DE2948286A1 - ALL-METAL CONNECTION - Google Patents

Description

two associated flanges. Building each other opposing flange surfaces is chosen so that when the connection is disassembled, the net force required to do so tends to hold the sealing ring in position against one of the flange surfaces, is minimized. In particular, each flange surface is configured so that the remaining compressive forces that are present when the flange coupling mechanism is released, distributed over the surface of the gasket, in net effect are substantially equal to or greater than the frictional and binding forces which might tend to keep the gasket in contact with one of the flanges. To these catfish the sealing ring tends to break away from the mating flange surfaces when the connection is disassembled.

Background of the invention

The invention relates to an improvement in the gas-tight flange coupling technology, and is particularly applicable to high vacuum and high pressure flange connections.

All-metal flange connections for use in applications at which a high temperature and / or frequent heating of an assembled connection are required are known. In particular shows the US-PS 32 08 758 an all-metal flange connection in which a gas-tight seal between associated flanges is obtained in that a soft metal sealing material flows into an annular groove between the flange surfaces which are to be facing one another is formed when the two associated flanges are pressed together.

In the flange connection according to US-PS 32 08 758 they were each other opposite flange surfaces configured so that a soft metal Seal could be received in a recess formed between them when the flanges were pressed together. Correspondence

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dating annular beads were provided on the opposing flange surfaces so that they are in the recess in the Way that they penetrate into different sides of a peripheral area of the gasket arranged in the recess. In this way, part of the sealing material flows into an annular groove that formed the periphery of the recess between the opposing flange surfaces. This groove was dimensioned so that its volume was greater than the volume of the sealing material which could flow into the groove so that the sealing material was prevented from completely filling the groove. When an excess of sealing material was allowed to penetrate the annular groove, the opposing flange surfaces would be forced apart. A perfect dimensioning the groove was used to provide a gas seal in the manner of a compressed O-ring that could withstand pressure differences limited only by the tensile strength of the metal gasket.

In known flanges of the type described, however, difficulties occurred when disassembling the flange connection after manufacture a seal on. Typically the known flanges were coupled by bolting the two opposing flanges together. Such a bolt or other compression coupling of the associated flange surfaces ensured compression of the interposed gasket and resulted in the soft metal being extruded from the periphery of the gasket into an annular groove, which was formed on the periphery of the recess between the opposing flange surfaces. When the related Flanges were subsequently unbolted to disassemble the connection, but the metal gasket often remained on one or the other of the flange surfaces or both.

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When a soft metal gasket has been pressed hard against the surface of a harder metal, a weld-type surface bonding phenomenon occurs. Additionally tends a friction holding force that depends on the coefficient of friction of the Soft metal gasket material depends on the harder surface of the flange, causing the gasket to move away to counteract from the flange.

In the prior art, the tendency of the metal seal was to stick to one of the two, or both, associated flanges, not an insurmountable problem when dismantling the connection when sufficient leverage was available to apply an external force to separate the flanges. if After separating the flanges, attach the soft metal seal stuck to one or the other of the flanges, the gasket could usually be removed fairly easily with a hand tool removing the gasket from the flange to which it was adhered. could be pried away. With the recent heavy demand for mini flanges (i.e., flanges with a gasket diameter of less than about 1 inch = 25 mm) is the inaccessibility of mini flange seals in terms of removal with hand-held pry tools become a significant problem. Large diameter flanges (i.e., diameters greater than 2 3/4 inches = 70 mm) also occurred Difficulties in disassembling flange connections due to the large external force that is required to do this Separate the seal from one of the two flange sides. In many applications it is also from the standpoint of system design _ It is advantageous to place flange coupling openings in locations that are relatively inaccessible, and accordingly a flange connection that is not easily disassembled is a serious inconvenience.

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An all-metal flange connection is therefore required which tends to break the gasket away from the mating flange surfaces when the connection disassembles will.

Summary of the invention

The object of the invention is to provide an all-metal flange connection with a soft metal sealing ring between related To provide flange surfaces where the sealing ring can be easily removed when the connection is disassembled.

In particular, the invention is intended to provide an all-metal compound for coupling mini-flanges (i.e. flanges with a diameter of about 1 inch = 25 mm or less) that consists of a soft metal sealing ring between each other facing surfaces of the mating mini-flanges, the sealing ring being easily removable when the Connection is disassembled.

