GB1567814A

GB1567814A - Stackable tank container for overland trasnport

Info

Publication number: GB1567814A
Application number: GB44892/77A
Authority: GB
Original assignee: Westerwaelder Eisenwerk Gerhard GmbH
Current assignee: Westerwaelder Eisenwerk Gerhard GmbH
Priority date: 1976-11-05
Filing date: 1977-10-28
Publication date: 1980-05-21
Also published as: JPS63180593U; SE7711901L; SE8004703L; SE418952B; JPS5363612A; JPH0311193Y2

Description

(54) STACKABLE TANK CONTAINER FOR OVERLAND TRANSPORT (71) We, WESTERWALDER EISENWERK GERHARD GmbH of 5241 Weitefeld/Sieg, Federal Republic of Germany, a German company, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed to be particularly described in and by the following statement: The invention relates to a stackable tank container for overland transport comprising end frames including corner fittings, the container being defined by curved longitudinal walls and carved ends attached to the frames. At least one end is formed as a convex part which is seated upon the outer end surface of a frame and extends beyond the corner fittings in the longitudinal direction of the tank.

The tank container has preferably a manhole or handhole cover of low structural height. The lower part of the cover rim has a slightly smaller diameter than the free diameter of the manhole flange and is designed at the same time as an inner clamping and retaining ring for a sealing ring of elastic material. The radial cross-sectional diameter of this sealing ring is greater than the width of the circular gap between the cover rim and the hole flange. A pressure ring, which is connected with the cover functionally and configuratively and with which engage clamp bolts anchored in the hole flange, extends beyond the sealing ring and ensures perfect sealing without stressing the sealing ring in shear.

Exchange vessels and exchange superstructures for the loading of piece goods in standardised sizes have been known and popular in road transport for years; the transport of liquids with the use of exchange tanks has not yet been sufficiently developed. Known carrier vehicles are suitable not only for exchange vessels but also for ISO containers of series I C (20 feet), as the connection dimensions are in agreement, however the gross weight of the ISO tank containers of this size is over 20 tonnes and is therefore considerably above the maximum weight for exchange vessels (13 tonnes) permissible in Europe.

Moreover generally ISO tank containers are not equipped with a centering device (guide channel) in their base group, contrary to exchange vessels, and the position of the centre of gravity of the known tank containers is unfavourable.

This situation cannot at present be improved in tank containers for combined sea and overland transport for various reasons. For inland transport were however suggested successfully tank containers of reduced height and oval or square-shaped tank cross-section as stackable tanks for liquid for exchange superstructures.

They have a reduced height of at the most 1500 mm and when empty may be stacked two-high on the vehicle without exceeding the permissible maximum heights for road trucks. Thanks to the low height also the position of the centre of gravity is low when they are loaded. The oval to square-shaped tank cross-section allows good utilisation of space, but is not readily suitable for resistances to pressure which are often needed for safety reasons.

Also known are pressure-resistant tank containers of reduced height, the longitudinal walls of which are made of longitudinally parallel cylinder shells intersecting each other.

Their length corresponds however to the standardised length of ISO containers of series IC, i.e. 6058 mm, while most vehicles for transport ing exchange vessels are about 7 m long. A part of the vehicle length remains therefore unused in both types of tank containers of low construction.

A tank container according to the invention has in contrast the advantage that while fully preserving the low position of the centre of gravity and possibility of the described tank container to be stacked two-high, and possibly also resistance to pressure suitable for the transport of dangerous liquids, the whole length of the vehicle may be used. At least one of the ends of the tank container is formed as a convex part seated on the outer end face of one of the frames and extending in the longitudinal direction of the tank container beyond the corner fittings. In this way the full loading area of the carrier vehicle may be used at low position of the centre of gravity, without the permissible total weight of the exchange vessel being exceeded Advantageous developments and improvements of the new tank container are obtainable by the means referred to in the subsidiary claims.Particularly according to Claim 2 the end frames may be made of hot rolled T-sections of structural steel or of extruded aluminium sect ions, in which only the inwardly extending web of the T-section is surrounded by the material of the tank or is made of that material.

This design, which is possible due to small stacking height, is much more economical than the hitherto employed end frames of tubes of rectangular cross-section made of alloy steel.

In order to make use of the whole height of the space between the corner fittings it is desirable to keep the structural height of the manholes, handholes or similar holes in the top or the bottom of a tank container as small as possible. If it is too high the corresponding cross-section over the whole length of the tank container is lost.

