Tank container

The present invention relates to a tank container (1) having a tank (2) and a framework which receives the tank (2) via end frames (3). Here, the end frames (3) are connected to one another in the lower region via a longitudinal frame structure (5), wherein at least two lateral longitudinal carriers (12) are provided which, in their end regions, have in each case one lateral diagonal member (14) which extends between the longitudinal carrier (12) and a corner support (18) and one base diagonal member (16) which extends between the longitudinal carrier (12) and a lower transverse spar (26, 26′), wherein the base diagonal member (16) and/or the lateral diagonal member (14) have/has an open cross-sectional profile.

The invention at hand relates to a tank container (1) having a tank (2) and a framework which receives the tank (2) via end frames (3). Here, the end frames (3) are connected to one another in the lower region via a longitudinal frame structure (5) that has two lateral longitudinal carriers, with the latter being additionally connected to the end frame at their ends in each case via a lateral diagonal member and a base diagonal member. Here, the lateral diagonal members each run in lateral vertical planes at a slant between the longitudinal carrier and a corner support and the base diagonal member—also at a slant—in a horizontal plane close to the bottom between the longitudinal carrier and a lower transverse spar. Here, the corner support and lower transverse spar are elements of the end frame.

Tank containers in which the tank is coupled to an end frame at each of its ends have been known from DE 202 11 594 U1, DE 297 05 851 U1 and from EP 0 425 190 A1, for example.

DE 297 05 851 U1 and DE 202 11 594 U1 show a coupling between tank and end frame via so-called end ring saddling mechanisms.

EP 0 425 190 A1 shows specific saddle elements that connect the tank to the end frame in particular in the area of the corner fittings. This way, transport and handling forces are to be transmitted to the corner fittings as directly as possible and in particular in the area of the lower corner fittings. However, such saddle structures have the disadvantage that they are costly to manufacture and complicate the insulation of the tank since, on the one hand, insulation layers and coverings must be interrupted in this area and, on the other hand, the specific saddle structures represent thermal bridges that cause a great thermal transfer between the tank and its surroundings.

In the meantime, in order to solve this problem, the majority of tank containers that are being manufactured are those in which the tank is connected to the end frame only via the end rings or, respectively, end ring segments. For reinforcement and stabilization, the end frames are provided with additional longitudinal frame structures at least in the area of the lower corner fittings.

FIGS. 7 through 9show such a tank container. Here, the tank container50has a tank52that is connected to the end frames56via end ring structures at its two ends. Here, upper longitudinal carriers60and lower longitudinal carriers62run between the upper and lower corner fittings58. Normally, the tank container50is fixed to a transport vehicle (e.g. semi-trailer, container car, ship) via the lower corner fittings58. In order to direct the transport stresses that act in the transport direction along the longitudinal axis64and that are generated by acceleration forces safely away from the tank into the corner fittings58, a very sturdy construction is required in particular in the bottom area. To this end, the longitudinal carrier is made of a very sturdy and thus relatively heavy hot-roll profile (e.g. EPI220). In addition, the connection to the end frame is reinforced by lateral diagonal elements66and base diagonal elements68. These base and lateral diagonal elements68and66are constructed of compact rectangular tube profile and connect the longitudinal spars62with the transverse spars72or, respectively, the corner supports70. Such a known construction can be found inFIGS. 7 and 9.

During switching operations during rail transportation, acceleration forces may occur in the direction of the longitudinal axis64that are caused by acceleration forces that amount to four to six times those of gravity (g). Therefore, the longitudinal carrier62is made very strong in conventional tank containers. Only in this way can it absorb the reaction forces introduced locally by the base and lateral diagonal members68,66without any plastic deformation. In particular the structural elements of the frame make this known design relatively heavy.

Starting from this set of problems, the objective of the invention at hand is to provide an end-saddled tank container with a lighter frame structure. An additional objective may be the optimization of the transfer of forces between tank and frame structure in such a way that the frame structure and in particular the introduction of forces between corner supports, lateral diagonal members and longitudinal carriers or, respectively, between transverse spars, base diagonal members and longitudinal carriers is carried out in such a way that in particular these structural components can be made lighter while having the same stability.

