DE2046962A1 - Die-forged pipe coupling - Google Patents

Description

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The present invention relates to that Field of pipelines and pipe couplings for manufacture of pipe connections. More precisely, the invention relates to metal pipe couplings, in which the sealing Grip on the contained pipe is achieved by a uniform narrowing deformation of the coupling on the pipe section.

The use of couplings and the like to form pipe connections is known by means of in the technology of known devices has been · ■ known, a pressure-tight seal between the interconnected

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To form pipe sections by couplings, in which usually bolt connections, threaded connections or mechanical pressing is used; for the latter, U.S. Patents 3,068,563 give 3,149,861 and 3,244,441 examples.

Pin couplings are commonly used for pipe sizes of 100 millimeters and more, while for pipe sizes of 50 millimeters and less the thread

fc couplings are the most common. Except for the double-threaded nipple, which is usually not called a a coupling is considered, however, the threaded coupling consists of an array of separate threaded ones trained parts. When installing it is required that each part is individually on one of the each other opposite pipe sections is attached, whereupon the coupling parts are then screwed together. It can be seen that the reliability of the pipe connection largely depends on the experience and skill of the Depends on the person doing the installation. On the other hand, are known coupling connections by pressing or the like as it was formed by the above

"said patents is taught from the pressing or the optional drop forging not only of the coupling part but also of the received pipeline part. Therefore, this known pressing technique has been deemed inadequate when used in forming the sealed Connection there was no interlocking between the coupling and the pipe. It can be seen that the latter Teohnik is limited in its application to substances and a use in which a contraction or constriction the pipe wall is permissible as such. It does not matter whether the dioke of the pipe wall is caused by such a constriction has been compressed and / or the inner flow cross-section at the locking engagement between the coupling and the pipe

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has been reduced, such pipe connections are not considered satisfactory in most applications where it is desirable to maintain the pipe's physical properties as much as possible. For example, longer distribution pipes for gas, water or the like are dependent on the pipe wall thickness for safety reasons and for the largest possible flow cross-section in order to reduce distribution losses. Although it is known to connect pipe sections together by some form of drop forged coupling part, this known use is restricted to particular circumstances which largely limit its usability. Despite the knowledge of these limitations according to the prior art, it was not previously known how a drop forged coupling connection must be formed without affecting the pipe wall or the flow area in the drop forging area in order to increase the usability of the coupling part for more versatile applications.

The present invention relates to a new metal coupling for the leak-tight connection of pipe sections. More precisely, the invention relates to a cylindrical tubular unitary coupling part which is designed so that it contains an annular elastic sealing ring and responds to uniformly exerted radially inwardly exerted force so that it is forged inwardly onto the received pipe . The swaging of the coupling draws the sealing ring together into a leak-tight connection with the contained pipe without the need to press, constrict or otherwise affect the physical properties of the pipe at the joint.

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Through the present invention, the above discussed disadvantages Overcome those nit the known drop forged couplings were connected, so that their usefulness is expanded. It has been discovered that through the use of precisely controlled geometric parameters at the coupling end in which the sealing ring is included, this end is responsive to externally applied radially inward force to the sealing ring pull together evenly inwards into a leak-tight connection with the contained pipe, without the coupling part attacks even on the pipe wall or attacks to a significant extent and without any significant impairment of the Pipe properties.

Therefore, the underlying object of the present invention is to provide a novel Coupling part with which pipe sections can be brought into leak-tight connection with one another.

Furthermore, according to the invention, a novel metal pipe coupling part is intended be created, which responds to a radially exerted die forging force to a leakproof Form connection with the recorded pipe.

Furthermore, according to the invention, a novel coupling part is intended which serves to effect a joint formed by a die forging process, the does not affect the properties of the pipe contained in the area of the connection.

Furthermore, a novel coupling part for connecting pipes is to be created according to the invention, which both in terms of manufacture and installation

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is properly economical and at the same time creates a reliable seal that can withstand high pressures.

