EP3887241B1 - End base - Google Patents

Description

The invention relates to a weight-optimized end floor.

An end cap closes off a tube. Many storage tanks or chemical reactors have end floors. These end heads are often implemented in the form of dished ends, as described in DIN 28011, for example. A dished end has two different radii of curvature, a large radius in the central area and a radius that is 10 times smaller in the edge area. But there are also other end floors, for example basket arch floors according to DIN 28013 or elliptically shaped end floors. Also in document DE102014202972 a known end floor is disclosed.

Even if these constructions lead to stable end floors, they still have a comparatively high weight, especially if these end floors have to withstand high pressure.

In addition, these end floors reduce the enclosed volume, especially in the edge area, and thus also reduce accessibility.

These problems arise in a military application, for example in the area of a pipe in a submarine. In addition to the normal pressure loads, there are also the requirements for a shock case, which means extremely high loads. In order to meet shock resistance, constructions are therefore regularly designed to be comparatively strong.

Bionics, for example, are used for further optimization. Such methods are known from DIN ISO 18459, for example. In particular, the method of drawing triangles with a method for rounding the contour should be mentioned here. First, a triangle with an angle of 45° is constructed. From its center, a circle is constructed with its center at the intersection of the first triangle and the wall, and a connection is constructed between the center of the first triangle and the intersection of the circle and the wall. Then, starting from the center of the resulting second triangle, again constructed a third triangle. The construction resulting from these three triangles is then rounded.

The object of the invention is to create an end floor which, due to its stability, requires a smaller wall thickness and is therefore lighter with the same compressive strength.

In addition, there is regularly the task of realizing inlets and outlets, especially in the area of an end base, i.e. openings through which material can be added or removed or control lines can also be laid inside the pipe. In addition, such entrances or exits can also be used for cleaning and/or maintenance purposes.

This problem is solved by the method with the features specified in claim 1 and by the end floor with the features specified in claim 4 . Advantageous developments result from the dependent claims, the following description and the drawings.

1. a) Konstruieren eines ersten Dreiecks, wobei zwischen der ersten Tangente und der Rohrwand ein Winkel von 46 ° bis 60 °, bevorzugt 48 ° bis 55 °, ausgewählt wird
2. b) Konstruieren eines zweiten Dreiecks, wobei die zweite Tangente des zweiten Dreiecks durch die Schnittpunkte eines zweiten Kreises mit dem flachen Boden und der ersten Tangente konstruiert wird, wobei der zweite Kreis den Schnittpunkt zwischen der ersten Tangente und dem flachen Boden als Mittelpunkt und die halbe Länge der ersten Tangente als Radius des zweiten Kreises aufweist,
3. c) Konstruieren eines dritten Dreiecks, wobei die dritte Tangente des dritten Dreiecks durch die Schnittpunkte eines dritten Kreises mit dem flachen Boden und der zweiten Tangente konstruiert wird, wobei der dritte Kreis den Schnittpunkt zwischen der zweiten Tangente und dem flachen Boden als Mittelpunkt und die halbe Länge der zweiten Tangente als Radius des dritten Kreises aufweist,
4. d) Abrunden der sich aus den drei Tangenten ergebenden Verlaufs, wobei zum Abrunden drei unterschiedliche Radien verwendet werden, wobei zunächst
5. e) in einem zweiten Bereich ein Teil der ersten Tangente, die zweite Tangente und ein Teil der dritten Tangente abgerundet wird, wobei der sich durch die Abrundung ergebende zweite Kreisausschnitt mit einem zweiten Krümmungsradius an dem Schnittpunkt mit der ersten Tangente die gleiche Steigung wie die erste Tangente aufweist, wobei der sich durch die Abrundung ergebende zweite Kreisausschnitt mit einem zweiten Krümmungsradius an dem Schnittpunkt mit der dritten Tangente die gleiche Steigung wie die dritte Tangente aufweist,
6. f) in einem ersten Bereich zwischen dem Schnittpunkt der Abrundung im zweiten Bereich und der ersten Tangente sowie dem Rohr mit einem ersten Krümmungsradius, wobei der sich durch die Abrundung ergebende erste Kreisausschnitt mit dem ersten Krümmungsradius an dem Schnittpunkt mit der ersten Tangente die gleiche Steigung wie die erste Tangente aufweist, wobei der sich durch die Abrundung ergebende erste Kreisausschnitt mit dem ersten Krümmungsradius an dem Schnittpunkt mit dem Rohr die gleiche Steigung wie das Rohr aufweist,
7. g) in einem dritten Bereich zwischen dem Schnittpunkt der Abrundung im zweiten Bereich und der dritten Tangente sowie dem Mittelpunkt desflachen Boden mit einem dritten Krümmungsradius, wobei der sich durch die Abrundung ergebende dritte Kreisausschnitt mit dem dritten Krümmungsradius an dem Schnittpunkt mit der dritten Tangente die gleiche Steigung wie die dritte Tangente aufweist, wobei der sich durch die Abrundung ergebende dritte Kreisausschnitt mit dem dritten Krümmungsradius am Mittelpunkt des Endbodens die gleiche Steigung wie der flache Boden aufweist,
8. h) wobei der Endboden ausgehend von dem konstruierten Verlauf mit konstanter Materialdicke konstruiert wird.

