US2638878A - Water heater having extensive heat transfer surfaces - Google Patents

Description

May 19, 1953 A, I EMOS, JR., ErAL 2,638,878

WATER HEATER HAVING ExTENsIvE HEAT TRANSFER SURFACES Filed Jan- 19, 1951 4 Sheets-Sheet l May 19,1953 Af. LEMos, JR., ETAL 2,638,878

` Filed Jan. 19 1951 4 Sheets-Sheet 2 WATER HEATER HAVING EXTENSIVE HEAT TRANSFER SURFACES INVENTORS.v CZ! ex Lanos, Jr. LC/zazd Czllznyhazmdjv May 19, 1953 A. Limos, JR.,

ETAL

WATER HEATER HAVING EXTENSIVE HEAT TRANSFER SURFACES Filed Jan. 19 1951 4 Sheets-Sheet 5 1720 c/zaui Cz INVENToRs l@ .5', Z 1212112 ,di

May 19, 1953 A. LEMos, JR., ETAL WATER HEATER HAVING ExTENsIvE HEAT TRANSFER sUREAcEs Ei-.ld Jan. 19, 1951 4 Sheets-Sheet 4 INVENToRs.

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Patented May 19, 1953 WATER HEATER HAVING EXTENSIVE HEAT TRANSFER SURFACES Albert Lemos, Jr., Hinsdale, and Richard `Cunningham, Jr., Downers Grove, Ill., assignors to Vapor Heating Corporation, Chicago, Illv.,a corporation of Delaware Application January 19, 1951, Serial No. 206,888

This invention relates to improvements in water boilers and has for one of its principal objects to provide an exceptionally compact as well as highly eiiicient water boiler unit which is particularly well adapted for use where space is at a premium.

Another major object is to effect an improvement in heat transference with the end in View of greater efficiency in the utilization of available heat units, whereby a larger volume of fuel may be burned than is practicable in other boilers of similar size and whereby a correspondingly larger volume of water can be heated in a comparatively small boiler.

The boiler structure of the present invention was designed primarily to supply hot water to the hot water heating system of buses, private or railway office cars and standby hot Water heaters for diesel locomotives, automobile parking lots, and for other installations where it is of special importance that the unit be as small as practicable in order to conserve space and at the same time have an exceptionally large output of hot water. But the novel features of the invention are substantially, if not equally applicable, to larger units intended for use Where space conservation is not of paramount importance,

i The novel features characterizing the subject invention will be pointed out in conjunction with the ensuing detailed description, having reference to the accompanying drawings, wherein:

Fig. 1 is a side elevation of a small size but 'high capacity boiler incorporating the novel features of the invention and designed more especially for use where conservation of space is a major factor;

Fig. 2 is an endwise elevation of the same unit Viewed at the left-hand end of Fig. 1;

Fig. 3`is an endwise elevation as viewed at the right-hand end of Fig. l

Fig. 4 is a longitudinal sectional view through the Water heater itself, together with a blower `for delivering combustion air into the re chamber, certain other components of the structure being shown in elevation; and

Fig. 5 is a transverse section taken at line 5-5 of Fig. 4

Some of the major components of the illustrated unit are: the water heater per se or boiler I; an oil burner I2; an electric motor I4; a blower I; a fuel pump I6, air damper control I3, and a magneto or othery spark voltage generator I'l. Still other major components, such as the switch cabinets II, Ila, stack switch 8, and thermostats 9 andV 9EL for controlling the operation of 5 Claims. (Cl. 122-136) the burner are shown, but not specifically' described, since they are of no special significance so far as the subject invention is concerned.

The motor I4 is connected at one end to the magneto Il and at its other end to the shaft of the blower I5 and fuel pump It. The motor operates under the control of the thermostats 8, 9 and 9a to drive the fuel pump and blower as Wel-1 as the magneto and is under the control of various switches and other control devices enclosed in control cabinets II, Ila.

