BE1019903A5 - VAT FROM COMPOSITE MATERIAL, METHOD FOR MANUFACTURING IT, AND END CAP FOR USE IN A VAT. - Google Patents

Abstract

Vessel of composite material comprising a hollow tubular section with at least one open end; an end cap mounted in the at least one open end of the tubular portion, said open end forming a protruding skirt around the end cap for suspending the vessel.

Description

Va-b from composite material, method for manufacturing it, and end cap for use in a vessel

The present invention relates to a vessel made of composite material, in particular for a tank container with a frame. The invention further relates to a method for manufacturing a vessel, in particular a vessel for a tank container with a frame. Finally, the invention relates to an end cap for use in such a vessel.

The traditional tank containers typically consist of a barrel (for example, made of stainless steel) that is placed in a normalized frame (an ISO frame). Such a frame is made up of steel profiles. The vessel must be able to stand at a variable pressure which can typically vary from 0 to 20 bar. The barrel can be attached to the frame for example by means of a saddle construction or via a suspension construction with a skirt. The suspension structures are typically welded to the tank, which implies that there will be a transition between stainless steel and normal carbon steel. Such transitions are typically susceptible to fatigue and corrosion.

DE 19832145 describes a vessel 1 with a bottom 3 with a cylindrical circumferential portion 5 that is connected to inner wall 6 of a cylindrical body 2.

The present invention has for its object to propose a vessel with improved properties in comparison with the properties of conventional vessels. A further object of the invention is to provide a method for manufacturing such a vessel.

According to an embodiment of the invention, the composite material vessel comprises a hollow tubular section with at least one open end, and an end cap mounted in the at least one open end of the tubular section. This open end preferably forms a protruding skirt around the end cap for suspending the barrel. The barrel is preferably intended for a tank container that can be suspended in an annular saddle of a frame. Such an embodiment has the advantage that a suspension vessel of composite material is obtained in a simple manner.

The term "tubular section" is to be interpreted broadly as a section that can form any circumferential wall of a vessel. This can for instance be a cylindrical or conical circumferential wall, but also any other circumferential wall with a constant or variable cross-section.

According to a preferred embodiment, the tubular section is substantially cylindrical. The term "cylindrical portion" is to be interpreted broadly here as a surface described by a straight line moving parallel to a fixed straight line and intersecting a closed plane curve. The cylindrical portion may thus have, for example, a circular cross-section, or an elliptical cross-section, or a square cross-section, etc. (or a combination thereof).

According to an embodiment, the end of the tubular section is round, and the end cap has a round cylindrical peripheral section with an outside diameter that is approximately equal to the inside diameter of the round end, the skirt protruding beyond the peripheral section of the end cap. This circumferential part will allow a simple connection, for example by gluing, of the end cap to the tubular part.

According to an embodiment, the end cap is formed with a convex closure part that optionally merges into a cylindrical peripheral portion. The convex closure member preferably has a central first zone and a surrounding second zone, the central first zone protruding from the end while the second zone is within the tubular section. In this way a vessel with the largest possible volume is created within a beam-shaped standard frame.

According to a preferred embodiment which is particularly suitable for a tank container, the tubular section has two open ends in which an end cap is arranged in each case. According to an advantageous embodiment, each end cap is substantially in the form of a klopper bottom.

According to an embodiment of the method according to the invention, the method comprises the following steps: - manufacturing a tubular section with at least one open end substantially from a composite material; - manufacturing an end cap substantially from a composite material; and - inserting the end cap into the end of the tubular section; - connecting the end cap to the inner circumference of the tubular section in this position. The end cap is preferably inserted into the tubular section until the end thereof extends around the end cap to form a skirt for suspending the vessel in a saddle of a frame. The method is intended, for example, for manufacturing tank containers that can be suspended in a standard container frame.

According to an advantageous embodiment, the tubular portion is formed with a round end, and the end cap is formed with a circular cylindrical circumferential portion with an outer diameter approximately equal to the inner diameter of the end of the tubular portion, with the circumferential portion slid into the tubular portion is becoming.

According to another aspect of the invention, a vessel is formed by winding a tubular section from resin-impregnated fibers, and by manufacturing the end cap using a resin molding process, such as the traditional RTM (resin transfer molding) processes and / or a vacuum infusion process.

According to yet another embodiment of the invention, there is provided a vessel which is substantially made of composite material, and which has a tubular section with at least one open end; and an end cap for closing the at least one open end, which end cap has a thickness that is variable for better distribution of forces in the vessel.

