Pipe coupling having clamping effect on pipe and method of installing pipe coupling

Abstract

The invention relates to a pipe connection arrangement (1, 30, 36), in particular for connecting thin-walled metal pipes (4), comprising a pipe (4) having a shaped end portion (3, 31), the shaped end portion (3, 31) exhibiting a frustoconical shape (6) having a diameter (9) that tapers towards the connection end and a pipe end taper angle (), thereby forming an outer circumferential sealing surface; a connecting member (2) having a receiving recess (13) having a frustoconical shape with a diameter gradually increasing towards the connecting end and a receiving recess taper angle (), thereby forming an inner circumferential sealing surface; and a support ring (15, 26, 33) arranged circumferentially around at least a portion of the tube end (3, 31) of the tube (4). At least a portion (24) of the support ring (15, 26, 33) rests on the receiving recess (13) of the connecting member (2).

Description

[0001] This invention relates to a pipe connection arrangement, and more specifically to a pipe connection arrangement for connecting thin-walled metal pipes.

[0002] Transporting gases, liquids, and general fluids between different locations and devices is a standard task in various industries, research, technology, and machinery. The locations and devices that must be connected may be close to each other (e.g., a few centimeters or decimeters apart) or very far apart (e.g., hundreds of kilometers). This statement encompasses all the different scales in between, such as distances on the order of meters, tens of meters, hundreds of meters, and kilometers. Pipes, conduits, and hoses are well known to be used for this transfer of gases and liquids.

[0003] Depending on the specific requirements of the task under discussion, appropriate dimensions, wall thickness, materials, etc., must be selected for the pipes and hoses to be used. These requirements include, but are not limited to, pressure, temperature (of the fluid and the surrounding environment), state of matter, chemical composition, fluid flow rate, presence of vibration, corrosive conditions, permissible diffusion into / out of the pipe, and so on, to name just a few. For example, if transporting hydrogen, diffusion can become quite problematic due to its high diffusion rate.

[0004] A well-known subsequent problem is the inevitable connection of pipes / hooks to the device, and the connection of the two pipe ends to each other (especially given the limited possible lengths of pipes and hoses). Here, not only the overall framework described above must be considered, but also the ease of operation of the various components. It should be noted that under certain conditions, such as if vibration does occur, the connections between the pipe ends and between the pipe and the connected device are particularly prone to leakage, breakage, and failure.

[0005] However, given the frequent and almost ubiquitous use of pipes and hoses, and therefore the corresponding connection arrangements, it is not surprising that a wide variety of recommendations have been made regarding pipe connection arrangements.

[0006] One example is the collar assembly for catheter fittings described in WO 2010 / 068762 A1. Here, two collar-type catheter clamping devices to be used in combination are arranged on the tube end. When the tube end is connected to the concave connector body via a connecting nut, the two clamping devices, which are in contact with each other via tapered contact surfaces, move closer together, causing one of the radially inner clamping devices to cut into the circumferential surface of the tube end. This, in turn, creates a forced locking contact that inhibits axial movement of the clamping devices relative to the tube. Thus, the corresponding compounds of the tube end and clamping devices can be tightly screwed onto the concave connector assembly using the connecting nut. As can be seen from U.S. Patent US 3,103,373 A, the basic design of the assembly disclosed in this application has been known for decades and works very well in practice. However, it remains prone to leakage problems, which become more pronounced when the gas exhibits a high diffusion rate, as is the case with hydrogen. Another problem is that the assembly of this arrangement is susceptible to various assembly errors (e.g., due to incorrect placement of the clamping devices). Furthermore, due to the design concept itself, this connection arrangement is unsuitable for thin-walled tubes, as the tube ends must be able to withstand high radially inward pressure applied by the clamping device. Another issue related to the design concept is that this type of connection is relatively prone to leakage problems and even mechanical failure when used in environments with significant vibration.

[0007] Another suggestion is made in European Patent EP 2 872 811 B1. This suggestion proposes deforming the end of the pipe to form an inwardly tapered end portion, wherein the outer tapered surface of this end portion is designed to contact the corresponding inner tapered contact surface of the connecting member. This establishes a tapered connection with a relatively large tapered contact area, which is quite leak-proof for fluids and gases. To further increase the tightness of the connection between the pipe and the connecting member, sealing devices such as O-rings or circumferentially applied sealing materials can be provided. To achieve the required pressure between the pipe end and the connecting member, thereby establishing good mechanical contact between the contact surfaces, the pipe end is provided with a second curved region with a gradually decreasing diameter (in the direction opposite to the pipe opening). This second curved region forms a shoulder that serves as a support surface for the connecting nut. Again, this design undeniably has certain advantages. However, a disadvantage is that a relatively high installation force must be applied between the pipe end and the connecting member to achieve a sufficiently tight connection. This limits the applicability of the design. In particular, a certain thickness of pipe material must still be provided.

[0008] EP 1 260 750 B1 discloses a screw-type pipe connector with a support ring. This screw-type pipe connector includes a connecting pipe with a socket opening and a screw-on nut. The support ring, fitted onto the pipe between the annular bead flange and the screw portion, forms a contact bearing surface with the bead flange. This contact bearing surface forms an angle greater than 45° relative to the screw axis, such that there is no radial force component in this area when the screw connection is tightened. While this design does increase the clamping force at the pipe end, it is still far from perfect due to the very limited axial range of the clamping area at the pipe end.

[0009] Therefore, it is clear that an improved design for pipe connection arrangements is desired.

[0010] Therefore, the object of the present invention is to provide a pipe connection arrangement, particularly a pipe connection arrangement for connecting thin-walled metal pipes, which is superior to pipe connection arrangements known in the prior art.

[0011] Another object of the present invention is to provide a method for connecting pipe ends and connecting members in a pipe connection arrangement, which is superior to such methods known in the prior art.

[0012] The pipe connection arrangement according to claim 1 achieves this objective. The method according to claim 14 also achieves this objective.

[0013] The proposal suggests designing pipe connection arrangements, particularly those for connecting thin-walled metal pipes, such that the pipe connection arrangements include:

[0014] The tube has a modified end portion, wherein the modified end portion exhibits a frustoconical shape, the frustoconical shape having a diameter that gradually decreases toward the connecting end (the open end of the tube) and a tube end taper angle. This forms an external circumferential sealing surface.

[0015] A connecting member having a receiving recess having a frustoconical shape, the frustoconical shape having a diameter that gradually increases toward the connecting end (the open end of the connecting member) and a cone angle of the receiving recess. This forms an internal circumferential sealing surface, and

[0016] A support ring, which is arranged circumferentially around at least a portion of the pipe end.

[0017] At least a portion of the support ring rests on a portion of the connecting member, particularly on a portion of the receiving recess of the connecting member.

[0018] The concept of a "pipe connection arrangement" can refer to an arrangement in which pipe ends are connected to a machine, a part of a machine, or a similar device. Therefore, the corresponding connection member can be fixedly attached to the corresponding machinery or device. It should be noted that "fixedly" can refer to situations where removal of the corresponding connection member may not be possible without significant effort (e.g., if the connection member is welded, glued, or otherwise fixedly attached to the corresponding part of the machinery). Furthermore, "fixedly" can additionally or alternatively refer to situations where, for example, when using a threaded connection (possibly with a sealing device, etc.), the corresponding connection member can be relatively easily removed from the corresponding machinery or device. However, additionally or alternatively, the concept of a "pipe connection arrangement" can refer to a situation where two pipe ends are connected to each other, typically by using a so-called "intermediate" or "middle" connection member. This can be understood as the end of a first pipe being connected to a first side and / or a first position of the connection member, while the other end of a second pipe is connected to the connection member on a second side and / or a second position. It should be noted that the design of the currently proposed pipe connection arrangement is applicable to virtually all types of pipes and possibly even hoses. In particular, when it comes to hoses, it may be possible to design a tubular (“rigid,” inelastically deformable) end at the corresponding end of the hose. This can be considered as a kind of plug-like device or convex connector at the end of the hose. However, if the hose sheath is sufficiently robust, the end of the hose can be used as a so-called “direct replacement” for the pipe end. However, based on the inherent advantages of the currently proposed pipe connection arrangement, it is particularly suitable for use with thin-walled metal pipes and may be used with other types of pipes and hoses that do not allow for large radially inward forces. This may be due to the limited mechanical stability of the corresponding pipe or hose (shroud thickness, sheath material, other influences, etc.).

[0019] It is well known that pipes (and possibly hoses) typically exhibit a substantially circular cross-section. This does not preclude the possibility of using different cross-sections, particularly elliptical ones, and even triangular, rectangular (square), pentagonal, hexagonal, heptagonal, octagonal, or generally n-gonal (polygonal) cross-sections, especially those associated with slightly rounded corners. While (substantially) symmetrical cross-sections (n-axis symmetry) can be used, asymmetrical cross-sections are also conceivable. However, regardless of the cross-section, pipes or hoses typically exhibit essentially no (significant) cross-sectional variation along their longitudinal direction (axial direction) during production. This is typically due to the production process, where the pipe or hose is frequently extruded using a die. It should be noted that this does not necessarily preclude the possibility of axial thickness variation, as in the case of corrugated hoses, to give just one example. Here, the die is typically arranged at an angle relative to the forward production direction of the pipe / hose, such that the production process involves helically winding the corrugated hose. Furthermore, certain types of axial variations can be introduced in later production steps, such as if external threads are cut using a thread-cutting tool.

