US1734111A - Spiral-finned tubing and method of making same - Google Patents

Description

Nov. 5, 1929. H. w. BUND Y SPIRAL FINNED TUBING AND METHOD OF MAKING SAME 2 Sheets-Sheet 1 Fil ed June 20, 1927 INVENTOR. "ZanZ y A TTORNE Y. I

Nov. 5, 1929.. H. W. BUNDY SPIRAL FINNED TUI BING AND METHOD OF MAKING SAME Filed June 20, 1927 2 Sheets-Sheet .2

R I Q I NVEN TOR. 17%??? Zandy Y K M A TTORNEY.

m Z QN ME I? stars I HARRY W. BUNDY, OF DETROIT, MICHIGAN, ASSIGNOR, BY MESNE ASSIGNMENTS, TO BUNDY TUBING COMPANY, OF DETROIT, MICHIGAN, A. CORPORATION OF MICHIGAN SPIRAL-FINNED 'ronmo'nnn METHOD or MAKING salsa Application filed June 20,

This invention relates to spiral finned tubing and method .of making same which 1s useful for the dissipation of heat, as for example in mechanical refrigeration devices,

radiators for automobiles, and the like.

Finned tubing is old in the art, and various ways have been proposed for winding fin stock on a preformed tube. Also spiral tubing is old; or in' other words, tubing made of w flat strip stock wound spirally in the form of a tube with the edges of the convolutions secured together in some manner.

The present invent'on contemplates a method of making finned tubing'by spirally winding flat stri stock, and at the same time .shaping the stoc 'so'that fins are formed on the tube as the same is made.

Fig. 1 is an assembly view showing the method of making the tubing.

Fig. 2 is a detail of the stock forming and crimping mechanism.

Fig. 3 is a sectional view on line 3-3 of Fig. 1 showing some of the rollers which aid in the forming of the tube.

Fig. 4 is a sectional view taken on line 4-4; of Fig. 2 showing rolls which are suitable for shaping the stockprior to its being wound into a tube. Fig. 5 is a longitudinal vertical sectional view taken through a set of rolls on the mechanism shown in Fig. 1 and showing how these rolls finally form the tube.

Fig. 6 is a sectional view section of completed tubing.

Fig. 7 is a sectional view on Fig. 6.

The method consists in drawing flat strip stock from a supply roll (not shown). The strip stock, after leaving the supply roll, may

be drawn over a roller l through an acid bath 2, and from here the strip stock passes upwardly over a roller 3, and then downwardly over rollers 4 in a solder bath 5, to thus tin or apply a coating of solder to thestock.

The solder in the bath is kept in a molten condition by suitable burners 6. The strip stock'may then be drawn over the roller 7 and then through a cooling water bath 8 over roller 9.

As thus far described, ordinary trip stock taken through a line -7- 7 of 1927. Serial No. 200,273.

made of copper or other desirable material maybe used, and it is tinned in the manner described immediately before it is acted upon to be formed into a finned tube. However, if desirable, the strip stock can be previously tinned, so that it can be drawn from a supply roll directly to the forming mechanism. Either procedure may be followed to meet the particular requirements, although it is thought to be preferable to tin the stock just prior to its being formed into tubing.

' However, the strip. stock thus tinned, or if it has been previously tinned, it is ready to be formed into tubing. The stock is drawn over the guide roller 10 which is positioned at an angle to give the stock a twist or turn of approximately ninety degrees. The stock is then drawn through a set of shaping rollers 11. These shaping rollers may take the form shown in Fig. 4, and consist of coacting rollers 11 and 11 driven by gears through a shaft 12, and which shape the stock into angle form, as shown in Fig.,4=.- The angle form has a portion 13 whichbecomes the fin, and a portion l l which is spirally wound to form the body of the tube. The stock thus angularly formed is drawn through a guiding die '15 located immediately adjacent the winding mechanism, and for the purposeof guiding and holding the stock in proper position with respect to suchmechanism.

For the purpose of spirally winding the stock, there is provided a spinning arbor 20 rotated by a suitable mechanism, as by means of a pulley 21 and belt 22. The stock is wound upon the spinning arbor in spiral form and it will be understood that it is desirable,

and in some cases necessary, to crimp the portion '13 of the stock in order that the stock can be nicely woundin this manner. For this purpose a pair of interengaging crimping rollers 23 and 24 are provided, and one of which is suitably mounted on a shaft and driven by suitable 1means, as at 25. These crimping rollers are well known to those familiar with the art to crimp or corrugate the stock to expedite the step of winding it.

The spinning arborand crimping rollers are rotated with proper relative speeds and the stock is spirally -wound upon the arbor,

engage between the fins of the tubing. The

rollers are preferably power-driven as by portion, and then by compressing the-conthrough asolder that the wall of the tube is and in the first instance takes the form as shown at the right-hand side of Fig. 5. The tube-forming portion 14 of each convolution overlaps, substantially half way, the adja cent convolution, as will be seen by inspection of Fig. 5. The tube passes from right to left through a set of rollers 26. There are, preferably, three of these rollers, as will be seen in Fig. 3, referenced 26, 26 and 26, and each roller is in the form of a Worm so as to means of a gear wheel 27 idler 28, and may be keyed rollers function to draw or move the tube lengthwise. These rollers are arranged to compress the tube against the spinning arbor thus to form an ofiset in each portion 14.. By overlapping each portion 14 substantially half way with respect to the next adjacent and an interposed volutions against the arbor it will be seen formed of a double thickness throughout.

