GB2553887A

GB2553887A - Arrangement of line connections

Info

Publication number: GB2553887A
Application number: GB1709616.5A
Authority: GB
Inventors: Bahr Mathias; Schmalz Manual; Wunschmann Manfred
Original assignee: Witzenmann GmbH
Current assignee: Witzenmann GmbH
Priority date: 2016-07-19
Filing date: 2017-06-16
Publication date: 2018-03-21
Anticipated expiration: 2037-06-16
Also published as: FR3054284B1; GB2553887B; GB2553887A9; FR3054284A1; DE102016113255A1; GB201709616D0

Abstract

An arrangement of line connections 1 comprises first 2 and second 3 line elements each with a terminal widening, and a flexible line element 4, in particular a bellows, which is arranged between the line elements. The flexible line is overlapped by the widening of the two line elements, and the widening of the first line element overlaps the widening of the second line element in an overlapping region UB. A sliding element 6 is arranged between the first and second line elements in the overlapping region, preferably approximately centrally in a corrugated portion 4c, and symmetrically to a middle plane M of the flexible line element, which is transverse to the longitudinal axis L. A contact surface between the sliding element and one of the line elements is planar in longitudinal section and is oriented parallel to a longitudinal axis L of the arrangement of line connections 1 in an unloaded state. The sliding element can be formed in a graphite or a sintered material. A further line element 5 can be arranged on the inside of one of the line elements, and it extends in the manner of a flame tube into the flexible line element.

Description

(54) Title of the Invention: Arrangement of line connections Abstract Title: Flexible line connection (57) An arrangement of line connections 1 comprises first 2 and second 3 line elements each with a terminal widening, and a flexible line element 4, in particular a bellows, which is arranged between the line elements. The flexible line is overlapped by the widening of the two line elements, and the widening of the first line element overlaps the widening of the second line element in an overlapping region UB. A sliding element 6 is arranged between the first and second line elements in the overlapping region, preferably approximately centrally in a corrugated portion 4c, and symmetrically to a middle plane M of the flexible line element, which is transverse to the longitudinal axis L. A contact surface between the sliding element and one of the line elements is planar in longitudinal section and is oriented parallel to a longitudinal axis L of the arrangement of line connections 1 in an unloaded state. The sliding element can be formed in a graphite or a sintered material. A further line element 5 can be arranged on the inside of one of the line elements, and it extends in the manner of a flame tube into the flexible line element.

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1/2

FXK* 2 /2

Arrangement of line connections

Description

The application relates to an arrangement of line connections according to the preamble of claim 1, comprising a first line element having a terminal widening; a second line element having a terminal widening; a flexible line element, in particular a bellows, which is arranged between the first line element and the second line element, and which is overlapped at least partially by the widening of the first line element and by the widening of the second line element; said first line element with its widening overlapping at least partially the second line element in the region of its widening in an overlapping region; wherein a sliding element is arranged between the first line element and the second line element in the overlapping region.

Such arrangements of line connections are also referred to as compensators or ball joints. They are used in fluid lines which require a certain degree of angular deflection and do not introduce axial reaction forces into the lines. A preferred application is in the field of aerospace for the conduction of fluids which are under relatively high pressure.

According to the prior art, a distinction is made between high-pressure applications and low-pressure applications, wherein the above-defined arrangement of line connections according to the prior art is only used for low-pressure applications (pressures of significantly less than 10 bar).

For high-pressure applications, gimbal-anchored compensators (so-called gimbal joints) have been used which have a relatively strong, metallic anchoring ring. This results in a relatively high weight, combined with relatively high production costs, since the anchoring rings are generally produced from titanium or other special alloys.

The object of the present invention is to upgrade the arrangement of the line connections defined above (ball joint with bellows seal) for use also at higher pressures in the range of about 60 bar to 70 bar, in order to save weight and material compared to the use of gimbal-anchored compensators.

According to the invention this object is achieved by an arrangement of line connections with the features of claim 1. Advantageous further developments of the inventive idea are defined in the dependent claims.

An arrangement of line connections according to the invention, comprising a first line element having a terminal widening; a second line element having a terminal widening; a flexible line element, in particular a bellows, which is arranged between the first line element and the second line element, and which is overlapped at least partially by the widening of the first line element and by the widening of the second line element; said first line element with its widening overlapping at least partially the second line element in the region of its widening in an overlapping region; wherein a sliding element is arranged between the first line element and the second line element in the overlapping region, is characterized in that a)a contact surface between the first line element and the sliding element or b) a contact surface between the second line element and the sliding element in each case is planar in longitudinal section and is oriented parallel to a longitudinal axis (L) of the arrangement of line connections (1) in an unloaded state thereof.