According to a further aspect thereof, the end cap has a central part and the thickness of the end cap decreases from the tubular part in the direction of the central part of the end cap. According to a possible embodiment, the thickness gradually decreases from the circumference of the end cap towards the center of the end cap. According to another variant, the thickness decreases substantially stepwise from the circumference of the end cap in the direction of the center of the end cap. The thickness varies, for example, in at least one step, or in at least two steps or in at least three steps. It goes without saying that combinations with (an) area (s) where the thickness varies gradually and (an) other area (s) where the thickness varies in steps are also possible.

According to a preferred embodiment, the outside of the end cap has a step-shaped profile.

According to a further embodiment of the end cap, it has an average thickness near the center that is more than twice and preferably more than three times smaller than the average thickness near the circumference of the end cap. According to a further aspect, the end cap has a convex shape, in particular substantially the shape of a klopper bottom.

According to a possible embodiment, the end cap is intended to connect to the cylindrical part with a substantially constant diameter and the end cap has a middle part with a substantially constant internal radius of curvature. The ratio between the internal radius of curvature R and the diameter of the cylindrical portion is preferably between 0.75 and 5.0, even more preferably between 0.80 and 1.20.

The variable thickness of the end cap is obtained according to a possible embodiment with a laminate construction. The end cap can herein be made from a combination of fibers, resin and optional foam.

According to yet another embodiment, the method for manufacturing a vessel from a composite material comprises the following steps: manufacturing a tubular section with an end from a composite material; manufacturing an end cap with a variable wall thickness from a composite material; and connecting the end cap to the tubular section.

According to a preferred embodiment thereof, the tubular section is wound, and the end cap is manufactured with a resin molding process, optionally using foam locally.

The invention also relates to an end cap for use in a vessel as described above, wherein the described properties of the end cap can be present separately or in combination.

According to yet another aspect of the invention, an end cap is provided for a vessel, in particular for a tank container, wherein the end cap is provided with a bottom outlet flange, which bottom outlet flange is made of a composite material and is preferably incorporated into the end cap by laminating.

According to a preferred embodiment thereof, the bottom outlet flange is provided with a number of recesses regularly spread over the circumference in which steel inserts with a tapped hole are arranged.

The end cap may further optionally have one or more of the properties described above.

Further, the axis of the bottom outlet flange preferably makes an angle between 30 and 60 degrees with an axis perpendicular to the center of the end cap, and for example an angle of about 45 degrees. The bottom outlet flange is typically disposed near the outer circumference of the end cap.

The present invention will be further elucidated on the basis of a number of by no means limiting exemplary embodiments of a vessel according to the invention with reference to the attached drawings, in which:

Figure 1 is a schematic perspective view of a first embodiment of a vessel according to the invention; Figure 2A is a side view of the vessel of Figure 1;

Figure 2B is a top view of the vessel of Figure 1; Figure 3 is a vertical longitudinal section;

Figures 4A and 4B show in detail two embodiments of the connection between the tubular section and the end cap of the vessel of Figure 3;

Figure 5 shows a schematic vertical longitudinal section of a first embodiment of an end cap according to the invention;

Figures 6A and 6B show a schematic vertical section and a front view of a second embodiment of an end cap according to the invention, respectively;

Figures 7A and 7B show a schematic vertical section and a front view of a third embodiment of an end cap according to the invention, respectively;

Figure 8 shows in detail the lower left corner of the section of Figure 3;

Figure 9 shows a schematic section of a coiled mounting flange;

Figure 10 shows a schematic top view of a mounting plate; and

Figure 11 is a schematic perspective view of a standard frame for a 260000 liter barrel.

Figure 1 illustrates a schematic perspective view of an embodiment of a tank for a tank container according to the invention. In this embodiment, such a vessel is intended to be placed in a frame, for example a standard frame of a tank container, which is illustrated in Figure 11. The assembly is based on a frame 110 without front frame 111. The tank container is first - for example supported on rollers - slid into ring 112, after which the front frame 111 is placed and the four corners of this frame are welded to the rest of the frame.

The vessel 1 is substantially made of a composite material as will be explained further below. The vessel 1 comprises a tubular section 2 formed in one piece with a front end 3 and a rear end 4 in which respective end caps 5, 6 are attached.

