US1795055A - Hot-air heater - Google Patents

Description

March 3, 1931. R. T. TAYLOR ET AL HOT AIR HEATER Filed Aprii 25. 1928 3 Sheets-Sheet l INVENTORS 1 By Attorneys, a- MW w/ l l l L March 3, 1931. R. T. TAYLOR ET AL HOT AIR HEATER 3 Sheets-Sheet 2 Filed April 25, 1928 INVENTORS By Attorneys;

March 3, 1931. R. T. TAYLOR ET AL 1,795,055

HOT AIR HEATER Filed April 25, 1928 3 Sheets-Sheet 5 INVENZORS m I 10%w/[5 b By Attorneys,

Patented M... 3, 1931 "UNITED .sTATss;

PATENT OFFICE REUBEN '1. TAYLOR, OF BROOKLYN, AND

WILLIAM u. WALLACE, m, or norms,

NEW YonK; assrenons 'ro CHARLES HARTMANN serum, or BROOKLYN, new YonK, A CORPORATION on NEW YORK nor-am HEATER I Application filed April 25,

This invention relates to so-called hot-blast heaters used mainly in heating and ventilating outfits for heating the air entering an. apartment, the heating medium being steam or hot water. It relates to such heaters ofthe type having a series of parallel tubes containing the heating medium, the blast or current of. air being circulated across and between-the tubes in a direction transverse to be made manifest as the top through the tubes; usually the tubes are vertical and are flattened, the heating medium entering at a header, and the discharge being collected. at the bottom by another header; between the headers the air current passes usually in horizontal direction. The

invention further relates to. heaters of this character wherein the air is broken u by metal plates applied against or aroun the tubes and in heat-conducting contact with them, so that these plates are heated by the tubes'and afford an extended surface for conductin heat to the air. Such plates have hereto ore been made with angular or sinuous surfaces so as to slightly bafile the flow of air and cause the air to impinge alternately against the upper and lower surfaces of contiguous plates, whereby to cause the air to more effectively take up heat from the plates. v

The invention aims to improve the construction and increase the efiiciency of heaters of the type described. I-ts novel features will the description proceeds. The accompanying drawings show suitable embodiments of the invention a plied both in heaters having a singlerow of attened tubes and in those having a double row of tubes. Inthe drawings,-'*-

Figure 1 is a side elevation ofa heater partly broken away so as to show the headers, tubes, and bafile plates, in vertical section, the plane of this section being on the line l-1 in Fig. 2;

Fig. 2 is a 2-2 1, V 5

Fig. 3 is an end elevation of theconstruction shown in Figs. 1 and 2'.

Fig. 4 is a similar end elevation, but showing a p rt of the casing enclosing the heater and illustrating also a heater having only a horizontal section on the line 192s. Serial no, 272,71

single row of steam tubes and showing also a different shape for the headers.

Fig. 5 is a detail on a larger scale of the lower part of Fig. 4, being partly in vertical sectionthrough the axis of one of the tubes.

Fig. 6 is a vertical section on the same scale as Fig.5, and on the line 6--6 therein.

Fig. 7 is a perspective view of a nozzle or plug.

Fig. 8 is a plan thereof.

Fig. 9 is a plan of a fragment of one of the bafile plates, and a Fig. 10 is an edge view thereof.

Fig. 11 is a sectional elevation similar to Fig. 1, but showing also the supporting casing and illustrating the single tube construction shown in Fig. 4.

Fig. 12 is a fragmentary view, being'a perspective or oblique projection of the upper partof the heater shown in Figs. 4 and 11. a

Fig. 13 is a plan of the top header of Fig. 11. v a

Fig. 14 is an elevation of a modified form of header.

Referring to all of the drawings, a is-an inlet pipe conducting steam or other;heating medium into an u per header A; B B are the heating tubes wh1ch.receive steam from the upper header A and which dischar the spent medium into a lower header from which leads a drainage or outlet pipe 0. The inlet and outlet pipes are shown in Figs. 1, 2 and 3 as horizontal pipes adjoining the ends of the respective headers; in Figs. 11 and 13 they are shown as vertical pipes, the one entering the top side of the upper header A, the other leading from the bottom side of the lower headerC. The casing D is shown in Figs. 4

and11 and consists simply of a four-sided these ba it .ima

' to traverse the heater are well understood and form no part 'of'thepresent invention.