The method according to the invention for defining a cross-section of an end base starts from a tube and a flat base perpendicular to the longitudinal axis of the tube, the method comprising the following steps:

1. a) Constructing a first triangle, an angle of 46° to 60°, preferably 48° to 55°, being selected between the first tangent and the pipe wall
2. b) Constructing a second triangle, the second tangent of the second triangle being constructed through the intersections of a second circle with the flat bottom and the first tangent, the second circle taking the intersection between the first tangent and the flat bottom as its center and half has the length of the first tangent as the radius of the second circle,
3. c) Constructing a third triangle, the third tangent of the third triangle being constructed through the intersections of a third circle with the flat bottom and the second tangent, the third circle taking the intersection between the second tangent and the flat bottom as the center and the half has the length of the second tangent as the radius of the third circle,
4. d) Rounding off the course resulting from the three tangents, with three different radii being used for rounding off, with initially
5. e) in a second area, part of the first tangent, the second tangent and part of the third tangent are rounded, with the second sector of a circle resulting from the rounding having a second radius of curvature at the point of intersection with the first tangent having the same slope as the first has a tangent, the second sector of a circle resulting from the rounding having a second radius of curvature at the point of intersection with the third tangent having the same gradient as the third tangent,
6. f) in a first area between the point of intersection of the rounding in the second area and the first tangent as well as the pipe with a first radius of curvature, wherein the first sector of a circle with the first radius of curvature resulting from the rounding has the same slope at the point of intersection with the first tangent as has the first tangent, wherein the first sector of a circle with the first radius of curvature resulting from the rounding has the same slope as the tube at the intersection with the tube,
7. g) in a third area between the point of intersection of the rounding in the second area and the third tangent and the center of the flat bottom with a third radius of curvature, the third sector of a circle with the third radius of curvature resulting from the rounding being the same at the point of intersection with the third tangent has a slope as the third tangent, with the resultant third sector of a circle having the third radius of curvature at the mid point of the final bottom having the same slope as the flat bottom,
8. h) where the end floor is constructed starting from the constructed course with constant material thickness.

The flat bottom perpendicular to the longitudinal axis of the tube is not a real bottom, it serves only as a theoretical starting point. In the case of a round cross-section, the flat bottom corresponds to the circular area on the bottom or top of the cylinder. The flat bottom needs to be square to the pipe so the center point of the end point has exactly this slope and thus each half of the end floor covers exactly 90°.