The applicant has recognized by extensive studies and comprehensive simulations or calculations that it is crucial for the compressive strength of the above-defined arrangement of line connections that at least one of the contact surfaces between the first line element and the sliding element or the second line element and the sliding element is planar in longitudinal section and thus, in an unloaded state of the arrangement of line connections, extends parallel to its longitudinal axis. An unloaded state of the arrangement of line connections in this case is in particular to be understood to mean a state in which the arrangement of line connections is completely axially aligned, that is, not deflected angularly. Specifically, ball joints are known from the prior art in which the sliding element has contact surfaces with the first line element and the second line element that are curved or that are inclined towards the longitudinal axis. In this case, due to manufacturing tolerances, an angular deflection of the ball joint can lead to a tilting of the sliding element such that its effective contact surface with the first line element and the second line element is reduced. As a result, the compressive strength of the entire arrangement of line connections is reduced, which according to the invention is avoided by the planar design of said contact surface. In this way, an increased compressive strength of the entire arrangement of line connections is obtained without the need for using a configuration as a gimbal-anchored compensator for this purpose. In this way, the abovementioned drawbacks with regard to production costs and weight are avoided.

It must be taken into account here that a configuration of the arrangement of line connections as a ball joint is already inherently more cost-effective than a configuration as a gimbal-anchored compensator because, in the case of a ball joint, the use of rotary parts, forgings or casting parts that are relatively expensive to produce, can be completely dispensed with, whereas in the case of gimbal-anchored compensators, at least the abovementioned anchoring ring is generally configured as such a rotating part, forging or casting part.

In general, the configuration of the abovementioned contact surface as a contact surface which is planar in longitudinal section has the major advantage that substantially no transverse forces act on the sliding element or the line element which is in contact therewith at the planar contact surface. This contributes to the desired increase in the compressive strength of the arrangement of line connections as a whole.

A first further development of the arrangement of line connections according to the invention provides that the respective planar contact surface according to variant b) is arranged on an outer side of the second line element facing the first line element. Such a variant is particularly advantageous, since the sliding element can then be arranged further to the inside in the radial direction, so that large lever forces cannot develop during a pressure load and/or deflection of the arrangement of line connections which may cause a deformation of the arrangement of line connections in the region of the first line element and/or the second line element.

In the course of another further development of the arrangement of line connections according to the invention, it can be provided that, in the context of variant a), the respective planar contact surface is formed on an inner side of the first line element facing the second line element. This configuration offers a particular advantage in that a separating point (weld seam) of the radially outward first line element is regularly arranged in the overlapping area in order to be able to produce the arrangement of line connections according to the invention. As no transverse forces act in the region of the planar contact surface, as described above, the first line element does not experience any load in the transverse direction in the region of the said separating point, as a result of which the stability and the compressive strength of the arrangement of line connections can be further increased.

Yet another further development of the arrangement of line connections according to the invention provides that a further line element is arranged on the inside of the first line element and/or on the inside of the second line element, as is, in the manner of a flame tube, extending into the flexible line element. As a result, the flexible line element, which is preferably configured as a bellows, can be protected from harmful media effects, in particular temperature effects.

The configuration of the further line element as a type of flame tube implies that it is radially spaced from the flexible line element, even if the arrangement of line connections experiences a (maximum) angular deflection.

In another further development of the arrangement of line connections according to the invention, it can be provided that the sliding element is arranged in a corrugated portion of the flexible line element, preferably approximately centrally. If the flexible line element is configured as a bellows, it has per se such a corrugated portion. With regard to the achievable compressive strength or force distribution, it has been found to be advantageous according to the applicant's findings if the sliding element is arranged in the abovementioned way, where, according to the prior art, it was often arranged at least partly outside a selected distance of the flexible line element, which was associated with relatively low compressive strength.

Furthermore, in a further development of the arrangement of line connections according to the invention, it can also be provided that the sliding element is formed and arranged symmetrically with respect to a plane of the flexible line element, preferably middle plane, oriented perpendicular to the longitudinal axis of the arrangement of line connections. As a result, the compressive strength of the arrangement of line connections can be particularly effectively influenced or increased. The abovementioned configuration can advantageously be used in variant a) of the line arrangement according to the invention.

In order to further positively influence the compressive strength of the arrangement of line connections according to the invention, a further development of the same may provide that the sliding element spans a large part of a corrugated portion of the flexible line element, preferably at least half. In the above-described symmetrical configuration or arrangement of the sliding element, even substantially the entire corrugated region of the flexible line element can be spanned correspondingly by the sliding element.

