FLUSHABLE PRESSURE VESSEL

Abstract

A pressure vessel with a flushing lance, a transport container with pressure vessels and methods of filling and producing this pressure vessel are disclosed which comprises an inner vessel, an outer layer applied on the inner vessel, a valve connection piece arranged on one of the terminal caps of the inner vessel and a hollow flushing lance that is open to the outside and is guided through the valve connection piece and held therein in a sealing manner, wherein the flushing lance protrudes into the storage volume and is provided with a perforation along its entire length up to a first end of the flushing lance facing the terminal cap that lies opposite the valve connection piece in the storage volume for a gas exchange with the storage volume, wherein the flushing lance extends to the terminal cap which lies opposite the valve connection piece.

Claims

1. A pressure vessel, comprising an inner vessel produced from an inner vessel material having a cylindrical middle part with a cylinder axis and having two terminal caps that seal the cylindrical middle part so as to provide a storage volume in the pressure vessel, an outer layer which is applied on the inner vessel in order to reinforce said inner vessel, a valve connection piece that is arranged on one of the terminal caps so as to fill and empty the storage volume with a filling gas at a desired degree of purity, and a hollow flushing lance that is open to the outside and is guided through the valve connection piece and held therein in a sealing manner with respect to the valve connection piece, wherein the flushing lance protrudes into the storage volume and is provided with a perforation along its entire length up to a first end of the flushing lance facing the terminal cap that lies opposite the valve connection piece in the storage volume for a gas exchange with the storage volume, wherein the flushing lance extends so far to the terminal cap, which lies opposite the valve connection piece, that the gas exchange takes place throughout the perforation of the flushing lance up to the opposite terminal cap, the flushing lance being produced at least in the area within the storage volume from a dimensionally stable material, wherein the first end of the flushing lance is arranged free-floating in the storage volume of the pressure vessel, characterized in that an additional weight is arranged on the first end of the flushing lance.

2. The pressure vessel according to claim 1, characterized in that the dimensionally stable material is a plastic that is softer than the material of the inner vessel.

3. The pressure vessel according to claim 1, characterized in that the first end of the flushing lance is suitably connected to the terminal cap opposite to the valve connection.

4. The pressure vessel according to claim 1, characterized in that the flushing lance is connected in a reversible manner by way of suitable means to the valve connection piece.

5. The pressure vessel according to claim 1, characterized in that the material of the flushing lance is so stiff that as a gas filling of the storage volume is drawn off by means of suction through the flushing lance, said flushing lance remains dimensionally stable and its shape does not collapse.

6. The pressure vessel according to claim 1, characterized in that the perforation of the flushing lance comprises gas inlet openings and gas outlet openings, whose number, position and diameter are dimensioned such that thorough mixing of a gas filling in the storage volume as well as durations of the procedures of filling and emptying the storage volume with, or of, the filling gas are optimized.

7. A transport container comprising a plurality of pressure vessels according to claim 1, whose storage volumes are connected to one another by way of a common sealable pipe system by way of the respective valve connection pieces and a respective second end of the flushing lance.

8. The transport container according to claim 7, characterized in that the pipe system is connected to a device so as to fill the pressure vessels with the filling gas and to pump out the gas filling that is located within the pressure vessels.

9. A method of filling a pressure vessel according to claim 1 with a filling gas at a desired degree of purity in the pressure vessel that comprises an inner vessel produced from an inner vessel material having a cylindrical middle part having a cylinder axis and having two terminal caps that seal the cylindrical middle part so as to provide a storage volume in the pressure vessel; an outer layer applied on the inner vessel in order to reinforce said inner vessel; a valve connection piece on one of the terminal caps and a hollow flushing lance that is open to the outside, is guided through the valve connection piece and held therein in a sealing manner with respect to the valve connection piece; comprising the following steps: filling the pressure vessel with the filling gas for a gas exchange with the storage volume by way of the flushing lance that protrudes into the storage volume and is provided with a perforation along its entire length up to a first end of the flushing lance facing the terminal cap that lies opposite the valve connection piece in the storage volume; performing the gas exchange up to the opposite terminal cap, in that the flushing lance extends far enough to the terminal cap that lies opposite the valve connection piece; subsequently pumping out the accordingly thoroughly-mixed gas filling that is located in the pressure vessel by means of a suitable device through the flushing lance to the exterior of the pressure vessel; and repeating the previous steps until the gas filling in the pressure vessel corresponds to the filling gas at the desired degree of purity.