The tubular section 2 is typically wound from resin-impregnated fibers, using a standard winding process on a mandrel. Where necessary, the process can be adjusted in function of the dimensions and possible details of the tubular section. The tubular section can be wound in one or more winding passes.

According to a possible embodiment, the tubular section is made in one winding pass, wherein a specially shaped profile can be provided on the mandrel for obtaining a part with larger dimensions. Thus, the ends 3, 4 of the tubular section can be made with a larger diameter by providing a profile piece 30 which extends along the circumference of the mandrel, as shown in Fig. 4A for the front end 3. In this way a stop 33 is made. formed for the end cap 5. The same applies to the end cap 6.

According to another possible embodiment, the tubular section 2 is wound in two winding passes as illustrated in Fig. 4B for the front end 3: a first winding pass to form the central portion 31 of the tubular section 2, and a second winding pass to form two end sections 32 at the front and rear ends 3, 4, respectively, of the tubular section 2. In this way, a stop 33 can also be formed for the end caps 5, 6.

The end caps 5, 6 each have a spherical closing part 7 which merges into a cylindrical peripheral part 8, as can best be seen in the cross-section of Fig. 3 and in the detailed view thereof shown in Figs. 4A or B. The cylindrical peripheral part 8 has an outer diameter which is substantially equal to the inner diameter of the ends 3, 4 of the tubular section 2, such that the end caps 5, 6 can be slid into the tubular section 2 and can be connected thereto.

In the embodiment shown, the end caps 5, 6 are introduced into the front and rear ends 3, 4, respectively, of the tubular section, the ends 3, 4 forming projecting skirts at the ends of the vessel for suspension thereof. The advantage of such a suspension construction is that the forces that occur in the event of, for example, collision, are efficiently passed through, without delamination occurring. Furthermore, wrapping the skirt with the tubular section ensures better resistance to the bending of the end cap construction. Furthermore, the necessary reinforcements can be built in to offer extra resistance to this bending.

The connection between the end caps and the tubular section can be made in any suitable manner and, for example, by gluing.

The tubular section 2 is further typically provided with a number of reinforcement rings 12. These can for instance be provided during the winding process by means of so-called "pile windings".

A possible embodiment of the end caps 5, 6 will now be discussed in detail with reference to figure 5. The general form of this exemplary embodiment of the end cap 50 in the embodiment shown is that of a clump bottom. However, the invention also applies to differently shaped end caps. The end cap is here characterized by a total height H, an external diameter D, an edge height h of the cylindrical edge part 58, an internal angle radius r at the transition from the edge part 58 to the closing part 57, and an internal curvature radius R of the middle part ( beyond the transition) of the closure part 57. The internal curvature radius R may, for example, be approximately equal to the external diameter D. The internal angular radius r is, for example, approximately ten times smaller than the external diameter D. In the exemplary embodiment illustrated, the internal angular radius r and the internal curvature radius R curvature rays for the inner surface of the end cap. As will be further explained, an end cap with a variable wall thickness is preferably used and the curvature rays of the outer surface of the end cap will therefore be different from those of the inner surface.

In the illustrated variant of Figure 5, the thickness of the spherical closure member 57 gradually decreases toward the center of the cap. According to a second variant illustrated in Figs. 6A and 6B, two zones of different thicknesses can be distinguished in the closure part 57: a first central zone 51 with a diameter 2 * R1 and with a first thickness d1, a second surrounding it zone 52 with an outside diameter 2 * R2 and with a thickness d2. According to a third variant shown in Figs. 7A and 7B, an additional surrounding annular third zone 53 with an outside diameter 2 * R3 and a thickness d3 is also provided. In the second and third variant, the thickness of the closing part 58 thus increases stepwise from the central zone 51 to the outer zone 52 or 53. As can best be seen in Figs. 6A and 7A, the outer surface of the closing part 57 has a stepped profile around to create this increasing thickness. As a result, the corner radius at the transition to the closing part 57 will typically be smaller on the outside than on the inside (r '> r).

Those skilled in the art will understand that the variable thickness can also be realized in the form of a stepwise increasing thickness with then three steps, and more generally according to any profile with an increasing thickness starting from the center in the direction of the outer edge. Furthermore, the skilled person will understand that the thicknesses can be optimized in function of the dimensions of the vessel and of the applications for which the vessel is intended. As a limitative example in no way, the thickness dimensions for a vessel with a volume of about 26,000 liters for the end caps can vary, for example, between 5 and 50 mm depending on the desired properties of the vessel.