[0020] However, currently, the pipe must exhibit a modified end portion with specified characteristics. The cross-section of the modified end portion of the pipe can show substantially the same cross-sectional shape as the (main part) of the pipe itself. However, the modified end portion can also show a different cross-section compared to the (main part) of the pipe, particularly a (different) cross-section compared to the aforementioned list. While modified end portions can be achieved using some kind of die-forming process, pipes or hoses typically having "straight" ends (without significant changes in the axial direction) will be modified through appropriate manufacturing steps. Such modification steps are known in the prior art and will not be elaborated further here. For completeness, such modification processes are described in EP 2 872 811B1 or WO 2017 / 102190 A1. It should be noted that the modification process can be carried out not only at the production site of the pipe or hose but also by the user of the pipe connection arrangement. It should be noted that this is usually not the end user (although this is possible), but rather another type of production site typically where pre-produced parts are joined together (not excluding the possibility of parts produced on-site). This can also refer to machine shops, maintenance, etc. For this purpose, automated reshaping kits are typically produced to varying degrees and sold to consumers, enabling them to perform the necessary reshaping of the end portion adjacent to the tube opening. It should be noted that such reshaping processes usually result in a (substantially) circular cross-section (at least to some extent, regardless of the cross-section of the main portion of the tube). Typically, the truncated conical portion of the reshaped end portion of the tube begins immediately at the tube opening itself. However, this does not preclude the possibility that the starting point of the truncated conical portion of the reshaped end portion may be offset a certain distance from the tube opening. As an example, cylindrical end portions can be envisioned for facilitating the insertion process, enhancing tightness, etc. Typically, the cone angle... The axial range of the truncated conical portion along the modified end of the tube is (essentially) the same.

[0021] Another possibility is that the cone angle changes. This is especially true when a conical surface transforms into a non-conical surface (e.g., a cylindrical surface). However, the change in cone angle can even occur within the conical section, allowing for a varying cone angle along the axial range of the corresponding conical section. In particular, this change can be limited to one or both of the end regions of the truncated conical area at the tube end. This allows for a smooth transition to different parts of the tube end. In particular, this can reduce mechanical stress in the tube material, thereby reducing the likelihood of early material fatigue, etc. Typically, the “straight sections” of the cone angle (i.e., sections where the cone angle does not change) should constitute a significant portion, particularly the majority, of the conical section of the tube. In particular, the “straight sections” should constitute at least 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, or 90% of the “complete” conical section (including sections with varying cone angles). More specifically, and typically, a “straight section” usually does include sections that provide most, or even (essentially) all, of the sealing functionality for pipe connection arrangements and / or corresponding sealing surfaces.

[0022] The connecting member has a truncated conical receiving recess into which the tube end is fitted. As the diameter towards the connecting end (open end; insertion hole) gradually increases, the receiving recess exhibits a funnel-shaped shape. The cone angle of the receiving recess forms the internal circumferential sealing surface. The extent of the truncated conical portion of the connecting member can be (substantially) identical. However, at least similarly, variations in the truncated conical shape as described above with respect to the pipe end portion can occur. This can particularly involve changes in the cone angle at the transition ends of the corresponding sections of the connecting member (especially in cases where a change occurs from a conical section to a straight section, or vice versa). For completeness only, it should be mentioned that the truncated conical receiving recess of the connecting member typically exhibits a cross-sectional shape substantially the same as the modified end portion of the pipe. Again, the “straight section” of the cone angle (i.e., the section where the cone angle does not change) should constitute a significant portion, particularly the majority, of the conical section of the receiving recess. In particular, the “straight section” should constitute at least 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, or 90% of the “complete” conical section (including sections with varying cone angles). More specifically, typically, the “straight section” usually does indeed include the section that achieves most, or even (substantially) all, of the sealing function of the pipe connection arrangement and / or the corresponding sealing surfaces.

[0023] A sealing surface can be understood as a portion of a surface intended, designed, and / or arranged to contact another (sealing) surface in such a way that a (substantially) leak-proof (more specifically, leak-proof of liquids, fluids, and / or gases) connection can / will be established between two adjacent (sealing) surfaces in contact with each other. It is possible that at least one of these sealing surfaces exhibits an advanced surface finish, such as a polished surface. However, the surface may also exhibit a standard surface finish. Typically, however, the surface does not exhibit obvious surface structures such as corrugations, scratches, protruding fins, mesh fins, etc. It should be noted that the corresponding sealing surface may not necessarily be in complete contact with the adjacent surface to establish a leak-proof connection. Instead, it is possible that only a portion of one or both of the adjacent sealing surfaces will eventually reach leak-proof contact. This is often especially true for thick-walled pipes. Here, due to the higher forces required to deform thick-walled pipes, a relatively short / small contact area often proves sufficient to achieve a leak-proof connection.

[0024] Furthermore, support rings are provided for the pipe connection arrangement. Support rings themselves are known in the prior art. They are typically arranged by placing them on the pipe from one end. In the case of a shaped end portion, the support ring can be placed on the pipe before the shaped portion is formed (or, in some cases, by placing the support ring on the pipe from the other end). Typically, the inner diameter of the support ring is approximately the same as the outer diameter of the unshaped pipe / hose (the main part of the pipe / hose), where a certain clearance is to be expected. In addition, the cross-sectional shapes of the pipe / hose and the support ring are usually chosen to be approximately the same. Support rings are generally used to increase the stability of the connection between the pipe and the connecting member against bending forces. Furthermore, when support rings are used, the sensitivity of the connected arrangement to vibration is generally reduced, especially by clamping at least a portion of the pipe by means of the loose portion of the support ring(s). Generally, good clamping behavior is advantageous because various bends in the shaped end portion of the pipe exhibit reduced strength relative to the unshaped portion. This is because cold deformation of the material (metal), which is often used for shaped pipe ends, typically leads to a reduction in the strength of the material. Clamping typically prevents repeated small deformations of the pipe bends due to vibration, thus usually significantly increasing the lifespan of the arrangement. This is certainly advantageous. Arrangements in the prior art include the use of a single support ring or multiple (two, three, four, or even more) support rings at at least one end of the pipe.

[0025] According to this recommendation, at least a portion of the support ring rests on a portion of the connecting member. Specifically, the support ring may rest on a portion of the receiving recess of the connecting member. These statements are generally equivalent to the following: at least a portion of the support ring rests on an inner surface portion of the connecting member (the inner surface of the receiving recess), typically on a portion of a frustoconical portion of the connecting member. This, in turn, is generally equivalent to a portion of the inner circumferential sealing surface of the receiving recess of the connecting member. It should be noted that the concept "rests on" can be interpreted as the pipe connection arrangement (or a portion thereof) being designed and arranged such that the support ring is mechanically supported by means of the connecting member, such that outward (radial) movement of the support ring (a portion thereof) is hindered, preferably prevented, and more preferably even during and / or when the pipe connection arrangement is assembled, inward (radial) movement of the support ring (a portion thereof) is achieved. This can also be interpreted as the connecting member applying at least a portion of a force vector pointing in the inward (radial) direction to the support ring during and / or when the pipe connection arrangement is assembled. In a sense, this enhances the stability of the support ring through an external device, namely, the connecting member. It should be noted that the connecting member typically exhibits a slightly rigid, strong, and / or non-deformable design. Therefore, even if the support ring is not designed to be particularly rigid / strong / non-deformable, it can still generate strong forces in the radially inward direction. This is because the support ring can stabilize itself by using a robust design of the connecting member (which is often necessary to perform its purpose). In other words, it is sufficient to design the connecting member to be sufficiently robust. However, the support ring can be designed to be relatively simple and non-robust, but the presence of a robust support ring can still be effectively simulated by using the support of the connecting member. Of course, the support ring must not be too elastic (as is the case with rubber rings, etc.). This is because the support ring should be able to transmit a certain amount of force. A cost-effective design can be achieved using the proposed design. Furthermore, the size (wall thickness) of the support ring can be reduced, which allows for a smaller installation space. Thanks to this recommendation, very effective support of the pipe within the connecting member can still be achieved. Furthermore, especially when using the tapered surface of the connecting member, it is even possible to convert the axial movement of the support ring (a portion of it) into a radially inward (gradually increasing) force, thereby increasing the holding capacity of the support ring and thus increasing the stability of the pipe connection arrangement.

[0026] Another possible embodiment of the pipe connection arrangement is that the axial extent of the truncated conical section of the pipe end is designed to be smaller than the axial extent of the truncated conical section of the receiving recess of the connecting member. When using this design, it is particularly simple to design and arrange the support ring such that at least a portion of the support ring rests on a portion of the connecting member, particularly on a portion of the receiving recess of the connecting member. More specifically, it can rest on a portion of the conical surface of the receiving recess of the connecting member. Thus, it is possible that the axial movement of the support ring (a portion thereof) can be converted into a radially inward force. Effectively, for at least some designs, the generation of this radially inward force will occur "automatically" when a (leak-proof, gas-proof, liquid-proof) connection is established between the pipe end and the connecting member. In this way, a single fastening process can yield multiple (partially at least two) favorable results for the pipe relative to the connecting member, such as fluid tightness / gas tightness / liquid tightness and reliable support of the pipe relative to the connecting member; the latter, in particular, is related to any vibrations that occur.

