US1685270A - Method of making finned tubing - Google Patents

Description

Sept .25,1928. v 1,685,270

H. W. BUNDY METHOD OF MAKING FINNED TUBING Filed July 14, 1927 2 Sheets-Sheet 1 INVENTOR.

59272 if fiand q 'A TTORVEY.

Sept. 25, 1928.

v H. W. BUNDY METHOD OF MAKING FINNED TUBING.

Filed July 14, 1927 '2 Sheets-Sheet 2 INVEN-TOR. 1 20729 ATTORNEY. I

. Patented Sept. 25, 1928.

UNITED STATES PATENT "OFFICE.

mm? W. BUNDY, or nn rao nr, MICHIGAN.

T, amnion or MAKING. mma) TUBING.

.Applicatic'n filed m 14, 1927.- Serial No. aoam'.

This invention relates to 'a method of makby utilizing the rotary movement of the tube, ing finned tubing and it has to do especially as effected by the ro1ls2 and 3. v with a method wherein spiral fin is placed Strip stock is drawn from a supply of upon a preformed tube. I stock 5 The method consists in the taking of a tube shown This stri stock me be tinned reof any desired character and advancing the viously p flg to being put in the supply roll.

tube longitudinally while rotating the same. ever, it may not be tinned in the supply roll"- referably inthe form of a'roll (not While the tube is thus handled fin stock is spiand a coating of tin or solder may be applied rally wrapped upon the tubeand secured as the stock is drawn from the supply. This thereto. The 'fin stock is treated in a novel is optional,

manner and so that a relatively large contact step of tinning thestock after it is drawn between the fin and the tube is efiected. The from the supply. For this purpose the stock invention contemplates a method wherein the is drawn through an acid bath, a solder bath, fin stock can be wound upon the tube in such and then a cooling water bath in progressive a manner as to reinforce the body of the tube steps, as shown in Fig. 1. I

thus permitting the use of a preformed tu The stock is then drawn over a roller 5, of relativelythin stock, or a tube which does which is merely a guide roller and turns the not have the strength required in the finished stock through an angle of about 90. The finned tube, with the stock affording the stock is then drawn through a pair of rollers additional strength requlred. 6 for the purpose'of bending the stock so that In the accompanymgdrawmgs: it is angular in cross section. This is best Fig. 1 is an assembly v-rew showlng the shown in Fig. 4 and it will be noted that'the method by which the fin tubing is made. rollers 6 bend the stock so that the stock has Fig. 2 is an enlarged detail showing how one leg portion 7 and another leg portion 8. the fin stock is treated prior to being wound The bend, as shown, is one. of although upon the tube.. the anglemay be other than '90 as desired. Fig. -3 is a sectional viewtaken through a For the purpose of convenience the portion roller mechanism which may be employed for pressing the fin stock tightly. against the tube, zontal port'no 0 'Fig. 4 is an enlarged section taken on line 4-4of Fig.2. to limit the angle to- 90. The stock thus Fig. 5 is a section on line 5-5 of Fig. 1 bout is drawn througha guide die 10 posishowing one arrangement of the rollers which press-the fin stock against the tube, such rollthe stock is to be wound upon the tube. ers having been shown in section in Fig; 3.

Fig. 6 is a sectional view on line 6-6 of metal oftheupright portion must either be Fig. 3 showing the'completed tube. drawn or stretched to provide for the varybut I haveshown inFig. 1 the In winding the stock upon the tube, the

8 will hereinafter be referred to as the horitioned immediately adjacent the pointwhere A tube to which the fin stockis to be aping diameters between the outside. of the uplied is referenced 1. This tube is disposed right portion and the inner-edge thereof, or

10 etween a air of rollers2and3which are roit may be crimped or corrugated' I have tated and which engageopposite sides of the shown a pair of, crimping rollers 11 and 12 tube and thus cause a rotation of the tube between which the upright portion of the around its central axis. These rollers are instock is engaged and corrugated as shown dicative of any suitable mechanism for rotatat =13, in Fig. 6. The roller-.11 mounted ing the tube. The direction of rotation ofupon a suitable shaft .14 whiclrF-is driven,