The water heating unit or boiler I comprises an outer cylindrical shell 2t within which is disposed concentrically an interior cylindrical shell 2|, which latter forms, conjointly with the outer shell 2B, a water preheating chamber 22 of annular cross-section, as viewed in Fig. 5. This preheating chamber is also referred to herein as an outer water jacket 22; and the elements of which it is constituted may, conformably, be referred to as the outer water jacket assembly. End plates 23 and 24 and the dished header 25 Welded to the shells serve to completely enclose the outer water jacket or preheating chamber 22 so that it is water tight except for inlet and outlet connections,

Inside the interior shell 2I and concentric therewith is the main water heating chamber 3Ii-otherwise referred to as the inner water jacket. This is annular in form, as viewed in Fig. 5, and consists of concentric inner and outer smooth wall tubes 32 and 33, having their ends formed with complementary curved flanges, welded together as indicated at 34 and 35 in Fig. 4. A water inlet fitting 38 and water outlet fitting 39 are welded, as shown in Fig. 4, to the lefthand end of the inner water jacket assembly comprising tubes 32 and 33 and conduit fittings 38, 39 which provide water inlet and outlet conduits which communicate with the inner water jacket 30. Said fittings 38 and 39 enter the inner water jacket assembly 30 through tubular sleeves 4c and 4I welded to the end plates 23 and 25 of the outer Water jacket and heating chamber, respectively. The said fittings 33 and 39 are provided with flanges 42 and 43 which bear against the inner ends of said sleeves.

Water from a feed pump (not shown) or any source of supply enters the outer water jacket or preheating chamber 22 through an inlet port 45 shown at the lower left-hand corner of Fig 4- which inlet .port communicates with the cold water supply source through a pipe liiisee Figs. 1 and 2. Preheated water discharges from chamber 22 through an outlet port 4l (Fig. 4) and passes by way of a conduit 4S to the inlet fitting 38 where it enters the main water heating chamber or inner water jacket 3b, whence it emerges through the outlet fitting 39 and is conducted to the location where it is to be used. Ii the unit is employed as a part of a space heating system, water from the radiators may be returned to the inlet port 55; but if it is used purely for hot water supply the inlet port 45 is connected to a service water supply line or to a water reservoir, as the case may be.

A group of thermally conductive, usually steel, rings e, fourteen in number in this instance, are welded, with continuous welds, at their peripheries to the interior surface of tube 32; and an equal number of similar but larger diameter thermally conductive rings 5l are likewise welded to the outside surface of tube 33. Each ring or n 5b is formed to present a continuous series of inwardly projecting circumferentially spaced teeth 5de; and each ring 5| is similarly formed to present a continuous series of outwardly projecting circumferentially spaced teeth 51a. rThe spaces between consecutive teeth, in each instance, are preferably of the same order of width as the teeth themselves. However, the relative width of the teeth and intervening spaces is not extremely critical. Preferably, the depth of the teeth, radially, is at least a major part of the radial width of the ring and usually is at least equal to two-thirds of said radial width. Generally speaking, the greater the radial depth of the teeth the better, and in every case should be substantial. It is desirable that alternate rings be so positioned circumferentially that their teeth are at least approximately aligned, axiswise of the heating unit, with the spaces between the teeth of the adjacent rings. This is adequately illustrated in Fig. 4 wherein it will be seen that the plane of the section passes radially through the teeth of alternate rings, whereas it passes radially through inter-tooth spaces, as respects the remaining rings. The primary function of the rings 50 and 5l is, of course, to augment the transference of heat into the chamber 30; and they accomplish that result not merely by increasing the surface area exposed to the hot gases but also by creating a kind of turbulence, which experience proves to have the effect of increasing heat transference to a substantially greater degree than could be realized in practice With untoothed rings, or with toothed rings which are not staggered.