The hitherto used manhole structures are largely similar to those used customarily for road and rail tankers. There the height limitation is of secondary importance so that cap stan-head screws, curved shackles etc. may be used for closing. The height of these closing elements makes them unsuitable for incorpora tion in the top of tank containers without considerable reduction of the height of the liquid container proper.

Other solutions used in the past for tank containers are of flatter design but they may easily be damaged due to the very small radii or edges in the area between the sealing edges of the cover and the manhole ring on the one hand and the rubber sealing therebetween on the other hand so that on strong surge due to inertia forces losses of the cargo may take place through the manhole.

In order to avoid these disadvantages it is suggested to provide the lower part of the cover rim with a slightly smaller diameter than the inner diameter of the manhole flange and to make such lower part as an inner clamp and retaining ring the radial cross-sectional diameter of which is greater than the width of the circular gap between the cover rim and the circular flange, and to arrange that a pressure ring, which is connected functionally and/or configuratively with the cover and with which engage clamping bolts, extends beyond the sealing ring.

This arrangement, the application of which is not limited to the tank container according to Claim 1, has the advantage that in spite of the low constructional height the elastic sealing is only pressure stressed and not shear stressed. A further advantage is that the manhole cut-out in the wall of the tank con tainer may be used, in general, as material for the cover. This brings about considerable saving of valuable non-corrosive austenitic steel in comparison with known solutions.

Several embodiments of the invention are illustrated in the drawing and explained in more detail in the following description.

In the drawings: Figure 1 is a perspective view of a tank container having the features of Claim 1 Figure 2 is a front view of the same tank container, Figures 3 and 4 are sections through two embodiments of the end frame along line A-A in Figure 2, and Figures 5 to 8 are various embodiments of the new manhole or handhole.

In Figures 1 and 2 is shown a tank contain er the longitudinal walls 1 of which are made of cylinder shells which intersect each other.

The longitudinal walls are made resistant to pressure by longitudinal members 2 and their tie bars 18. The longitudinal walls 1 are mounted on a base group 3 resistant to distor tion and the ends of the longitudinal walls 1 are attached to frames 4 which are provided with corner fittings 5 for stacking and lifting.

To the outer end surfaces of the frames 4 are fixed convex parts 6 which serve as the end walls of the tank container. The convex parts consist of the two halves of a cylindrical pressure vessel 7 having dished ends 8 which has been cut in two in longitudinal direction. Each of these pressure vessel halves is positioned horizontally across, i.e. with its longitudinal axis extending perpendicularly to the container axis, onto the outer end sur face of a frame 4 and welded thereto.

The diameter of the attached convex parts need not correspond to the frame height but may be according to the required additional contents either larger or smaller; care must only be taken that the end surface of the frame is sufficiently wide. According to their position in height the convex parts may be used for air compensation in the gas space above the liquid level and/or for the connection of the bottom lines of the lower cylinder shells 1 of the con tainer. For this purpose only the fraine parts 10 or 11 which project inside the tank must be provided with openings 12 or 13 in the vicinity of the bottom line or top line.

The convex parts may be situated on both the container end walls symmetrically or may be so situated only at one end or they may be situated at different heights. When, for instance, the convex part of the container is positioned high at the front end, which lies generally slightly higher on the vehicle, and at the rear end low, air compensation is ensured at the front and complete emptying is ensured at the back.

As the corner supports of the end frame need only carry twice or three times the dead weight, in contrast to the ISO container, the frames may be made of hot rolled or extruded T-sections 10a, 1 la (Figure 3 and 4), which may be manufactured economically. Only the web of the T-section which projects inside the container gets into contact with the liquid and must therefore be made of corrosionresisting material or must be covered with such material. The T-section 1 0a according to Figure 3 is made wholly of structural steel which is not corrosion resistant but its web 14 is surrounded by a corrosion-resisting cover 15 (e.g. of alloy steel or aluminium).On the contrary in the embodiment according to Figure 4 the frame section l la is formed by an outer flange 16 and a central web 17 welded thereto, the flange 16 being of a material which is not corrosion-resisting and the central web 17 of a corrosion-resisting material. To the face of the central web 17 or of its cover 15 are welded the ends of the cylinder shells 1, while a dished end 8 (illustrated in two different sizes) is welded to the outer face of the central web.

One embodiment of the tank container which was manufactured was 2438 mm wide and 1500 mm high, and its total length was 7150 mm. The centre spacing of the corner fittings was of the standardized size of 5853 mm and the radius of the convex parts was 541 mm.

The capacity of the container was 1 7.2m3 and was rated for 1.75 bar of pressure in excess of atmospheric pressure. The dead weight was 3100 kg and the total weight 20300 kg.

