contact between the hot gases in the flue and the heat absorbing surfaces, to the end that the heat of the gases will be efficiently absorbed and also efficiently conducted to the water to be heated. The invention generically may be used with burners of any type adapted to the purpose, whether using gas, liquid fuel or other fuel, and whether operating under pressure on the fuel or air supplied, or both, or under natural draft.

An important problem overcome by the invention generically, is the eiflcient absorption of the heat from the hot gases passing through a ,flue, the construction being such as to facilitate a relatively long path of travel of the hot gases in the flue in such a manner that they are in intimate Wiping engagement with the surfaces of the heat directing and/or absorbing devices and also with the inner surface of the flue, over a large part of the path of flow of the gases in the flue, but at the same time without detrimental obstruction to said flow.

The invention more specifically, is well adapted for use with burners of the natural draft type, for example liquid fuel burners, and it operates effectively with liquid fuel burners of the wick type in which liquid fuel, for example kerosene, is burned after having its heated vapor intimately mixed with the air required to support the combustion, the flow of the gases in such cases being due largely, if not entirely, to the draft of the flue. With burners of the natural draft type, it

is essential to employ a chimney to develop the flow of the gases, and furthermore, the chimney must have a particular net draft for any particular burner, to the end that the draft produced on the burner will be sufficient to promote effective combustion of the fuel, and at the same time water contained therein. The invention genernot great enough to interfere with the eflicient burning of the fuel. In its particular embodiment illustrated in the present specification, the considerations referred to are taken into account and the water heating surfaces as well as the heat directing devices in the flue, are particularly constructed to not so seriously impede the flow of the hot gases through the flue, as to materially interfere with the chimney effect of the flue in producing a satisfactory draft on a liquid fuel burner of the wick type. In such cases the small flow-impeding effect of the heat directing devices of the invention, may be compensated for by having the flue somewhat longer than would be required for an entirely unobstructed chimney for the burner, so that the net draft effect of the flue acting as a chimney, is substantially the draft required by the burner to efliciently burn the liquid fuel; in some cases a draft-controlling damper may be used to advantage in the flue, particularly where the altitude of the place of use of the water heater, cannot be definitely determined in advance.

To accomplish the results described the heat directing devices are preferably in the form of spaced metal discs of material having a high degree of heat conductivity, for example, copper or copper alloy, which discs are preferably provided with vanes extending from their outer peripheries nearly to the central portions of the discs, the vanes of the discs being similarly inclined to impart to the gases flowing through the flue, a circuitous path of travel through the flue. The heat-attenuated condition of the gases engaging the vanes, results in pressing the gases upwardly against the lower surfaces of the vanes,

thus bringing the highly heated gases into intimate engagement with the vanes, and the inclined surfaces of thevanes produce a wiping movement of the-gases against the lower surfaces of the-vanes over substantially the entire area of each of the discs employed,which results in acircuitous motion of the gases in the flue, the action of the vanes of each disc continuing the directive action of the preceding disc on the gasespassing through the flue, so that the gases have a continuous circuitous movement through the fiue;,

this action, by the inertia of the gases, also presses the gases against the inner surface of the flue and produces intimate wiping engagement of the gases therewith over a long path of travel through the flue, thereby facilitating heat transfer to and through the flue. The column supporting the vanes is illustrated as a water heating pipe which is preferably made of material having a high degree of heat conductivity, for example, copper or copper alloy, and the vanes are intimately .connected with the heating pipe preferably by' brazing or soldering, to afford an efficient communication of the heat of the vanes to the pipe and thereby to the water in and flowing through the pipe. The water heating pipe illustrated, is preferably straight and provided -with an uninterrupted and continuous inner surface, as a result of which the water heated in the pipe flows rapidly through it without obstruction of any kind, which greatly increases the emciency of operation of the'heater over a period of time by eliminating most of the precipitation of mineral matter from the water which otherwise would occur, there being no pockets or branches from the pipe to facilitate sluggish movement of the water therein and result in the deposit of said mineral matter.

It is an object of the present invention generically, to produce a water heater of the flue type, inwhich a column which may or may not be a water heating pipe as desired, extends through a flue and which is provided in the flue with heat directing devices of a highly efllcient nature which produce a large area and length of travel of effective and efficient wiping engagement between the hot gases in the flue and the heat absorbing surfaces.