In order to avoid disadvantageous deformations of at least the first line element as much as possible, another advantageous further development of the arrangement of line connections according to the invention provides that at least the first line element has an oblique, preferably (multiple times) stepped course with respect to the longitudinal axis of the arrangement of line connections in at least one region facing away from the second line element. A corresponding configuration may be considered, in principle, additionally or alternatively for the second line element in at least one region facing away from the first line element. According to the prior art, the terminal widening of the first line element has often been realized in such a way that the latter has been bent directly at an angle of approximately 90° radially outwards and thereby has been widened correspondingly. The applicant has now found in the course of the investigations already mentioned that the oblique course described above can achieve major advantages with regard to the introduction of forces into the component. Specifically, for reasons of stability, it can be advantageous if the abovementioned oblique course is realized by (multiple) steps of the first line element in the region mentioned.

In order to keep the sliding element securely in a desired position and thus to ensure the functionality of the arrangement of line connections according to the invention permanently, another development can provide for the sliding element to be enclosed and held laterally by bends of the first line element or the second line element, depending on the variant selected. In the variant a), a lateral enclosure of the sliding element is preferably considered by bending the first line element, whereas in variant b) the sliding element can be held laterally by bending the second line element.

Yet another further development of the arrangement of line connections according to the invention provides for the first line element and/or the second line element to abut a respective terminal edge of the flexible line element. This makes it possible, in particular, to realize a particularly compact design.

Finally, in another further embodiment of the arrangement of line connections according to the invention it can also be provided for the sliding element to be formed in graphite or in a sintered metal, so that a proper functioning of the arrangement of line connections according to the invention can be ensured over wide temperature and pressure ranges.

Further characteristics and advantages of the invention will be apparent from the following description of exemplary embodiments with reference to the drawing.

Fig. 1 shows a first configuration of the arrangement of line connections according to the invention, partly in longitudinal section; and

Fig. 2 shows a second configuration of the arrangement of line connections according to the invention, partly in longitudinal section.

Figure 1 shows the arrangement of line connections as a whole with reference numeral

1. It comprises a first line element 2, which has a terminal widening of a complex geometry, as shown. The arrangement of line connections 1 furthermore comprises a second line element 3, which also has a terminal widening of complex geometry, as shown. Furthermore, the arrangement of line connections 1 comprises a flexible line element in the form of a bellows 4, which is arranged between the first line element 2 and the second line element 3 and connects these to one another in a fluid-tight manner, in particular a gas-tight manner. In this case, the bellows 4 is at least partially overlapped by the widening of the first line element 2 and by the widening of the second line element

3. The bellows 4 is secured on its smooth cylindrical connecting ends 4a, 4b, preferably integrally, on the inside of the second line element 3 or the first line element 2. Between the aforementioned smooth cylindrical connecting ends 4a, 4b, the bellows 4 has a corrugated region or portion 4c, in which a series of corrugations (not denoted) are formed. At an end facing away from its widening, the first line element 2 is connected to a further line element in the manner of a flame tube 5 (integrally) with the flame tube 5 extending into the flexible line element - approximately halfway through its axial extension. Specifically, it should be noted that in Figure 1 and Figure 2 the longitudinal axis of the arrangement of line connections 1 is denoted by the reference character L.

As is also apparent from Figure 1, the first line element 2, with its widening, overlaps the second line element 3 in the region of its widening in an overlapping region, which in the figures is denoted by the reference character UB, and in this case, strictly speaking, can extend beyond the widened portion of the second line element 3. A sliding element 6 is arranged between the first line element 2 and the second line element 3 in said overlapping region UB. This sliding element can be annular and can be made, for example, of graphite or a sintered metal. According to Figure 1, it is laterally enclosed and held between a terminal, radially outwardly directed bend 3a of the second line element 3 and a radial bulge 3b of the second line element 3 which is axially spaced therefrom. Here, the sliding element 6 on its inner side 6a, and the second line element 3 in its portion 3c between the elements 3a and 3b are formed resulting in a contact surface which is planar in longitudinal section and oriented parallel to the longitudinal axis

L of the arrangement of line connections 1 between the second line element 3 and the sliding element 6, as shown. On the other hand, the opposing contact surface between the first line element 2 and the sliding element 3 is curved in order to enable the angular movability of the arrangement of line connections 1 in the manner of a ball joint.

As can be seen also from Figure 1, the sliding element 6 is arranged approximately centrally with respect to the corrugated portion 4c of the bellows 4. Here, it spans a part of the corrugations of the bellows 4.

As can be seen in Figure 1 also, the first line element 2 has a stepped course in a region 2a, in which it has a widening starting from its minimum diameter (in Figure 1 left), so that the maximum (radial) widening of the first line element 2 is not achieved all at once, but in several steps, resulting in an overall oblique course with respect to the longitudinal axis L for the first line element 2 in said region 2a. This has proved to be favorable with regard to an introduction of force into the component in the case of a load. Next to said region 2a, the first line element 2 has the curved course already mentioned and is then bent back terminally as far as the outer side of the second line element 3, resulting in a compact, closed arrangement.

