US2224346A - Tube structure - Google Patents

Description

R. H. HOBROCK TUBE STRUCTURE Dec. 10, 1940.

Filed Nov. 29, 1939' Patented Dec. 10, 1940 UNITED STATES TUBE sTRUoTUnE Raymond B. Hobrock, Grosse Pointe, Mich assignor to Bundy Tubing Company, Detroit, Mich a corporation of Michigan Application November 29,1939, Serial No. 306,759

, Claims.

This invention relates to tube structure, and it has to do with tubing made from strip metal stock.

The principal object of the invention is the.

5 provision of a novel tube Structure comprised of at least two metal strips, one of which has corrosion resisting characteristics, while the other is for imparting strength and body to the tube, and need not have corrosion resisting characteristics.

The corrosion resisting metalis usually relatively expensive, and in order to produce the tube cheaply this strip is preferably relativelythin. The structure is such that a strip of corrosion re.

. sisting metal, which may be relatively thin, forms the outer and innersurfaces of the tube, while the strength impartingstrip is conflnedwithin the tube wall, and it gives to the tube wall, requisite thickness, body and strength, The strength giving strip may be relatively thick, but this is subject to variation, depending upon require- 7 ments as to strength, tube wall thickness, etc.

In carrying out the invention a number of corrosion resisting metals may be used for the one strip, such, for example, as nickel, copper, Monel metal, and in some instances, silver or gold, or various alloys of the above or similar metals, while the strip for giving body and strength to the tube may be a ferrous metal such as a low carbon steel. There may be instances, however,

where a non-ferrous metal would be desirable as the strength giving strip, used probably in conjunction with a corrosion resistant strip of more expensive metal.

A tube structure for carrying out the invention stock. The other strip of stock has a considerably greater width, considered in the flat form, and it is fashioned so as to substantially completely envelop the ferrous metal strip. This is the corrosion resistant metal and is fashioned to r form an outer ply 2 and an inner ply 3. An intermediate portion of this strip is fashioned to extend from the outer ply to the inner ply and so as to lie between the adjacent edges of the strength giving strip. This intermediate portion is shown at l. The-corrosion resisting metal is thus fashioned through, substantially 360 to form the outer ply 2, and is formed with the oilset portion 4, and -'fashioned substantially through 360 to form the inner ply. J p

The edges of the strength giving strip are pref- 5 erably fashioned with contours of a substantially mating nature and which facilitate the forma tion of the offset 4. For example, one edge of the strip i is preferably rounded or formed on a radius as at! and provided with a relatively sharp-Q 10 ly extending; edge 6, while the other edge in a mating fashion is similarly formed on a'radius 'l with an extending edge 8. The ofiset 4 thus is not fashioned or bent too abruptly from the inher and outer plies, but joins thereto on generous l5 curves.

The edges of the strip l accordingly slightly overlap each other circumferentially, although spaced apart by the offset 4.

This tube may be fashioned from two strips of metal stock which are moved lengthwise from 20 reels or rolls and fashionedinto tubular form by a suitable tube forming mill, the general arrangement of which is .well known to those versed in the art. The tube is sealed by uniting the contiguous surfaces of the plies and joints. Both the 25 inner and outer pliesof the corrosion resisting metal are united'to the contiguous surfaces of the strength giving ply and the ofiset 4 is united 7 to the edges of the strength giving ply. The I edges of the corrosion resisting metal are brought 30 parts. .The curved portions 5 and I of the strip 1 form a supporting base for the adjacent curved portions in the corrosion resisting strip so that 40 considerable pressure may be applied at the edges. The tube is preferably sealed by the use of a molten sealing metal such as a 'soft solder, or a hard solder'or brazing metals, the selection of which may be influenced by the requirements of 45 the finished tube and by the particular metals employed invthe tube. Soft solders are those which melt at a relatively low temperature, such as a mixture of tin and lead, while hard solders or brazing metals melt at-higher temperatures, 50

and accordingly thus would form a .tube capable of withstanding higher temperatures in use. In some instances, as for example, where the-strips forming. the tube are of steel and Monel inetal,' the sealing metal may be substantially pure coppletely envelop the first strip.-

per, which, insofar as the present invention is concerned, may be called a brazing metal. In some instances it may be feasible to fuse the metal of the strips without a third sealing metal. All these variations are covered by the language used in the appended claims which, in effect, state that the surfaces are united by a fused sealing metal.

