US2849991A

US2849991A - Fluid heating unit

Info

Publication number: US2849991A
Application number: US476471A
Authority: US
Inventors: Floyd L Kallam
Original assignee: IND ENGINEERS Inc
Current assignee: IND ENGINEERS Inc; INDUSTRIAL ENGINEERS Inc
Priority date: 1954-12-20
Filing date: 1954-12-20
Publication date: 1958-09-02
Anticipated expiration: 1975-09-02

Description

Sept. 2, 1958 F. l.. KALLAM FLUID HEATING UNIT Filed Dec. 20, 1954 Sept. 2, 1958 F. L. KALLAM .2,849,991

\ FLUID HEATING UNITn Filed Dec. 20, 1954 2 Sheets-Sheet 2 a f5.5 57 7 Igsf j f ,/a/ 5,

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"I A 1 l ,L l l $1 t 43 z3 23 Vp l 5a I la E g /7 2p /7-5 l 055" /8 g sa FL. KALLYAM ATTQRNEY aten dl latenteel Sept. 2, 1958 tice FLUID HEATING UNIT Floyd L. Kallam, Pasadena, Calif., assigner to industrial Engineers, lne., Los Angeles, Calif., a corporation of California The invention relates -to a unitary heater or furnace providing successive coaxial zones of hot-gas heating for ya tube-carried fluid by radiation and convention respectively.

A general object of the invention is to provide a particularly efficient heat exchange in an annular convection zone of a heater of the present type.

Another object is to provide for the ready incorporation of a novel baiiie member used in delining the annular convection zone in heaters of a well-known type.

A further object is to provide for a complete circulation of the heating gases circumferentially through a circular bank of duid-carrying tubes in the convection zone of the heater.

An `added object is to provide a heater structure which is particularly adapted for utilizing a baffle member of the presently disclosed type.

The invention possesses other `objects and features of advantage, some of which, with the foregoing, will be set forth or be apparent in the following description of typical embodiments thereof, and in the accompanying drawings, in which,

Figure 1 is a partly sectional elevation of a verticaltube liquid heater provided with the features of my invention.

Figure 2 is an enlarged fragmentary sectional View showing a portionl of the structure 'shown in section in Figure l.

Figure 3 is a broken-away perspective view of a special baille member which is utilized in carrying out the present invention.

Figure 4 is an enlarged fragmentary sectional View showing `a portion of the structure shown in section in Figure 1.

Figure 5 is an axial section taken at the line 5-5 in Figure 1.

Figure 6 is a fragmentary sectional View taken at the line 6 6 in Figure 1.

Figure 7 is a fragmentary section taken at lthe line 7-7 in Figure 1.

Figure 8 is a section taken on the stepped line 8--8 in Figure 5.

Figure 9 is a fragmentary sectional view taken at the line 9 9 in Figure l.

Figure 10 is a section taken lat the plane of Figure 7, and showing an alternativeinstallation of the baie member in the present heater assembly.

As particularly illustrated, the features of my invention are incorporated in the structure of an industrial liquid heater having a circular bank of liquid-carrying tubes 17 extending axially through 4a cylindrical combustion and -heat-transferv chamber defined within an upright cylindrical metallic shell 18 of circular cross-section provided with la heat-insulation lining 19 disposed between it and the tubes. 'In the present structure, the tubes 17 extend lthrough and between shell-carried lowerand intermediate and uppertube plates 21 :and 22 and 23 respectively.

yThe tubes 17 `are connected in pairs at their tops above the tube plate by U-bend, or junction box, ttings 24, and adjacent tubes of the pairs are connected at their bottoms by like U-bend iittings 25, except that adjacent said tubes of one pair thereof are connected at their bottom ends by elbow fittings with intake and discharge pipes 27 and 2S extending radially of the heater, whereby the tubes of their bank are connected in series between the pipes Z7 and 28 in the arrangement taught in U. S. KPatent No. 2,634,712, which issued to me on April 14, 1953. The upper yand

intermediate tube plates

23 and 22 are annular, and the present tube assembly is suitably supported .from the intermediate tube plate 22 in a manner to provide for and permit the necessary longitudinal free thermal expansions of the supported heater parts.

At its upper end and at one side thereof, the shell 1S mounts an upright stack assembly 31 comprising a cylindrical base portion 31 extending in generally tangential relation to the shell portion opposite said section and upwardly of the plane of the intermediate tube plate 22, and has its ue passage suitably connected with the interior of the shell by connecting radial discharge ports 32 provided in a longitudinal line along the shell, the bottom of the stack section being closed. An upper stock section 31 mounted above the base section 31 mounts a crane arm 33 for use over and from over the top of the shell 1S which is closed by a suitable cap member 34 encloses the top ends of the tubes 17 and the top tube fittings 24 and is removably mounted on the top of the shell portion; the crane arm 33 is provided for use in installing and removing the shell cap 3d and a cylindrical baille member 35 which comprises an element of the present structural and operative combination, said baille member being operatively supported within the tube array at its top and upon the intermediate tube plate 22.