In a region 3d, in which it has its radial widening as far as the radial bulge 3b, the second line element 3 also has an overall oblique course with respect to the longitudinal axis L, which in turn is favorable for reasons of force introduction. Furthermore, the second line element 3 can abut the first line element 2 on the inside in the region of the abovementioned radial bulge 3b.

Figure 2 shows an alternative configuration of the line arrangement 1 according to the invention, which substantially differs in terms of the configuration and arrangement of the sliding element 6 from the configuration according to Figure 1.

As readily apparent from Figure 2, the sliding element 6 is configured and arranged in such a way that the abovementioned planar contact surface is now located between the first line element 2 and the sliding element 6. The first line element 2 is formed in a planar manner in longitudinal section, in a region 2b, which adjoins the already mentioned region 2a and partially coincides with the overlapping region UB, and thus forms a corresponding planar contact surface with the sliding element 6, which in said region is formed in a complementary manner. On its inner side 6b, the sliding element 6 has a surface which io is curved in longitudinal section, which interacts with a corresponding curvature of the second line element 3 in a region 3e, as shown. The sliding element 6 is now laterally held between at least partially radially extending portions of the first line element 2. It is particularly advantageous in the configuration according to Figure 2 that a separating point (weld seam) of the first line element 2, which is regularly present at reference character TS, is arranged in a region in which there is no transverse force load on the first line element 2.

Both configurations according to Figure 1 and Figure 2 have in common that the first line element 2 or the second line element 3 abuts the bellows 4 laterally in the region of a terminal wave edge. This is apparent from the abovementioned figures, but is not further denoted in said figures for reasons of clarity.

In the configuration according to Figure 2, the sliding element 6 is also formed and arranged symmetrically with respect to a middle plane of the flexible line element or bellows 4 which is oriented transversely to the longitudinal axis L of the arrangement of line connections 1. Said middle plane is indicated in Figure 2 by means of a dashed line M.

Claims

1. An arrangement of line connections (1), comprising:

a first line element (2) having a terminal widening;

a second line element (3) having a terminal widening;

a flexible line element (4), in particular a bellows, which is arranged between the first line element (2) and the second line element (3), and which is overlapped at least partially by the widening of the first line element (2) and by the widening of the second line element (3);

said first line element (2) with its widening overlapping at least partially the second line element (3) in the region of its widening in an overlapping region (UB); wherein a sliding element (6) is arranged between the first line element (2) and the second line element (3) in the overlapping region (UB);

characterized in that

a) a contact surface between the first line element (2) and the sliding element (6) or

b) a contact surface between the second line element (3) and the sliding element (6) is planar in longitudinal section and is oriented parallel to a longitudinal axis (L) of the arrangement of line connections (1) in an unloaded state thereof.

2. The arrangement of line connections (1) according to claim 1, characterized in that the respective planar contact surface is formed on an outer side of the second line element (3) facing the first line element (2).

3. The arrangement of line connections (1) according to claim 1, characterized in that the respective planar contact surface is formed on an inner side of the first line element (2) facing the second line element (3).

4. The arrangement of line connections (1) according to one of claims 1 to 3, characterized in that io a further line element (5) is arranged on the inside of the first line element (2) and/or on the inside of the second line element (3), which extends in the manner of a flame tube into the flexible line element (4).

5. The arrangement of line connections (1) according to one of claims 1 to 4, characterized in that the sliding element (6) is arranged in a corrugated portion (4c) of the flexible line element (4), preferably approximately centrally.

6. The arrangement of line connections (1) according to one of claims 1 to 5, characterized in that the sliding element (6) is formed and arranged symmetrically with respect to a plane (M), preferably middle plane, of the flexible line element (4) which is oriented transversely to the longitudinal axis (L) of the arrangement of line connections (1).

7. The arrangement of line connections (1) according to one of claims 1 to 6, characterized in that the sliding element (6) spans a large part of a corrugated portion (4c) of the flexible line element (4), preferably approximately at least half.

8. The arrangement of line connections (1) according to one of claims 1 to 7, characterized in that at least the first line element (2) has an oblique, preferably stepped course with respect to the longitudinal axis (L) of the arrangement of line connections (1) in at least one region (2a) facing away from the second line element (3).

9. The arrangement of line connections (1) according to one of claims 1 to 8, characterized in that the sliding element (6) is enclosed and held laterally by bends of the first line element (2) or of the second line element (3).

5

10. The arrangement of line connections (1) according to one of claims 1 to 9, characterized in that the first line element (2) and/or the second line element (3) abuts a respective terminal edge of the flexible line element (4).

io

11. The arrangement of line connections (1) according to one of claims 1 to 10, characterized in that the sliding element (6) is formed in graphite or in a sintered metal.

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