WO2008031497A1

WO2008031497A1 - Detachable flange and counterflange device for fixed coupling of pipes

Info

Publication number: WO2008031497A1
Application number: PCT/EP2007/007533
Authority: WO
Inventors: Paolo Seghi
Original assignee: Manuli Rubber Industries S.P.A.
Priority date: 2006-09-12
Filing date: 2007-08-28
Publication date: 2008-03-20
Also published as: CN101517302A; ITMI20061740A1

Abstract

A coupling flange (2) for pipes, comprising an annular body which is adapted to be associated with the end of a tubular element and is provided, at the outer lateral surface, with an abutment surface (20) for a locking counterflange (3), at least part of the abutment surface having a curved profile.

Description

DETACHABLE FLANGE AND COUNTERFLANGE DEVICE FOR FIXED COUPLING OF PIPES Technical Field

The present invention relates to a flange and counterflange device for detachable fixed coupling of pipes. Background Art

In the field of piping for hydraulic and pneumatic systems and applications, devices of the flange and counterflange type for the detachable fixed coupling of pipes are known. Such devices are used for example to fix the end of a pipe to a fixed wall of a machine or system.

Known devices comprise a flange which is designed to be rigidly associated with the end of the pipe to be connected and has, on the opposite side with respect to the end of the connected pipe, a flat face for making contact with a coupling wall, which is also flat and belongs for example to a machine or system.

The contact face of the flange has an annular seat for accommodating a sealing ring, O-Ring, which is adapted to be compressed between the flange and the coupling wall. A counterflange for clamping rests against the flange and is constituted by an annular element along which a plurality of threaded holes is distributed; connecting screws engage in said holes, and corresponding threaded holes are defined in the coupling wall.

The surface for contact between the counterflange and flange is constituted by an annular flat surface which lies parallel to the coupling wall.

In particular, the flange has, along the portion directed toward the head of the pipe, a reduction in its transverse cross-section which defines a right-angled step. The surface of said step constitutes the abutment surface of the counterflange; such abutment surface is annular, flat and parallel to the face with which the flange makes contact with the coupling surface.

Likewise, the internal surface of the ring of the counterflange has a step (reduction in inside diameter) which defines a corresponding complementary abutment surface, which is likewise annular and flat and is adapted to make contact with the abutment surface of the flange.

Both the abutment surface of the flange and the complementary abutment surface of the counterflange are blended with the body respectively of the flange and of the counterflange with sharp blending portions which form an angle of more than 45°, generally equal to 90°. Therefore, the axial clamping force, the stresses produced by the pressure of the fluid contained in the pipe, the flexural and torsional stresses induced for example by the vibrations to which the pipes are subjected are discharged onto the two abutment surfaces which are in mutual contact and parallel to the coupling surface. Moreover, the compression of the annular gasket for fluid tightness is entrusted to the clamping pressure of the two abutment surfaces that are in mutual contact.

Connecting devices such as those described above are used, for example, for connecting pipes with operating pressures up to 420 bars. However, such known devices suffer drawbacks, including the fact that the abutment surfaces of the flange and of the counterflange have an extension which is limited by the size of the head of the pipe and by the space occupation of the coupling regions on the machines, which cannot be increased, and this accordingly entails a concentration of loads and stresses and an increase in specific contact pressure.

Another disadvantage of known devices consists in that the sharp- edged blending regions between the abutment surfaces of the flange and of the counterflange with their body constitute trigger points for the known notch effect, consequently increasing the risk of fractures and breakages. Another disadvantage of known devices consists in that in case of errors in the centering and alignment of the flange and counterflange, an uneven contact pressure is generated between the two abutment surfaces and this accordingly entails abnormal and dangerous load concentrations.

Still another disadvantage of known devices consists in that they do not ensure correct compression of the annular gasket, with consequent losses of hydraulic tightness.

Finally, the use of known devices is limited to operating pressures which do not exceed 420 bars. Disclosure of the Invention The aim of the present invention is to devise a detachable flange and counterflange device for fixed coupling of pipes which allows to reduce the specific contact pressure between the flange and the counterflange and to improve the distribution of the loads that affect the flange and the counterflange. An object of the present invention is to provide a detachable flange and counterflange device for fixed coupling of pipes which allows to distribute the contact pressure between the flange and the counterflange uniformly even if centering and alignment are not perfect.

Another object of the present invention is to provide a detachable flange and counterflange device for fixed coupling of pipes which allows to eliminate the notch effect and to increase the fracture resistance and breaking strength of the flange and counterflange.

Another object of the present invention is to devise a detachable flange and counterflange device for fixed coupling of pipes which can be used in full safety with operating pressures even higher than 420 bars and ensures perfect hydraulic tightness of the coupling.

Still another object of the present invention is to provide a detachable flange and counterflange device for fixed coupling of pipes which meets the dimensional and space occupation requirements that are standardized and prescribed in the field and thus can be used for known applications without requiring any modification of the connection to the machine.