It will now be noted that the heat-exchange space within the shell 13 is divided at the intermediate tube plate 22 into a lower part 36 which provides a chamber for heat exchange by radiation, and that the cylindrical baiile member 35 is cooperative with the radially opposed shell portion above the tube plate 22 to define about the baffle an annular chamber 38 which comprises what may be termed the convection zone of the heater. The bottom of the lower chamber 36, which comprises the radiation zone of the heater, is dened by the lower tube plate 2l and an overlying lining 39 of tire brick or the like, beneath which one or more suitable fluid burners 4l are provided for discharging llame jets into the chamber through a jet passage provided through a tubular member i2 mounted in the chamber bottom. Alternatively, hot gaseous combustion products from a separate combustion zone may enter the heating chamber through the members 42 for accomplishing the present tube-heating purpose. Also, the hot gases which are to provide a tubeheating stream through the chamber `3e are not necessarily combustion products, and may, for instance, cornprise air which has been electrically, or otherwise, heated within or Without the chamber.

The hot gases entering or generated in the lower chamber 36 are arranged to flow upwardly therein to and through the central opening of the intermediate tube plate 22 which is defined inwardly of the bank of tubes 17, and therefore provides thereat a slight contraction of the rising stream of the hot gases which pass upwardly and longitudinally in the lower chamber 36 to provide for a chiefly radiant transfer of heat from the gases to the tubes and so to the liquid stream Vcirculating through the tubes whereby this space comprises a radiation zone of the heater by reason of this major manner of heat exchange therein. It will be understood that the iinal heat-exchange action of the present heater occurs in the zone 3S in which the convection flow of the heating gases into the stack is responsible for the gas flow relations provided through l the heater, and that the heating gas reaching the convection zone 38 is cooler than the heating gas supplied at or to the bottom of the radiation zone provided by the lower heater chamber 36.

A present baille member 35, it will now be noted, essentially comprises a hollow cylindrical body which has a closed upper end 43, a side wall 44, and is fully open at its bottom edge rim 45 from` which it is supported on the intermediate tube plate 22. The side 44 of the mounted baffle member 35 is cooperative with the opposed upper shell lining portion 19 to provide the annular convection heating zone 38 in which heat exchange takes place by the flow of gases laterally against and about the tube portions therein. The heating gases are arranged to flow from the cavity of the baffle member 35 into theconveo tion zone 38 through a line of openings 47 provided through and along its side 44 as comprising the operative equivalent of a single elongated port thereat. For facilitating the heat exchange action in the convection zone 38, the tube portions within the space may mount annular heat-conducting tins 4S for assuring a maximum heatexchange action with respect to the liquid stream in the tubes.

As particularly brought out in Figures 2 to 5 inclusive, the baille 35 has its top 43 and side wall 44- formed of a refractory material, has a rigid metallic plate 50 xed to and against its upper end 43, and is fixed to a suitable overhead assembly 51 in a manner to facilitate its handling and preserve its entity. In the present structure, the assembly 51 comprises a shallow drum-like structure having the diameter of the baille and comprising upper and lower circular plates 52 and 53 integrally connected by a cylindrical wall 54, and the baille 35 is connected to the assembly S1 by tension rods 55 extending longitudinally through its side 44 at spaced points thereabout, and from a ring member providing the rim edge 45 of the baille to a bolted connection with the bottom plate 53 of the as sembly 51. A lifting lug 57 providing an eye for engagement by a hoisthook is provided Aon the upper side of the member 52 of the assembly 51 for use in installing and removing the baffle by the use of the crane 33.

The present baille assembly, while carried on the intermediate tube plate 22, is preferably placed in either one of two relations with respect to the row of port openings 32 leading to the stack. In Figures 1 and 5 to 7 inclusive, the baille discharge port provided by the linevof port openings 47 is shown as disposed diametrically opposite the shell discharge port provided by the line of ports 32 whereby hot gases entering the convection zone 3S through the baille 47 are divided for flowing semi-circumferentially through the convection Zone 38 to and through the discharge ports 32 leading to the stack` Figure Vl 0 shows an alternative arrangement in which the convection zone 3S about the baffle is divided adjacent the ports 32 by a radial partition 58, and the baille ports 47 are disposed at the opposite side of the partition 58 from the ports 32 whereby hot gases entering the convection zone must flow in the same direction completely around the baille before they reach the stack. With either disclosed positioning arrangement ofthe baille 35 in the heating chamber, the peripheral flow of gases in the convection zone 38 to utilize to the fullest the heat remaining in the hot gases after they have left the radiation zone 36 of the heater in which heat exchange initially occurs.