The tank container in accordance with Claim1meets this objective, being characterized by the fact that the base and/or lateral diagonal members have an open cross-sectional profile. Such an open cross-sectional profile permits a design of the respective structural elements (base and/or lateral diagonal members) so that the tensions occurring during periods of stress are distributed more evenly and local tension peaks at the connection locations of the structural elements in question (longitudinal carrier, lateral diagonal members, corner support; longitudinal carrier, base diagonal member, transverse spar) are reduced. The open cross-sectional profile permits a “soft” connection that permits a high degree of own elasticity of the overall structure without reducing the necessary stability too much. Therefore, considerably lighter structural elements can be used as longitudinal carriers and as corner supports without reducing the stability of the overall structure too much.

In the further development of the invention in accordance with Claim2, an open trapeze cross section is provided for the lateral diagonal member, with two lateral portions protruding from a base flange at an angle of between 145 and 165° each. This design permits an extended connection segment of the lateral diagonal member to the longitudinal carriers and to the corner supports. The specially selected slant assures in the marginal areas (i.e. in the areas of the lateral portions) a relatively soft and long coupling with the upper side of the longitudinal carriers that becomes gradually stiffer towards the base flange. Undesired point loads are avoided and buckling stresses on the longitudinal carrier are reduced. The symmetric structure in accordance with Claim3permits a cutting scrap-poor manufacture of the lateral diagonal members by trimming correspondingly profiled materials sold by the meter.

The further embodiment of the invention in accordance with Claim4permits a further improved load transmission between longitudinal carrier and corner support. The longitudinal design of the lateral diagonal member in accordance with Claim5optimizes the free buckling lengths on the longitudinal carrier and leads, together with the measure in accordance with Claim6, to a further optimized construction in terms of material and weight.

The version in accordance with Claim7improves the flow of forces between lateral diagonal member and longitudinal carrier. In this version—with a corresponding design of the longitudinal carrier as a hollow profile—the relatively stable base flange area engages with a relatively soft connecting segment of the longitudinal carrier. This results in an elastic coupling of components with improved stress distribution as well.

The further embodiments of the invention indicated in Claims8through13relate to the design of the base diagonal member which in accordance with Claim8has a cap profile cross section that is open downward. Such a cap profile has structural advantages similar to the open trapeze cross section of the lateral diagonal member described above. But here, the free edges of the lateral shanks are stiffened by means of additional brim shanks (Claim9). This makes it possible to design the overall profile even flatter while still having sufficient buckling or, respectively, bulging stability. This flat construction allows more ground clearance for connections or, respectively, for insulations of the tank in particular in the connecting area of the base diagonal member to the end-side transverse spars.

This effect is additionally reinforced through the inclination in accordance with Claim10; at the same time, this design prevents wetness and dirt from collecting on the main flange of the base diagonal member, thereby creating corrosion problems. The arrangement of the angle relative to the longitudinal carrier in accordance with Claim11permits a structurally particularly favorable connection here as well and an improved load transfer between transverse spar and longitudinal bearing.

The tapering in accordance with Claim12permits a weight-optimized design of the base diagonal member together with a tension-optimized load transfer between transverse spar and longitudinal carrier. The profile depth of the cap profile (height H) in accordance with Claim13permits the connection of a relatively flat (low) transverse spar to a relatively high longitudinal spar (seen in vertical direction)—here with a “soft” connection between base diagonal member and longitudinal carrier or, respectively, transverse spar as well.

The overlapping connection areas in accordance with Claim14permit a particularly buckle-optimized load introduction of the base and lateral diagonal members into the lateral longitudinal carriers.

The form of the longitudinal carrier in accordance with Claim15permits the further optimizable load introductions into the longitudinal carriers in vertical direction (lateral diagonal members) and horizontal direction base diagonal members).