Figures 5 to 8 illustrate various examples of embodiments of the manhole or handhole cover 19 shown in Figure 1.

In a suitable part of the container wall 33 is welded a manhole ring 34 to the inner side of which is welded a circular flange 35. On the periphery of the circular flange 35 are distributed bolts 36 extending upwards, which serve for securing the manhole cover. According to the pressure conditions of the media to be transported the cover may be made as a flat cover 23 (Figure 6), inwardly dished cover 24 (Figure 5) or as an outwardly dished cover 25 (Figures 7 and 8). The outwardly dished cover 25 is particularly suitable for higher inner pressures. If the inwardly dished cover 24 is used the height which is saved may be utilised e.g. for the installation of safety valves.

The manhole ring 34, the circular flange 35 and the covers 23, 24, 25 are made of corrosion-resisting material, preferably of alloy steel.

The rim 22 of the cover is made or flanged inwardly so that it may serve as an inner clamping or retaining ring for an elastic sealing ring 21a, 21b, 21c. According to the conditions of installation this sealing ring may be of a flat cross-section (21a), square crosssection (21b) or circular cross-section (21c). The ring is so prestressed that it is directly held by the rim 22 of the cover dish. The sealing ring is is maae or a matenal resistant to rue media to be transported, preferably of carrier material covered with rubber of PTFE. The ring is seated on the cover rim 22 with small prestressing so that its inner sealing edge 28 bears onto the cover rim under stress.The radial cross-sectional diameter of the sealing ring is greater than the width of the circular gap 29 between the circular flange 35 and the cover rim 22 so that the lower edge 32 of the sealing ring 21 bears fully onto the upper side of the flange 35. The contact surface formed on the circular flange may be horizontal (Figure 6 and 7), inclined (Figure 5) or rounded (Figure 8).

Beyond the sealing ring 21 extends a pressure ring 26 which is connected with the cover either functionally and/or configuratively.

The pressure ring 26 is either welded to the rim 22, as is shown in Figures 5, 7 and 8, or is formed on the outer rim of a plate 27 which is seated on the cover dish (Figure 6). The last mentioned embodiment will be considered particularly when a flat cover 23 is used.

The pressure ring 26 is provided outside the sealing ring 21 with holes 37 for bolts through which pass bolts 36 attached to the circular flange 35. Nuts 30 are screwed onto the bolts 36 above the pressure ring 26.

When the nuts 30 are tightened the sealing ring 21 is held at three sides and pressed firstly at its inner edge 28 by the rim 22 of the cover dish pushing against the circular flange 35, secondly at the upper edge 31 by the pressure ring 26 and thirdly at the lower edge 32 by the circular flange 35, so that the sealing ring 21 can spread elastically only outwardly. This fully safeguards perfect sealing at minimum constructional height, while shearing of the sealing is fully prevented.

Particularly when a flat sealing ring 21 a (Figure 7) is used, the bolts 36 seated in the manhole flange 35 may be kept exceptionally low.

As both the circular flange 35 and the pressure ring 26 must have only planar sealing surfaces, they may be made lighter and thinner than the corresponding elements in the known embodiment with a groove and tongue joint.

The pressure ring 26 and plate 27 need not be made of material resistant to the media as the sealing due to the three-sided pressing ensures perfect sealing relative to the stored medium.

As the cover dish has a relatively small diameter and need not extend beyond the circular flange 35 it is in general possible to use the circular piece of material left over on cutting out of the manhole from the container wall 33 for the manufacture of the cover: with the known manhole designs the circular piece of material cut out for the formation of the manhole had to be discarded due to the required outer overhang.

WHAT WE CLAIM IS:-- 1. Stackable tank container for overland transport comprising end frames including corner fittings. the container being defined by curved longitudinal walls and curved ends attached to the frames. wherein at least one of the ends is formed as a convex part seated on the outer end surface of one of the frames and extending in the longitudinal direction of the tank container beyond the corner fittings.

'. Tank container according to Claim 1.

wherein the end frames are made of T-sections the webs of which extend in the central plane of the frame and are welded at one side to the longitudinal walls and at the other side to the ends.

3. Tank container according to Claim ' wherein the webs of the T-sections are at least on their surface of corrosion resisting material.

4. Tank container according to Claim 1 wherein each of the curved ends has the form of a longitudinally halved cylindrical pressure vessel having dished ends and is so situated that its longitudinal axis extends across the axis of the tank container.

5. - Tank container according to one of the preceding claims wherein the longitudinal walls are composed of longitudinally parallel interconnected part-cylindrical shells.