To solve these tasks are the opposing ones Faces of the mating flanges configured to form a recess therebetween in which a soft metal gasket can be placed when facing each other Flange surfaces are pressed together. Annular beads arranged opposite one another on the end faces of the associated Flanges protrude into the recess in such a way that they penetrate the two sides of a peripheral part of the sealing ring. The compression of the sealing ring caused by the compression the opposing flange surfaces is caused, ensures that a part of the sealing material in an annular groove is extruded, which is formed on the periphery of the recess between the two opposing flange surfaces. This

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compressed smoke material in the annular groove ensures a gas-tight seal in the manner of a compressed, metal one O-ring in the groove between the flange surfaces. As in the prior art, the annular groove is dimensioned so that its volume is greater than the volume of sealing material that can flow into the groove. This way the volume of the groove can do that take up all of the gasket material flowing into the groove and any excess gasket material that may otherwise tend to do so could push the associated flange surfaces away from each other, is prevented from penetrating into the groove. as In contrast to the prior art, the configuration of the opposing flange surfaces according to the invention is selected so that that the remaining compression forces, which are present when the flange coupling mechanism is released, distributed over the Surface of the sealing ring, are essentially the same size as or are greater than the frictional and binding forces that are necessary for this tend to keep the sealing ring in contact with one of the flanges.

In particular, the surface parts of the flange surfaces that the Define annular groove into which the gasket material can be extruded at an angle other than a right angle with respect to FIG the boundary surface between the flange surfaces belonging to one another is inclined to one another. In this way, the distributed compressive force exerted by each surface defining the groove on the Seal is applied, a component that tends to push the seal away from contact with the flange surface. According to the invention, the seal tends to be of the associated Break away flange surfaces when the connection is dismantled.

The invention will be explained in more detail with reference to the drawing; show it:

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FIG. 1 shows a longitudinal section through an all-metal connection between two associated flanges which are coupled by means of a screw connection which consists of a coupling part with an external thread on one flange and a coupling part with an internal thread on the other flange;

FIG. 2 shows part of the connection between the associated flange according to FIG. 1;

FIG. 3 shows a section through part of the surface of one of the flanges according to FIG. 2;

4 shows a longitudinal section through a ganzmetallene connection between two mating flanges which are coupled to Piner screw connection, consisting of a coupling member with an external thread on each flange and a clutch · ¹ · part with two internal threads for engaging in both other coupling parts;

FIG. 5 shows a longitudinal section through part of an all-metal connection between two associated flanges which are coupled by bolts;

Figure 6 is a force diagram showing the distributed compressive forces exerted on a gasket by the surfaces of a flange face in accordance with the invention when the flange coupling mechanism is released; and

Figure 7 is a force diagram showing the distributed compression forces represents exerted on a gasket by the surfaces of a prior art flange face when the flange coupling mechanism is released.

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Figure 1 shows an all-metal flange connection according to the invention, in which a gas-tight seal between flanges provided end parts 10 and 20 of tubes 11 and 21, respectively. The flanges 10 and 20 are coupled by means of a screw connection, which consists of a coupling part 12 with external thread, which is on the pipe 11 presses, and a coupling part 22 with an internal thread, which presses on the tube 21.

According to Figure 1, the coupling part 12 is annular with an external thread and is arranged to be slidable longitudinally along the tube. The inner diameter of the coupling part 12 is smaller than the outer diameter of the flange 10, so that the coupling part 12 is prevented from being flanged from the Slide off the end of the tube 11. In a corresponding manner, the coupling part 12 has a ring shape and internal thread and is arranged in such a way that that it can be displaced along tube 21. The coupling part 22 has an inner diameter which is smaller than the outer diameter of the flange 20 so that the coupling part 22 is prevented from slipping off the flanged end of the tube 21.

When the opposing surfaces of the flanges 10 and are brought into mating contact, the coupling part 22 extends over the flanges 20 and 10 and engages the external threads of the coupling part 12. This way the clutch becomes of the flanged pipes 11 and 22 by tightening the coupling part 22 around the coupling part 12.

