US2892253A

US2892253A - Method for making jet tubes

Info

Publication number: US2892253A
Application number: US339638A
Authority: US
Inventors: Hugh A Hutchins; Bruce C Jones
Original assignee: Individual
Current assignee: Individual
Priority date: 1953-03-02
Filing date: 1953-03-02
Publication date: 1959-06-30
Anticipated expiration: 1976-06-30

Description

Filed March 2, 1953 June 30, 1959 H. A. HUTCHINS ETAL 2,892,253

METHOD FOR MAKING JET TUBES 2 Sheets-Sheet 1 i o o o p/ \0 a 4 5'0 1 61 6'0 66 a! 41 40 40 4 34 s I HUGH A. HUTCH/N5,

,eucs C. (IO/v55, B 4 a 2 5 fll WM 6083 B A i i am e y.

June 30, 1959 H. A. HUTCHINS ETAL 2,892,253

METHOD FOR MAKING JET TUBES Filed March 2, 1953 2 Sheets-Sheet 2 lllllLil j nvenzors.

Huey A. HJTCH/NS, BRUCE C. rib/v55,

U ited States Patent 2,892,253 lVIETHOD FORMAKING JET TUBES Hugh A. Hutchins, Arcadia, and Bruce C. Jones, Monrovia, Calif. Application March 2, 195$,Serial No. 339,638

7 v v 6 Claims. (Cl. 29-421) This invention has to do with a method for the making ,of jet tubes, thatis, forthe making of tubular units for the handling offluids at high pressure and temperatures, ,as for, instance, units for use in jet motors or propelling apparatus.

The tubes or nozzle-like elements. employed in jet en- .gines, and the like, are, in the nature of venturi tubes, and they operate under severe conditions both as topressure and as to temperature. The handling and distribution of heat;incidental. tothe operation of units of this character presents a diflicult problem and such a unit must be of uniform flawless construction, as otherwiseit is likelyttonfail and may result in serious damage inthe event of failure.

It is a general object of this invention to provide a .method whereby a jet tubein thegeneral nature of a venturi tube can be formed to. have a fluted or corrugated .liner within a smooth-walled jacket, and in which the construction isfree of joints or seams that are likely to fail.

It is another object of this invention to provide a method by which simple, straight, metallic tubes, preferably seamless metal tubes, are combined into a unit wherein the tubes are bonded together and by which corrugations are established in the innertube by the application of fluid pressure thereto.

It is another object of this invention to provide a .method of the general character referredto, by which a smooth-walled outer-tube or jacket is combined with an inner tube or-linerhaving corrugations formed byfluid pressure, sothat the'tubes are in uniform continuous contactt-hroughoutthe length ofthe structure and are bonded ltogether where they are in contact with each other, thus -.providing a structure that is highly eflicient and effective 1 for the j general purpose intended, which is eifective and .Walled' jacket, ,with a liner, and for'the formation ofcorrugationsinithe liner by the application of .fluidpressure.

:ln {the following detailed description, reference :is made to a typical apparatus-for carryingout the methodofthe present invention.

Eig. 1 isa sideelevation of-a typical tubularpartthat I will be referredto asaliner stock, and attherighthand end thereof this elementis indicated by dotted lines .in the flared condition, resulting from the first .operation performed thereon. ;Fig. 2 is'aview illustratingithe liner ,stoek partially formed, that is, having its :large end por- .li :il? l 1 h vin a inte m di t portion re u e rtwfi h i ne k .as sp nin o er mand el o p determ inedvsize and shape. -Eig. 3 is a view similar ;to "1, showing the element of the structure that forms the casevor jacket of the finished unit, being a view of thejacket stockcorresponding to Fig. 1 which illustrates thelliner stock. Fig; 4 isla view similar to Fig. 2, showin the nd l u t at itals 2 .li PhP dbY a manf ir p ded b th rre s lt ri smi a an s owi th ia st ed es 9 h s mme -9 ormed ov o sa s. th

liner stock. Fig. 5 is a detailed transverse sectional view ice .longitudinal sectional view of apparatus employed ill].

carrying out the invention, showing the mandrel. and the elements thereon as illustrated inFig. 4 located inapressure chamber or chest andindicating the presence of pressure which serves tofornithe corrugationsin the liner stock. Fig. 7 is a detailed transverse sectional view of a structure that maybe employed in the course ,of bonding the jacket .and liner together at the. conclusion of the process, and Fig. 8 is a view of the finished tube or unit, with the parts broken away to illustrate details of construction.