10. A method of producing a pressure vessel according to claim 1, comprising the following steps: providing an inner vessel produced from an inner vessel material having a cylindrical middle part with a cylinder axis and having two terminal caps that seal the cylindrical middle part so as to provide a storage volume, said inner vessel comprising an outer layer that is applied thereto in order to reinforce said inner vessel, wherein a valve connection piece is provided on one of the terminal caps so as to receive a valve in order to seal the storage volume; guiding a hollow flushing lance that is open to the outside through the valve connection piece, wherein the flushing lance is configured so as to protrude into the storage volume and is provided with a perforation along its entire length up to a first end of the flushing lance facing the terminal cap that lies opposite the valve connection piece in the storage volume for a gas exchange with the storage volume, wherein the flushing lance extends so far to the terminal cap, which lies opposite the valve connection piece, that the gas exchange is performed throughout the perforation of the flushing lance up to the opposite terminal cap; and fixing the flushing lance to the valve connection piece so that said flushing lance is held by the valve connection piece in a sealing manner with respect to the valve connection piece.

Description

BRIEF DESCRIPTION OF FIGURES

[0037] These and other aspects of the invention are shown in detail in the figures as follows:

[0038] FIG. 1: two embodiments of the pressure vessel according to the invention in lateral section, (a) with free-floating flushing lance and (b) with the flushing lance fixed at both ends;

[0039] FIG. 2: an embodiment of the pressure vessel with flushing lance in a partial view;

[0040] FIG. 3: an embodiment of the transport container according to the invention;

[0041] FIG. 4: an embodiment of the method according to the invention for filling the pressure vessel according to the invention;

[0042] FIG. 5: an embodiment of the method according to the invention for manufacturing the pressure vessel according to the invention.

DETAILED DESCRIPTION OF EMBODIMENTS

[0043] FIG. 1 shows two embodiments of the pressure vessel 1 according to the invention in lateral section, (a) with free-floating flushing lance 5 and (b) with the flushing lance 5 fixed at both ends 52, 53. The pressure vessel 1 comprises an inner vessel 2 produced from an inner vessel material having a cylindrical middle part 21 with a cylinder axis ZA and having two terminal caps 22a, 22b that seal the cylindrical middle part 21 so as to provide a storage volume SV in the pressure vessel. An outer layer 3 is applied on the inner vessel 2 in order to mechanically reinforce said inner vessel; for instance, a wound outer layer made of fiber composite material. The valve connection piece 4 for filling and emptying the storage volume SV with (or of) a filling gas FG having a desired degree of purity RG is arranged on one of the terminal caps 22a, whereas the opposite terminal cap 22b has no such connection. Since the valve connection piece 4 provides a connection to the storage volume SV, a hollow flushing lance 5 that is open to the outside is guided through the valve connection piece 4 and held therein in a sealing manner with respect to the valve connection piece 4. This flushing lance 5 protrudes into the storage volume SV and is provided with a perforation 51 along its entire length L5 up to a first end 52 facing the terminal cap 22b that lies opposite the valve connection piece 4 in the storage volume SV for a gas exchange with the storage volume. The flushing lance 5 extends so far to the opposite terminal cap 22b that the gas exchange takes place throughout the perforation 51 of the flushing lance 5 up to the opposite terminal cap 22b. At least in the area 5b within the storage volume SV, the flushing lance 5 is produced of a dimensionally stable material, for instance a plastic which is softer than the material of the inner vessel 2. The material of the flushing lance 5 is so stiff, however, that as a gas filling GF of the storage volume SV is drawn off by means of suction through the flushing lance 5, said flushing lance remains dimensionally stable and its shape does not collapse. In FIG. 1a, the first end 52 of the flushing lance 5 is arranged so as to be free-floating in the storage volume SV of the pressure vessel 1. In this embodiment, an additional weight 54 is arranged on the first end 52 of the flushing lance 5. The term “on the first end” designates, in this context, not only the first end 52 but also a surrounding area, where in this case the additional weight 54, for instance a ball made of lead or other metal, is fastened. In FIG. 1b, the first end 52 of the flushing lance 5 is connected to the terminal cap 22b opposite to the valve connection 4 by means of a loose bearing 23, preventing movements of the flushing lance 5 vertical to the cylinder axis ZA of the inner vessel. However, the flushing lance 5 is supported movably reversibly in parallel to the cylinder axis ZA of the inner vessel 2 so as to be able to compensate for alterations in length of the pressure vessel 1 which occur during pressure filling. The loose bearing 23 is embodied here as a hollow sleeve having an inner diameter equal to the outer diameter of the flushing lance 5, the sleeve 23 comprising an insertion funnel 231 which opens in the direction of the valve connection piece 4. The loose bearing 23 can be made of an elastic material. Furthermore, the flushing lance 5 is reversibly connected to the valve connection piece 4 by suitable means (see also FIG. 2).