The opposing faces of the flanged Ends 10 and 20 are configured so that a recess 30 is formed between them, in which a soft metal seal 31 can be arranged. The seal 31 has a ring shape and consists of a material which is more easily deformable than the material from which the flanged ends 10 and 20 are composed. Typically, there are flanged ends 10 and 10

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made of stainless steel, and in this case the metal gasket expediently be an annular copper ring with a planar shape. Other suitable sealing materials for use in conjunction with mating stainless steel flanges include nickel, aluminum, various alloys and combinations a base metal coated with a soft metal.

As shown in more detail in Fig. 2, the face of the with Flanged portion 10 of tube 11 configured so that an annular bead 13 protrudes into recess 30. Similarly stands an opposing annular bead 23 on the end face of the flange part 20 of the tube 21 from the opposite direction into the recess 30, so that the beads 13 and 23 into the soft metal penetrate from opposite sides on the periphery of the sealing ring 31. The compression of the sealing ring 31 by the contraction of the two flanges 10 and 20 causes the sealing material to be extruded into a groove formed on the periphery of the recess 30.

As can further be seen from Fig. 2, the annular bead 13 is on the The end face of the flange 10 is formed by the intersection of conical surface areas 14 and 15, and an annular trough 16 is formed by the intersection of conical surface areas 15 and 17. In a similar way, the annular bead 23 is on the face of the Flange 20 is formed through the intersection of conical surface portions 24 and 25, and an annular trough 26 is formed through the intersection formed by conical surface areas 25 and 27. When the flanges 10 and 20 fit closely together, the conical surface areas 15, 17, 25 and 27 together form the boundary of the annular groove in which the soft metal sealing material is extruded. This extruded gasket material is the equivalent of a compressed one metal O-ring, which ensures a gas-tight seal between the flanges 10 and 20.

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The annular groove, which is delimited by the surface areas 15 and 17 on the flange IO and the surface areas 27 and 25 on the flange 20, is dimensioned so that its volume is greater than the volume of the sealing material, which is due to the squeezing effect of the beads 13 and 23 the seal 31 can be extruded into this. The amount of sealing material that can penetrate into the annular groove is therefore small enough to prevent the flanges 10 and 20 from separating.

In Fig. 3, the orientations of the surface areas 24, 25 and 27 with respect to each other on the end face of the flange 20 are shown in more detail. Corresponding symmetrical orientations of the surface areas 14, 15 and 17 on the end face of the flange 10 are provided in a similar manner.

According to FIG. 3, the surface region 25 inclines away from the bead 23 towards the trough 26, and from there the surface region 27 extends to the interface plane between the associated flanges 20 and 10. The conical surface region 24 closes an acute angle ♦ with the interface plane of the associated flanges. In a similar manner, the surface region 25 forms an acute angle θ with the same interface plane . The angle φ is preferably in the range from 60 to 75 ° and the angle θ is preferably in the range from 15 to 30 °.

In a symmetrically similar manner, the conical surface area ₁ , 14 on the end face of the flange 10 forms an acute angle ♦ with the interface plane between the flanges 10 and 20, and the conical surface area 15 forms an acute angle θ with the same interface plane. The facing surfaces of the flanges 10 and 20 are thus arranged symmetrically to one another.

Both the conical surface area 27 on the flange 20 and the corresponding conical surface area 17 on the flange 10 move

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an acute angle β with the interface plane of the associated flanges 10 and 20. According to the invention, the angle β an acute angle. In the prior art, there was no suggestion to make the angle β acute.

Flg. 7, on the other hand, shows schematically flange connections according to the State of the art, wherein, unlike the connection according to the invention, the end wall 27 'of the annular groove in which the extruded seal «» material was trapped, perpendicular to the interface plane between

-1st the associated flanges / the angle β according to the invention is In contrast to the prior art, an acute angle (preferably 1m range from 60 to 75 °). This novel configuration for the end wall of the annular groove (i.e. the wall formed by surface areas 27 and 17) along with the prescribed one Configuration for surface areas 24 and 14 enables the seal 31 is much easier to remove when the connection disassembled than was possible with the prior art.