With the tube thus formed it is sealed by further application of solder. pose a suitable fluxing acid is applied by means of a conduit 30 and then the tube goes applying device. This may take the form of apct 30 holding solder which is kept molten by burners 31 and which includes an automatic solder lift 32. The solder lift 32 is rotated by suitable means in bearings 33, and includes a solder lifting device for raising the molten solder and pouring it over the tube. The details of the solder lifting device are not essential to the present method, as any suitable structure can be used. However, an example of such a device 1s.

shown in my Patent #1,605,326, granted November 2, 1926.

Inasmuch as thestockis tinned before it is wound, either by a tinning operation immediately preceding the winding operation. or by a previous tinning operation, the tube can be sweated together by merely advancing it through a heated zone, for melting the coating'of tin or solder and causing all parts of the tube to thus adhere together. However, it is thought preferable to apply additional solder as just described.

As the tube leaves the solder applying device 32 the excess molten solder maybe remox'ed by applying a stream of air against the tube by means of the nozzle device 34..

Following this operation, the tube may be cooled by passing the same through a, water chamber 35 which is supplied with cold water by conduit 36 whichwater is-permittedto drain off through the drain 37. In order to aid in the advancing of the tube, a second set of rollers 38, similar to the set of rollers 26, may be used. These rollers are also preferably power-driven and'may also 'press the tube to insure final and correct shaping of to shafts 29. These.

For this pur- 'liable to become loose;

with the tube the heat within the tube, or the enced 14; by the the tube. For this purpose the arbor 20 may take the form of a floating arbor and have its free end extending entirely through'the device so as to lie within the tube at the point where the rollers 38 press against it.

By this method a spirally wound tube with a double .wall and integral fins is made in a continuous length. 'As the .formed tube emerges from the forming mechanism it may be cut into desired lengths either by an automatic or a hand operated cut-01f. It is thought to be preferable to make the tube with the spiral convolutions overlapped in the manner described to provide a tube of a double wall. However, the invention is not intended to be limited to this sortof tube, and the invention contemplates the making of a tube wherein the wall is not of a double thickness throughout as a tube of this nature may not be required in all places. For example, in some uses the strength of the tube may not be important so that the double wall is not essential, and a tube can be made by the method wherein the overlap of the convolutions is just sufficient to secure adjacent convolutions together.

Thus a spirally wound finned tube can be made in continuous lengths from a single supply of flat strip stock. Due to the fact that the tube is provided with a double wall it .has considerable strength, and also the thickness of the stock can be varied. The fins are inegral with the Wall of the tube and are not and being integral heat in the material or liquid within the tube is efficiently conducted-to the fins Where the heat is dissipated by radiation, or vice versa Where the material in the tube is to be heated instead of cooled.

i In the claims appended hereto the terms iorizontal portion and upright portion of the stock are utilized; by the term horizontal portion is meant the portion referupright' portion is meant that referenced 13. By using these terms it is not intended that the two portions of the stock, after the same is bent, be perpendicular to each other, for it is withinthe invention to have the upright portion at an angle to the horizontal portion which is other than a right angle so that in the finished tube right portion rojecting outwardly from the body of the tu e to form an integral spiral fin on the tube, and then compressing the overlapped convolutions together.

2. The method of making spiral-finned tubing, which consists in drawing flat strip stock from a supply, turning up one edge of the stock to form an upright portion leaving a horizontal portion, spirally winding the thus-formed stock with the adjacent convolutions of the horizontal portion overlapped to form the body of the tube, right body fin on the tube, compressing the overlapped convolutions together, and then finishing the tube by the application of solder to cause the convolutions to adhere together.

3'. The method of making spiral-finned tubing, which consists in drawing flat strip stock f om a supply, bending the stock longitudinaltly to form an upright portion and to leave a substantially horizontal portion, winding the stock spirally, overlapping each convolution of the horizontal portion subportion projecting outwardly from the and with the up of thetube to form an integral spiral together.

8. A tube with a helical fin, which includes a tubular body foamed by a helically wound angular strip stoc each convolution of one the angle overlapping substantially a leg of the angle overlapping substantially a part ofthe next adjacent convolution of the same leg of the angle to form a continuous double wall for the tube and the other leg of the angle forming a continuous helical fin.

In testimony whereof I'aflix m signature.

HARRY W. UNDY.

stantially one-halfthe distance of the adjacent convolution, compressing the overlapped convolutions to form the body of the tube with the upright portlon forming an integral spiral fin on the tube. j 4. 'The method of making spiral-finned tubing, which consists in drawing fiat strip stock from a supply, bending the stock longitudinally to form an upright portion leaving a horizontal portion, spirally winding the stock over an arbor with the convolutions of the horizontal portion overlapping and forming the bod upright portion orming a continuous spiral fin around the tube, passing the tube lengthwise with continuous movement, and applying solder thereto to connect the convolutions together.

5. The method of forming a tube consisting in rolling a strip offlat, thin material to provide a laterally extending flange and then rolling the strip spirally on a mandrel having the ed es of succeeding windings overla ping the e ges of previous windings wit the flange projecting radially and spirally directed of the periphery.

6. A spiral finned tube which includes a tubular body stock formed into an with portions angular cross section angle projecting outwardly to form a spiral fin, the overlapping portions of the strip stock beingpressed together to make the body 'of uniform double thickness, the stock of the overlapped leg being slightly ofiset toform a of the tube and with the formed by spirally wound strip of one of the legs of the angle overlapped and with the other leg of the-

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