The fuel burner l2 comprises a nozzle or spray head assembly 55 located axially of the heater unit and supported by a header 55 which forms a closure for the right-hand end of the unit, as viewed in Fig.. 4. Forwardly of the spray head assembly 55 and Isupported thereby are a pair of spark electrodes 51 which are connected to the magneto I7 (Fig. 1) and serve to ignite the atomized fuel discharged from the spray head.

A stabilizing cone 58 is mounted just forwardly of the spray head and. spark electrodes and is bolted to a plate 59 which, in turn, is welded to a tubular sheet metal member 60 ysurrounding and defining the space El known as the repot; and the latter is terminated forwardly in a frusto-conical sheet metal member 62 known as the flame deiiector cone. Concentric with and encircling the tubular member Sii is another tubular sheet metal member 53 known as the air baiile and radiant heat shield. The latter is supported by the header 5S through the medium of several bolts t4, and is centrally located by means of spacers 65. The assembly comprising the tubular member Eli, plate 59 and stabilizing cone 58 is supported at its left-hand end, Fig. 4, by three brackets a equally spaced circumferentially and welded to the member and, in turn, attached to an annular plate or ring 65 by means of bolts 61. The plate or ring 66 is removably attached to the ring 24 by means of studs I0 and nuts ll. These latter serve also to grip a gasket T2 and a ilange 'i3 which is welded to a tubular shell 74 of the same diameter as the outer shell 20. It will be observed that the right-hand end of shell M, Fig. 4, is flanged outwardly to match the adjacent edge of the header 5B and that said header and shell are detachably coupled together by means of a band clamp 15, the ends of which are drawn together by a tie-bolt 'i5 as shown in Fig. l. The radiant heat shield 53 is unattached at its left-hand end, and such being the case, it will be apparent that by first removing the band clamp 'i5 the header 56 together with the nozzle 55, spark electrodes 51 and radiant heat shield 63 can be withdrawn from the unit as an integral sub-assembly. Thereafter, the elements 58 to 62 inclusive can be released for detachment by removing the nuts from bolts E51.

A discharge conduit connects the blower i5 with the chamber 3| through the outer shell 'i4 and is so oriented that the blast of incoming air strikes the baiiie 63 tangentially, see Fig. 5, and is thus caused to follow a vortex path around the baiiie, thereby creating a whirlwind or turbulence effect. A part of the rotationally circulating air` passes through the openings 58a of the stabilizing cone 58 into the firepot 6i; another part enters the repot through an annular slot-like opening 82 between the stabilizing cone 58 and the plate 59 and still another part proceeds along the annular passageway 83 leftwardly, as viewed in Fig. 4, and enters the repot 6I through a slot-like annular opening 84. It will be clear from the foregoing that the hot gases of combustion are whirling at a rapid rate within the iirepot 6I and that they continue to whirl at a like rate as they emerge from the opening in flame detector cone.

52 and enter the heat transfer chamber or bore 85.

The whirling hot gases in the heat transfer chamber 85 move forwardly, that is -leftwardly as viewed in Fig. 4, while at the same time being urged outwardly from the longitudinal axis of bore 85 by the centrifugal force resulting from the whirling action. Thus, the hot gases are kept in agitation and in intimate contact with the interior surface of the inner tube 32 and with the rings 5i! and teeth 59d thereof. Manifestly, if the rings 50 were not ldentured, as above described, there wculd be pockets of -cooled gases between adjacent rings which would behave to a great extent as thermal barriers and thus keep the hot gases from making fully effective contact with the heat-absorbing surfaces. The inter-tooth spaces prevent or at least lessen the formation of such thermal barriers, While at the y same time the staggering of the teeth as between consecutive rings introduces enough impedance to the forward movement of the hot gases so that the heat is efficiently extracted therefrom Without allowing the gases to become trapped to any serious extent. Furthermore the turbulence of the flame and hot gases insures complete combustion of the gaseous fuel and insures repeated wiping contact of the flame and hot gases with vthe toothed rings 5i) and with the surfaces of the'tube 32 kbetween said rings vso as to procure high efciency in heat transfer.

