DE29818606U1 - Pressure vessel with end ring - Google Patents

Description

Pressure vessel with front ring

A tank container with the properties mentioned in the preamble of claim 1 is known from DE 32 12 696 C2. In this document, a front ring belonging to a saddle structure is welded with its radially outer and inner edges to the part of the tank base surrounded by the rim zone. The main task of the saddle ring described there is to transfer static and dynamic transport loads between the tank and the frame with as little stress as possible.

From DE 29 705 851 Ul, another tank container is known with the features specified in the preamble of claim 1, which works with an angle saddle ring, the outward-facing radial flange of which can be welded to both the cross members and the corner supports of the front frame. The cylinder formed by the axial flange is welded to the container base at its tank-side end at the radially inner or outer edges. Here too, the ring has the task of transferring static and dynamic loads between the container and the container frame.

In the construction of containers and equipment, tank bottoms are used to close cylindrical tank bodies at the ends to form pressure vessels or to divide these cylindrical tank bodies into chambers. The tank bottoms used should be as pressure-resistant as possible given the available container thickness and offer good space utilization. Hemispherical bottoms are particularly pressure-resistant, but are not very common due to their poor space utilization.

Rotationally symmetrical heads with differently curved three-dimensional surfaces are common. Heads with torispherical or elliptical surfaces are particularly suitable for pressure vessels. For torispherical heads, dished or basket-shaped heads are used in particular. For

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For elliptical floors, a semi-axis ratio of 2:1 is the most common.

All of these bottoms are formed by a surface that, starting from a slightly curved area arranged perpendicular to the tank axis, merges into the cylindrical shell of the tank in a more strongly curved edge zone. Two radii of curvature can merge tangentially into one another (torispherical bottoms), or the radius of curvature can taper outwards from the center of the tank following an ellipse (elliptical bottoms).

The wall thicknesses of pressure vessels and therefore also those of the bottoms are generally dependent on the internal pressure of the vessel. The wall thicknesses are determined according to calculation rules contained in national pressure vessel regulations (e.g. AD Merkblätter, ASME, CODAP, British Standard 5500). In principle, all of these regulations determine stresses in the component, to which a certain minimum wall thickness is then assigned depending on the strength of the tank material used.

In particular, in tank bottoms, there is no uniform stress state when subjected to internal pressure. While the stresses in the central, slightly curved area are relatively low, they increase sharply in the edge zone, before falling back to the lower level of the cylindrical part. Since tank bottoms up to three meters in diameter are normally made from one or more sheets of the same thickness, the high stresses in the edge zone determine the minimum wall thickness of the entire bottom.

The invention is based on the object of reducing the maximum stresses in the edge zone area of the soil so that a soil according to the invention can withstand higher pressures with the same wall thickness or the same pressures with a reduced wall thickness as conventionally manufactured soils.

The solution to this problem according to the invention is described in claim 1. The floor arrangement comprises a floor

and a ring that is welded to the bottom of the vessel in the area of maximum meridional stresses that arise from a concave-side overpressure (internal vessel pressure) in the bottom wall. The ring reduces the meridional stress that is decisive for determining the minimum wall thickness so much that the starting material used to make the bottom can be significantly thinner, thus creating significant weight and material cost advantages that outweigh the additional attachment of the ring. Particularly when the ring is made of a less noble metal than the bottom itself.

The meridional stress mentioned above refers to a tensile stress on the concave surface of the bottom, it runs tangentially to the surface of the bottom and diagonally radially to the tank axis. Its maximum value is decisive for the design of a tank bottom.

The greatest potential for saving material (or the greatest increase in strength) is achieved by arranging the ring according to claim 2, 3 or 4 for the various most common bottom shapes. The following table gives the optimum diameter ranges depending on the outside diameter Da of the container:

Floor shape 2:1) 0, optimal 95 Diameter D _r Dished shape O, 92 - 90 There Basket arch shape 0, 86 - 90 There elliptical shape (A:a = 86 - There - oh, - oh, - oh,

An embodiment of the ring in cylindrical shape is particularly advantageous since the ring thus formed is either mounted between two bottoms of coaxial containers and thus forms a further chamber according to claim 6, or it can serve as a saddle element according to claims 7 and 8.

A truncated cone-shaped design of the ring according to claim 5 can be advantageous when using the bottom as an intermediate bottom, but it is also suitable as a saddle element.

useful, for example, when assembling small containers into relatively large frames.

According to claim 10, the front ring does not need to be a closed ring; the invention is also applicable if the front ring is interrupted in sections or is composed of individual segments according to claim 9. In the lower area of horizontally arranged containers, an interruption is often expedient because of the fittings provided here. In these areas, however, free edge zones of the base must then be reinforced in another way (doubling, particularly reinforced cutouts).

Claim 11 relates in particular to embodiments of the rings in which, in addition to the reinforcement and saddle function, further structural requirements exist, such as insulation of a tank against its frame, elastic suspension of a tank in the frame.

Embodiments of the invention are explained in more detail below with reference to the drawings.

It shows:
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Figure 1 shows a broken section of a pressure vessel in a side view;

Figure 2 shows the area-defining contour of a torispherical floor.