The method as provided" by the present inventionis particularly useful andpractical'for the formation of a jet tube orrventuri type duct as shown in Fig. 7 oft-he drawings, which unit is characterized by a smooth-walled jacket .10 and a corrugated liner 11 within the-jacket, which parts are in bearing engagernent with each other (from one end portion to the other of the unit and are preferably bondedtogether where they contact, the unit being an elongate tubular element in the nature of a verituri tube. The unit is characterized by end portions connected by an intermediate or neckportion ofreduced diameter, and it may, in practice, he provided at itsends with fittings or accessories as illustrated inFig. 8 of the drawings.

In accordance withthe broader-principlesof the present invention, a smooth-walled jacket is formed primarily by means of spinning, whereas the fluted or corrugated liner is formed preferably by spinning andthe-application of fluid pressure in the courseof which the liner is related to a formingrnernber having longitudinal grooves pr flutes therein, and to which the liner is shaped to give-it the desired fluted or corrugated-form. Inthe particular form of the invention illustrated in the drawings, and

which-is to;be referredto in detail, the member,wi th which the liner is related asfluid pressure'is applied in the course of forming thefcorrugations, is'located within the-liner and is in thenature of a mandrel and, ingthis case, after thejacket-has been, established over theliner,

theliner is corrugated or fluted, leavingthejjacket and liner with parts in contact ready for .thefinishin jQPQration or bonding.

In the particular case .illustrated in the -drawings, a simple, straight length of tubing, preferably seamless metal tubing, suchas is shown in Fig. .1 of th'edrawings isprovidedas the liner stock, and in accordance withthe firstloperation, this liner stock is flared orbellediatone n f n a w hap uc a is ind ca i ii d tte l e at h qr eht n' is- Th be n flarin o the liner stock may, in practice, he carried out by any suitable forming or working of the metal of theliner stock, it being preferred ordinarily that this operation. beperformed by spinning.

Following flaring ofthe liner stock atone end a mandrel A is inserted in the liner stockandhas an end portion 1-2 which is straight and round and which snugly or slidablyfits into the end portion :13 ofthe liner stock.

The other end portion 14 of themandrelA is 'flared as shown in Fig. 2 and-the

end portions

12 and 14 are conneeted by a reduced portion or neck 15, where the mandrel is divided or-split as at 16 so that it is sectional.

A suitable means is provided for holdingthe mandrel sections together and, in the case illustrated, thisineans is shown as including a rod 17 extending longitudinally through the mandrel sections centrally thereof and the rod has ahead 18 at one end and has a nut .19 threaded ontoitat the other end. When them1t19is made tight, the liner sections are tightly .clamped together. The mandrel A with the flared liner stock thereon, as indisuch as a lathe ready for spinning. In the case illustrated, the assembly is carried between centers 20, and a drive dog 21 carried by a rotating head 22 is engaged with the assembly to drive it.

As the assembled flared liner stock and mandrel A are rotated as a unit, a suitable forming or spinning tool 25 is employed to spin the flared end portion of the liner stock onto the flared or tapered end 14 of the mandrel, and the liner stock is spun inward at the neck portion 15 to form the liner stock with a reduced portion or neck 26 as clearly illustrated in full lines in Fig. 2.