It is a further object of the invention to provide a water heater of the type described and provided with a water heating pipe and heat directing devices generically of the kind referred to, in which the water heating pipe has a straight inner surface which is unbroken throughout the heating zone, facilitating the free flow of water therethrough and substantially retarding the precipitation and deposit in the water heating pipe of mineral matter from water flowing through said pipe.

It is a further object of the invention to produce a water heater of the flue type, which flue is provided with heat directing devices eflecting efiicient heat transfer to the water, and in such a manner that the flue will eifectively serve as a chimney for a liquid fuel burner of the natural draft type, and produce a net draft suflicient for effecting the eillcient combustion of the fuel, but insufllcient to too rapidly remove the burning gases from the burner.

It is a further object of the invention to provide a waterheater with a water heating pipe in a flue, which pipe is straight and has a continuous and unbroken inner surface and which is entirely free from water pockets or recesses opening from the pipe, and to provide on the heating pipe, heat conducting and directing metallic vanes inclined to produce a circuitous flow of the gases in the flue, which vanes extend nearly, if not quite, to the inner surface of the flue, the vanes being of substantial extent angularly to aiford eflicient heat direction and absorption, there being preferably a sufficient number of sets of vanes spaced along the pipe, to produce the coordinated relation and maintaining that re-' tion,

Fig. 3 is a vertical sectional view to an enlarged scale of a part of the structure shown in Fig. 2, taken along the line 3-3 of the latter figure,

Fig. 4 is a horizontal sectional view to an enlarged scale of a part of the construction shown in-Fig. 1, taken along the line 4-4 in the latter figure,

Fig. 5 is a view similar to Fig. 1, showing a portion of a modified construction of water heater, and

Fig. 6 is a horizontal, sectional view to an enlarged scale, of the structure shown in Fig. 1, taken along the line G6 in Fig. 1.

Similar numerals refer to similar parts throughout the several views.

As shown in Fig. l, the water heater consists of a cylindrical tank 10 of suitable sheet metal having upper and lower end walls Illa and lllb through which a cylindrical flue H extends, the flue being rigidly connected with said end walls, for example by welding. A water heating pipe I! extends vertically and centrally through the flue H and is connected at its upper end by suitable pipe fittings l3 with the upper portion of the tank l0, and at its lower end by suitable pipe fittings H with the lower portion of the tank Ill. The pipe connection l3 may also serve as the discharge pipe for water delivered from the tank I. Water is supplied to the tank by a pipe I5 extending through the top wall Illa and nearly to the bottom wall I017.

The tank I0 is surrounded by a cylindrical shell l6 spaced from the tank, suitable insulating material I! being preferably provided between the shell and the tank. The shell l6 extends substantially below the lower end of the tank ill to form a compartment l8 to contain a liquid fuel burner l9 supported on a fuel reservoir 20 movable horizontally in channel guides II and 22 into and from the compartment I8 through a door 23 shown in Fig. 2. The upper end of the flue H is enclosed by a dome 24 provided with a baffle 25 in line with an upper discharge opening 26, communicating with a discharge pipe 36, said dome having also side perforations 21 for the flow therethrough of air to compensate for the draft of the pipe '36. The pipe 36 is provided with a damper 31 for adjusting the flow into and through said pipe. A second damper 31a is shown in Figs. 1 and 6, to control the discharge from the flue II, to accurately adjust thedraft efiect of the flue to suit particular conditions of use.

The burner l9 supports a short lower chimney section 28 upon which the lower flanged end of a sleeve 29 rests, which sleeve constitutes a continuation of the lower end. of the flue ll, so that the draft effect of the flue Ii is exerted on the burner I9. A passageway 30 of small vertical extent is provided between the lower chimney section 28 and the lower end of the sleeve 29 to admit to the upper portion of the combustion zone, the air required for complete combustion,

assume which inlet, however, is of sufficiently restricted height vertically to not materially interfere with the draft action of the flue H, which flue in any event is long enough to compensate for the checkdraft effect of the passageway 30.