In the drawings in which an execution form of the invention is illustrated, for example

Fig. 1 is an isometric view of a coupling part according to the present invention, with the a pipe connection has been made,

2 shows a sectional view through a coupling part according to the invention in a state prepared by a drop forging, in which the pipe ends to be connected are received,

3 is a partially enlarged sectional view of the drop forge end portion of the coupling in the pre-forged condition and FIG

Fig. H a similar to Figure 3, partially enlarged sectional view of the swaged end portion of the coupling in its nachgeschmiedeten state.

Reference is first made to FIG. The coupling part according to the present invention is with 10 denotes and consists of an elongated, tubular and substantially round unitary structure in the axial direction, in which pipe sections 11 and 12 close have been connected to a coupling connection. As shown in the drawing, each pipe section was attached to the Coupling part attached at one of its opposite ends. It should be noted, however, that the present invention also includes such couplings in which the one or the other end duroh screw ·) flange, welded connections or the like is attached to the to meet special situations and conditions.

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As shown in Figure 2, the coupling part 10 according to the invention is shown in its preferred embodiment for the connection brought about at both ends by a forging process. The coupling part consists of a steel metal part, such as a welded steel pipe, that is heat treated and cold rolled has been in order to have a uniform yand thickness everywhere obtain. As can be seen from the description below, the wall thickness is generally between about 2.38mm and 12.7mm as a function of material, coupling size, and the like, and is usually about% mat for a 50.8mm pipe size. As it can be seen from the drawing, the coupling part consists of a unitary body, the one in axial Towards the middle, non-deforming body part 14 between in the radial direction-widened, deformable End parts 16 and 17, each having an inner annular recess 19. The end sections 17 and 19 are bounded by an axial dimension "A" and in the recess 19 of each end portion is an annular one compressible sealing ring 18 made of rubber or a contain other suitable elastic sealant. The sealing ring can, for example, be of the type as disclosed in another proposal by the applicant (U.S.A. patent application 6 34 714 filed April 28, 1967). The axial dimension of each body end part 17 or 19 includes in cross-sectional view, a radially widened middle part 20, which merges into a wall 23 which is inclined near the front and a wall 21 which is inclined to the rear. Any of the latter Walls is inclined or curved near the inside, the wall 21 with the central part 14 at an annular recess or recess 22 is connected. The wall 23 ends at 25, and its innermost surface 27 in the radial direction forms one

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Central bore 24 in which the pipe sections before manufacture find the connection free admission.

The wall thickness of the axial section A is essentially uniform everywhere, the recess has a larger axial than radial dimension. The sealing ring 18 is contained in the recess, and on his The outside is essentially complementary to the geometric shape of the recess 19 on which it rests. As a result, the sealing ring has a substantially trapezoidal cross-sectional shape and has one in the axial direction extending radial inner surface 26. In order to easily accommodate the pipe section 11 or 12, the inner Coupling diameter at 27 and the inner surface 26 of the sealing ring sufficiently larger than the outer diameter of the pipe to allow adequate clearance for installation. It should be noted, however, that the The inner diameter of the inner surface 26 is at least slightly smaller than the inner diameter of the coupling part on the Recess 22. Fern- he noted that it was crucial Significance for the present invention is that the ratio between the axial length "1 * (Figure 3) of the Sealing ring to the radial depth "t" at least 1 l / 2: i and is preferably 2: 1. This creates an optimal combination of practical gasket length and effective Guaranteed use of a minimum volume of rubber.

As shown more clearly in Figure 3, each extension 20 has an outside diameter that is around twice the amount of the dimension labeled "R" is greater than the outer diameter of the central portion The original (unforged) annular space in the radial direction between the inner sealing ring surface 26 and the outside of the tubes Ii or 12 is through the

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Dimension ^w c "shown. The angular deviation of the rear and front wall parts 2i and 23 relative to the radial direction is shown by the angle fl> .

As indicated above, the geometric shape of the deformable body end parts i6 and 17 of the coupling part is of essential importance for the invention Ensuring the desired uniform, radially inward contraction in the event of an exterior Sufficient drop forging force exercised. Not only the above-mentioned ratio of the dimensions of the sealing ring is considered essential, but also the Angle ft, which must be at least 15 ° and essentially not exceed 75 °, is more decisive Significance to a two-way relationship with respect to the Ensure outside of the included tube.