[0044] FIG. 2 shows an embodiment of the pressure vessel 1 with flushing lance 5 in a partial view of the area of the terminal cap 22a at the valve connection piece 4 which is here fastened to the terminal cap 22a by means of a screw-type connection and provides a sealing with respect to the inner vessel 2 by means of a sealing cone 6. The vessel is provided with an outer layer 3 for reinforcement. The perforation 51 of the flushing lance 5 comprises gas inlet and gas outlet openings whose number, position and diameter are dimensioned such that both a gas filling GF is thoroughly mixed in the storage volume SV and that the durations of the procedures of filling and emptying the storage volume SV with the filling gas FG are optimized. The circular perforations 51 shown here are only one example of possible perforations 5. In other embodiments, the flushing lance may comprise longitudinal, oval or other perforations 5. The distance and the size of the perforations 5 may also vary depending on the embodiment.

[0045] FIG. 3 shows an embodiment of the transport container 10 according to the invention which here comprises, by way of example, five pressure vessels 1 according to the invention, two of the pressure vessels 1 containing free-floating flushing lances 5 and the other three pressure vessels 1 containing flushing lances 5 which are fixed on both sides. For the details on the pressure vessels 1, we refer to FIG. 1. The storage volumes SV of the pressure vessels 1 are connected to one another by way of a common sealable pipe system 11 by way of the respective valve connection pieces 4 and a respective second end 53 of the flushing lance 5, the pipe system 11 being additionally connected to a device 12 so as to fill the pressure vessels 1 with the filling gas and to pump out the gas filling that is located within the pressure vessels 1. Such a device 12 within the transport container 10 makes it possible to reduce the flushing effort and to lower the gas consumption necessary to achieve the desired degree of purity RG. Hydrogen transport containers according to the state of the art are flushed at least 3-6 times (depending on the desired degree of purity) so as to remove the unloaded transport gas nitrogen before the next filling. In case of an assumed storage capacity of 1000 kg of hydrogen in a 40-feet container and a hydrogen price of 7 €/kg, one flushing procedure results in costs of 7000 € for consumed hydrogen. Five flushings therefore result in hydrogen costs of 35,000 €. If greater work efforts are included, the costs of five flushings make up in total approximately 50,000 €. With the pressure vessel 1 according to the invention, half of the flushing costs can be saved with the flushing lance 5. To achieve a degree of purity of 5.0 (which corresponds to a purity of 99.999%), only three flushings are needed with the pressure vessel 1 according to the invention, whereas pressure vessels according to the state of the art require six flushings or more to obtain the same result.