As shown in Fig. 1, the pipe I2 is provided with a plurality of heat directing and absorbing devices 3|, of sheet metal and each constructed preferably asillustrated in Fig. 4 in which said device is shown as comprising a disc closely fitting the pipe I! and provided with a plurality of radial slits extending from its outer edge nearly to said pipe, the vanes or baifles 3|a thus formed being bent into an inclined or oblique position and in the same direction to impart a whirling motion to the hot gases passing upwardly in the flue II. The discs 3| are preferably of such diameter as to nearly or quite engage the inner surface of the flue II, it being preferable that the fit of the discs in the flue shall be sufficiently loose so that by releasing the pipe fittings at the ends of the pipe l2, the assembly consisting of the pipe I! and the discs 3| thereon may be removed as a unit from the'flue, which facilitates assembly and replacement if the latter should be required. I

As a result of the construction described, the only obstruction to the free flow of the hot gases upwardly in the flue ll, consists of the vanes or baffles 3la on the discs 3|. The thickness of for example by welding. This holds the insulating material I! in place. and provides a convenient support to which the shell It may be attached. As shown in Fig. 3 the leg 33 which is of channel cross section having filled-in ends, has the upper end portions of its legs notched as shown at 330 to rest under and engage the lower edge of the side wall lllc of the tank, when the upper end of the leg is in engagement with the member 32, the depth of the channel legs being suflicient so'that with the upper end portions thereof notched as referred to, the remaining portion of the channel flts in the angle section of the member 32, thus holding the notch 33a in engagement'with the lower'edge of the side wall lllc, in which position it is secured, for example by bolts 34. The lower edge portion of the shell I6 is provided withan annular reinforcing band 35 to which the lower portion of the leg these vanes, however, may be small, since they need not be over 1 6" thick, and on account of the vanes being all inclined in the same direction and each contributing its part to producing the circuitous flow of the gases through the flue ll,

the obstructing effect of the vanes to gas flow through the flue is so small as to be readily compensated for by the length of the flue ll employed, which is preferably such as to produce the net draft required for most effective operation of the burner IS. The large area of the vanes 3la, the pressure of the moving gases upon them, and the wiping action of the gases against the flue of heat from the gases; the whirling movement also effects a commingling of the ascending gases. By providing a multiplicity of similar discs 3| on the pipe l2, as illustrated, and spacing said discs from each other closely enough so that the vanes on each disc effectively engage the gases leaving the-next lower disc, the progressive action of extracting the heat from the gases delivereddnto the lower end of the flue I I, so efficiently transfers to the water in the tank the greater part of the heat of the gases, that although the gases delivered into the lower end of the flue H by the burner l9 are intensely hot, the gases delivered from the dome 24 are only warm.

As shown in Figs. 1 and 2, the side wall lilo of the tank is continued below the bottom wall lb, and spaced from the shell l6 by an annular member 32 which as illustrated is an angle bar, and which is rigidly secured to the side wall lllc,

. able.

ing vanes making a relatively small angle with 33 is preferably secured, the leg extended sufllciently below the shell l8 to provide for the free pasasge of air to the burner around the lower edge of the shell. Each of the legs 33 shown in Figs. 1 and 2 is constructed as described in connection with Fig. 3, and the result is a substantial, reliable and inexpensive support for the water heater.

As illustrated in Fig. 5, the pipe I2 is provided with a plurality of discs 38 similar to the discs 3| and similarly spaced and connected with the pipe II, the difference being that the vanes 38a of the disc 38 are inclined at a larger angle to a horizontal plane than are the vanes 3|a. This illustrates the adaptability of the invention for use at different altitudes, even in cases where definite draft regulation on the burner is desir- Thus, discs 3| as illustrated in Fig. 1, hava horizontal plane, may be used effectively for a zone of altitudes at and not greatly above sea level, whereas for a zone of high altitudes, such as mountainous locations, discs 38 having vanes making a substantially larger angle with a horizontal plane, may be used equally effectively, the vanes 38a affording freer flow of the gases through the flue H, than do the vanes 31a. In either case, the damper 31 controls the flow into and through the pipe 38 for different discharge stack drafts, and the damper 31a affords a convenient means for adjusting the net draft effect of the flue l I to a particular amount where such a result is desired. Only part of the water heater construction is shown in Fig. 5, the parts not shown being preferably substantially the same as shown and described in connection with Figs. 1 to 3 inclusive.

While we have illustrated our water heater as provided witha liquid fuel burner, it will be understood that the water heater may be used with any source of heat applicable to the purpose. It will also be understood that water heaters in accordance with our invention, may be used for a variety of purposes, for example they may be used as water heaters for domestic purposes generally, or again, they may be used for space heating purposes in systems in which the heating is accomplished by hot water radiation in the usual manner, or again, our water heaters may be employed as steam boilers generally, by maintaining the water level in the heaters sufficiently below the upper ends of the tanks of the heaters to provide spaces for the steam produced.