In heaters of this general character it is customary to flattenthe tubes B B carrying the steam or other heating medium, their flat sides being in planes corresponding to the direction of flow of air through the heater. It is also customary to apply to or between these tubes, baffle plates E E in such manner as to force the air to flow in a slightly sinuous or zigza path. The principal purpose of lates is to receive heat from the tubes and istribute the heat to the flowing air. In the constructions heretofore proposed the baflle plates have had only edge contact with the tubes, their union being efl'ected by soldering or brazing whereby the heatconductive joint is somewhat improved as compared with. a mere edge contact of metal, although the heat conductivity thus attained is ot in proportion to the increased area of the soldered surfaces because the alloys used for soldering or brazing have heat conductivity greatly inferior to that of copper or brass, which are the metals best utilized for the-baflie plates. .According to the present invention we greatly increase the heat conductivity at the j unction between these plates and the tubes by forming the'plates with upturned flanges which closely embrace the sides or external faces ofthe tubes over a considerable area. This construction is best shown in Figs. 5, 6 ,and 10, where the balfle plates E E are formed with upturned flanges I b b which lieclose against the outer faces of the tubes and are best made of such a close fit that they require to be forced into place in passing them over the tubes. In this manner such'in timate and extended contact is secured as to afford a greatly improved heat conductivity without necessarily any, resort to solder. It is preferable, however, to sol-' der the parts by dipping in a solder bath, fwhich leaves mlnute films of solder filling any slight interstices between the flanges and the tubes; and the poorer heat conductivity of the solder is compensated for by the great- 11yl increased surface contactaccomplished by t e turning up of the flanges. Y To insure the correct and equal spacing of the baflle plates the upturned flanges, or at least some of them, are made also to serve as s acing .stops. Referring to Fig. 10, the anges 6 project a distance equal to therequ-ired spaces .between theplates so that, as shown in Figs. 5 and 6, they insure the correct spacing of the plates by simply pressing each upper plate down until it rests upon these gaugingefi'ect, applies on both sides. This, in connection with the pe endiciilar upturn? ing of the flanges, insures t at the plates shall he parallel, as shown in Fig. 6. The plates are punched out by dies-which form an offset slit m, shown in Fig. 9, and the flanges are then turned up onboth sides as far back as the dotted line 3 in Fig. 9, with the result of .forming alternating shorter and longer flanges b b, as shown in Fig. 10. r

The baffle plates, instead of being corrugated in curves, or in very sharp and abrupt steps as heretofore (which constructions have the disadvantage of obstructing'the flow of air by breaking up the air current into numerous eddies "which oppose the flow), are bent to form angularly-related surfaces, as clearly shown in the cross-sections, Figs. 5 and 10. The angles of these surfaces are such as to alternately deflect the currents of air flowing through between the plates so as to promote the most intimate contact between the air and the plates, but without the formationof-eddy currents, which would obstruct such flow. The preferable angular relation is that shown, whereby the successive planes present an angle of 150 degrees to one another, or depart by 15 degrees from a medial horizontal plane. This angular relation has been carefullyascertained .as that which attains the most efficient heat convection with the least obstruction to the flow of air.

The baflle plates are shown as having five such angular portions of equal width, plus a The headers A, C, are constructed of sheet metal (preferablybrass or copper) 'and are best made as duplicates; they are formed each of an upper and lower section having meeting flanges f united by brazing. For vertical inlet and outlet pipes it is preferable to use the construction shown in Figs. 4, 11, 12 and 13, where the upperand lower sections 9, h, are of equal width, so that the abutting flanges 7 forma medial joint, as clearly shown in Figs. 11 and 1-2. The sections 9, h, are thus made exactly alike, except that one of them isperforated to receive the tubes B B. They have flat upper and lower faces which are perforated where the respective tube or pipe connections are made. The inlet a is screwed'into a nipple i (Fig. 11) having a flange j which issoldered within the header; similarl the outlet pipe c is screwed into a nipp e 71' having a flange j which issoldered into the lower section 9 ofthe header C. The sections h 7:. of the two headers have their flat sides perforated to re- I ceive theends of the tubes B B the ends of the tubes pass through the holes thus puncgad m m the" flattened portion and the joint is united b brazing, as shown at k in Figs. 5 and 6. Tile construction just described is suitable for heaters having a single row of tubes B; for those having a double row of tubes the construction shown in Figs. 1, 2 and 3 is preferable. In this construction the headers A and C are made of sections g, h, of unequal width, so that their flanges f form a joint which is in a plane somewhat "closely approaching the plane of the flat side of the section it, this flat side being of increased width in order to be punched with holes for receiving the two rows of tubes B B. These tubes B B are preferably in staggered relation,

as clearly'shown in Fig. 2. This construction best lends itself to the application of inlet and outlet pipes at, 0, at the ends of the headers. For this purpose the header ends are made as separate pieces or heads m, n, respectively; the heads m are of cast metal" suficiently massive to form threaded openings for receiving the respective pipes; the

- heads at at the opposite endsof the headers may be made of thin metahas their function iss'olely to close the ends of the headers; in the case of both heads, the sheet metal of the header sections is brazed toflanges or portions'of the headswhich enter within the ends of the sheet metal sections. Y

In order to effect a uniform distribution of steam (or other heating fluid) from "the header A into the tubes B B, inlet nozzles in the form of plugs are provided, lettered G G; one of these is shown separately in Figs. 7 and 8. These nozzle plugs are formed with a convex portion ,0 having an outer flan e g and diminishing therefrom to a reduced ottom portion in which is punched a contracted opening r. The plug portion 1) is of such shape and size as to fit tightly within the end of the tube B; the flange g overlies the end of the tube, thereby limitingthe entrance of the plug into the tube; and the contracted openings r r serve to distribute the heating mediumand prevent its flowing more readily into the tubes B nearest the inlet, thereby attaining an approximately equal flow of heating medium'through all the tubes of the series. lit is preferable to omit the nozzle plugs G G from the last tube or tubes B.