It will now be noted that the intermediate tube plate 22 must have a particularly rigid assembly and support by reason of the fact that the tubes 17 are supported therefrom in their line inwardly of the supporting shell 18. As particularly brought out in Figures l and 4 and 9,l this tube plate comprises a unitary assembly fabricated of mutually parallel spaced upper and lower annular metallic

flat rings

61 and 62 respectively provided with mutually coaxial holes freely but closely receiving the tubes 17 of the bank thereof. The outer peripheries of the

rings

61 and 62 are 'welded or otherwise secured directly to the heater shell 18, and a continuous tubular element 63 is welded or otherwise securd'tothe initier priphries of the

rings

61 and 62. Spreader plates 64 extend radially and axially in the annular space between the

rings

61 and 62, and are welded or otherwise fixed to said rings and the connecting element 63, whereby the assembly provides a rigid cellular tube plate for the tubes i7. For avoiding excess heat effects, the cells of the tube plate assembly 22 are preferably connected with the atmosphere exteriorly of the heater by means of holes 66 provided at points of the shell 18'opposite them.

The independent support of each tube 17 on the tube plate 22 is effected by suitably fixing, as by welding, a ring or collar 67 to the tube below the lower tin 43' for its direct bearing on the upper ring 61 of the tube plate. By particular reference to Figures 4 and 9, it will be noted that the upper portion 19' of the refractory shell lining rests upon the upper tube-plate ring 61 and is annularly'extended inwardly thereover and beneath the lower fin 48 and to the tube circle thereat as a flange 68, the edge of the lining base flange so provided being formed with semi-cylindrical notches at each tube, each said notch having a radius slightly greater than that of the collar 67 to permit an upward removal of the tube from its seated position on the tube plate 22.

The top of the lower lining portion `19" is provided with an inwardly directed flange port 70 having a lower radial portion 71 perforated in the tube` circle to freely receive the tubes and providing an annular seat for the tube plate unit 22 at its top face. Inwardly, of its platesupporting seat, a tubular portion 72 of the flange 70 extends upwardly and is surmounted by a radial portion 73 which extends outwardly from the portion 72 in the plane of the flange 68 of the upper lining section 19 to the circle of the tubes and has its outer edge complementarily notched as the flange `65S for receiving the heater tubes 17. For sealing the tubes 17 with respect to the tube plate 22, the annular spaces defined above the support collar 67 by and between the complementary notches of the flange 68 and the flange portion 73 `is preferably sealed with a friable sealing filling 74 of fire clay or the like above the collar 67 whereby to permit an independent upward removal of each tube from theL heater. The arrangement of the flange 70 is essentially such that the bai-lle 35 may supportedly rest upon the portion 73 thereof inwardly of the tubes, it being noted that the metallic tube plate 22 is thermally insulated by 'the present arrangement from both the radiation chamber 36 and from the convection zone 38.

It will be understood that 'the present provision for the common support of the tubes 17 and the baille 35 upon the intermediate tube plate structure 22 provides for the corresponding longitudinal elongation and contraction of the furnace and baille structures in opposite direction with respect to the tube plate 22 by reason of temperature changes therein whereby 'thermally induced strains in the assembly are kept at a minimum. Also, most of the present novel features of invention relating to the baille 35 may be advantageously provided in a furnace having the longitudinal axis of its tube bank horizontal and the stack Vconnections at its upper side.

From the foregoing description taken in connection with the accompanying drawings, the advantages of the present heater construction will be readily understood by those skilled in the art to which the invention appe'rtain's. While I have shown anddescribed arrangements which I now consider to be a preferred embodiment of my invention, I desire to have it understood that the showings are primarily illustrative, and that such changes and developments may be made, when desired, as fall Within the scope of the following claims.

I claim: p v

1. In a fluid-heater, a metallic wall defining an upright cylindrical chamber having a closed top end and arranged for the upward heat-exchange flow of initially hot gases longitudinally therethrough and provided with a discharge port for the gases adjacent its said top end, a bank of liquid-carrying tubes disposed about the periphery of the chamber space and extending longitudinally therethrough, an annular tube plate assembly extending inwardly from the furnace wall in xed relation thereto intermediate of the chamber and supportedly and sealedly engaging the bank of tubes thereat, said tube plate assembly comprising spaced annular metallic plates connected by the chamber wall and by a tubular wall at their inner edges to deline between them an air space which is radially partitioned to dene spaced portions having the tubes passing through the different portions thereof, and support flanges fixed to the tubes and resting on the upper plate member of the tube plate assembly, said furnace wall being provided with vent openings opposite each of the said 15 spaced portions.

2. A structurel in accordance with claim 1, having a baille element carried directly on and above said intermediate tube plate assembly and cooperative with the opposed chamber side wall portion and the said plate assembly to provide an annular convection-flow chamber containing corresponding portions of the tubes of the bank thereof.

References Cited in the le of this patent UNITED STATES PATENTS 2,514,279 Gleber July 4, 1950 2,592,608 Sherman Apr. 15, 1952 2,625,140 Weir Ian. 13, 1953 2,634,712 Kallam Apr. 14, 1953