In accordance with the present invention, it is contemplated that the liner stock may be a seamless tube of a suitable metal or alloy, for instance, in practice, it may be steel. To facilitate and expedite the desired working of the liner stock, it is preferred to anneal it, following the spinning as hereinabove described to render it soft and ready for fluting or corrugating as hereinafter described. If desired or necessary, the liner stock may be annealed in the course of spinning it into the desired form and if desired or necessary, the mandrel A may be temporarily removed to facilitate or expedite proper annealmg.

The element which is to form the jacket is initially a simple, straight, elongate, tubular part, this element or jacket stock being illustrated in Fig. 3, where the initial form is indicated in dotted lines. It is contemplated that the jacket stock be a seamless tube of suitable metal or alloy, for instance, in practice, it may be steel.

The jacket stock as shown in Fig. 3 is there illustrated after the initial belling operation has been performedas by spinning to establish the stock flared at one end as at the right hand end. The flared end X of the jacket stock is preferably formed to correspond in taper or flare with the flared end of the liner stock.

Following the flaring of the jacket stock to establish this element in the form shown in Fig. 3, the jacket stock is applied to the flared and spun liner stock carried on mandrel A while the mandrel A is maintained within the liner stock. The assembled liner stock and jacket stock carried on mandrel A are then placed in a lathe, or the like, and a spinning operation is performed on the jacket stock the same as that which was performed on the liner stock, to the end that the jacket stock has a neck portion 67 formed or spun in to fit close around and over the neck portion 26 of the liner stock, and has end portions 68 and 69 fitting snugly around the

end portions

13 and 33 respectively, of the liner 11. The manner in which the liner stock and jacket stock fit together at the conclusion of this operation is clearly illustrated in Fig. 4 of the drawings.

When the jacket has been formed over or established on the spun liner stock so that these parts correspond to the shape of the mandrel A, the sections of mandrel A are released as by removal of nut 19, and the mandrel A is removed from the liner stock as by separating the parts.

The assembled jacket stock and liner stock, after being free of mandrel A, have a mandrel B applied thereto. Mandrel B is, like mandrel A, sectional and such that it can be assembled into the liner stock from the ends thereof. The mandrel B as shown in Fig. 4 of the drawings has an end portion 30 fitting into the long straight end portion 13 of the liner stock, and it has a flared end portion 31 fitting into the flared end portion 33 of the liner stock. The mandrel B has a reduced portion or neck 34 fitting snugly into the portion 26 of the liner stock and the mandrel B is split at 35 so that it is sectional as shown in Fig. 4 of the drawings.

In accordance with the present invention, the exterior of the mandrel B, instead of being smooth and plain as is the exterior of mandrel A, is grooved or fluted, being preferably uniformly grooved or fluted from one end to the other, as by like parallel grooves 40 which join at ribs or crests 41.

The sections of the fluted mandrel B are releasably secured or tied together as by a rod 60 having a head 61 at one end and a nut 62 threaded on it at the other end. The interior of the mandrel B within the grooved portion thereof is recessed as at 80, establishing an open chamber 83 in the mandrel around the rod 60. Bleed holes 81 extend from the bottom of grooves 40 to the chamber 83.

It is preferred that the jacket stock be shorter than the liner stock, so that parts of the liner stock project beyond the terminal ends of the jacket stock and the grooves 40 in mandrel B are of such length and are so located as to extend beyond the tenninal ends of the jacket stock and terminate within said parts of the liner stock and before reaching the terminal ends of the liner stock (see Figs. 4 and 6).

The assembly formed by the initially formed liner stock, the jacket thereon, and the mandrel B is arranged in a chest C, or the like, which is closed and which establishes a pressure chamber 43. In the particular case illustrated, the chest C has a tubular or cylindrical body 44 closed at its ends by headers 45 and the assembly including the mandrel B is arranged in the body 44 and is held tight between the headers 45 with the ends of the liner stock sealed with the headers as by seals 46 or other suitable means.

A fluid handling duct 47 is provided to supply fluid under pressure, preferably liquid, into the body 44 around the assembly located therein, and a valve controlled pressure relief connection 48 is provided so that air can be exhausted from the chest as desired. A drain connection 49 is shown at the bottom of the chest.