For the sake of convenience of manufacture, the conical surfaces 24 and V on the end face of the flange 20 can be parallel to one another, ie it is possible that Φ = e, provided that θ is an acute angle U. However, it is not necessary for the implementation of the invention, that Φ »B. It is desirable that the angle β is less than 75 ° so that the normal to the surface area 27 has a relatively large component perpendicular to the interface plane between the associated flanges. If e becomes too small, however, the outer diameter of the flanges 10 and 20 would become inconveniently large for common design considerations. It is not desirable for φ to be considerably smaller than about 30 °, because the extension of the bead 23 into the recess 30 becomes smaller as Φ becomes smaller. A suitable range for the angle φ is between 60 ° and 75 °, and a suitable range for the angle θ is between 15 ° and 30 °.

When the flanges 10 and 20 are pressed together, it does not matter whether with the technique according to FIG. 1, in which the coupling part 22 with inner

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Thread is tightened on the coupling part 12 with external thread, or by any other suitable coupling technique, as will be discussed in connection with FIGS. 4 and 5, the beads 13 and 23 protrude into the soft metal seal 31 and ensure that a peripheral Part of the same is extruded into the annular groove which is delimited by the surface areas 15, 17, 27 and 25. In the flange coupling technique according to FIG. 4, the coupling part 22 with an internal thread according to FIG. The inner diameter of the coupling part 42 is smaller than the outer diameter of the flange 20, so that the coupling part 42 is prevented from slipping off the flange end of the pipe 21. The coupling part 42 is externally threaded, as is a corresponding part of the coupling part 12 on the pipe 11. A cylindrical coupling part 52 with an internal thread can simultaneously engage the external threads of the coupling parts 12 and 42 when the flanges 10 and 20 are in contact. In practice, the coupling part 52 is first firmly tightened onto one of the coupling parts with an external thread (for example coupling part 42), and then the other coupling part 12 is screwed into the coupling part 52 and tightened. In this way the flanges 10 and 20 are brought into touching contact.

Another flange coupling technique is shown in FIG. 5, wherein a flange element 10 ′ is attached to one end of the pipe 11 by a suitable technique, for example by welding. Similarly , a flange element 20 ′ is attached to one end of the tube 21. The soft metal seal 31 is pressed together between the opposing flange elements 10 'and 20' in that one flange element is bolted to the other. 5, a bolt passes through aligned holes in the flanges 10 'and 20' and a nut 62 is threaded onto the protruding end of the bolt 61. The bolt 61 and nut 62 are representative of a plurality of similar bolts and nuts circumferentially circumferentially around the mating flanges 10 'and 20', preferably at regular intervals.

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29A8286

When the flange parts 10 and 20 according to FIGS. 1 and 4 (or the flange elements 10 'and 20' of the embodiment according to FIG. 5) are pressed together, the beads 13 and 23 of the opposing flange surfaces penetrate into the soft metal seal 31, so that a peripheral part of the sealing material flows into an annular groove which is formed on the outer periphery of the recess 30 between the opposing flange surfaces. This groove that goes through the faces 15 and 17 on the flange part 10 and the surfaces 27 and 25 on the flange part 20 is limited, has a total volume that is greater than that Volume of sealing material that can be extruded into the groove. As has been explained above, the mutually contacting surfaces of the flange parts 10 and 20 are not pressed apart by the sealing material in the groove, since less than the total volume of the groove can be ingested by sealing material. The compressed sealing material in the ring groove functions as a metal O-ring underneath Compression in order to ensure a gas-tight seal between the opposing end faces of the flange parts 10 and 20.

The remaining distributed compression forces F 1, F " ^and d 'S", which are present when the flange coupling mechanism is released and which are exerted on the seal 31 by the surface areas 27, 25 and 24 of the flange part 20, are shown in FIG. 6 represented by arrows normal to the respective surfaces. These compression forces tend to push the seal 31 out of contact with the flange portion 20. Correspondingly symmetrically acting, distributed compression forces, which are exerted by the corresponding surface areas 17, 15 and 14 of the flange part 10 on the other side of the seal 31, similarly tend to push the seal 31 away from contact with the flange part 10.