The die forging of the coupling ends for Formation of the coupled connection is effected by a hydraulically operated tool that is not part of the present invention and, for example, of the type disclosed in U.S. Patent 1,889,795 can. The tool includes a plurality of curved, contacting jaws, two of which are shown in phantom Lines are shown and denoted by 28. For the attachment of the jaws for the purpose of drop forging one or the other end 16 or 17 enclosed and the tool aligned by a flange which is in the recess 22 is recorded. If sufficient hydraulic pressure is applied, the jaws will be caused to to contract radially inward and on the coupling part gfeiohmäß a concentric, radially inwardly directed To exert force, which is indicated by arrows 19.

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The Gresenkschniiedekraft, which is developed by the tool is sufficient to contract around the coupling part to the coupling part of the example shown in Figure 3 assumes the state k in FIG deformation state shown. As shown most clearly in Figure k , the central end portion 20 has been deformed from its original condition shown in dashed lines to the forged condition shown in solid line by a diameter distance equal to twice the amount of the dimension d shown. At the same time, the angle ß 'can be increased from the original angle ρ by the amount of the angle Q. The axial dimension A ¹ has been increased from A by the dimension "e ⁿ . As the end 16 or 17 is deformed radially inward, the sealing ring 18 is increasingly compressed on the tube 11 until it is firmly engaged with the outer tube wall The die forging process continues until the sealing ring ^{is pushed out by an amount n} s ^M , which ensures the physical separation between the inside of the coupling and the outside of the pipe. Daduroh only attacks the inside surface of the sealing ring on the pipe while The coupling has no direct contact with the pipe Any unintentional excessive contraction of the coupling causes the sealing ring to be pushed out further between the coupling and the pipe walls, so that the coupling is further prevented from directly attacking the pipe or otherwise adversely affecting the pipe to influence.

Typical and approximate dimensions for the above-mentioned reference symbols for a tube size of 50.8 mm are the following:

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o- range of 0.3048 mm for max. coated Tube and min.coupling up to 1.143 stroke for min. bare drill and uz. coupling.

R - 2.3368 WB to 3.3512 mm d - 1.905 mm to 4.191 s - 0.794 mi to 3.175 e - 2.54 wi to 3.048 mm 1 - 25.4 mm I ¹ - 30.15 er «

β - 75 ° - 30 ° β - 83 ° - 60 °

These dimensions will of course change for different pipe sizes and take into account expected ones Manufacturing tolerances that are required to produce a commercial product.

In order to establish a connection with the

^ To achieve the necessary reliability, it is not essential that the coupling and the tube be within certain critical limits of relative buckling strengths can be selected. While the coupling according to the present invention is preferably used to connect metal pipe sections is to serve, the coupling can also be used to connect pipes made of plastic or other synthetic material Substances are used. The pipe should of course have sufficient resistance to buckling to the corresponding To endure the pressure of the sealing ring, which is on its own should be higher than the line pressure of the planned Pipeline. The ratio of the pressure of the sealing ring to the line pressure should be at least two-fold Be 2: 1. A 50.8 mm pipe (Form No. 40) holds for

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usually a sealing ring pressure on the order of 140 kg / cm. With thinner drilling walls are higher Kink strengths are desirable, or rather a reinforcing ring or other annular insert may be used instead can be used to increase the kink resistance. If the pull-out resistance is not important, you can click on the reinforcement of the buckling strength can be dispensed with.

For this purpose it is desirable that the finished joint have the strength of steel or malleable iron. A suitable coupling material is steel with a buckling strength of about 1680 kg / cm, although it is easily feasible to use materials which have buckling strengths of the order of magnitude of 2310 kg / cm or more. It is important, however, that the coupling material have a high degree of forgeability, which is expressed by the percentage elongation that occurs during rupture tests on a test bar. With a measuring length of 50.8 mm, a preferred material has an elongation of .30 % during the tear test to the point of break. A minimum elongation of about ± 5 ^c / c as with malleable iron can also be used, as well as elongation properties up to 35 %. The desired forgeability can be achieved in that the coupling is completely relaxed or softened after it has been formed. With the 50.8 mm pipe size, only about 8-10% of the total available 30% is required for the drop forging process.