While we have illustrated our water heaterias provided with a single heating flue, it will/be understood that where the tanks are of large size or a relatively large radiation surface is required,

7 described, or their equivalent. Where it is de-,

sired to employ a plurality of flues and particularly where the tank is of small size, it may be advisable under some conditions to dispense with I the water heating pipes in the flues and make the supporting columns of the heat directing devices in the form of solid columns, for while such an arrangement may not afiord the emciency per flue that may be secured with a water heating pipe in the flue, the amount of heat transferred from the hot gases through the wall of the flue to the water in the tank is so considerable under the action of our improved heat directing devices, that satisfactory results may be secured for some purposes without the use of the water heating pipes in the flues.

Tests of water heaters in accordance with our invention show a high degree of thermal efficiency of heat absorption by the water, and with- .out noticeable condensation of any kind in the result of whichwater in the tank in contact with the flue is rapidly heated and given a vigorous ,movement upwardly in the tank, thereby minimizing the insulating effect of the fllm or layer of water immediately around the flue.

We are aware that heating experts advance the theory in connection with transferring heat through a heat conductive wall, that the nature ofthe films in contact with the surfaces of the wall exercise much greater resistant efiect to heat transfer, than does the material of the wall itself, so that the material of the wall makes little difference in the effectiveness of transferring heat, for example from hot gases on one side of the wall, to a medium, for example water, on the other side of the wall. Regardless of theory, our tests indicate that the heat transfer through the flue of the water heater, although said flue be ,made of mild steel, is quite effective, and that a substantial part of theefllciency of heating the water referred to is due to the heat transferred from the hot gases through the flue to the water in the tank. We prefer to make the flue l l with a substantial wall thickness, thereby facilitating the maintaining of the inner surface of the flue in highly heated condition, which tends to eliminate condensation on said inner surface. The action of the heat directing devices in the flue H doubtless minimizes the resistant effect of gas films on the flue by the rapid w ir nseeetle of the gases and pressure thereof against the flue. either preventing the formation of said films or breaking up the same after they are formed; and the rapid convection of the water in the tank that is in contact with the flue, due to the rapid transfer of heat to the flue, doubtless minimizes the resistant effect of the water fllm around the flue. In any event, our tests clearly show a high heating efllciency of the water in the tank, and they further show that the heat transfer through the flue and the heat transfer through the water heating pipe where the latter is used, are both substantial factors in securing the results stated.

While we have shown our invention in the particular embodiment above described, it will be understood that we do not limit ourselves thereto as we may employ equivalents thereof without departing from the scope of the appended claims.

'Having thus described our invention, what we claim is a 1. In a water heater, the combination of a tank having an open flue extending throughit, a liquid fuel burner of the wick type at the lower end of said flue and depending for its operation upon a particular amount of draft developed in said flue, and devices including a pipe in said flue for tranfserring heat from within said flue to water in said'tank, the area of cross-section of the said pipe being substantially less than the area of cross-section of the space between said pipe and the flue, the length of said flue and the retarding effect of said devices on flow through said flue being so arranged and related that the resultant flue draft is that required for efficient action of I said burner.

2. In a water heater, the combination 'of a tank having an open flue extending through it,

a liquid fuel burner of the wick type at the lower end of said flue and depending for its operation upon a particular amount of draft developed in said flue, devices including a pipe in said flue for transferring heat from within said flue to water in said tank, the area of crosssection of the said pipe being substantially less than thearea of cross-section of the space between said pipe and the flue, the length of said flue and the retarding effect of said devices on flow through said flue being so arranged and related that the resultant flue draft is that required for eiiicient action of said burner, and means for adjusting said flue draft, whereby the water heater may be used eflectively under different conditions of atmospheric pressure.

3. As a means for transferring heat from hot gases to water in a tank having a vertical and open flue extending through it, which heat transferring means includes in combination a waterheating pipe of substantially smaller diameter than said flue and extending through said flue and connected at its ends with said tank, the area of cross-section of the pipe being substantially less than the area of cross-section of the space between the pipe and the flue, and inclined metal vanes secured to and extending laterally from said pipe in said flue and spaced longitudinally of said pipe, said vanes being in a plurality of groups, each group being substantially in a plane perpendicular to the axis of the pipe, said pipe having an uninterrupted and continuous inner surface, the vanes of each group covering substantially all of the angular extent around the pipe.