[0027] Furthermore, the pipe connection arrangement can be designed such that a support ring protrudes into the gap formed between a portion of the pipe end section and a portion of the receiving recess of the connection device, wherein the support ring preferably exhibits an axial protrusion protruding into said gap. Using this design, the tapered angle of the receiving recess... This can be used to push at least a portion of the support ring toward the outer circumference of the pipe and / or to generate a radially inward force toward the outer circumference of the pipe. Therefore, the pipe can be tightly held in place, allowing for particularly high resistance to vibration. Furthermore, it should be noted that the connecting member can generally be designed to be relatively rigid. Therefore, the directional force (action = reaction) of the support ring (of its respective protrusion) pushing the corresponding annular portion of the connecting member radially outward generally does not widen any part of the pipe connection arrangement in a problematic manner or to a problematic extent. Again, it should be mentioned that when using this design, the axial movement / axial force applied when establishing a tight connection between the pipe end and the connecting member will generally generate an inward radial force applied to the pipe via the support ring. The corresponding protrusion of the support ring may or may not be tapered (if it is tapered, the taper angle may or may not match the taper angle of the receiving recess). The tapering of the protruding portion of the support ring (the surface facing the adjacent surface of the receiving recess) can generate a particularly prominent radially inward clamping force, a lower likelihood of any surface deformation of the receiving recess, and a generally higher number of attachment-disconnection cycles possible in pipe connection arrangements. However, a non-tapered protruding portion of the support ring may be advantageous because less force must be applied to achieve the connection of the pipe ends in the connecting member, and / or a smaller distance must be used to establish the connection (e.g., the number of turns of the connecting nut).

[0028] On the opposite axial side of the support ring, the support ring may also exhibit a tapered surface. Specifically, the tapered angle can be considered as a range between 40°, 50°, 60°, 70°, 80°, 85°, or 90° (lower limit) and 90°, 95°, 100°, 110°, 120°, 130°, and 140° (upper limit). This tapered surface may be accompanied by a similar tapered surface located at a corresponding position on the tensioning device (pipe nut). Combined, these tapered surfaces can convert the axial movement of the various parts of the pipe connection arrangement into a radially inward force toward the pipe, thereby clamping the pipe into place in this section as well. Thus, another clamping point is provided. Another possible advantage of this design is that these tapered surfaces will cause radially inward deformation of the support ring in this section (the clamped state of the support ring). However, this can disengage the elastically deformable member from one of the corresponding surfaces of the pipe connection arrangement, meaning that the support ring and tensioning device will become (essentially) independent devices. This usually facilitates reopening the connection (e.g., to check if the support ring fits snugly in the receiving recess of the connecting member). Even if the deformation only causes partial disengagement, the force between the support ring and the tensioning device will typically be significantly lower than initially. This also applies to deformation of the support ring caused by other design features, particularly other tapered surfaces.

[0029] Another possible embodiment for achieving the pipe connection arrangement is a modified pipe end comprising a mounting collar. Preferably, the mounting collar is adjacent to a frustoconical region of the pipe end (typically facing away from the pipe opening). The combination of this frustoconical region and the mounting collar can exhibit a slightly acorn-like appearance. The mounting collar can engage with a force-acting device (tensioning device; pipe nut; see below) to establish the connection of the pipe end in the connecting member. In this way, the axial force that can be applied by the corresponding force-acting device can be transmitted to the pipe in a simple and efficient manner (directly or indirectly; directly generally implies direct contact between the corresponding surface of the force-acting device and the corresponding surface of the mounting collar; indirectly generally implies the existence of a portion between the corresponding surface of the force-acting device and the corresponding surface of the mounting collar; for example, this portion can be a support ring (part of)). Therefore, sufficient thrust can be achieved between the pipe end and the connecting member, and thus sufficient thrust can be achieved between the sealing surface of the frustoconical pipe end and the sealing surface of the frustoconical receiving recess of the connecting member. It should be noted that the mounting collar can be used at various angles. Although the surface of the mounting collar can be perpendicular / orthogonal to the axial direction of the pipe end / connecting member (equivalent to an opening angle of 180°), it can form an angle (different from 180°), and in particular, it can also exhibit a truncated cone shape (with a third, possibly different, angle). In particular, the angle of this mounting collar. The angle can be between 80°, 90°, 100°, 110°, 120°, 130°, 140°, and 145° (lower limit) and 150°, 155°, 160°, 165°, 170°, 175°, and 180° (upper limit). By using angles other than 180°, the tube can be held in place particularly tightly because some radially inward force can be generated, thereby achieving particularly high vibration resistance (in particular, this makes it easy to provide a second clamping point / second device for generating radially inward force). In this context, it should be noted that the relatively large taper angle of the mounting collar generally favors achieving high connection force between the connecting member and the tube end (without excessive radially inward clamping force that could deform the tube), which is generally disadvantageous in terms of material weakening due to the (usually) significant cold deformation of the corresponding portion of the reshaped end of the tube. Advantageously, a good compromise should be chosen. Preferably, the pipe connection arrangement should be designed such that the force applied to the pipe end by the tensioning device (if present) is preferably directed towards the less deformed portion of the pipe end, particularly, for example, the straight / flat portion of the mounting collar (especially slightly offset from the bend that restricts the mounting collar). This is because there is typically less deformation here, and therefore less material weakening due to cold deformation of the corresponding section. This does not preclude the possibility of applying a certain force to relatively strongly bent / weakened sections. However, such force should not be excessive, and attention should be paid to the material weakening of these sections. For completeness, it should be mentioned that, in the case of using mounting collars and support rings with axial protrusions, the axial protrusion of the support ring should be designed and arranged such that it protrudes between the portion of the pipe end section located near the mounting collar and facing away from the pipe end portion (and placed circumferentially around the corresponding pipe section) and a portion of the receiving recess of the connection device.

[0030] It is further proposed that the pipe connection arrangement be designed such that it includes a tensioning device for pressing and / or securing the modified end portion of the pipe into a receiving recess in the connecting member. While virtually all types of tensioning devices can be conceived to be used, in particular, a pipe nut can be used for this purpose. In other words, the tensioning device / pipe nut can serve as a force-acting device for first pressing the pipe end into the connecting device and / or subsequently securing the pipe end and the connecting device tightly together. When using a pipe nut, it will typically exhibit a hexagonal external shape, allowing it to be turned using a standard wrench. Furthermore, an internal thread can be provided on the inside of the pipe nut to achieve axial force by turning it. In particular, a machinist can achieve high axial force with relatively little effort. For completeness only, it should be mentioned that, in this case, the connecting member should be equipped with a corresponding external thread.

[0031] Another possible embodiment of the pipe connection arrangement is that at least a portion of the at least one support ring is arranged between the mounting collar of the pipe and the force-realizing surface of the tensioning device. Preferably, the support ring may be provided with a radially outward protrusion for this purpose. Thus, direct (pushing) contact is not required between the tensioning device (e.g., a pipe nut) and the pipe end and connecting member, but only an "indirect" contact is established via the support ring. Although this may seem complicated at first glance, this design can be advantageous in that it makes the connection more resilient to bending of the connecting member relative to the pipe end, which can produce a significantly increased resistance to vibration. This is because the support ring can be used to stabilize the pipe by limiting its angular movement. Effectively, the protrusion can be an annular protrusion arranged circumferentially around the support ring (typically limited to a certain axial range of the support ring). Typically, the protrusion and the rest of the support ring form a single piece. However, different designs are also possible, such as separately manufactured protrusions of a generally sleeve-shaped basic shape that are typically fixedly attached to the support ring. The raised side surfaces typically define a portion of these limiting surfaces (as discussed further below). Using this design, particularly simple pre-assembly of the pipe connection arrangement is possible before tight connection. Furthermore, when using such a protrusion, axial movement of the support ring can be advantageously limited, particularly to a position near the area of ​​the pipe end including the mounting collar. Even further, by using the protrusion, the installation force required for the tensioning device can be easily increased significantly at a certain point (typically when the attachment movement has reached its optimal value). By varying the thickness (axial range) of the protrusion, the point at which the installation force increases can easily be adapted to the optimal sealing position of the pipe connection arrangement.

[0032] It should be noted that one or both of the raised side surfaces of the support sleeve may exhibit a taper angle different from 180°. (Where 180° corresponds to a perpendicular arrangement relative to the axial direction of the support sleeve). Specifically, the cone angle... It can be selected from extreme values, such as the cone angle of the mounting collar. As described above, a cone angle other than 180° is used. A clamping effect can be provided to the tube by generating a radially inward force on the support sleeve and therefore on the tube below the support sleeve.