To establish the connection, the coupling part is first attached to two pipe sections, which Find loosely in the coupling part. Then a suitable forging tool, such as the one described above, is arranged around one end and the radially inward

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directional pressure exerted. If sufficient leakage of the sealing ring appears under the wall 23, the school pressure is terminated, whereupon the opposite end of the coupling part in a corresponding manner is processed. The pressing out of the sealing ring under the wall 23 is a sure sign that the required deformation has taken place and that the connection is adequate and reliable has been made. No further testing is required, and a double ended connection can be made a 50.8 mm pipe in about 30 to 45 seconds forging time be formed per end. The required forging pressure that must be applied to the coupling ends changes of course with the pipe size, the choice of material, etc., in order to limit the kinking of the pipe so that it is no more than about 0.4 mm. Using the above materials requires a 19.05 mm tube to be an axial length a 25.4 mm tube generally has a pressure of about 595 kg / cm, while a 50.8 mm tube about 350-455 kg / cm requires. The pump or tool pressures are then correspondingly greater.

Through the above description, a novel coupling part has been disclosed, which allows the manufacture of a Pipe connection in a more convenient and economical way and in a much shorter time than the devices according to the prior art. It is evident that even small savings in large installations can add up to significant sums of money. Further Attention is drawn to the high level of security and reliability that the connection offers in the manufacture of Has connections that are able to withstand sealing pressures of the order of 105 kg / cm, which for Lines of flammable substances such as gaseous fuels are required. "NcpTcn

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Since many changes could be made in the above training, and many of various kinds Embodiments could be provided without the To leave the scope of the invention, all features contained in the drawings and in the description are intended should be construed as illustrative and not in a limiting sense.

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Claims (1)

Patent Claims (I.) Forged metal pipe coupling part, marked duroh a) a uniform elongated tubular Body (1O) in which the Iiohrabschnitte to be connected be included, b) an end part (16, 17) at at least one end of the body which is expanded in the radial direction and the walls of which have an annular inner recess for a sealing ring with a certain cross-section with a larger form axial length as radial depth, and c) a sealing ring (18) contained in the recess and substantially complementary to its Boundary walls is formed, the thickness of the sealing ring in the radial direction is greater than that Depth of the recess (19), and the inner diameter of the sealing ring is greater than the outer diameter of a in the coupling part received pipe section (11,12) with which a connection is to be made, and wherein the end part (l6,17) of the body responds to an externally applied radial pressure of sufficient magnitude, which is applied concentrically and evenly around the circumference in order to permanently pull the coupling part together and compressing the sealing ring radially inwardly into a sealing cone grip on the pipe section. 2. Coupling according to claim 1, characterized in that that the ratio of the axial length of the sealing ring to Heiner's radial thickness is at least 1 1/2: 1. ORIGINAL INSPECTED 10 9 8 17/1277 _ ₁₅ _ 2LUG962 3. Coupling according to claim 1, characterized in that at least the one exerted on him Force-responsive end part consists of a material that has a buckling strength of at least 1680 kg / cm and has a malleable extensibility of at least 15%. k. Coupling according to Claim 3, characterized in that the magnitude of the pressure to which the end part responds by contraction is in the range from about to about 770 kg / cm. 5. Coupling according to claim h, characterized in that when the end part is contracted or constricted, there is a radial decrease and an axial increase in the outer dimensions, 6. Coupling according to claim 1, characterized in that that the wall (23) of the end extension which coincides with your axial end of the body (10) to the To form the tube receiving opening, opposite which the recess (19) forming surface (20) is inclined inward in the radial direction by an angle which is between 15 and 75 ° compared to the perpendicular to the body axis. 7. Coupling according to claim 6, characterized in that the wall (21) of the end part extension, which is remote from the body end, ends in the middle body part {lh) in an annular constriction on which a tool for exerting pressure can be applied . 0 17/12/7 20AG962 H. Coupling according to claim 7, characterized in that the body at each end substantially has geometrically identical, pressure-sensitive end parts (16 and 17). 9. Coupling according to claim 2, characterized in that the sealing ring is substantially trapezoidal Has cross-section. 10. Coupling according to claim 2, characterized in that the radial inner diameter of the sealing ring is smaller than the adjacent and adjacent inner diameter of the body.