[0046] FIG. 4 shows an embodiment of the method 100 of the present invention for filling the pressure vessel 1 according to the invention (see also FIGS. 1 and 2) with a filling gas FG having a desired degree of purity RG in the pressure vessel 1, comprising the subsequent steps of filling 110 the pressure vessel 1 with the filling gas FG for a gas exchange with the storage volume SP by way of the flushing lance 5 that protrudes into the storage volume SV and is provided with a perforation 51 along its entire length L5 up to a first end 52 of the flushing lance 5 facing the terminal cap 22b that lies opposite the valve connection piece 4 in the storage volume SV; of performing 120 the gas exchange up to the opposite terminal cap 22b in that the flushing lance 5 extends far enough to the terminal cap 22b that lies opposite the valve connection piece 4; of subsequently pumping out 130 the accordingly thoroughly-mixed gas filling GF that is located in the pressure vessel 1 by means of a suitable device 12 through the flushing lance 5 to the exterior of the pressure vessel; and of repeating 140 the previous steps until the gas filling GF in the pressure vessel corresponds to the filling gas FG at the desired degree of purity RG. Advantageously, the composition of the pumped-out gas filling can be measured for this purpose. As soon as it exhibits the desired degree of purity, the pressure vessel 1 needs to be filled only once more with the filling gas to ensure that the storage volume is filled with gas of the desired degree of purity. After this, the filling process 100 is stopped 150 because the desired degree of purity RG has been reached.

[0047] FIG. 5 shows an embodiment of the method 200 according to the invention for manufacturing the pressure vessel 1 according to the invention, comprising the following steps of providing 210 a pressure vessel as shown in FIG. 1 without a flushing lance 5, of guiding 220 a hollow flushing lance 5 that is open to the outside through the valve connection piece 4, wherein the flushing lance 5 is configured so as to protrude into the storage volume SV and is provided with a perforation 51 along its entire length L5 up to a first end 52 of the flushing lance 5 facing the terminal cap 22b that lies opposite the valve connection piece 4 in the storage volume SV for a gas exchange with the storage volume, wherein the flushing lance 5 extends so far to the terminal cap 22b that lies opposite the valve connection piece 4 that the gas exchange takes place throughout the perforation 51 of the flushing lance 5 up to the opposite terminal cap 22b; and of fixing 230 the flushing lance 5 to the valve connection piece 4 so that said flushing lance is held by the valve connection piece 4 in a sealing manner with respect to the valve connection piece 4. Now the method according to FIG. 4 can be applied to the pressure vessel 1 manufactured in this manner.

[0048] The embodiments described here are only examples of the present invention and are therefore not to be understood as limiting. Alternative embodiments considered by the person skilled in the art are equally comprised by the scope of protection of the present invention.

LIST OF REFERENCE NUMERALS

[0049] 1 pressure vessel [0050] 2 inner vessel [0051] 21 cylindrical middle part [0052] 22a sealing terminal cap on the side of the valve connection piece [0053] 22b opposite terminal cap [0054] 23 loose bearing on opposite terminal cap [0055] 231 open insertion funnel [0056] 3 outer layer of fiber composite material [0057] 4 valve connection piece [0058] 5 flushing lance [0059] 5b area of flushing lance in the storage volume [0060] 51 perforation [0061] 52 first end of flushing lance [0062] 53 second end of flushing lance [0063] 54 additional weight [0064] 55 means of fastening the flushing lance to the valve connection piece [0065] 6 sealing cone [0066] 10 transport container according to the invention [0067] 11 pipe system [0068] 12 device for filling the pressure vessels with filling gas and for pumping out the gas filling in the pressure vessels [0069] 100 method of filling a pressure vessel according to the invention [0070] 110 method of filling the pressure vessel with the filling gas for gas exchange with the storage volume [0071] 120 performing gas exchange up to the opposite terminal cap [0072] 130 subsequent pumping out of the thoroughly mixed gas filling [0073] 140 repeating the preceding steps [0074] 150 end of filling method [0075] 200 method of manufacturing a pressure vessel according to the invention [0076] 210 providing a pressure vessel without flushing lance [0077] 220 guiding a flushing lance through the valve connection piece [0078] 230 fixing the flushing lance to the valve connection piece [0079] FG filling gas for filling the storage volume [0080] GF gas filling of the storage volume [0081] L5 length of flushing lance in the storage volume [0082] RG desired degree of purity of the gas filling in the pressure vessel [0083] SV storage volume [0084] VR vertical direction [0085] ZA cylinder axis