With the parts assembled as illustrated in Fig. 6 fluid under pressure, say, for instance, oil or water under a substantial pressure, is applied to chest C, and acts to collapse or form the liner stock inwardly so that it becomes grooved or fluted to be, in effect, corrugated. It will be apparent that by applying a suitable pressure to the exterior of the liner stock, it is forced in, onto, or against the mandrel B so that it takes on the exact shape or contour of the exterior of mandrel B. It is to be understood, of course, that, in practice, the sections of mandrel B are keyed together as by one or more pins 50, or the like, so that the flutes or grooves in the sections of mandrel B are aligned so that the liner stock is pressureformed to have uniform continuous corrugations formed in it extending continuously lengthwise of it from one end to the other. As the pressure forming operation is carried out, the air in grooves is exhausted through the holes 81 and into the chambers occurring in the mandrel B.

At the conclusion of the pressure forming operation, the mandrel B is removed, leaving the liner stock and jacket stock both in finished form and assembled as shown in Fig. 8 of the drawings, where these parts are shown provided with suitable fittings or accessories. For some purposes this assembly may be adequate; however, it is preferred for most uses that the liner and jacket stocks be bonded together where they contact or are in engagement with each other. It is therefore preferred in carrying out the invention that a bonding operation be performed, for instance a suitable flux, bonding agent, or possibly a coating can be applied to either one or both of the stocks prior to the steps hereinabove set forth, or after the structure has been assembled as shown in Fig. 8 and with suitable materials present or conditions prevailing, heat may be applied to effect the desired bonding of the stocks. In Fig. 7 there is illustrated in a somewhat diagrammatic manner the assembled stocks in a heating venturi tube, or the like, and wherein the inner tube is continuously and uniformly corrugated from one end portion of the structure to the other. By employing the present invention, a jet tube as shown in Fig. 8 is provided having uniform seamless structural character, except insofar as the liner and jacket are engaged and there joined, and it will be apparent that the structure resulting from the invention presents a maximum surface for exposure to fluid handled by the structure, and an efficient and effective construction for the transfer of heat from the inside to the outside of the structure without resulting in hot spots and all without any weak points or parts likely to become over-stressed or subject to weakening or failure. As the structure is used, a suitable fluid may be handled by the fittings at the ends thereof, so as to be circulated through the duct-like passages 90 that are established between the liner and jacket as shown in the drawings.

Having described only a typical preferred form of apparatus and a typical manner of carrying out the method of our invention, we do not wish to be limited or restricted to the specific details herein set forth, but wish to reserve to ourselves any variations or modifications that may appear to those skilled in the art and fall within the scope of the following claims.

Having described our invention, we claim:

1. The method of fabricating a jet tube of the character referred to which includes, spinning a neck portion of reduced diameter in a first inner tube intermediate the ends thereof, arranging the formed inner tube within and in telescopic relation with a second outer tube, then spinning a reduced neck portion in the outer tube corresponding to the neck portion of the inner tube and in contact therewith, arranging a longitudinally inwardly fluted member within the inner tube, sealing the end of inner tube with the said member and then applying fluid pressure to the exterior of the inner tube to urge said inner tube into conformity with said member and forming inwardly projecting grooves therein longitudinally thereof and throughout the neck portion thereof.

2. The method of fabricating a jet tube of the character referred to which includes, flaring a straight round first inner tube at one end thereof, inserting sections of a plain round mandrel having a reduced intermediate portion in the inner tube to abut therein where the mandrel is of reduced diameter, spinning the said inner tube into the reduced portion of the mandrel to form a neck portion intermediate the ends thereof, then applying a flared second outer tube over the inner tube and spinning the outer tube to establish the outer tube in contact with the outermost parts of the first menioned tube, replacing the said plain mandrel with a sectional mandrel having an inwardly fluted exterior, then sealing the ends of the inner tube with the fluted mandrel and then applying fluid pressure to the exterior of the inner tube only whereby the inner tube is formed to conform to the shape of the fluted mandrel, then removing the sections of the fluted mandrel and then bonding the tubes together where they are left in contact with each other.