The gases of combustion move the entire length of chamber 85, as viewed in Fig. 4, and then enter the left-hand end of the annular passageway 86, along which they -proceed in the opposite direction to a flue 8l, Figs. 2 and 4, near the righthand extremity of said passageway.

The partially cooled gaseous product `of combu'ston traversing passageway 80 gives up a portion of its residual heat to the Water in the inner water jacket 30 and a further portion to the cold water in the outer water jacket or preheating chamber 22; and by the time it reaches the flue 8l its temperature has dropped to a low value. Hence, very little heat is lost. Obviously, the staggered inter-tooth spaces of rings 5| have much the same effect as the analogous spaces between the teeth of rings 50.

The inner water jacket or main heating chamberv 30 contains only a small quantity of Water;

and that coupled with the large heat transfer area aorded by the rings 50 and 5|, in conjunction with the exposed-surfaces of the inner :and outer tubes 32 and 33, makes it possible to heat large bodies of water at locations remote from the boiler, for example, the radiators of a railway car heating system or to deliver stand by heat to the engines of diesel locomotives and/or bus engines stationed in a parking lot. The described arrangement of the heat absorbing rings and their teeth produce a high degree of turbulence in the heating chamber 85, together with the further varrangement whereby a major -portion of the residual heat is absorbed by the Water in the outer water jacket 22 makes for extraordinary eiciency of fuel utilization.

The revolving gases of combustion give rise t0 turbulence not only in the heating chamber 85 but also in the passageway 8'6, and this is responsible in large 4degree for the efficiency with which the heat is transferred to the Water in both the inner and outer water jackets.

A feature of the invention which should not be overlooked is that the water in the outer Water jacket serves, in effect, as a thermal insulator so that it is not necessary to lag the outside of the unit. The preheated water is never so hot as to give rise to inordinate losses via the vouter shell 20, either by way of conduction or radiation. Similarly, the water in chamber 81a at the lefthand end of the unit, Fig. 4, which chamber forms an integral part of the outer Water jacket, serves also Vas an insulating medium, making it unnecessary to lag that end of the unit and also prevents overheating of the end Wall or header 25.

Another feature contributing to the high efficiency of the described heater is that the structure of the main or inner Water jacket :assembly comprising the tubular members 32 and 33 to- -gether with rings 50 and 5| is supported at its right-hand extremity in a ring 90 of re clay or other suitable material which, in turn, is supported by a frusto-conical flange 9| Welded to the plate v|56. The ring 90, While affording :ample lphysical support, is effective to restrict losses due to thermal conduction away vfrom the very hot inner water jacket.

It is preferable Where sulcient space is available to mount the unit in horizontal posture, as depicted; but it will operate equally well in vertical posture :and may be -so mounted whenever space limitations demand. When the unit 1s mounted in a horizontal position, any accumulation of condensation on the walls of the passage 86, when the unit is out of service, may be drained "6 through part 92 by removingv the plug92a. When the unit is supported in a vertical position wherein the end :at the left of Fig. 4 serves as the bottom of the unit, the said -condensation will ldrain into the space v93'and discharge through a central opening 94.

In order to prevent undue cooling .of the heating chamber, when there is momentarily shut off, the air inlet passage 95 is provided with a normally closed damper 96. The damper is supported on :a shaft 91 which extends out of the air passage 95 and is provided with a slotted operating lever 98. A piston 99 Operating in a cylindrical fitting |00 is provided with a stem |0'|, the upper yend |02 of which is turned at an angle and extends into the slot of the damperA operating arm 98. A tube |03 connects the cylinder |00 with the oil pump |6 -so that when oil is delivered -under pressure to the spray head the Aoil pressure Will also be transmitted through the tube |03 to the piston 99 so as to move the piston upwardly and thereby open the Idamper 93. When operation of the fuel pump is discontinued a coil Spring |04 returnsthe piston 99 to its lower position (Fig. 1) and, therefore, moves the damper 96 to a position to -substantiallyclose the air inlet duct 95. The fitting |00 may be secured to the inlet conduit-95 by means of a bracket |05.