[0033] This allows for an advantageous design of pipe connection arrangements: the pipe connection arrangements are designed and arranged such that, at least in the area of ​​these sealing surfaces, the pipe end taper angle is [not specified] before the modified end portion of the pipe is fixed within the receiving recess of the connection device. Compared to the concave cone angle of the receiving part The angle is at least 1.5°, preferably at least 2°, more preferably at least 3°, and even more preferably at least 4°. This can be understood as the case before the shaped end portion of the tube is fixed within the receiving recess of the connecting device. That is, it relates to the tube end taper angle as the tube end leaves the shaping machine. And “completely fresh” (unused) connecting members. It should be noted that other angles can even be envisioned, such as 0.5°, 1°, 2.5°, 3.5°, 4.5°, 5°, 5.5°, 6°, 7°, 8°, 9°, or 10° (and even larger) (lower limit). It should be understood that when establishing the connection between the pipe and the connecting member, at least partial deformation of one or both of the frustoconical sealing surfaces will occur (typically, the sealing surface of the frustoconical portion at the pipe end will show a greater degree of deformation). In other words, when establishing the connection, partial deformation of the (other) sealing surface will occur (typically, the frustoconical portion of the modified end portion will show a greater amount of deformation). This actually seems to be a very advantageous aspect of the currently proposed design: the insertion movement of the pipe end appears to cause some grinding process, making the surfaces of these sealing surfaces fit together, resulting in a particularly tight fit of these sealing surfaces, which in turn causes a particularly leak-proof and diffusion-resistant contact. When certain parameters were used in the initial experiments, it even seemed possible that some initial stage of friction welding might occur, leading to a particularly anti-diffusion contact. However, this did not appear to result in a fully developed, forced material-locked contact, at least not to the point where disconnecting the connection at a later point would be problematic. These initial experiments showed that, in many cases, no observable friction welding occurred, but only very tight surface contact. This appears to be particularly advantageous if the connection must be (re)opened (disconnected) and later (re)connected (possibly several times). Here, detectable friction welding could adversely alter these surfaces, potentially reducing the number of possible (re)opening and subsequent (re)attachment cycles of the tube ends in the connected component. It should be noted that, due to the proposed design, contact between the sealing surfaces does not occur simultaneously during the connection process. In fact, initial contact will essentially occur at the tip of the tube end. As the connection process continues, the resulting deformation will cause the contact area between the sealing surface of the tube end and the sealing surface of the connected component to gradually increase.

[0034] It is important to emphasize that after the modified end of the pipe is fixed in the recess of the connecting component, the taper angle of the pipe end (pipe end taper angle) ) and the cone angle of the receiving recess of the connecting member (receiving recess cone angle) The taper angle will (essentially) appear at the location where the two sealing surfaces have already made contact. That is, when the connection has been established, the pipe end taper angle will be the same in the contact area. Conical angle of the receiving recess Basically the same. Cone angle The final equality is usually (but not always) mainly determined by the pipe end taper angle. This is caused by deformation. For efficiency reasons, it is typically preferred that, at the time of connection establishment, the size of the sealing surface is shown as a relatively large percentage of the (initial) size of the sealing surface (the size of the axial range of the pipe end cone angle and / or the size of the axial range of the receiving recess cone angle) before the connection is established (“original state”). To name just a few figures: this percentage can be at least 10%, 15%, 20%, 25%, 30%, 33%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 66%, 70%, 75%, 80%, or 85%. As an upper limit, 25%, 30%, 33%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 66%, 70%, 75%, 80%, 85%, 90%, 95%, or 100% can be achieved. This can involve the axial range of the truncated cone shape of the pipe end and / or the axial range of the truncated cone portion of the receiving recess (the smaller one is usually relevant if the dimensions differ). It should be noted that the axial range of the truncated conical end portion and the axial range of the truncated conical receiving recess of the connecting member can be the same or different. As already mentioned, especially for thick-walled tubes, the corresponding figure can be slightly lower, while for thin-walled tubes, the corresponding figure can be slightly higher.

[0035] Furthermore, it is proposed that, at least in the area of ​​the sealing surface, the pipe end taper angle... Conical angle of the receiving recess The difference between them should not exceed 10°, preferably 7.5°, more preferably 5°, and even more preferably 3.5°. It should be noted that different upper limits can also be achieved, such as 30°, 25°, 20°, 15°, 12°, 9°, 7°, 6°, or 4°. It should be noted that excessive deformation during the connection process can be counterproductive to sealing issues and to early material fatigue that may occur during the connection process and / or prior deformation processes used to reshape the modified pipe ends. Furthermore, the movement required to assemble the pipe connection arrangement (e.g., the number of turns of the connecting nut) should not become excessive, thereby accelerating the assembly process.

[0036] Initial experiments have shown that it is also advantageous for the pipe connection arrangement to be implemented such that, at least in the area of ​​the sealing surface, the pipe end taper angle is... and / or receiving concave cone angle The size is between -15° and 15° near the standard cone angle of the pipe connection arrangement with a truncated cone shape, preferably between -10° and 10°, even more preferably between -5° and 5°, and even more preferably between -3° and 3°, wherein the standard cone angle is preferably taken from the following group of cone angles: this group includes 24°, 40°, and 60°. It should be noted that, as proposed, combinations of lower and upper limits of different intervals are also considered to be explicitly disclosed, and thus the range between -15° and 5° should also be considered to be explicitly disclosed. In addition, different lower limit angles, such as -20°, -7.5°, -2°, and -1°, and / or upper limits, such as 1°, 2°, 7.5°, and 20°, can also be used (the limits can also be combined with the ranges mentioned above). Furthermore, the upper and lower limits of the ranges (which may be different ranges) from different standard cone angles can be combined. Initial experiments have shown that the above ranges appear to produce particularly good connections, exhibiting very high resistance to diffusion / leakage. It should be noted that pipe connection arrangements using truncated cone structures to achieve leak-proof connections and which are already commercially available often exhibit certain standard angle values ​​to allow for interoperability with parts from competing manufacturers. Therefore, some standard values ​​have gained widespread use, particularly cone angles of 24°, 40°, and 60°. However, other standard values ​​are also conceivable (including, but not limited to, other standard values ​​that may evolve in the future).

[0037] It should generally be mentioned that the cone angle is measured from one side to the other (full angle). Therefore, when considering the angle between one side of a pipe and / or connecting member and the axial direction (centerline, central axis), half the size of the disclosed figure (half angle) must be taken into account.

[0038] Furthermore, the pipe connection arrangement can be designed such that the annular end surface of the pipe end opening substantially does not contact the connecting member. This avoids any head-to-head contact, which could create a "jamming" effect (movement blocking effect) when the sealing surfaces are pushed together. This "jamming" effect can lead to a reduction / insufficiency in the contact area between the sealing surface of the connecting member and the sealing surface of the pipe end, potentially causing leakage / diffusion problems. Avoiding such problems is certainly advantageous. Another advantage of this design is that it generally allows for interoperability with commercially available parts. This obviously enhances the marketability of the currently proposed design. In other words, the (metallic) sealing surface (or possibly all areas achieving the sealing effect) is (substantially) limited to a sealing surface provided by tapered sections (possibly "straight tapered sections") provided by the truncated tapered end portion of the pipe and / or the truncated tapered receiving recess of the connecting member. As mentioned in this disclosure, these sealing surfaces can be reused at least several times. This contrasts with recessed / sharp surfaces that, for example, are deformed and / or jammed by metal welding. Those typically used only once, or at least only a very limited number of connection / disconnection cycles. It should be further noted that limiting the sealing surface to the tapered section (possibly a "straight tapered section") may also mean that a single material / material composition is used for sealing purposes (or at least for the main part of the overall sealing effect). In other words, no additional sealing components, such as O-rings, metal sealing rings, etc., are required to provide the sealing effect (the main part of the sealing effect). This is particularly advantageous for certain gases (such as highly diffusive helium or hydrogen). For completeness only, it should be noted that the material / material composition may be different for the sealing surface of the tapered portion of the tube and the sealing surface of the receiving recess of the connector (although they can advantageously be substantially the same).

[0039] Furthermore, it is proposed that the pipe connection arrangement be designed such that the dimensions, design, and arrangement of the contact area and / or cone angle of the pipe ends and / or connecting members and / or support rings are determined, designed, and arranged such that when the pipe is being attached to the connection device, particularly when the tensioning device is actuated, and even more particularly when the connecting nut is turned, the rotational movement between the connection device and the pipe is reduced, preferably impeded. This can be achieved, in particular, by a sufficiently high frictional force between the support ring (if present) and the connecting member, and a reduced frictional force between the support ring and the pipe end, particularly the mounting collar. In particular, appropriate selection of various cone angles will enable those skilled in the art to achieve this objective, wherein the selection of the exact angle and / or the size of the contact area will be clear to those skilled in the art.

[0040] Furthermore, it is proposed to design the piping connection arrangement such that at least the contact surfaces of the pipe and / or connecting members and / or support rings, preferably at least a portion of the pipe and / or connecting members and / or support rings, comprise materials selected from the group consisting of metals, copper, copper alloys, iron, ferroalloys, steel, hardened steel, stainless steel, and aluminum. When discussing stainless steel, V2A and V4A steels are particularly considered. Using such materials allows for arrangements with particularly strong diffusion and leakage prevention. Moreover, the resulting piping connection arrangement can maintain high pressure, which may be essential for certain applications. Preferably, the contact surfaces (at least a portion) are unstructured, i.e., they do not exhibit any grooves, fins, etc. While the contact surfaces (at least a portion) may be polished or finished in some way, the presence of surfaces obtained by standard machining operations is generally sufficient. Furthermore, most of the sealing surfaces, particularly (substantially) all of the sealing surfaces, may comprise (or be substantially composed of) the aforementioned materials.