Thus a tube is formed, the novel structure of, which employs a single strip for the inner and outer plies which completely envelops, except, of course, for the ends, the intervening strength giving strip. The corrosion resisting metal may, of courseg'. be quite thin, but in this regard it is to be pointed out that even though the corrosion resisting metal is thin, it is to be distinguished from a tubing which merely has a plating or coating of metal which may be formed, for example, by processes such as a hot dipping process or an electroplating process. The corrosion resisting strip is thus a structural part of the tube and not merely a thin coating or plating. Tubing of this kind can be made in various sizes and may be used for fluid conducting purposes or for structural ,or semi-structural purposes, wherever corrosion resisting characteristics are desired,

I claim:

1. A tube comprising, a metal strip fashioned substantially into tubular form with its edges in spaced facing relationship, another metal strip having a part fashioned around and contiguous to the outer surface of the first strip, a part ex tending between and contiguous to the edges of the first strip and a part'fashioned into tubular form inside of and contiguous to the inner surfaces of the first strip, edge portions of the second strip being disposed in contiguous relationship to some of the said aforementioned parts of the second strip, the contiguous surfaces; of the strips and the contiguous surfaces of the edge portions and said parts of the second strip being united by fused sealing metal to seal the tube and substantially completely envelop the first strip.

2. A tube comprising a metal strip fashioned into tubular form with its edges in spaced facing relationship, said strip being relatively thick to -give the tube body and strength, another metal strip of relatively thin corrosion resisting metal having a part fashioned around and contiguous to the outside surfaces of the first strip, a part extending between and contiguous to the edges of the first strip and a part fashioned into tubular form inside the first strip and contiguous to the inner surfaces thereof, edge portions of the second strip being contiguous tosome of the aforementioned parts of the second strip, the contiguous surfaces of the two strips and the contiguous surfaces of the edge portions and said parts of the second strip' being united by fused sealing metal to seal the tube and substantially com- 3. A tube comprising, a relatively thick ferrous metal strip fashioned into tubular form with its edges in spaced facing relationship, another stripof relatively thin corrosion resisting metal having a part fashioned into tubular form outside of and contiguous.to the outer surfaces of the first strip, a part fashioned into tubular form inside the first strip and contiguous to the inner surface thereof and an intermediate integral part lying between and contiguous to the edges of the first strip and connecting the inner and outer tubular forms of the second strip, edge portions of the second strip being disposed in contiguous relationship to some of the aforementioned parts of the second strip, the contiguous surfaces of the two strips and the contiguous surfaces of the edge portions and the said parts of the second strip being united by fused sealing metal to seal the tube and substantially'completely envelop the 4. A tube comprising, a relatively thick metal strip fashioned into tubular form and having its edges disposed in spaced facing relationship, the edges being of beveled formation so as to overlap each other circumferentially, another strip of relatively thin corrosion resisting metal having a part fashioned into tubular form around and contiguous to the outer surfaces of the first strip, a part fashioned into tubular form inside of and contiguous to the inner surfaces of the first strip,

and an intermediate integral part lying between and contiguous to the edges of the first strip and connecting the inner and outer tubular forms of the second strip,'edge portions of the second strip being disposed-in contiguous relationship with some of the aforementioned parts of the second strip, the contiguous surfaces of the two strips, and the contiguous surfaces of the said edge portions and parts of the second strip being united by fused sealing metal to seal the tube and substantially completely envelop the first strip.

5. A tube comprising, a relatively thick metal strip fashioned into tubular form and having its edges disposed in spaced facing relationship, the

edges being-of beveled formation so as to overlap each other circumferentially, the contour of the strip substantially at the juncture where the edges meet the surfaces of the strip at an obtuse angle presenting a curved formation, another strip of relatively thin corrosion resisting metal having a part fashioned into tubular form around and contiguous to the outer surfaces of the first strip,

a part fashioned into tubular form inside of and contiguous to the inner surfaces of the first strip, and an intermediate integral part lying between and contiguous to the edges of the first strip and connecting the inner and outer tubular forms of the second strip, said intermediate part joining with the inner and outer tubular formations on curved lines where the same passes over the curved formations of the first strip, the edges of the second strip being beveled and disposed contiguous to the said curved portions of the second strip, the contiguous surfaces of the two'strips and the contiguous surfaces of the edge portions and curved portions of the second strip being united by fused sealing metal to seal the tube and substantially completely envelop the first strip.

RAYMOND H. HOBROCK.

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