Figure 3 shows the area-defining contour of an elliptical floor.
Figure 4 shows a design option for a multi-chamber

pressure vessels;

Figures 5 and 6 show different designs of the front ring when it consists of an angle profile;

According to Fig. 1, the pressure vessel 10 with the outer diameter Da consists of a cylindrical shell 13 and two opposite end plates 12, each of which is provided with a ring 11 with a mean diameter D _r in the region of the maximum

•♦·»♦ «·

Meridian tension are welded to the outer and inner edges 14a, 14b of the ring 11.

The definition of torispherical bottom surfaces 20, 21 is evident from Fig. 2. The convex (outer) 20 and the concave (inner) 21 surface of the bottom are described by the rotation of the bottom contour around the container axis 30. The distance between the two surfaces is determined by the wall thickness S of the bottom.

The base contour is composed of three differently curved areas: namely the area 22 defining the base dome with the dome radius R, the area 23 forming the base brim with the brim radius r and the area 24 forming the cylindrical edge of the base.

The radii of curvature of the different areas for dished and basket arch heads are defined depending on the outside diameter Da of the cylindrical part of the pressure vessel according to the following table:

Dimensional relationships of typical torispherical floors

Radii Dished shape There Basket arch shape R (dome) 0.1Da 0.8 Da r (brim) 0.154 Da

The definition of an elliptical base surface is evident from Fig. 3. The convex outer surface 20 and the concave inner surface 21 of the base 12 are also defined by a rotation of the contour around the container axis 30. The base contour of an elliptical base is made up of an elliptical part 25, which describes the three-dimensionally curved area of the base, and an area 24, which, as with the torispherical base, describes the cylindrical rim. The distance between the two base surfaces is defined by the wall thickness S.

In a preferred embodiment of the elliptical base, the two semi-axes A and a are in a ratio of 2:1 to each other.

According to Fig. 4, the ring 11 forms a further pressure chamber

40, which is arranged between two pressure vessels 10. The ring 11 lies between the two vessel end bottoms 12 and is welded to them in the area of their maximum meridional stresses at its inner and outer edges 14a and 14b.

According to Fig. 5, the reinforcing front ring is formed by an L-shaped ring 11' which is welded to the base 12. The ring 11' consists of a leg 17 which forms a cylinder running parallel to the tank axis and a leg 18' which points radially inwards perpendicular to it.

According to Fig. 6, the radial flange 18" of the ring 11" points outwards.

Claims (11)

1. Pressure vessel ( 10 ) with a torispherical or elliptical bottom ( 12 ), to the convex surface ( 20 ) of which a ring ( 11 ) arranged concentrically to the longitudinal axis ( 30 ) of the tank is welded, characterized in that the ring ( 11 ) is connected to the vessel bottom ( 12 ) in the region of the maximum meridional stresses arising from a concave-side overpressure on the vessel inner wall ( 21 ). 2. Pressure vessel according to claim 1, characterized in that the ring ( 11 ) is welded to a torispherical dished bottom ( 12 ) and has at its welding end an average diameter (D _r ) of 0.92-0.95 × D _a . 3. Pressure vessel according to claim 1, characterized in that the ring ( 11 ) is welded to a torispherical basket arch bottom ( 12 ) and has at its welding end an average diameter (D _r ) of 0.86-0.90 × D _a . 4. Pressure vessel according to claim 1, characterized in that the ring ( 11 ) is welded to an elliptical bottom ( 12 ) with a semi-axis ratio of 2:1 (A:a) and has at its welding end a mean diameter (D _r ) of 0.86-0.90 × D _a . 5. Pressure vessel according to one of claims 1 to 4, characterized in that the ring ( 11 ) has a rectangular cross-section, the longitudinal axis of which is at an angle to the longitudinal axis of the tank, so that the resulting truncated cone shell is welded to the bottom at its smaller opening. 6. Pressure vessel according to one of claims 1 to 4, characterized in that the ring ( 11 ) is designed as a cylinder and is arranged between the convex sides of two bottoms ( 12 ) and thus forms a pressure-resistant chamber ( 40 ) between two coaxial pressure vessels ( 10 ). 7. Pressure vessel ( 10 ) according to one of claims 1 to 5, characterized in that the ring ( 11 ) serves as a saddle element for horizontal or vertical mounting of the vessel. 8. Pressure vessel ( 10 ) according to claim 7, characterized in that the ring ( 11 ) represents an element of the end ring saddle of a tank container. 9. Pressure vessel ( 10 ) according to one of claims 1 to 8, characterized in that the ring ( 11 ) consists of one or more segments. 10. Pressure vessel ( 10 ) according to one of claims 1 to 9, characterized in that the ring ( 11 ) can be interrupted in sections by built-ins or attachments arranged in the bottom edge zone. 11. Pressure vessel ( 10 ) according to one of claims 1 to 4 and 7 to 10, characterized in that the ring ( 11 ', 11 ") has an L-shaped cross-section, one leg ( 17 ) running parallel and concentrically to the tank axis, forming a cylinder, and the other leg ( 18 ', 18 ") starting at the edge of the cylinder remote from the bottom ( 12 ) and running radially thereto.