When the flanges 10 and 20 are to be uncoupled, make the connection To disassemble it, it is usually desirable to remove the seal 31 as well. However, with the prior art it was very often difficult to to break the seal between two associated flanges,

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because of the binding and frictional forces that tended to reduce the Keep the seal in contact with the faces of the flanges. Cold weld type bonding forces develop from the compression of the gasket against the flanges. Frictional forces develop also that act parallel to the surfaces of the flanges in directions counter to the forces that tend to push the gasket away from contact with the flanges. Even after the prior art mating flanges were separated, the Seal often stick to one or the other of the flanges. According to the invention are the surfaces of the opposing flanges configured to minimize the forces which tend to prevent the seal from being removed after the flange coupling mechanism has been loosened (e.g., the bolts of FIGS Fig. 5 are loosened and removed).

According to Fig. 6, the remaining compression force component F, which is to tends to slide the gasket 31 out of contact with the flange 20, given by the following equation:

F = F. cos e + F ₂ cos θ + F, cos Φ

This net compression force component F increases as the angles β, θ and φ become smaller. It is desirable that θ be in the range of 15 to 30 °, and that φ is in the range of 60 ° to 75 ° so that the bead 23 protrudes sharply enough into the recess 30 to cause the material to extrude from the periphery of the seal 31. According to the invention, the angle β is practically feasible minimized in order to provide a component of the compression force F. 1n in the opposite direction to the frictional force component, which tends to to keep the seal 31 in contact with the surface area 27.

Easy dismantling of all-metal flange connections of the type as used in high pressure and high vacuum applications,

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is the main aim of the invention. The diameter of the to be connected Flanges is not essential to the definition of the invention, although the invention is particularly valuable with respect to mini-flange connections located in areas that may be disassembled are not easily accessible by hand-held tools.

In practice, the invention can be used with a wide variety of coupling techniques that enable the opposing coupling techniques to be used. End faces of the flanges to be connected are brought together. In particular, the coupling technique according to Fig. 4 (i.e. the use of a screw connection with a coupling part with an external thread each flange and a coupling part with internal thread that goes with each the other coupling parts interacts), a convenient way to to connect a number of sections of flanged pipe without the need to arrange the components so that Matching screw coupling parts with internal or external thread attached to the respective ends of the flanges to be connected * need to be arranged. In appropriate cases, a helium gas access hole could be provided through one or both of the mating flanges peripheral region of the recess formed therebetween, so that the gas-tight integrity of the flange connection through known techniques could be monitored. The type of tubing to be connected may vary depending on the type of system in which the Piping is used. It is contemplated that a flanged joint according to the invention can be used to connect pipes of any diameter and shape, including pipes with expandable "bellows" sections. Other uses for an all-metal compound according to the invention result for the expert by itself.

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Claims (2)

Vl P503 D Claims (1. y All-metal connection consisting of two flange elements, each of which has an end face which is configured in such a way that it faces a corresponding end face of the other flange element when the flange elements are combined and these flange elements are in contact with one another in a connection plane, the The end face of each flange element has at least three surface areas, of which the second and third intersect each other in such a way that a bead is formed which is spaced from the connecting plane, and the second and the first surface area intersect each other on the end face of each flange, and the wedge on one of the flanges is spaced apart from the wedge on the other flange so that an annular recess is formed between the opposing end portions of the flange members when the flange members are united, the peripheral portion of which is defined by the first and second surface regions, respectively of the flange members is limited, and a soft metal gasket configured to be received in the recess, the bead on the face of each flange penetrates a peripheral area of the gasket when the flange members are united, so that sealing material extruded into the peripheral area of the recess and contacting the first surface area on the face of each flange member when the flange members are united, and the first and second surface areas on the face of each of the flange members are configured so that the volume of the peripheral part of the recess is greater than the volume of the sealing material which can be extruded into this peripheral region of the recess when the flange elements are united, characterized in that the first surface regions of the two flange elements enclose an angle with one another which is less than 180 °, so that the distributive co pressure exerted by each of the three surface areas on the face of each flange element on the 030026/0636 ' Sealing material within the peripheral area of the recess is exercised has a component perpendicular to the plane of connection. 2. A compound according to claim 1, characterized in that the first Surface area on the face of each of the flange elements Connection plane at an acute angle in the range from 60 ° to intersects and the third surface area on the end face each the flange element intersects the connection plane at an acute angle in the range of 60 ° to 75 °. 030026/0636