US1997373A - Tube ring - Google Patents

Description

April 9, 1935. v A. P. MccoRMlCK TUBE RING Filed Oct. 13, 1930 tube rings and UNITED. STATES PATENT OFFICE TUBE Rumv Augustus P. McCormick, Alton, 111., assignor to Standard Oil a corporation of Company (In na),

Indiana Chicago, 111-,

Application October 13, 193i), Serial No. 488,261

1 Claim.

This invention relates to an improvement in i more particularly to tube rings for the heat exchanging tubes of preheaters and similar equipment.

It is common preheaters, heat exchangers or similar equipment to increase contact between the tube and the by means of cast iron rings, fins or gills. Cast iron rings are objectionable on steel tubes because of their diflerent coefiicients found that a strain is set up in the encompassed portion of the tube and that this strain results in abnormal corrosion. It has also been found that the shrunk-on rings do not give as good heat transfer as welded rings and that the heat transfer from the ring to the tube in the latter case occurs through the weld, the rate being too low to indicate that the total surface of the ring is actually utilized. The object of my invention is to avoid all strains and corrosion in structures of this character and at the same time to obtain maximum heat transfer between the ring and the pipe. A further object is to increase the heat-transfer area of a pipe without materially increasing its weight. A further object is to reinforce the preheater pipe.

The rings may be simply and cheaply applied to a tube by bending or swaging a bar of metal around a tube by suitable jaws operated by a reciprocating piston. In order to obtain maximum heat conductivity I prefer to weld the ring to the tube over a relatively wide area so that the weld will be as the ring. It should wide as the thickness of be particularly noted that my improved rings are closed and that they are spaced on the tube so that maximum reinforcement and heat transfer may be obtained'with a minimum weight and a minimum amount of material. By welding steel to steel I obtain a more perfect union and I avoid the difficulties which would ensue from the use of metals having different coefficients of expansion. Thus with alloy steel tubes such as high chromium tubes,

I prefer to use rings of similar material to avoid expansion strains.

My invention will be more clearly understood from the detailed description of a preferred embodiment which is illustrated in the accompanying drawing wherein similar parts are designated by like reference characters, and wherein practice in the manufacture of bar and the degree of the taper Figure 1 is a side elevation of my improved machine for mounting rings on tubes.

Figure 2 is an end elevation of said machine, showing the swaging mechanism in its initial position. v

Figure 3 is a similar view showing the swaging mechanism in its second position.

Figure 4 is a similar view showing the swaging mechanism in the third position.

Figure 5 is the same view showing the final position of the swaging mechanism.

Figure 6 is a transverse section through my reinforced tube showing the welded ring structure.

Figure 7 is a horizontalsection showing rings welded from one side only, and

Figure 8 is a similar section showing the rings welded from both sides.

The steel tube Ill may be of any suitable steel or alloy, and is preferably a tube of the type generally used for oil preheaters in the petroleum industry. This tube may be mounted on suitable chucks II and I 2, which may be supported and rotated in any 'desired manner. A steel bar I3 is formed with tapered ends it, the length of the being adjusted so that the tapered ends will meet when the .bar is swaged around the tube. I preferably heat the bar for the swaging operation and I position the hot bar under the tube by comprising supports l5 mounted on each end of cross piece l6 which is centrally attached to a suitable handle ll.

Under the tubes I mechanism i8 pivoted at 2| which will be on pins carried by links 26 which are, in turn,

pivoted by pins 21 to bar 28. Bar 28 is mounted on the end of piston 29 and is reciprocated thereby. A suitable spring 30 urges the links 26 toward bar 28 and a suitable linkage system 3| is adapted to push links 26 upwardly against the tension of spring 30.

The operation of the apparatus may be briefly described as follows: The fork supports the hot bar l3 under pipe ID in the path of jaws I9 and 20, as shown in Figure 2; On the first upward stroke of piston 29 the bar is bent into a U shape, as shown in Figure 3. When the piston is remeans of a fork tracted, pins 25 are directed from the outside of the .I slot to the inner short leg of said slot, as shown in Figure 4. This changes the point of application of force on jaws I9 and 20 and enables the continued operation of piston 29 to swage the bar around the tube, forming a true ring (see Figure 5) If desired, the ring may be swaged around a separate mandrel and then slipped over the pipe and welded. In any event, it is desirable to use a weld which is substantially the same width as the thickness of the ring and I prefer to pronotches on both sides of the ring which may be filled by the weld 32. During the welding proc- 1 ess it is usually desirable to weld the abutting ends of the bar so that the ring is substantially one piece'and integral with the tube. Rings at-' tached in this manner add a great deal of strength to the tubes, especially when closely spaced. When the tubes are for use in high pressure systems, this is especially important,- tubes designed to withstand 3000 pounds per square inch must be thick, heavy and cumbersome unless they are reinforced by integral] I welded steel rings or equivalent structure.

The provision of a relatively wide welded area is an important feature of my invention since I have discovered that substantially all of the heat transfer is through the weld and that rings which are shrunk on become comparatively ineffective as heat transferring media. It should be noted that the steel rings are of substantially the same composition as the tubes and that there is, therefore, no appreciable difference in their coefficients of expansion. This avoids the internal stresses which are so troublesome and costly when cast iron gills are used. It should be further noted that the rings may be relatively light and thin and at the same time very effective as reinforcing means and heat transfer means.

While I have described a preferred embodiment of my invention it isunderstood that I do not limit myself to the details'hereinabove set forth except as defined by the following claim.

I claim: I

In high pressure heatin equipment of the type used in oil preheaters in the oil industry, a tube of alloy steel for withstanding high pressure at the high temperatures to which it issubjected in the preheater, a plurality of rings of substantially the same alloyencompassing the tube at regular intervals apart of said rings being welded to said tube to form a bond between eachring and the tube entirely encompassing the tube and of a width substantially equal to the width of the inner-most and adjacent wall of the ring so that the tubes and rings are substantially integral whereby maximum heat transfer may be'obtained and whereby the 'bond, as well as the ring, may serve to strengthen the tube to withstand said high pressure thereby obviating the necessity of providing excessively thick tube wall structure.

AUGUSTUS P. MCCORMICK. I

from one another, each 7

Images