The nozzle plugs G G may also be used with some advantage at the lower ends of the tubes B B; and they are so shown in Figs.- 5 and 6, as well as in Figs. 1 andll;

but in this location their restricted nozzle openings r r have no necessary function, since there is no need of regulating or obstructing the outflow of condensation in the. case of steam; nevertheless, thus used, they have the advantage of strengthening the joint between 7 the tubes and the header; in either location the flanges g assist in forming a capillary chamber which is filled by the solder 10 forminjury by reezing. Such heaters are commonly used in factories, lofts, and thelike, which are closed down overnight or over week-ends, and there is always some risk that steam used as the heating medium may condense and-the condensation may fill either or both of the headers, and by freezing therein might rupture the headers and occaslon leaks. To guard against this danger the headers are so constructed as to make them expansible to the extent necessary to tolerate the expansion incident to the conversion of water into ice. This is provided for in part by the formation of the headers with one or both sides flattened, so that such flattened side may bulge slightly if ice forms within the header. It is also in part provided for by the formation of the header with corrugations t 25, best shown in Figs. 12 and 13, which corrugations aiford a surplus of metal .further contributing to expansibility of the header.

Figure 14: shows a header (being either the top or bottom header) for two rows of tubes similar in construction to that shown in Figs. 4, 11, 12 and 13, except that the sections 9 h are made wider to accommodate the two rows For the mechanical support of the heater in the casing D any suitable construction may be provided; and to the casing'may be added any ornamental outer portion which may be desired. In Figs. 4 and 11 two supporting connections are shown; in Fig. d'the headers are connected by bracket pieces a s to the upper and lower plates e e of the frame; in Fig. 11 the frame D has plates or strips u, u, which receive between them the projecting flanged joints f of therespective headers, and thereby strongly support the latter. These strips u, u, also serve as strengthening members of the frame D, so that the end portions d d may be formed by filling plates of thin sheet metal. I

The various details of construction shown and described as being part of the preferred embodiment of the invention may be varied or departed from according to the precise location and proportions of the heater, such variations being within the skill of heating engineers or designers.

Obviously, the construction herein shown and described may be ,used for cooling instead of heating; thus it is applicable for cool ing air by using a refrigerated circulating medium within the tubes.

' d a eaeea -,to one another, and substantially 15 degrees to the general medial plane of the lates, and the plates uniformly spaced with t eir plane 1 portions parallel to form zigzag passages to 5 re deatedly deflect the air without forming e we.

2. In a heater of the type comprising hot tubes and bafie plates, the tubes flattened and the'bafie plates applied in regular succession upon the tubes and bent into successive angular planes adapted to be traversed in succession by air flowin between the tubes and parallel with their attened face s, whereby to repeatedly deflect the air as it flows past or between the respective tubes, but without breaking .up the flow of air-into eddies.

3. A heater of the described type having a sheet metal header with holes receiving the ends of the tubes and flanged plu s entering. the ends of the tubes for strengthening the 'oint between the tubes and header, said plugs aving flanges underlying such oints to form an annular capillary channel for holding solder.

I 5 4. A heateroof the described t having a sheet metal header with elongated holes receivingthe-flattened ends of the tubes and sheet metal plugs fitting within the tube ends for strengthening the soldered joints,

i 5. A heater of the described type, having an enclosing casing, the heater having a header with external flanges, and the casinghav ing oppositemembers embracing such flanges v between them to support the heater within the 5 casin e 6. n a heater of the type comprising flattened hot'tubesand bae plates, the bee plates slitted and struck up to form flanges closely embracing the flat sides of the tubes,

I "4 these flanges being intermittent and of unequal depth, the deeper flanges serving to cor- 'rectly space the plates and being alternated. on opposite sides of the tubes. 7. In a heater of the type comprisin flattened hot tubes and bafie plates, the atter formed with bent flanges closely embracing v the flat, sides of thetubes, the bafie plates,

angularl bent at intervals and their flange termed w such bends, the flanges of M a depth to insure the correct spacing of the lates and alternated n opposite sides of the attened tubes. 4

8. A heater of the escribed type having sheet metal headers and hot tubes extending between them with individual contracted nozzles entering the tubes, their wider portio substantially filling the ends of the tubes and serving to strengthen the joints between the tubes and the header. J

In witness whereof, we V have hereunto signed our names,

' REUBEN T. TAR;

, IAMML WALLAGKJn

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