A pipe within the meaning of the invention is a body which has a longitudinal direction and a wall running on the outside in the longitudinal direction. A tube preferably has an oval, in particular a round (circular) or an elliptical, cross section. The cross-section does not have to be constant over the entire length of the tube. For example, the diameter of a round cross-section can be varied with length. A tube with a round cross-section is also referred to as the lateral surface of a cylinder. A tube with an elliptical cross-section is also referred to as the lateral surface of an elliptical cylinder.

The tube and thus the end base preferably have rotational symmetry and/or mirror symmetry. Therefore, it is sufficient to calculate half of the cross section. The opposite side results from reflection on the axis of symmetry or the point of symmetry.

If the tube and thus the end base has an oval but not round cross section, the end base can only be fixed in a limited number of cross sections by the method, for example. In order to reduce the computational effort, the course of the end floor is interpolated between these calculated courses. For example, only four half-sections are calculated accordingly, which are each arranged at right angles to one another.

The advantage of the end floor designed in this way is a 1.4% reduction in weight with a 23% reduction in stress at an angle of 54°. The wall thickness can thus be further reduced with the same dielectric strength, as a result of which further weight can be reduced. In addition, the internal volume is increased due to the steeper starting angle.

The method presented results in a final bottom shape that cannot be represented by a simple ellipse equation or circle equation.

The end floor can be used, for example and in particular, for the production of storage, reaction and pressure vessels for gaseous and liquid substances. Particularly preferably, the bottom plate can be used to produce tubes which are passed through a pressure hull, for example and in particular for use in submarines.

In a further embodiment of the invention, the tube is closed at both ends by an end cap according to the invention.

In an alternative embodiment, the tube is closed at one end by an end base according to the invention and has an openable lid at the other end.

In a further embodiment of the invention, in step a) the angle between the first tangent and the pipe wall is selected to be between 51° and 57°.

In a further embodiment of the invention, in step a) the angle between the first tangent and the pipe wall is selected to be between 53° and 55°.

In a further aspect, the invention relates to an end floor, wherein the end floor has a first radius of curvature in a first area, a second radius of curvature in a second area and a third radius of curvature in a third area. The end of the first region remote from the second region adjoins the tube, the end of the third region remote from the second region has the region orthogonal to the tube, and the second region is arranged between the first region and the third region. The first radius of curvature, the second radius of curvature, and the third radius of curvature were constructed using the method of the present invention.

In a further aspect, the invention relates to a watercraft with a tube and an end floor according to the invention. The watercraft is preferably a submarine.

Of course, the end base according to the invention can also be used in other areas, for example in storage tanks or chemical reactors.

The method according to the invention and the end base are explained in more detail below with reference to an exemplary embodiment illustrated in the drawings.

Fig. 1 method for defining a cross section

The figures show the definition of a cross section only schematically and not exactly and to scale.

In 1 the procedure is shown step by step. In Fig. 1a one starts with the tube 10 and the flat bottom 20. A first tangent 30 with an angle of 54° is put inside, as in Fig. 1b shown. Next, the midpoint of the first tangent 30 is identified and a circle is constructed from the intersection of the first tangent 30 and the flat bottom 20 with the radius from the intersection of the first tangent 30 and the flat bottom 20 to the midpoint of the first tangent 30 . The intersection of this circle with the flat bottom 20 and the first tangent 30 results in the second tangent 40 in Fig. 1d . Analog becomes in Fig. 1e constructed another circle, from the intersections of which the third tangent 50 results. For rounding off, there is now a second area 100 which adjoins a first area 90 and a third area 110 . In 1f the axis of rotation of the tube or the central axis 80 is also shown. The transition from the first area to the second area 60 and the transition from the second area to the third area 70 result from the points at which the rounding tangentially meets the first tangent 30 and the third tangent 50 . This then results in the designed curve 120 which runs tangentially to the flat bottom 20 at the central axis 80 . Fig. 1h shows only the designed course 120 without defining a cross section through the three triangles. Taking into account the wall thickness, the result is in Figure 1i the end floor, which can be formed by rotation about the axis of rotation of the tube 80 in all three dimensions.