Such a shape of the cap allows the volume of the tank to be larger when using a smaller amount of composite material compared to the prior art. Furthermore, the strength of the end cap is guaranteed by the adapted design and the variable thicknesses. Moreover, such a design allows the inside of the tank to have the same geometry as that of a standard stainless steel tank.

Such an end cap can for instance be manufactured with a laminate process using a composite material consisting of fiber and resin, whether or not in combination with foam, which can for instance be applied locally where thickenings are needed. The end cap can, for example, be manufactured with the aid of a resin molding process, such as the traditional RTM processes, the vacuum infusion processes, etc. According to a possible embodiment, in a first step one or more cloths consisting of pre-stitched fibers (in which local foam may be enclosed for formation) thickening). In a second step, one or more molds are provided, after which the resin is injected. In this way, end caps can be manufactured with a high percentage of fibers.

A cap manufactured in this way can then be slid into one end of the tubular section 2 described with reference to Fig. 1 and attached to the tubular section by means of, for example, an adhesive connection. To this end, it may be necessary to process the end cap prior to insertion into the tubular section to a calibrated size, for example by milling or grinding, in particular using diamond tools.

Such a design and method will make it possible to manufacture transportable pressure tanks with a very large volume. Examples are pressure tanks with a volume between 1,000 and 30,000 liters and more, for example between 24,000 and 26,000 liters, but also smaller tanks such as IBC containers for paint products, for example. Pressure tanks according to the invention can be intended, inter alia, for liquids, or gases, or granulates. The scope of the invention is not limited to tank containers, but also relates to any type of stationary tank.

For gas transport in particular, the difference in weight between a pressure tank according to the invention and a traditional tank will be very considerable, which offers advantages in the field of transport and environmental impact.

Figure 9 further illustrates how connectors for fittings, such as mounting flanges 60-65 shown in Figure 2A, can be fitted during the winding of the tubular section 2. In Figure 9, a mounting flange 90 of a composite material is mounted on a winding process. first wrapped layer 94 and then co-wound. A number of tapped holes (e.g. 6 or 8, see Figure 2A) are typically provided in the mounting flange, which are obtained here by stainless steel inserts 91 which are mounted in the mounting flange 90 of composite. After the winding process, the necessary recesses are provided to clear the central portion with the opening (see reference number 92) and to provide access to the inserts 91 (see reference number 93). In the case that several connections have to be provided in the tank in the vicinity of each other (for example flanges 60-62 in figure 2B), it is also possible to work with a mounting plate 100 of composite, see figure 10. A plate with a number of connections 102-104 and the necessary inserts 102 co-wound with the tubular section.

Furthermore, Figure 8 illustrates how a bottom outlet flange 80 of a composite material can be laminated with the end cap 6 of the tank. As described with reference to Figure 9, steel inserts 81 with internal threads may also be provided in the flange. The flange is arranged such that its axis makes a desired angle, for example 45 degrees, with the bottom of the tank.

According to a possible method, a resin shaping process will be used, in which the outlet flange is applied at a desired location in a mold (for example fixed in the pre-stitched fibers), after which the resin is injected whereby the flange is firmly mounted in the end cap after curing.

The present invention is not limited to the exemplary embodiments described above, and those skilled in the art will appreciate that many modifications are conceivable without departing from the scope of the invention that is only determined by the following claims.

Claims (37)