Within this aim, another object of the present invention is to achieve said aim and objects with a structure which is simple, relatively easy to provide in practice, safe in use, effective in operation, and relatively low in cost.

This aim and these objects are all achieved by the present coupling flange for pipes, which comprises an annular body which is adapted to be associated with the end of a tubular element and is provided, at the outer lateral surface, with an abutment surface for a locking counterflange, characterized in that at least part of the abutment surface has a curved profile.

This aim and these objects are also achieved by the present locking counterflange, which comprises an annular plate provided at the inner lateral surface with a complementary abutment surface adapted to make contact with the abutment surface of the flange and is characterized in that at least part of the complementary abutment surface has a curved profile which substantially duplicates the curved profile of the abutment surface of the flange. Brief description of the drawings Further characteristics and advantages of the present invention will become better apparent from the detailed description of a preferred but not exclusive embodiment of a detachable flange and counterflange device for fixed coupling of pipes according to the invention, illustrated by way of non-limiting example in the accompanying drawings, wherein: Figure 1 is an exploded view of the device according to the invention;

Figure 2 is a partially sectional view of the device according to the invention in the assembly configuration. Ways of carrying out the invention

With reference to the figures, the reference numeral 1 generally designates a detachable flange and counterflange device for fixed coupling of pipes.

The device 1 comprises a flange 2 and a locking counterflange 3.

As is known to the person skilled in the art, the flange 2 is adapted to be rigidly associated with the end of a tubular element to be connected for example to another tubular element or to a coupling surface 4, for example, of a machine or a hydraulic or pneumatic system.

The counterflange 3 is adapted to lock the flange 2 on the coupling surface 4.

The flange 2 comprises an annular body which is adapted to be associated with the end of a tubular element, not shown, and is provided, at the outer lateral surface, with an surface 20 for the abutment of a corresponding complementary abutment surface 30 defined on the counterflange 3.

At least part of the abutment surface 20 has a curved profile and at least one corresponding part of the complementary abutment surface 30 has a matching curved profile.

The curved profile of the abutment surface 20 is concave and arc- shaped, while the curved profile of the complementary abutment surface 30 is convex and arc-shaped, the two profiles being mutually complementary. The flange 2 has a first end 2a which is adapted to be associated with a tubular element, even of a flexible type, and a second end 2b which lies opposite the first end and is adapted to make contact with the coupling surface 4.

A portion 2c is defined between the first end 2a and the second end 2b and its outside diameter gradually increases from the first end 2a toward the second end 2b.

The outer lateral surface of the portion 2c defines the abutment surface 20 having a curved profile, which has the shape shown in Figure 2.

The flange 2 further comprises a first portion 2d, which lies from the first end 2a to the portion 2c, and a second portion 2e, which lies from the portion 2c the second end 2b, with a substantially constant outside diameter, i.e., constant except for ordinary tolerances.

The first portion 2d has an outside diameter which is smaller than the outside diameter of the second portion 2e. The inside diameter of the flange 2 can substantially have a cylindrical profile which has a constant or variable diameter along its entire axial extension except for a flared portion 21 which is defined at the second end 2b.

The second end 2b defines a substantially flat contact face which is adapted to make contact with the coupling surface 4.

An annular seat 22 for accommodating an annular gasket (of the O- Ring type), not shown, is defined on the contact face.

The counterflange 3 comprises an annular plate which is provided with a first end face 3 a which, in the assembled configuration, is directed toward the tubular element to which the flange 2 is connected, and with a second end face 3b, which lies opposite the first end face and which, in the assembled configuration, is directed toward the coupling surface 4.

The complementary abutment surface 30 is defined on the inner lateral surface of the counterflange 3 and, as mentioned above, is at least partly shaped with an arc-like profile which matches the arc-like profile of the abutment surface 20 of the flange 2.

The counterflange 3 has at least one intermediate portion 3 c which has an inside diameter which gradually increases from the first end face 3 a toward the second end face 3b, the inner lateral surface of the portion 3c defining the curved profile of the complementary abutment surface 30 which has the shape shown in Figure 2.

The counterflange 3 has a first portion 3d, which is arranged between the first end face 3 a and the portion 3 c, and a second portion 3e, which is arranged between the portion 3 c and the second end face 3b, having a substantially constant inside diameter. The first portion 3d defines a containment seat for the first portion 2d of the flange 2; likewise, the second portion 3e defines a seat for containing the second portion 2e of the flange 2.

The counterflange 3 is provided with a plurality of through holes 31 in which threaded elements, in practice screws 32, can be inserted which are adapted to engage in corresponding threaded holes 40 defined in the coupling surface 4.

For the person skilled in the art, operation of the coupling device according to the invention can be deduced easily from the present description and from the accompanying figures.