[0041] Furthermore, the pipe connection arrangement can be implemented in such a way that at least one restrictive surface is provided between the connecting member, the support ring, and / or the tensioning device, wherein the at least one restrictive surface of the pipe connection arrangement is sized, designed, and arranged to impede axial movement of the pipe end and the connecting member relative to each other through a certain point and / or through a certain point where the required fixing force is significantly increased, particularly for providing tactile feedback to the user of the pipe connection arrangement when connecting the pipe end to the connecting member. This design is superior to many designs known in the prior art. Until now, mechanics often need to attach the tensioning device by hand-tightening and then continue the tensioning process a certain amount. As an example, a mechanic can use his fingers to attach the connecting nut by hand-tightening. He must then use a wrench to turn the connecting nut by a specified rotation angle, such as 500° (approximately one and a half turns) or two more full turns (as an example). This method seems suitable, but is often difficult to implement in practice because, in unfavorable installation positions, the mechanic may only turn the connecting nut by an unspecified angle each time he repositions the wrench. Therefore, it is difficult to avoid errors in angular estimation / counting / total rotation angle, leading to a large number of faulty connections (over-tightening or under-tightening) based on experience. Furthermore, when the connecting member and receiving recess are not well aligned, a relatively high connecting force must often be applied to reach the "hand-tightened attachment" position. This is difficult to detect, which in turn increases the likelihood of faulty connections. However, with the currently proposed design, a reasonably skilled machinist will use, for example, a wrench to turn the connecting nut only until he achieves a sharp and significant increase in the required torque (holding force) (change in torque slope; change in torque per unit length of positional change, especially angular change). The machinist then has tactile feedback: he must stop further tightening of the tensioning device. Clearly, this results in a very intuitive operation.

[0042] Here are some figures for rapidly increasing required fixing forces (especially torque): the required fixing force can increase by at least 1.5, 2, 2.5, 3, 3.5, 4, or even 5 times over short distances (especially within angles of 2.5°, 5°, 7.5°, 10°, 12.5°, 15°, 20°, 25°, 30°, 35°, 40°, or 45°). Additionally or alternatively, the slope (of the change in required fixing force) relative to the (required distance) can change by at least 1.5, 2, 2.5, 3, 3.5, 4, or even 5 times, especially near a "some point." In the case of torque, this can be essentially equivalent to the change in torque over the rotational distance, i.e. Here is just one example from a test setup using a 12 mm tube (outer diameter): the measured required holding force (torque) is from... Become .

[0043] While the support ring and tensioning device can be supplied as separate parts for individual assembly on the assembly side, it is preferred that the tensioning device and support ring be pre-assembled together in a reversibly releaseable manner using a resiliently deformable member to form a pre-assembled tensioned arrangement. The tensioning device may include a forced-type locking device for forced-locking connection with a corresponding connecting member. The radial extent of the resiliently deformable member is smaller than the radial extent of the forced-type locking device of the tensioning device.

[0044] To maintain the tensioning device and support ring in their pre-assembled state, it is currently proposed to use reversibly deformable components for reversibly release fastening. The advantage of such reversibly deformable components is their ease of manufacture. Another advantage is that even if they are exposed to unexpected forces (such as mechanical shocks) during transport and storage, they generally remain in a usable (held) state (this may not be the case at the predetermined break point). Even more importantly, because the fastening is performed in a reversibly release manner, the parts can be reattached (or at least readjusted) to their pre-assembled state.

[0045] The resilient deformable member can be applied as a surface coating to a (typically) metallic or (hard) plastic surface, or as a separate part held in place. Typically, the (primary) action of holding the support ring and tensioning device in the pre-assembled position comes from applying friction between the two parts by means of the resilient deformable member (which acts as the friction-applying member; it should be noted that this typically requires deformability; as a note: the (primary) resilient deformable member that achieves the primary deformability can differ from the (primary) friction-applying member that achieves the primary friction force; a spring-loaded fracture pad is an example of this). Additionally or alternatively, forced form locking techniques (e.g., resilient O-rings arranged in circumferential grooves) and / or friction fixing and / or forced material locking fixing, or even a combination thereof, can be used. It should be noted that the forced form locking technique in the sense of this document will be performed in a reversibly release manner. This reversibly release fixing can be easily achieved by using a resilient deformable member. More specifically, the resiliently deformable O-ring placed between two adjacent grooves respectively located in the tensioning device and the support ring achieves a combination of reversibly release form-locking technology and friction fixation. When a locking varnish is additionally applied, a forced material locking technology is used "on top." It should be noted that in this example, the O-ring and locking varnish are used only as exemplary examples.

[0046] However, typically, at least one resilient deformable member, tensioning device, and / or support ring (and possible additional parts) is designed and arranged such that the resilient deformable member exhibits only abrasive / frictional contact on at least one side (and therefore no forced formal locking engagement and / or forced material connection). Additionally or alternatively, this can be interpreted as such that the resilient deformable member, tensioning device, and / or support ring (and possible additional parts) are designed and arranged such that the resilient deformable member is in contact with a smooth surface on at least one side. The size of this smooth surface can be limited such that it is smooth within a suitable / different and / or predefined range corresponding to the typical displacement of the individual parts of the pre-assembled tensioned arrangement when it is connected to the corresponding parts to complete the pipe connection arrangement. In other words, it can be adjacent to a smooth surface segment of appropriate size on an adjacent surface.

[0047] Typically, a single elastically deformable member is sufficient. However, two or more elastically deformable members may also be used. Furthermore, the force generated by the elastically deformable member that hinders the relative movement of the support ring and the tensioning device is generally low enough that the (and thus necessary) relative movement of the support ring and the tensioning device is relatively easy to perform (at least for a certain axial movement) when the corresponding parts of the pipe connection arrangement are connected during assembly. However, as already discussed, it is advantageous that such axial movement will be hindered or stopped when a certain (relative) position is reached.

[0048] By using a pre-assembled tensioning arrangement, the combination of the support ring and the tensioning device can be arranged onto the pipe in a single assembly step, which helps in manufacturing and reduces potential assembly errors.

[0049] A design and arrangement for the pre-assembled tensioning arrangement is proposed such that the radial extent of the resiliently deformable member is smaller than the radial extent of the forced locking device of the tensioning device. Using this surprisingly simple solution, any adverse alteration or damage to the surface of the resiliently deformable member by the tensioning device components (especially the forced locking device) during the pre-assembly of the support ring and tensioning device can be easily and inexpensively avoided. In the case of using a connecting nut as the tensioning device, this typically means that the connecting nut is designed to include (at least) two substantially cylindrical inner surfaces with different radii. Specifically, a first radius can be used in the first section of the connecting nut with internal threads (extending axially), while a second radius can be used in the second section of the connecting nut where the resiliently deformable member is applied and / or on which the resiliently deformable member acts (extending axially), to achieve a reversibly releaseable fixation, thereby securing the corresponding parts in the pre-assembled position of the pre-assembled tensioning arrangement.

[0050] Additionally or alternatively, it is proposed to design pipe connection arrangements, particularly for connecting thin-walled metal pipes, such that the pipe connection arrangement includes:

[0051] The tube has a modified end portion, wherein the modified end portion exhibits a frustoconical shape, the frustoconical shape having a diameter that gradually decreases toward the connecting end (the open end of the tube) and a tube end taper angle. This forms an external circumferential sealing surface;

[0052] A connecting member having a receiving recess having a frustoconical shape, the frustoconical shape having a diameter that gradually increases toward the connecting end (the open end of the connecting member) and a cone angle of the receiving recess. This forms an internal circumferential sealing surface.

[0053] A tensioning device, preferably a pipe nut, is used to press and / or retain the modified end portion of the pipe into the receiving recess of the connecting member.

[0054] At least one limiting surface is provided between the connecting member and the tensioning device, and

[0055] The at least one limiting surface is designed and arranged to prevent axial movement of the pipe end and the connecting member relative to each other through a certain point and / or to significantly increase the required fixing force when passing through a certain point, in particular to provide tactile feedback to the user of the pipe connection arrangement when the pipe end is connected to the connecting member.

[0056] A tensioning device is provided for pressing and / or securing the modified end portion of the tube into the receiving recess of the connecting member. Therefore, it can be considered (and / or regarded as) a force-acting device. While virtually all types of tensioning devices can be conceived to be used, a connecting nut is particularly suitable for this purpose. This connecting nut will typically exhibit a hexagonal external shape, allowing it to be turned using a standard wrench. Furthermore, an internal thread can be provided on the inside of the connecting nut to achieve axial force by turning it. In particular, a mechanic can achieve high axial force with relatively little effort. For completeness only, it should be mentioned that, in this case, the connecting member should be equipped with a corresponding external thread.

[0057] According to this recommendation, at least one limiting surface is provided between the connecting member and the tensioning device, wherein the limiting surface is designed and arranged in a way that prevents axial movement of the pipe end and the connecting member relative to each other through a certain point and / or significantly increases the required fixing force when passing through a certain point, in particular to provide tactile feedback to the user of the pipe connection arrangement when connecting the pipe end to the connecting member.