While we have illustrated and described only one embodiment of our invention, it will be evildent that there are numerous possible modifications and alternatives within the purview of our broad inventive concept. And although the invention is singularly Well adapted for incorporation in a small highly compact water heating unit such as that shown and described, it is none the less useful and practicable for employment in larger units. Hence, we do not wish to be limited either as to the particular details of construction or as to the size of the unit-the only inten-ded limitations being those clearly indicated by the express terms of the appended claims.

We claim:

1. A boiler structure of high capacity in relation lto its size comprising, in combination, a cylindrical Water jacket comprising concentrically arranged tubular sections, the inner section of which denes the side wall of a cylindrical heat transfer chamber, a fuel burner including :a cylindrical repot located at one end of said Water jacket and means for directing combustion air into the frepot tangential to its side wall and operative to form a vortex ame yand to direct said flame and hot gases of combustion axis-wise into the heat transfer chamber of said water jacket, and a plurality of thermally conductive rings of identical construction `arranged co-axial With and metallically bonded to the inner Wall of said -Water jacket and spaced apart axis-Wise thereof, whereby the vortex flame and hot gases swirl around the heat transfer chamber between said rings, each of said rings having a plurality of circumferentially spaced teeth projecting toward the axis of the Water jacket, the teeth of each ring being of a depth, radi-ally, lat least equal to a major portion of the radial width of the ring and arranged in staggered relation with the teeth of adjacent rings to provide tortuous passages for directing portions of said swirling flame and gases axially of said heat transfer chamber.

2. A boiler structure according to claim 1 characterized by the provision of a cylindrical structure surrounding said water jacket and cooperating therewith to define an annular passage communicatingwith the heat transfer chamber at the end remote from said repot and adapted to receive the hot gases from said heat transfer chamber and further characterized by the provision of a second group of toothed rings secured to the outer surface of said Water jacket and projecting radially outwardly in said annular passage into close relation to said cylindrical structure, each ring of said second group being formed with outwardly extending teeth having a depth equal at least to a major portion of the radial width of the ring and arranged in staggered relation relative to the teeth of adjacent rings to provide tortuous passages for1 ydirecting portions of the hot gases axially of the said annular passage.

3. A boiler structure according to claim 2 characterized in that said cylindrical structure is provided with spaced Walls defining a second water jacket having inlet and outlet `ports and means connecting the sai-d outlet port with the interior of the iirst mentioned Water jacket.

4. A boiler structure according to claim 3 characterized in that the second group of toothed rings are metallically bonded to the outer surface of the rst mentioned water jacket.

5. A boiler structure according to claim 4 characterized in that the second Water jacket in- 8 cludes a Water containing end portion which extends substantially across the heat transfer chamber at the end remote from-said repot and provides a Water cooled re Wall at the said remote end of said heat transfer chamber.

ALBERT LEMOS, JR. RICHARD CUNNINGHAM, Je.

References Cited in the file of this patent UNTED STATES PATENTS Number Name Date 551,409 Alley June 2, 1896 704,600 Vanderborght July 15, 1902 1,032,532 Constantinescu July 16, 1912 1,441,184 Smith et al Jan. 2, 1923 1,742,063 Didgeon Dec. 31, 1929 1,781,532 Summers Nov. 11, 1930 1,880,533 Thomas Oct. 4, 1932 2,187,917 Skinner et al. Jan. 23, 1940 2,225,606 Beauvais Dec. 24, 1940 2,288,021 Ostermann June 30, 1942 2,321,109 Sellers June 8, 1943 2,531,459 Marshall, Jr Nov. 28, 1950 FOREIGN PATENTS Number Country Date 511,138 Great Britain Aug. 10, 1939

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