Reference sign

10

Pipe

20

flat floor

30

first tangent

40

second tangent

50

third tangent

60

Transition first area to second area

70

Transition second area to third area

80

Axis of rotation of the tube, central axis

90

first area

100

second area

110

third area

120

constructed course

Claims (6)

1. Method for determining a cross section of a head proceeding from a pipe (10) and a flat bottom (20) which is at a right angle to the longitudinal axis of the pipe (10), wherein the method comprises the following steps:

   a) constructing a first triangle, wherein an angle of 48° to 60° is selected between the first tangent (30) and the pipe wall,

   b) constructing a second triangle, wherein the second tangent (40) of the second triangle is constructed by the points of intersection of a second circle with the flat bottom (20) and the first tangent (30), wherein the second circle has the point of intersection between the first tangent (30) and the flat bottom (20) as its centre, and half the length of the first tangent (30) as the radius of the second circle,

   c) constructing a third triangle, wherein the third tangent (50) of the third triangle is constructed by the points of intersection of a third circle with the flat bottom (20) and the second tangent (40), wherein the third circle has the point of intersection between the second tangent (40) and the flat bottom (20) as its centre, and half the length of the second tangent (40) as the radius of the third circle,

   d) rounding the profile resulting from the three tangents, wherein three different radii are used for the rounding operation, wherein, firstly,

   e) in a second region (100), a part of the first tangent (30), the second tangent (40) and a part of the third tangent (50) are rounded, wherein the second circle sector which is produced by the rounding and which has a second radius of curvature has the same gradient as the first tangent (30) at the point of intersection with the first tangent (30), wherein the second circle sector which is produced by the rounding and which has a second radius of curvature has the same gradient as the third tangent (50) at the point of intersection with the third tangent (50),

   f) in a first region (90) between the point of intersection of the rounding in the second region (100) and the first tangent (30) and the pipe (10) with a first radius of curvature, wherein the first circle sector which is produced by the rounding and which has the first radius of curvature has the same gradient as the first tangent (30) at the point of intersection with the first tangent (30), wherein the first circle sector which is produced by the rounding and which has the first radius of curvature has the same gradient as the pipe (10) at the point of intersection with the pipe (10),

   g) in a third region (110) between the point of intersection of the rounding in the second region (100) and the third tangent (50) and the centre of the flat bottom (20) with a third radius of curvature, wherein the third circle sector which is produced by the rounding and which has the third radius of curvature has the same gradient as the third tangent (50) at the point of intersection with the third tangent (50), wherein the third circle sector which is produced by the rounding and which has the third radius of curvature has the same gradient as the flat bottom (20) at the centre of the head,

   h) wherein, proceeding from the constructed profile (120), the head is constructed with a constant material thickness.
2. Method according to one of the preceding claims, characterized in that, in step a), the angle between the first tangent (30) and the pipe wall is selected to be between 51° and 57°.
3. Method according to one of the preceding claims, characterized in that, in step a), the angle between the first tangent (30) and the pipe wall is selected to be between 53° and 55°.
4. Pipe having a head, wherein the head has a first radius of curvature in a first region (90), wherein the head has a second radius of curvature in a second region (100), wherein the head has a third radius of curvature in a third region (110), wherein that end of the first region (90) which faces away from the second region (100) adjoins the pipe (10), wherein that end of the third region (110) which faces away from the second region (100) has the region orthogonal to the pipe (10), wherein the second region (100) is arranged between the first region (90) and the third region (110), wherein the first radius of curvature, the second radius of curvature and the third radius of curvature have been constructed by the method according to one of the preceding claims.
5. Watercraft having a pipe (10) and a head Claim 4.
6. Watercraft according to Claim 5, characterized in that the watercraft is a submarine.

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