[0058] The limiting surface is typically defined by mechanical contact between two parts of a pipe connection arrangement, particularly when the pipe connection arrangement is brought into a leak-proof position from an initial pre-assembled (or partially assembled and / or unassembled) state, between two parts of the pipe connection arrangement that at least partially perform axial movement. Various implementations are conceivable for this purpose, such as direct or indirect contact between the (surface) portions of tensioning devices (e.g., pipe nuts), the surface portions of connecting members and / or pipe ends (like mounting collars, etc.) (indirect contact using attachments, as described elsewhere in this disclosure).

[0059] Specifically, it is proposed that the pipe connection arrangement include at least a support ring arranged circumferentially around a portion of the pipe. By using such a support ring, it is not necessary to establish direct (pushing) contact between the tensioning device (e.g., a pipe nut) and the pipe end and connecting member; instead, only (or partially) "indirect" contact is established via the support ring and / or corresponding surface portions of the parts. It should be noted that combinations are also possible, such as components of force transmitted directly and components transmitted indirectly. Although providing a support ring may seem to complicate matters at first glance, this design can be advantageous in making the connection more resilient to bending of the connector / pipe end, which can result in a significantly increased resilience against vibration. This is because the support ring can be used to stabilize the pipe by limiting its angular movement relative to the connecting member (particularly by "clamping" a portion of the pipe, especially with respect to angular movement).

[0060] Further details of this additional or alternative design are described in different sections of this disclosure.

[0061] Furthermore, a method for connecting a pipe and a connecting member in a piping connection arrangement according to this disclosure is proposed, wherein at least one support ring generates a radially inward force acting on a portion of the pipe by axially pushing the pipe end and the receiving recess of the connecting member together, thereby preferably clamping the pipe relative to the connecting member in place. Therefore, when the operator of the piping connection arrangement assembles the various parts of the arrangement to establish a leak-proof connection, he automatically and simultaneously establishes a firm clamping fixation of the pipe relative to the connecting member. This also results in a particularly wear-resistant connection without any additional installation steps. This is, of course, highly advantageous.

[0062] Additionally or alternatively, a method is proposed for connecting pipes and connecting members in a pipe connection arrangement according to this disclosure, wherein the user of the pipe connection arrangement performs a tightening operation by operating a tensioning device until he detects a significant increase in the required fixing force at a certain point. This triggers the operator to stop further tightening of the tensioning device. In effect, this signals to him that the pipe connection arrangement has been completed according to the specification. When this method is implemented, at least similarly, similar features and advantages as described can be achieved. Furthermore, the method can be modified in the foregoing sense to at least similarly obtain similar or identical features and advantages as already mentioned.

[0063] When implementing at least one of the proposed methods, similar features and advantages as already described can be achieved, at least similarly. Furthermore, the method can be modified in the aforementioned sense to obtain at least similar or identical features and advantages, as already mentioned.

[0064] Further advantages, features, and objects of the invention will become clear from the following detailed description of the invention taken in conjunction with the accompanying drawings, in which:

[0065] Figure 1 : A cross-sectional schematic diagram of a possible embodiment of the pipe connection arrangement according to this disclosure;

[0066] Figure 2 : Figure 1 An enlarged sectional view of a portion;

[0067] Figure 3 : Showing and according to Figure 1 A graph showing the relationship between the torque and rotation angle of the connecting nut in an embodiment of the pipe connection arrangement.

[0068] Figure 4 : A schematic cross-sectional view of a second embodiment of the pipe connection arrangement according to this disclosure;

[0069] Figure 5 : A schematic cross-sectional view of a third embodiment of the piping connection arrangement according to this disclosure;

[0070] Figure 6 : Passing through can be used according to Figure 1 and Figure 2 A schematic cross-section of the pre-assembled tensioning arrangement of the pipe connection layout.

[0071] Figure 1 A possible preferred embodiment of the pipe connection arrangement 1 is shown in a partially cut schematic perspective view. Pipe connection arrangement 1 connects the connecting member 2 to the pipe end 3 of the pipe 4. It should be noted that... Figure 1The scenario does not show the complete connection location of pipe connection arrangement 1, as will be explained in more detail later.

[0072] To establish the connection of pipe connection arrangement 1, a pre-assembled sub-assembly 27 including a support ring 15 and a connecting nut 14 is used. If a certain axial force relative to each other is exceeded, the support ring 15 and the connecting nut 14 are movably attached together by means of an O-ring 21 that applies friction. The following will refer to... Figure 6 Let me explain this in more detail.

[0073] Figure 2 It shows Figure 1 An enlarged cross-sectional view of region 15 of the support ring is provided for better visibility. Please refer to the following for further information. Figure 1 and Figure 2 Please read the following detailed description.

[0074] Currently, the connecting member 2 is designed as a double-ended connecting member 2, which shows connectable ends for connecting pipe ends at both sides of the double-ended connecting member 2.

[0075] It should be noted that the pipe connection arrangement 1 may also show different designs for the connecting member 2, such as when the connecting member 2 is attached to a machine (not shown) to supply gas or liquid to the corresponding machine (e.g., by brazing or by threading). In this case, the connecting member 2 will be designed as a single-end connecting member 2 (i.e., a connectable end for connection to the pipe end 3 will be provided only on one side of the connecting member 2).

[0076] Starting from the pipe opening 5 of pipe 4, and more specifically from the pipe opening at pipe end 3 of pipe 4, pipe 4 displays a truncated cone-shaped portion 6 adjacent to the pipe opening 5. (As in...) Figure 1 (and similarly in Figure 4 As can be seen from the middle section, the cone angle of the truncated cone portion 6 at the end 4 of pipe 4 demonstrates the angle. .exist Figure 1 In the diagram, the angle is indicated due to the viewing angle shown. Only half of that, (The angle lies between the central axis 7 of pipe 3 and the flange of the truncated conical region 6). This applies to the state where pipe connection arrangement 1 is not yet fully connected. In the region of the truncated conical section 6, the radius of pipe 4 increases as it moves away from pipe opening 5. Currently, pipe opening 5 exhibits an inner radius that is substantially equal to the standard radius 9 of pipe 4. However, different radii can also be used.

[0077] Further away along the axial length of the pipe 4 in the direction away from the pipe opening 5, near the truncated cone portion 6, there is a mounting collar 8. In the region of the mounting collar 8, the radius of the pipe 4 is again reduced to the size of the standard radius 9 (undeformed radius) of the pipe 4.

[0078] like Figure 1 (Similarly) Figure 4 As indicated, near pipe end 3, the cone angle of the mounting collar 8 of pipe 4 has an angle. (And therefore, when measured relative to the central axis 7 of tube 4, it is) ).

[0079] After the collar 8 is installed, when facing away from the tube opening 5, the tube 4 finally exhibits the typical cylindrical shape of a tube (with a standard radius 9 present). It should be noted that the tube 4 can, of course, be bent, etc. Furthermore, the tube 4 also has a finite length, and thus there will be another tube opening (not shown) at a certain distance.

[0080] Corresponding to the pipe 4 having its central fluid conduit 10, the connecting member 2 also shows a fluid conduit 12, which is currently aligned with the fluid conduit 10 of the pipe 4. Although in the embodiment shown here the inner diameter of the fluid conduit 12 of the connecting member 2 varies slightly in the axial direction, this diameter can also be designed to be substantially constant.

[0081] In the embodiment shown, the connecting member 2 displays two pipe connection sections 11 (currently only one is used, i.e.) Figure 1 (One on the right side), the two pipe connection sections show a receiving recess 13 with a truncated conical recess 13. The receiving recess 13 has a tapered angle. (or relative to the central axis 7) ).

[0082] In the embodiment shown, the cone angle of the truncated conical portion 6 of the tube 4 for The cone angle of the receiving recess 13 of the connecting member for The key points are these two angles. They are different from each other. Currently, the difference is chosen to be 4°, where the cone angle of the truncated conical portion 6 of tube 4 is... The cone angle of the receiving recess 13 of the connecting member 2 is smaller than that of the connecting member 2. .

[0083] Again: Before establishing a leak-proof connection between the pipe end 3 of the pipe 4 and the connecting recess 13 of the connecting member 2 by firmly pressing the pipe end 3 into the receiving recess 13, the angle The indicated value is valid. This is Figure 1 In this case, only a very preliminary contact is established between the pipe end 3 and the receiving recess 13, and before any deformation of any part occurs due to sealing pressure (by fully tightening the connecting nut 14). Note that this is in Figure 1 and Figure 2A small, currently wedge-shaped gap is also visible between the outer surface of the truncated conical portion 6 of the tube end 3 (hereinafter referred to as the sealing surface) and the inner circumferential surface 35 of the receiving recess 13 of the connecting member 2 (hereinafter partially referred to as the sealing surface).