4. As a means for transferring heat from hot gases to water in a tank-having a vertical and open flue extending through it, which heat transferring means includes in combination a waterheating pipe of substantially smaller diameter than said flue and extending through said flue andconnected at its ends with said tank, the area of cross-section of the pipe being substantially less than the area of cross-section of the space between the pipe and the flue, and inclined from said pipe in said flue and spaced longitudinally of said pipe, said vanesbeing in a plurality pipe having an uninterrupted and continuous inner surface, the vanes of each group covering substantially all of the angular extent around the pipe, said pipe having separable connection with said tank, and said pipe and said vanes comprising ,a unitary structure readily insertible into and removable from said flue.

5. As a means for transferring heat from hot gases to water in a tank having a vertical and open flue extending through it, which heat transferring means includes in combination a waterheating pipe of substantially smaller diameter than said flue and extending through said flue and connected at its ends with said tank, the area of cross-section of the pipe being substantially less than the area of cross-section of the a liquid fuel burner of the wick type requiring a particular amount of draft for its effective operation, which tank has an open heating flue extending vertically therethrough to serve as a chimney for said burner, which heating means includes in combination a water-heating pipe of substantially smaller diameter than said flue and space between the pipe and the flue, and inclined metal vanes secured to and extending laterally from said pipe in said flue and spaced longitudinally of said pipe, said vanes being in a plurality of groups, each group being substantially in a plane perpendicular to the axis of the pipe, said pipe having an uninterrupted and continuous inner surface, the vanes of. each group covering substantially all of the angular extent around the pipe, said vanes comprising round sheet metal discs cut radially and bent to similar inclinations between said cuts to form said vanes.

6. As a means for heating water in a tank by a liquid fuel burner of the wick type requiring a particular amount of draft for its effective operation, which tank has an open heating flue extending vertically therethrough to serve as a chimney for said burner, which heating means includes in combination a water-heating pipe of substantially smaller diameter than said flue and extending through said'flue and connected at its ends with said tank, the area of cross-section of the pipe being substantially less than the area of cross-section ofthe space between the pipe and the flue, and inplined metal vanes secured to and extending laterally from said pipe in said flue and spaced longitudinally of said pipe, said vanes being in a plurality of groups, each group being substantially in a plane perpendicular to the axis of the pipe, said pipe having an uninterrupted and continuous inner surface, the vanes of each group covering substantially all of the angular extent around the pipe, said flue being of such height in cooperation with the draft-retarding effect of said vanes as to produce substantially the particular amount ofdraft required for effective operation of the extending through said flue and connected at its ends with said tank, the area of cross-section of the pipe being substantially less than the area of cross-section of the space between the pipe and the flue, and inclined metal vanes secured to and extending laterally from said pipe in said flue and spaced longitudinally of said pipe, said vanes being in a plurality of groups, each group being substantially in a plane perpendicular to the axis of the pipe, said pipe having an uninterrupted and continuous inner' surface, the vanes of each group covering substantially all of the angular extent around the pipe, said flue being of'such height in cooperation with the draftretarding efiect of said vanes as to produce substantially the particular amount of draft re-' 1 tion, which tank has an open heating flue extending vertically therethrough to serve as a chimney for said burner, which heating means includes in combination a water-heating pipe of substantially smaller diameter than said flue and extending through said flue and connected at itsv ends with said tank, the area of cross-section of the pipe being substantially less than the area of cross section of the space between the pipe and theflue, and inclined metal vanes secured to and extending laterally from said pipe in said flue and spaced longitudinally of said pipe, said vanes being in a plurality of groups, each group being substantially in a plane perpendicular to the axis of the pipe, said pipe having an uninterrupted and continuous inner surface, the vanes of each group covering substantially all of the angular. extent around the pipe, said flue being.

of such height in cooperation with the draftretarding effect of said vanes as to produce substantially the particular amount of draft required for effective operationof said burner, said vanes comprising round sheet metal discs cut radially and bent to similar inclinations be-- tween said cuts" to form said vanes.

CORTLAND w. DAVIS. WALTER a. m en.

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