A vessel made of composite material comprising: - a hollow tubular section with at least one open end; - an end cap mounted in the at least one open end of the tubular section, said open end forming a protruding skirt around the end cap for suspending the vessel. The vessel of claim 1, wherein the tubular section is cylindrical. The vessel as claimed in claim 1 or 2, wherein the tubular portion has a round open end, and wherein the end cap has a circular cylindrical circumferential portion with an outer diameter approximately equal to the inner diameter of the round end of the tubular portion, the skirt protrudes beyond the cylindrical peripheral portion of the end cap. 4. Vessel as claimed in any of the claims 1-3, wherein the hollow tubular section has a longitudinal direction, wherein the end cap is formed with a convex closing part with a central first zone and a second zone situated around it, the central first zone protruding in the longitudinal direction from the open end while the second zone is within the tubular portion. 5. Vessel as claimed in any of the foregoing claims, wherein the end cap is substantially in the form of a klopper bottom. Tank container comprising a vessel according to one of the preceding claims. A tank container according to claim 6 comprising a frame; the hollow tubular portion of the vessel having two open ends in which an end cap is each attached; wherein the barrel is suspended in the frame with each protruding skirt. Method for manufacturing a vessel from a composite material comprising the following steps: - manufacturing a tubular section with at least one open end substantially from a composite material; - manufacturing an end cap substantially from a composite material; and - inserting the end cap into the end of the tubular section; - connecting the end cap to the inner circumference of the tubular section in this position. The method of claim 8, wherein the end cap is inserted into the tubular portion until the end thereof projects around the end cap to form a skirt for suspending the vessel in a frame. A method according to claim 8 or 9, wherein the end cap is formed with a cylindrical circumferential portion with an outer diameter approximately equal to the inner diameter of the end of the tubular portion and wherein the end cap is slid into the tubular portion. A method according to any one of claims 8-10, wherein the end cap is formed with a convex end part with a central first zone and a second zone surrounding it, the end cap being introduced into the cylindrical body such that the central first zone protrudes from the end while the second zone is within the tubular section. The method of any one of claims 8 to 11, wherein the tubular portion is wound from resin-impregnated fibers. The method of any one of claims 8 to 12, wherein the end cap is made using a resin molding process. A method according to claim 13, wherein the resin molding process comprises one or more of the following methods: the traditional RTM (resin transfer molding) processes, a vacuum infusion process. A method according to any one of claims 8-14 for manufacturing a tank container with a frame, wherein the vessel is suspended in a frame with each protruding skirt. The vessel of any one of claims 1-5, wherein each end cap has a thickness that is variable for a better distribution of forces in the vessel. The vessel of claim 16, wherein the end cap has a central portion and the thickness of the end cap decreases from the tubular portion toward the central portion of the end cap. A vessel according to claim 16 or 17, wherein the thickness gradually decreases from the circumference of the end cap toward the center of the end cap. A vessel according to claim 16 or 17, wherein the thickness decreases substantially stepwise from the circumference of the end cap toward the center of the end cap. The vessel of claim 19, wherein the thickness decreases in at least one step, preferably in at least two steps and even more preferably in at least three steps. 21. Vessel as claimed in any of the claims 16-20, wherein the outside of the end cap has a step-shaped profile. The vessel of any one of claims 16 to 21, wherein the average thickness near the center of the end cap is more than twice and preferably more than three times smaller than the average thickness near the tubular portion. 23. Vessel as claimed in any of the claims 17-22, wherein the end cap has a convex shape, in particular substantially the shape of a klopper bottom. The vessel of any one of claims 17-23, wherein the tubular portion is a cylindrical portion with a substantially constant inner diameter and the end cap has a middle portion with a substantially constant internal radius of curvature, and wherein the ratio between the internal radius of curvature R and the inner diameter D 'of the cylindrical portion is between 0.75 and 5, preferably between 0.80 and 1.20. The vessel of any one of claims 16-24, wherein the variable thickness of the end cap is obtained with a laminate construction. 26. Vessel as claimed in any of the claims 16-25, wherein the end cap is made from a combination of fibers, resin and optional foam. A tank container comprising a vessel according to any one of claims 16-26. A tank container according to claim 27 comprising a frame; the hollow tubular portion of the vessel having two open ends in which an end cap is each attached; wherein the barrel is suspended in the frame with each protruding skirt. A method according to any one of claims 8-15 wherein the end cap is manufactured with a variable wall thickness. The method of claim 29, wherein the tubular portion is wound. The method of claim 29 or 30, wherein the end cap is made with a resin molding process using foam locally. An end cap for use in a vessel according to any of claims 1-5 or 16-26. An end cap according to claim 32, in particular for a tank container, wherein the end cap is provided with a bottom outlet flange, which bottom outlet flange is made of a composite material and is preferably incorporated into the end cap by laminating. An end cap as claimed in claim 33, wherein the bottom outlet flange is provided with a number of recesses regularly spread over its circumference in which steel inserts with a tapped hole are arranged. An end cap according to claim 33 or 34, wherein the end cap has a convex shape, in particular substantially the shape of a klopper bottom. The end cap of any one of claims 33 to 35, wherein the bottom outlet flange has an axis, and it is at an angle between 30 and 60 degrees with an axis perpendicular to the center of the end cap. An end cap as claimed in any one of claims 33-36, wherein the bottom outlet flange is arranged near the outer circumference of the end cap.