[0084] When the connection between the pipe end 3 and the connecting member 2 is established by tightly pushing the pipe end 3 into the receiving recess 13 (via the support ring 15, as explained in detail later, by means of the connecting nut 14), the frustoconical portion 6 of the pipe end 3 will (typically) deform, such that the corresponding opposing surfaces of the frustoconical portion 6 and the receiving recess 13 will fit together tightly after some grinding contact and some deformation work. This grinding contact appears to result in a surface finish of the corresponding adjacent surfaces. Although a very slight initial stage of friction welding may be observed when certain parameters are applied, observable friction welding usually does not occur. This typically increases the number of possible (re)opening and subsequent (re)attachment cycles of the pipe end 3 in the connecting member 2. Regardless of the exact nature of this connection, initial experiments have shown that when the connection is established, it is particularly leak-proof and particularly diffusion-proof, even for highly diffusing gases (such as helium or hydrogen) under high pressure.

[0085] It should be noted that, typically (as in the embodiment depicted here) there is no head-to-head / point-to-point / line-to-surface contact (or similar) between the annular end surface of the truncated conical portion 6 of the tube end 3 and the corresponding contact area of ​​the inner surface / receiving surface 13 of the connecting member 2. Such contact between a sharp protrusion and a (typically) flat surface usually results in a pressure welding effect. Furthermore, once the corresponding sharp protrusion / contact surface is opened, the corresponding sharp protrusion / contact surface cannot be reused for sealing purposes (or at least the sealing effect will be significantly reduced).

[0086] As in Figure 1 and Figure 2 As can be further seen, the axial range of the truncated conical portion 6 at the pipe end 3 of pipe 4... The axial range of the receiving recess 13 of the connecting member 2 is smaller than that of the connecting member 2. Therefore, an annular gap 16 will exist between the circumferential outer surface of the tube 4 (after the mounting collar 8) and the tapered surface of the receiving recess 13 of the connecting member 2. The use of this gap 16 will be explained below.

[0087] A connecting nut 14, including an internal thread 17, is placed around the pipe 4. The connecting nut 14 serves as a tensioning device for pushing the pipe end 3 into the receiving recess 13 by simply turning the connecting nut 14. To simplify attachment, the connecting nut 14 exhibits a hexagonal shape for attaching a wrench, as is known in the art.

[0088] Corresponding to the connecting nut 14 having its internal thread 17, the outer surface of the connecting member 2 is provided with an external thread 18 of a corresponding design at the corresponding position, as will be apparent to those skilled in the art. Furthermore, the connecting member 2 includes a section with a hexagonal external shape, allowing the use of another wrench to counteract any torque introduced by turning the connecting nut 14; again, this will be apparent to those skilled in the art.

[0089] The support ring 15 exhibits tapered pressure surfaces 19a, 19b, and 19c, which are used to make pressure contact with the corresponding surfaces of the pipe nut 14, the corresponding surfaces of the mounting collar 8 of the pipe end 3, and also toward the inner surface 35 of the receiving recess 13 of the connecting member 2.

[0090] Due to the conical pressure surfaces 19a, 19b, and 19c, the support ring 15 will be pushed toward the circumferential outer surface of the tube 4 in a radially inward direction, thus firmly holding the tube 4 in place, and in particular, preventing any angular movement of the connecting member 2 relative to the tube end 3. This feature advantageously avoids early fatigue of the sealing connection.

[0091] Furthermore, due to the shape of the various tapered pressure surfaces 19a, 19b, 19c, and especially because the pressure surfaces 19a, 19c point toward the tapered surface 35 of the receiving recess 13 and toward the connecting nut 14 (where the connecting member 2 and the connecting nut 14 are typically designed to be quite robust), outward pushing movement of any fragile parts can be avoided, which in turn reduces the tendency to develop any leaks.

[0092] More importantly, due to the conical surface 35 of the receiving recess 13 and the positioning of the support ring 15, the axial movement of the connecting nut 14 screwed onto the connecting member 15 will generate a radially inward force that firmly clamps the pipe end 3 in place.

[0093] It should be noted that the tapered pressure surface 19a of the protruding portion 24 of the support ring 15 protrudes into the gap 16 between the receiving recess 13 and the truncated tapered portion 6 of the tube end 3 of the tube 4. This tapered pressure surface can be designed without a cone angle. This will be referred to below. Figure 5 To describe it in further detail.

[0094] As in Figure 1 and Figure 2 As can be further seen, the support ring 15 includes an annular protrusion 20. The annular protrusion 20, together with the end surface of the connecting nut 14 and the connecting member 2 surrounding the receiving recess 13, acts as a mechanical stop during the connection process of the pipe connection arrangement 1. Specifically, when a mechanic connects the parts of the pipe connection arrangement 1, he will feel the development of the torque M required to turn the connecting nut 14, as... Figure 3As shown.

[0095] Figure 3 The diagram shows the angle of rotation of the desired torque M on the vertical axis (y-axis) relative to the horizontal axis (x-axis). Initially, the mechanic loosely turned the connecting nut 14 with his fingers (torque M was essentially 0); Figure 3 (Not shown in the image). Once a very preliminary contact has been established between the various tapered pressure surfaces 19a, 19b, 19c of the support ring 15 and the corresponding surfaces of the pipe end 3, the connecting member 2, and the connecting nut 14, and a further initial contact has been established between the truncated tapered portion 6 of the pipe end 3 and the receiving recess 13 of the connecting member 2 (by hand tightening), the mechanic will begin to use a wrench, because from this point (angle) A non-negligible torque M is initially required. This is because the tube end 3 must deform at this point when it is pushed into the receiving recess 13 of the connecting member 2. This causes the required torque M to be applied to increase slowly. Once the rotation angle... When the side surface 23 of the protrusion 20 contacts its corresponding connecting nut 14 and the mating portion of the connecting member 2 (around the end surface of the receiving recess 13), the required torque M will increase sharply. This can be easily felt by the mechanic. In fact, this is an indication to him that the connection process is complete and he must stop turning to avoid any over-rotation.

[0096] Avoiding any excessive rotation of this connection, in particular, avoids any possible overpressure acting on the pipe 4 section near the support ring 15 in the inward radial direction. Such overpressure in the inward radial direction could lead to a significantly increased risk of pipe wall collapse or pipe wall rupture over time (which is something that should be avoided in the first place by using the support ring 15).

[0097] To simplify the mechanic's work, in the embodiment shown, the connecting nut 14 and the support ring 15 are currently designed as pre-assembled sub-units 27.

[0098] Figure 6 The image shows a possible embodiment of this pre-assembled subunit 27. Specifically, Figure 6 A schematic cross-section of a pre-assembled subunit 27, including a connecting nut 14 and a support ring 15, is shown. An O-ring 21 (acting as a force-applying member) is positioned between the radially outer surface of the support ring 15 and the radially inner surface of the connecting nut 14, as shown. Figure 1 , Figure 2 and Figure 6As can be seen, the O-ring 21 provides a force-fit connection between the support ring 15 and the connecting nut 14. Thus, if a certain axial force is exceeded, the support ring 15 and the connecting nut 14 can move relative to each other in the axial direction. If such a force is not present (as is the case during transport or storage of the pre-arranged tensioning arrangement 27), both parts will remain in their current positions. For completeness: circular grooves for partially receiving the O-ring 21 could, of course, be provided in the support ring 15 and / or the connecting nut 14. However, currently, only the support ring 15 has a groove 37 for the O-ring 21.

[0099] As can be seen, the diameter of the connecting nut 14 in the section of the internal thread 17... (And further extending into the smooth surface section without threads, the first internal dimension of the connecting nut in the radial direction) and the diameter of the connecting nut 14 section where the O-ring 21 is located. The size is significantly larger. Thus, the pre-assembly of the connecting nut 14 and the support ring 15 can be achieved (at least under realistic conditions) without any grinding along the protruding peaks of the internal thread 17 on the outer circumference of the O-ring 21. Such grinding, unavoidable for at least some arrangements known in the prior art, typically results in adverse alterations or even damage to the surface of the O-ring 21. This could lead to later leakage problems, or the two parts may no longer be securely held together.

[0100] In a single assembly step, the pre-assembled sub-assembly 27 is placed on the undeformed end of tube 4. Therefore, the end of tube 4 will be reshaped... Figure 1 and Figure 2 The modified pipe end 3 can be seen in the image.

[0101] It should be noted that in the typical pre-assembled state of the pre-assembled subassembly 27, gaps 28 and 29 exist between the annular protrusion 20 of the support ring 15 and the corresponding adjacent surfaces of the connecting nut 14 (gap 28), and between the tapered pressure surface 19c of the support ring 15 and the connecting nut 14 (gap 29). Specifically, the gap 29 adjacent to the tapered pressure surface 19c of the support ring 15 should be slightly smaller than the gap 28 adjacent to the protrusion 20 of the support ring 15. This allows the tapered pressure surface 19c and the corresponding adjacent tapered surfaces of the connecting nut 14 to exert a radially inward force on the tube 4 to be inserted (to clamp the tube 4 in place) when the final assembly is tightened. However, at some point, further radially inward movement near the tapered pressure surface 19c will be impeded. This is the case when the gap 28 near the annular protrusion 20 closes. Due to this design, excessive clamping force that could cause the tube wall of the tube 4 to collapse is avoided. Those skilled in the art can easily design the relative sizes of the two gaps 28 and 29.

[0102] For the sake of completeness, it should be mentioned that the currently proposed pre-assembly tensioning arrangement is not limited to... Figure 6 The design of various parts; in particular, various designs of the support ring 15 can be selected. Specifically, similar designs can be used... Figure 5 The support ring shown.