Fig. 3. The rollers are preferably disposed positively driven, a s'will at" an angle to each other, as clearly shown in the nature of the work. Fig. 1, and thus a line contact is bad with the opposite sides of the tube. The forward end. ers is, coordinated with the rotativelmoveof the tube advances into the fin applying ment' of the tube so that-the strip stock is mechanism. The advancement of the tube corrugated andwound u on the tube. The

may be e ected by suitable driving rollers in tube with the strip stock t us wound thereon engagem nt with the tube (not shown), or advances through a set of rollers 15. As no theadvancement of the tube may be effected shown 1!; Fig. O'there are preferably three The Speedfof rotation of the crimpingrollo5 1... v these rollersis indicated by the-arrows in and the. roller 12 mayueither; bean idler. or be. determined by tube it may the tube, as shown in Fig. 3. These rollers are preferably positively driven by means of a suitable gear wheel 16 and an idler17. The speed of rotation of these rollers may be coordinated with that of the rotative movement of the tube so asto cause the advancement of the tube. 'If this should be done, the previously referred to driving roller could-be omitted. On the other hand, these rollers can be held stationary and the ro-' tative movement of the tube through these worm rollers would cause the advancement of the tube inasmuch as the spiral finengages in the grooves in the worm rollers much after the manner of a screw.

This applies the fin stock tothe tube. For the purpose of securing the fin stock to the be then passed through a heating die to meltthe coating of solder on the fin stock and cause the same to adhere to the tube. However, a second coating of solder may be apv lied tothis strip, and this is shown-in the di'awings, inasmuch, as it is thought to be preferre For this purpose an acid may be sprayed overithe finned tube by a suitable nozzle 20, whereupon the tube advances throu h a solder lifting device 21. This solder. lifting device may be of any one of thewell known constructlons for lifting molten solder from the' pot 22 and pouring the molten solder over the tube. The solderj is kept molten'by suitable desirable, the tube may be first passed through a sweating dieto melt the coating of the fin stock and the second co'atin may be applied'on'the outside. However, t e sweat-' ing operation may be omitted inasmuch as the heat-present in the solder bath 21 may be sufiicient to melt the coating of solder on the finstock thus simultaneously applying solder bath and melting the coating of cooling water'bathi26.

arm be utilized for Preferably, relatively long will be insertedinto the fin'applying msm, and if it is desirable to have the finished solder on the fin stock.

Following this ste excess solder may be blown 05 by air sup led to a suitable nozzle 25 and directed against thetube. The tube may then be cooled by through a ollowmg this, an-

other set of rollers insuring perfect formation of the completed tube. These rollers may be much the'sa'me as the set of rollers 15." y 1,

lengths of tube mechafin tubing in short lengths,'the tube may be cut off in such proper short lengths as-it advances through the rollers 27 This may be ting relation. burners 23. If.

accomplished by an automatic or hand out ofi device not shown.

Inasmuch as separate lengths of preformed tube are used, theproblem arises as to how to originally secure the fin stock to the tube when it first enters the fin applying mechanism. The preferred manner of doing this is that of providing the crimping rollers 11 and 12 so as to give suflicient curl to the stock to cause the stock to curl tightly around the tube. In other words, the curl given to the stock by the crimping rollers can be made so that the interior diameter of this curl is normally slightly less than the outside diameter of the tubing. Thus the fin stock will tightly grip the tube under a slight spring pressure. This is sufficient to hold the tube and the fin stock in proper relation as it advances and until they are secured together by the solder. After the first lengthv of tube has been started, a second length, and all following lengths, may be starte by merely causing the forward end of the following lengths to abut directly against the rear end of the tube just preceding, so that the fin stock wound continuously and covers the break between the two tubes.

After the fin stock is applied, the tubes canbe separated by cutting through the fin stock at the abutting ends of two lengths of tube.

On the other hand, a thimble device, can be used to grip a portion of the forward end of a length of tube and the first convolution of wind the cent convolutions are in substantially abut- In other words, the outer edge of the horizontal portion in each convolution lies against or very close to the point of juncture of the horizontal portionand the upright adjacent convolution.

portion in the next 'When the solder or other sealing metal is applied a' secure connectionsis made between the convolutions. Thus, there is a spiral reinforcing band covering all parts of the preformed tube. This adds strength to the tube and'permits' the use of tube made from relativelylight stock. 3

I claim: Y The method of m kin finnedtubing which consists in moving atu e longitudinally, rotatingthe tube while it is so moving, drawing stri 'ock from a supply, bending this strip stoc so that it is angular in cross section to provide an upright and a horizontal portion, crim ing or corrugating the upright portion, winding this stock on the tube with the upright portion forming-a continuous spiral fin on the tube directly engaging the body of the tube to form a spiraLban'd on the tube.

' n testimony whereof I aflix my signature. HARRY W. BUNDY.

and with the horizontal portion

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