The further embodiment of the invention in accordance with Claims16through18, in conjunction with the special lateral and base diagonal members, permits a considerably lighter version as compared with conventional end ring designs. In this regard, the coupling socket segment in accordance with Claim17is particularly easy to install in the alignment of the end frame with the tank, and the further embodiment in accordance with Claim18permits a particularly economical manufacture of the saddle ring elements.

The basic structure of a tank container1in accordance with the invention will now be explained in detail by way ofFIGS. 1 and 2. The tank container1comprises a tank2and a frame structure that accommodates the tank2via end frames3at its ends. For a coupling, one end ring arrangement4each is provided between the end frame3and the ends of the tank2that will be explained in detail below. A longitudinal frame structure5that serves in particular to transmit any forces acting along the tank axis runs between the end frames3in the bottom area.

The tank2is represented inFIGS. 1,2and5by the dash-umlaut line and is formed by a cylindrical body8whose ends are closed with curved end sections. The tank2moreover has controls and instruments as well as connections that are not shown here.

The left half ofFIG. 1shows a lateral view of the tank container1and the right one, a view in which the frontal frame elements have been cut off. The tank container as shown involves a so-called 20′ unit that is particularly common in the case of tank containers; but 10′, 30′ and 40′ units are common as well.

The longitudinal frame structure5here comprises lower longitudinal carriers12whose ends are in each case connected with the end frame3. In addition, lateral diagonal members14are provided that lead to the end frames3, starting from the lower longitudinal carriers and running upward at an angle. The base diagonal members16are provided in the bottom area that also extend at an angle to the end frames3in a vertical plane close to the ground, starting from the lower longitudinal carriers12(see alsoFIG. 6with regard thereto).

FIG. 2shows, also in a divided view, the end frames of the tank container1fromFIG. 1. Here the left half shows the front end and the right half, the rear end of the tank container1. In the case of tank containers, the end at which controls and instruments (not shown here) are provided at the bottom is designated as the rear end.

The end frames3are each composed of corner supports18, lower corner fittings20, upper corner fittings22, an upper transverse spar24, a lower transverse spar26or, respectively,26′, upper end diagonals28and lower end diagonals30.

The lateral diagonal members14each connect a segment L (seeFIG. 6) at the upper side of the lower longitudinal carriers12with a segment M (seeFIG. 1) on the side of the corner support18facing the tank2. A reinforcement shoe15is arranged on the end frame-side connection end of the lateral diagonal member14.

The cross section of the lateral diagonal member14represented inFIG. 4shows the connection of the reinforcement shoe15to the base flange31of the lateral diagonal member14from which two lateral shanks32jut out. In the example of an embodiment shown, the lateral shanks32stick out from the base flange at an angle γ of 155°. In other embodiments, this angle is between 145 and 165°. In the example of an embodiment shown, the depth t (seeFIG. 6) of the lateral diagonal member amounts to approximately half the width B of the lower longitudinal carrier12. However, it should amount to at least one third of that width.

The lateral diagonal members14, together with the lower longitudinal carrier, form an angle α (seeFIG. 1) of approximately 13°, in other embodiments this angle fluctuates between 10 and 16°. In this context, the upper or external edges of the lateral diagonal members14form upper chords that divide the lower longitudinal spars12into three segments T of approximately equal length. The upper or, respectively, inner edges of the lateral diagonal members14form lower chords that cut the external segments T approximately in half.

The structure and the arrangement of the lateral diagonal member14described above permit a particularly favorable transfer of the tension load between the connection area M to the corner supports18and the connection area L on the lower longitudinal carrier12. The open trapeze profile assures in this context favorable tension transitions with high structural strength and low weight.

Structure and arrangement of the base diagonal member16will be explained below in detail by way ofFIGS. 3 and 6. The lateral diagonal member represented inFIG. 6runs from a connection area N on the inner side—facing the tank axis6—of the longitudinal carrier12to a connection area O on the rear side—facing the tank2—of the lower transverse spar26′. Here, in the embodiment shown, the longitudinal axis33′ of the base diagonal member16forms an angle β of approximately 19° together with the lower longitudinal carrier12. In other embodiments, this angle fluctuates between 15 and 24°.