[0103] exist Figure 4 In the diagram, another possible embodiment of the pipe connection arrangement 30 is shown in schematic cross-section.

[0104] The design is very similar to that based on Figure 1 and Figure 2 The design of the pipe connection arrangement 1. Therefore, for similar parts, the same reference numerals are used, even if the corresponding parts are not exactly the same, but are similar only in design and / or function.

[0105] As from Figure 4 As can be seen, the axial range of the truncated conical portion 6 at pipe end 3 The axial range of the tapered portion of the receiving recess 13 of the connecting member 32 is greater than that of the connecting member 32. .

[0106] Therefore, the support ring 33 is appropriately adapted to fit into the corresponding gap between the connecting member 32, the connecting nut 34 and the radial outer region of the pipe end 31.

[0107] It should be noted that the support ring 33 does not exist in accordance with... Figure 1 and Figure 2 The support ring 15 of the embodiment has a similar protrusion 20. Therefore, the mechanic finds it somewhat difficult to observe an increase in force. However, the increase in force can still be fully felt.

[0108] Figure 5 Another possible third embodiment of the pipe connection arrangement 36 is shown in a schematic cross-sectional view. The third embodiment of the pressure connection arrangement 36 currently shown is very similar to that shown below. Figure 1 and Figure 2 The first embodiment of the pipe connection arrangement 1 is shown. However, the essentially only relevant difference between the currently depicted embodiments of pipe connection arrangements 1 and 36 is the design of the support rings 15 (first embodiment) and 26 (currently shown third embodiment). That is, instead of the tapered contact surface 19a, a non-tapered (i.e., cylindrical design) contact surface 25 is now anticipated for the protruding portion 24 of the support ring 26, which is intended to contact the receiving recess 13 of the connecting member 2.

[0109] The usefulness of this design is somewhat unexpected. A significant advantage is that the torque required to turn the connecting nut 14 to connect the pipe end 3 to the receiving recess 13 of the connecting member 2 is typically significantly lower. Therefore, the connection is easier to achieve. Somewhat unexpectedly, due to the materials typically chosen for the support rings 15, 26, 33 (rigid resin, soft metal, etc.), the support rings 15, 26, 33 are typically deformable to some extent. Therefore, the protruding portion 24 of the support ring 26 will deform when pressed against the receiving recess 13 of the connecting member 2. Initial experiments showed that although there were minor visible changes on the surface of the receiving recess 13 of the connecting member 2, no significant deformation occurred. Even when scratching the surface of the receiving recess 13 with a fingernail, no deformation was felt.

[0110] Therefore, this design can even be used to (re)open and (re)attach the connecting member 2 of the pipe connection arrangement several times.

[0111] Regardless of the adapted design of the support ring 33, there is still an effect of radially pushing the support ring 33 in order to hold the tube end 31 firmly in place, even if vibration does occur.

[0112] It should be noted that one or more features of one or both of the detailed embodiments disclosed herein may be used in combination with the general description of this disclosure.

[0113] Further disclosures can be found in two applications filed on the same day by the same applicant with the same filing office, with applicant reference numbers DAN2302DEWO (PA18042WO01, claiming priority to DE 10 2023 125 655.6) and DAN2305DEWO (PA18073WO01, claiming priority to DE 10 2023 125 657.2). The disclosures of these applications are intended to be fully incorporated in this application.

Claims

1. A pipe connection arrangement (1, 30, 36), particularly for connecting thin-walled metal pipes (4), the pipe connection arrangement comprising: Pipe (4), which has a modified end portion (3, 31), wherein the modified end portion (3, 31) exhibits a truncated conical shape (6), the truncated conical shape having a diameter (9) that gradually decreases toward the connecting end and a pipe end cone angle ( This forms an external circumferential sealing surface. Connecting member (2), the connecting member having receiving recess (13), the receiving recess having a truncated cone shape, the truncated cone shape having a diameter that gradually increases toward the connecting end and a cone angle of the receiving recess ( This forms an internal circumferential sealing surface. Support rings (15, 26) are arranged circumferentially around at least a portion of the pipe ends (3, 31) of the pipe (4). The feature is that at least a portion (24) of the support ring (15, 26) rests on a portion of the connecting member (2), particularly on a portion of the receiving recess (13) of the connecting member (2).

2. The pipe connection arrangement (1, 30) according to claim 1, characterized in that, The truncated conical section of the end portion (3, 31) of the tube (4) extends in the axial direction ( The axial range of the truncated conical section of the connecting member of the receiving recess (13) is smaller than that of the receiving recess (13). ).

3. The pipe connection arrangement (1, 30) according to any one of the preceding claims, and particularly according to claim 2, is characterized in that, The support ring (15, 26) protrudes into a gap (16) between a portion of the end section (3, 31) of the tube (4) and a portion of the receiving recess (13) of the connecting device (2), and is characterized in particular by the fact that the support ring (15, 26) includes an axial protrusion (24) protruding into the gap (16).

4. The pipe connection arrangement (1, 30, 36) according to any one of the preceding claims, characterized in that, The modified pipe end (3) further includes a mounting collar (8), which is preferably adjacent to the truncated cone region of the pipe end (3).

5. The pipe connection arrangement (1, 30, 36) according to any one of the preceding claims, characterized by a tensioning device, preferably a pipe nut (14), the tensioning device being used to press and / or retain the modified end portion (3, 31) of the pipe (4) into the receiving recess (13) of the connecting member (2).

6. The pipe connection arrangement (1, 30, 36) according to any one of the preceding claims, and particularly according to claim 5, is characterized in that, At least a portion of at least one support ring (15, 26, 33) is arranged between the mounting collar (8) of the tube (4) and the force-realizing surface (19c) of the tensioning device (14).

7. The pipe connection arrangement (1, 30, 36) according to any one of the preceding claims, characterized in that, Before the modified end portion (3, 31) of the tube (4) is fixed in the receiving recess (13) of the connecting device (2), at least in the area of ​​these sealing surfaces, the tube end taper angle is... Compared to the cone angle of the receiving recess The angle is at least 1.5°, preferably at least 2°, more preferably at least 3°, and even more preferably at least 4°.

8. The pipe connection arrangement (1, 30, 36) according to any one of the preceding claims, and particularly according to claim 7, is characterized in that, At least in the areas of these sealing surfaces, the pipe end taper angle Conical angle of the receiving recess The difference between them is no greater than 10°, preferably 7.5°, more preferably 5°, and even more preferably 3.5°.

9. The pipe connection arrangement (1, 30, 36) according to any one of the preceding claims, and particularly according to any one of claims 5 to 8, is characterized in that, At least one limiting surface (23) is provided between the connecting member (2), the support ring (15, 26, 33) and / or the tensioning device (14), and wherein the at least one limiting surface (23) is designed and arranged to prevent the axial movement of the pipe end (3, 31) and the connecting member (2) relative to each other through a certain point and / or to significantly increase the required fixing force when passing through a certain point, in particular to provide tactile feedback to the user of the pipe connection arrangement (1, 30, 36) when the pipe end (3, 31) is connected to the connecting member (2).

10. A pipe connection arrangement (1, 30, 36), particularly a pipe connection arrangement for connecting a thin-walled metal pipe (4), and more particularly a pipe connection arrangement (1, 30, 36) according to any one of the preceding claims, the pipe connection arrangement comprising: Pipe (4), which has a modified end portion (3, 31), wherein the modified end portion (3, 31) exhibits a truncated conical shape (6), the truncated conical shape having a diameter (9) that gradually decreases toward the connecting end and a pipe end cone angle. This forms an external circumferential sealing surface. Connecting member (2), the connecting member having receiving recess (13), the receiving recess having a frustoconical shape, the frustoconical shape having a diameter that gradually increases toward the connecting end and a cone angle of the receiving recess. This forms an internal circumferential sealing surface. A tensioning device, preferably a pipe nut (14), is used to press and / or retain the modified end portion (3, 31) of the pipe (4) into the receiving recess (13) of the connecting member (2). Its characteristic is that at least one limiting surface (23) is provided between the connecting member (2) and the tensioning device (14). The at least one limiting surface (23) is designed and arranged to prevent the pipe end (3) and the connecting member (2) from axially moving relative to each other through a point and / or to significantly increase the required fixing force when passing through a point, in particular to provide tactile feedback to the user of the pipe connection arrangement (1, 30) when the pipe end (3, 31) is connected to the connecting member (2).

11. A method for connecting a pipe and a connecting member (2) in a pipe connection arrangement (1, 30, 36) according to any one of the preceding claims, characterized in that, By pushing the tube end (3) of the tube (4) and the receiving recess (13) of the connecting member (2) together in the axial direction, at least one support ring (15, 26, 33) generates a radially inward force acting on a portion of the tube (4), thereby preferably clamping the tube (4) in place relative to the connecting member (2).

12. A method for connecting a pipe and a connecting member (2) in a pipe connection arrangement (1, 30, 36) according to any one of claims 1 to 10, particularly the method according to claim 11, characterized in that, The user of the pipe connection arrangement (1, 30, 36) performs a tightening operation by operating the tensioning device (14) until he detects that the required fixing force increases significantly when passing through a certain point.

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