6. Tank container according to Claim 5 including longitudinal members interconnect- ing the end frames. at least one web of the former extending in the plane containing section lines of the part-cylindrical shells and being connected to tie elements located in this plane.

7. Tank container according to Claim 1 having a part-cylindrical shell, wherein at least one of the frames has horizontally extending frame parts provided with openings in the vicinity of the bottom and/or top line of said shell.

8. Tank container according to Claim 1.

provided with an access hole defined by a flange carrying clamping bolts. the hole being closable by a cover having an outer rim the diameter of the which is smaller than the inner diameter of the flange whereby a circular gap is defined between the flange and the rim. the rim being formed as an inner clamping and retaining ring for an elastic sealing ring supported by the flange, the radial cross-sectional diameter of the sealing ring being greater than the width of the said gap.

a pressure ring being provided at an outside peripheral portion of the cover so as to extend beyond the sealing ring the pressure ring being fastenable by the bolts whereby the cover firmly closes the access hole.

9. Tank container according to Claim 8 wherein the sealing ring has a flat squareshaped or circular cross-section.

10. Tank container according to Claim 8 wherein the upper side of the flange in the contact area of the sealing ring is horizontal.

oblique or rounded.

11 - Tank container according to Claim 8 wherein the pressure ring is fastened on the cover rim.

12. Tank container according to Claim 8 wherein the pressure ring is formed on a plate situated on the cover.

13. Tank container according to Claim 11 or 12 wherein the pressure ring or the plate is made of a material which is not resistant to the transported liquid.

14. Stackable tank container for overland transport constructed, arranged and adapted to operate substantially as hereinbefore described with reference to. and as illustrated in. the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **.

medium.

As the cover dish has a relatively small diameter and need not extend beyond the circular flange 35 it is in general possible to use the circular piece of material left over on cutting out of the manhole from the container wall 33 for the manufacture of the cover: with the known manhole designs the circular piece of material cut out for the formation of the manhole had to be discarded due to the required outer overhang.

WHAT WE CLAIM IS:-- 1. Stackable tank container for overland transport comprising end frames including corner fittings. the container being defined by curved longitudinal walls and curved ends attached to the frames. wherein at least one of the ends is formed as a convex part seated on the outer end surface of one of the frames and extending in the longitudinal direction of the tank container beyond the corner fittings.

'. Tank container according to Claim 1.

wherein the end frames are made of T-sections the webs of which extend in the central plane of the frame and are welded at one side to the longitudinal walls and at the other side to the ends.

3. Tank container according to Claim ' wherein the webs of the T-sections are at least on their surface of corrosion resisting material.

4. Tank container according to Claim 1 wherein each of the curved ends has the form of a longitudinally halved cylindrical pressure vessel having dished ends and is so situated that its longitudinal axis extends across the axis of the tank container.

5. - Tank container according to one of the preceding claims wherein the longitudinal walls are composed of longitudinally parallel interconnected part-cylindrical shells.

6. Tank container according to Claim 5 including longitudinal members interconnect- ing the end frames. at least one web of the former extending in the plane containing section lines of the part-cylindrical shells and being connected to tie elements located in this plane.

7. Tank container according to Claim 1 having a part-cylindrical shell, wherein at least one of the frames has horizontally extending frame parts provided with openings in the vicinity of the bottom and/or top line of said shell.

8. Tank container according to Claim 1.

provided with an access hole defined by a flange carrying clamping bolts. the hole being closable by a cover having an outer rim the diameter of the which is smaller than the inner diameter of the flange whereby a circular gap is defined between the flange and the rim. the rim being formed as an inner clamping and retaining ring for an elastic sealing ring supported by the flange, the radial cross-sectional diameter of the sealing ring being greater than the width of the said gap.

a pressure ring being provided at an outside peripheral portion of the cover so as to extend beyond the sealing ring the pressure ring being fastenable by the bolts whereby the cover firmly closes the access hole.

9. Tank container according to Claim 8 wherein the sealing ring has a flat squareshaped or circular cross-section.

10. Tank container according to Claim 8 wherein the upper side of the flange in the contact area of the sealing ring is horizontal.

oblique or rounded.

11 - Tank container according to Claim 8 wherein the pressure ring is fastened on the cover rim.

12. Tank container according to Claim 8 wherein the pressure ring is formed on a plate situated on the cover.

13. Tank container according to Claim 11 or 12 wherein the pressure ring or the plate is made of a material which is not resistant to the transported liquid.

14. Stackable tank container for overland transport constructed, arranged and adapted to operate substantially as hereinbefore described with reference to. and as illustrated in. the accompanying drawings.