FIG. 3shows that the base diagonal members16in cap profile are provided with a main flange33, two lateral shanks34and35as well as two brim shanks36and37. The height h of the base diagonal member16amounts to at least one third of the height H (FIG. 1) of the longitudinal carrier12. The main flange33tapers along the axis33′ from the connection area O on the lower transverse spar26or, respectively,26′ towards the connection area N on the longitudinal carrier12so that the two lateral shanks include an angle of approximately 3°. In other embodiments this angle is between 0 and 5°.

In addition, the main flange shows an inclination of approximately 5° relative to the horizontal. In other embodiments this inclination is at least 2°. This measure prevents water or dirt from accumulating on the upper side of the base diagonal member16.

The cap profile cross section of the base diagonal member16represented inFIG. 3shows that the lateral shanks34and35run almost vertically and the brim shanks36and37almost horizontally. In other embodiments the lateral shanks34and35are opened wider and in each case include an angle of between 90 and 135° with the main flange. The brim shanks36and37may also be inclined at an angle of between 0 and 5′ relative to the horizontal to prevent deposits from forming on its upper side.

The construction and arrangement of the base diagonal member16described above permits a tension-optimized load transfer between the lower transverse spars26and26′ and the longitudinal carriers12, and at the same time a flat design. To this effect, the brim shanks36and37assure a soft attachment to the longitudinal carriers12or, respectively, the lower transverse spars26and26′ and at the same time provide relatively high buckling stability against pressure forces along the main axis with a flat design.

In the example of an embodiment shown the longitudinal carriers12are formed from a square tube with a square cross section. Here, the connection areas L and N of the lateral diagonal member16have an overlapping (shaded area inFIG. 6) of approximately 85% relative to the shorter connection area (here N). In other embodiments this overlapping should amount to at least 50% so that the forces engaging in different planes engage with the longitudinal carriers12in tension-optimized fashion. In this way, the resulting tensions can be adjusted to the existing cross-sectional profile and the available free buckle lengths.

FIG. 5shows the structure of the end ring arrangement4. Here, cylindrical end rings or, respectively end ring segments38are arranged at the domed bottoms10of the tank that are connected to the end frame3via conical saddle ring segments39or, respectively, saddle rings. Cylindrical coupling socket segments40or, respectively, coupling sockets are arranged at the narrow ends of the saddle ring segments39facing the tank that encompass the external cylindrical circumferential surfaces of the end ring segments38with their interior circumferential surfaces and that can be dislocated on the latter for positioning purposes during installation. The coupling socket segment40may, for example, be crimped to the conical saddle ring segment39, thereby forming one piece. But it may also be attached as a ring piece.

The wide end of the conical saddle ring segment39is connected via its end surface to the corner supports18, the upper end diagonal member28as well as to the lower end diagonal member30. End ring segments38and conical saddle ring segments39may either form a closed ring (see frontal view inFIG. 2) or may have interruptions (see rear view inFIG. 2) and expose corresponding recesses for the arrangement of controls and instruments or other accessories on the tank2. The conical design permits a material-saving and thin-walled execution of the end ring arrangement4, thereby assuring a stable connection between tank2and end frame3. In the example of an embodiment shown, the opening angle of the conical saddle ring segment is approximately 45°. In other embodiments, this opening angle may be between 30 and 60°.

In the example of an embodiment shown, the lateral diagonal member14has an open trapeze profile and the base diagonal member16, a cap profile. In other embodiments, the base diagonal member16may have a trapeze profile as well or, respectively, the lateral diagonal member may have a cap profile.

The base flange31of the trapeze profile and the main flange33of the cap profile are shown level inFIGS. 3 and 4. Particularly these flanges31and33may have additional edgings or profiles to improve their structural properties.

Additional embodiments and variations will be obvious to the expert within the framework of the patent claims set forth below.