The forces that act on the flange 2 and on the counterflange 3, produced by the clamping load of the screws 32, by the pressure of the fluid contained in the tubular element and by the flexural and torsional stresses of said tubular element caused for example by vibration, are discharged in the contact between the abutment surface 20 and the complementary abutment surface 30.

Due to the curved or arc-like profile of such surfaces, the load is not discharged only in an axial direction, as in known devices, but acts along the perpendicular to the tangent, in each point, of the curved profile and therefore is discharged partly axially and partly radially, acting in any case on larger contrast surfaces than in the known case.

The curved or arc-like profile of the abutment surface 20 and of the complementary abutment surface 30 gradually blends with the contiguous portions without sharp edges, particularly without recessed edges, which as is known are trigger points of the notch effect.

In practice it has been found that the described invention achieves the intended aim and objects.

The curved or arc-like profile of the abutment surfaces of the flange and counterflange of the device according to the invention allows to increase the useful contact surface and therefore reduce the specific contact pressure.

It is noted in particular that the sealing load between the flange and the counterflange acts along the perpendicular to the tangent of the two abutment surfaces in each point and is thus discharged onto larger resisting cross-sections than the known case.

By increasing the resisting cross-sections, the risks of deformation of the flange and counterflange, which would lead to a loss of compression of the sealing gasket, with a loss of tightness, are reduced.

The curved or arc-like profile of the abutment surfaces of the flange and counterflange eliminates the notch effect and therefore the risks of fractures and breakages of the connection.

The curved or arc-like profile (toroidal profile) of the abutment surfaces of the flange and counterflange ensures contact between the two abutment surfaces even in case of errors in alignment and centering, thus maintaining a uniform distribution of the contact pressure, avoiding abnormal concentrations thereof.

The flange and counterflange according to the invention can be provided in accordance with standardized and prescribed dimensions and space occupations, and therefore can be used as spare parts on known pipes without requiring particular modifications.

The device according to the invention allows to apply to the annular gasket a uniform compression, thus ensuring a perfect seal.

The device according to the invention allows to increase the contact surface between the flange and the counterflange without increasing their maximum space occupation, allowing a better distribution of loads, and can be used safely even with operating pressures up to 560 bars.

The invention thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the appended claims. All the details may further be replaced with other technically equivalent ones.

In practice, the materials used, as well as the shapes and dimensions, may be any according to requirements without thereby abandoning the scope of the protection of the appended claims. The disclosures in Italian Patent Application No. MI2006A001740 from which this application claims priority are incorporated herein by reference.

Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly, such reference signs do not have any limiting effect on the interpretation of each element identified by way of example by such reference signs.

Claims

1. A coupling flange for pipes, comprising an annular body which is adapted to be associated with the end of a tubular element and is provided, at the outer lateral surface, with an abutment surface for a locking counterflange, characterized in that at least part of said abutment surface has a curved profile.

2. The flange according to claim 1, characterized in that said curved profile is arc-like and concave.

3. The flange according to claim 1 or 2, characterized in that said annular body comprises a first end which is adapted to be associated with said tubular element, a second end which lies opposite the first end and is adapted to make contact with a coupling surface of said counterflange and a portion of outside diameter which gradually increases from said first end towards the second end, the outer lateral surface of said portion defining said abutment surface having a curved profile.

4. The flange according to claim 3, characterized in that between said portion and said second end and/or between said portion and said first end, said annular body has a substantially constant outside diameter.

5. The flange according to claim 3 or 4, characterized in that said annular body has an inside diameter which substantially has a cylindrical profile.

6. The flange according to claim 3, 4 or 5, characterized in that said second end comprises a substantially flat contact face adapted to make contact with said coupling surface, an annular seat for accommodating a sealing gasket being defined on said contact face.

7. A counterflange for locking the flange according to one or more of claims 1 to 6, comprising an annular plate provided at the inner lateral surface with a complementary abutment surface which is adapted to make contact with said abutment surface of said flange, characterized in that said complementary abutment surface has at least partly a curved profile which substantially duplicates the curved profile of said abutment surface of the flange.

8. The counterflange according to claim 7, characterized in that said curved profile of said complementary abutment surface is arc-like and convex.

9. The counterflange according to claim 7 or 8, characterized in that said annular plate comprises a first end face, which in the assembly configuration is directed towards the tubular element, a second end face which lies opposite the first end face and which, in the assembly configuration, is directed towards said coupling surface and portion having an inside diameter which gradually increases from said first end face towards said second end face, the inner lateral surface of said portion defining said curved profile of said complementary abutment surface.

10. The counterflange according to claim 9, characterized in that between said portion and said second end face and/or between said portion and said first end face said annular plate has an inside diameter which is substantially constant.

11. The counterflange according to one or more of claims 7 to 10, characterized in that said annular plate comprises at least one hole for the insertion of threaded fixing elements which are adapted to engage in said coupling surface.

12. A detachable fixed coupling device for pipes, comprising a flange according to one or more of claims 1 to 6 and a complementary locking counterflange according to one or more of claims 7 to 11.