3. The method of fabricating a jet tube of the character referred to which includes, forming a first inner tube with a neck portion of reduced diameter intermediate the ends thereof, arranging the formed inner tube within and in telescopic relation with a second outer tube, then forming the outer tube with a neck portion corresponding to the neck portion of the inner tube and in contact therewith, arranging an inwardly fluted member adjacent the inner wall of the inner tube, then sealing the ends of said inner tube with said fluted member, and then applying fluid pressure to the exterior of the inner tube to urge the said inner tube into conformity with the said member and to form longitudinal inwardly projecting grooves therein which grooves establish longitudinal passageways between the tubes and so the inner tube has longitudinal ridges that are in contact with the outer tube, and then removing said member from the inner tube.

4. The method of fabricating a jet tube of the character referred to which includes forming a first inner tube with a neck portion of reduced diameter intermediate the ends thereof, arranging a second outer tube over the inner tube and forming it with a neck portion engaged around the neck portion of the outer tube, inserting sections of a longitudinally inwardly fluted member in the inner tube from opposite ends thereof and to abut within the reduced neck portion thereof, sealing the end of the inner tube with the said member, then applying fluid pressure to the exterior of the first tube only to urge it into conformity with the said member and establish longitudinal grooves therein and then removing the said member.

5. The method of fabricating a jet tube of the character referred to which includes forming a first inner tube with a neck portion of reduced diameter intermediate the ends thereof, then arranging a second outer tube over the first tube and forming it to engage the inner tube substantially continuously throughout the longitudinal extent thereof, inserting sections of a longitudinally inwardly fluted member in the inner tube from opposite ends thereof and to abut within the neck portion thereof, sealing the end of the inner tube with the said member, then applying fluid pressure to the exterior of said inner tube only to urge it into conformity with the said member and establish longitudinal grooves therein, then removing the member from the inner tube and then bonding the tubes together where they are engaged with each other.

6. The method of fabricating a jet tube of the character referred to which includes forming a first inner tube with a neck portion of reduced diameter intermediate the ends thereof, then arranging a second outer tube over the inner tube and forming it to engage the inner tube substantially continuously throughout the 1ongitudinal extent thereof, inserting sections of a longitudinally inwardly fluted member in the inner tube from opposite ends thereof and to abut within the neck portion thereof, sealing the end of the inner tube with the said member, then applying fluid pressure to the exterior of said first tube only to urge it into conformity with the said member and establish longitudinal grooves therein, then removing the member from the inner tube and then applying heat to the tubes to effect bonding of the tubes together where they are engaged with each other.

References Cited in the file of this patent UNITED STATES PATENTS 167,688 Puffer Sept. 14, 1875 638,554 Burton Dec. 5, 1899 1,352,292 -Lord Sept. 7, 1920 1,378,442 Chalfant May 17, 1921 1,420,608 Andrew June 20, 1922 1,478,060 Richman Dec. 18, 1923 1,605,828 Frahm Nov. 2, 1926 1,623,807 Oakley Apr. 5, 1927 1,658,603 Kowal Feb. 7, 1928 1,709,865 Mufily Apr. 23, 1929 1,777,728 Kumpf Oct. 7, 1930 1,804,284 Smith May 5, 1931 1,953,422 McCann Apr. 3, 1934 1,990,738 La Porte Feb. 12, 1935 2,093,092 McElhany Sept. 14, 1937 2,180,992 Meyers Nov. 21, 1939 2,247,002 Rendleman June 24, 1941 2,273,830 Brierly Feb. 24, 1942 2,335,414 Hinrichs Nov. 30, 1943 2,582,358 Schoellerman Jan. 15, 1952 2,708,306 Lampton May 17, 1955 FOREIGN PATENTS 4,838 Great Britain 1901