METHOD AND SYSTEM FOR FILLING FLUID CONTAINERS

Abstract

The present invention relates to a method for filling fluid containers by creating a controlled atmosphere in a space that surrounds a fluid container, in which the pressure can be controlled and a pressure difference is set between the outside and the inside of the fluid container in such a manner that damage to an inner liner of the fluid containers is prevented when it is evacuated. When a target negative pressure is achieved, the holding space of the fluid container is filled with a fluid from a fluid tank.

Claims

1. A method for filling fluid containers, comprising the steps of: Creating a controlled atmosphere in a space that surrounds a fluid container and is embodied as a pressure chamber, in which the fluid container is positioned, in which the pressure can be controlled and a pressure difference is set between the outside and the inside of the fluid container in such a manner that damage to an inner liner of the fluid containers is prevented; evacuating the fluid container; and when a target negative pressure is achieved, at which a holding space of the fluid container comprises a vacuum or contains only a predetermined acceptable residual material, filling the holding space with a fluid, wherein the fluid is introduced into the holding space, from a fluid tank which is fluidically connected to the holding space.

2. The method of claim 1, wherein the inner liner is embodied so as to seal the holding space of the fluid container in a gas-tight manner with respect to the outside.

3. The method of claim 1, wherein after the evacuation step, the following further step is performed: switching from an evacuation state into a filling state, in which a fluidic exchange between the holding space of the fluid container and a fluid tank that is fluidically connected to the holding space is permitted.

4. The method of claim 1, wherein during the evacuation step, a fluidic exchange between the holding space of the fluid container and the pressure chamber interior is prevented.

5. The method of claim 1, wherein the target negative pressure is generated by means of using a compressor device.

6. The method of claim 1, comprising the further step: reducing the negative pressure difference in the pressure chamber interior in comparison with an ambient atmosphere that surrounds the pressure chamber until the pressure in the pressure chamber interior corresponds to the pressure of the ambient atmosphere.

7. The method of claim 6, wherein the step of reducing the negative pressure difference is performed during the step of filling the fluid container, wherein the pressure in the pressure chamber interior always comprises at most the pressure in the holding space.

8. The method of claim 1, wherein the negative pressure difference is compensated for in the evacuation step at the latest when the target negative pressure of at most 0.5 bar abs is achieved.

9. The method of claim 1, wherein the method is used for an initial filling of the fluid container.

10. The method of claim 1, wherein the fluid contains hydrogen.

11. The method of claim 1, wherein the fluid container is a type IV container.

12. A System for filling fluid containers, comprising: a pressure chamber that comprises a fluid-tight pressure chamber interior; a fluid container positioned within the pressure chamber interior; means for evacuating the fluid container; a compressor device that is embodied so as to generate a negative pressure difference in the pressure chamber interior with respect to the holding space of the fluid container for creating a controlled atmosphere, in which the pressure can be controlled and a pressure difference is set between the outside and the inside of the fluid container in such a manner that damage to an inner liner of the fluid container is prevented; and a fluid tank, which is fluidically connected to the holding space and configured to introduce a fluid into the holding space when a target negative pressure is achieved, at which the holding space of the fluid container comprises a vacuum or contains only a predetermined acceptable residual material.

13. The system of claim 12, wherein the fluid container comprises an inner liner that is embodied so as to seal the holding space of the fluid container in a gas-tight manner with respect to the outside.

14. The system of claim 12, wherein the system is configured as a closed system having adjustable pressure ratios to provide a controlled compact atmosphere in which the fluid containers are positioned, and in which the pressure can be controlled in a purposeful manner.

15. The system of claim 14, wherein a controllable multiport valve is provided that is fluidically connected to the fluid container and to a vacuum source and is embodied so as to switch from an evacuation state into a filling state, in which a fluidic exchange between the holding space of the fluid container and the fluid tank is permitted.

16. The method of claim 1, wherein the method is configured for filling fluid containers for operating hydrogen-operated fuel cells.

17. The method of claim 10, wherein the fluid consists of highly pure hydrogen.

Description

CONTENTS OF THE DRAWING

[0033] The present invention is explained in further detail hereinunder with reference to exemplary embodiments illustrated in the schematic figures of the drawings. In the drawings:

[0034] FIG. 1 shows a flowchart of a method for filling fluid containers in accordance with an exemplary embodiment;

[0035] FIG. 2 shows a schematic view of a system for filling fluid containers in accordance with a further exemplary embodiment.

[0036] The enclosed drawings are intended to provide a further understanding of the embodiments of the invention. They illustrate embodiments and are used in connection with the description of the explanation of principles and concepts of the invention. Other embodiments and many of the advantages that are mentioned arise with regard to the drawings. The elements of the drawings are not necessarily shown true to scale with one another.

[0037] In the figures in the drawing, identical, functionally identical and identically acting elements, features and components are in each case provided with the same reference characters, unless stated otherwise.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

[0038] The term pressure in the sense of the present invention refers to the absolute pressure, which according to the definition is the pressure with respect to the pressure zero in the empty space/vacuum.

[0039] In the context of the present invention, an inner liner is a core of a fluid container, which forms the inner barrier layer of the fluid container, in particular of fluid containers made of composite materials, in order to ensure a certain permeability and to provide the tightness of the fluid container. Materials such as steel, stainless steel, aluminium or plastic are used for this thin-walled barrier layer.

[0040] A vacuum in the sense of the present invention is a gas-filled (air-filled) space in which the pressure is lower than the pressure of the ambient atmosphere. The following applies: The fewer atoms there are within a limited space, the purer the vacuum, wherein it is impossible to generate an absolutely pure vacuum on earth with the technical means available to date. Depending on the pressure level, a distinction is made between coarse vacuum, fine vacuum, high vacuum and ultra-high vacuum (maximum vacuum).

[0041] FIG. 1 illustrates a flowchart of a method V for filling fluid containers 1. This method V is used, for example, for an initial filling of a fluid container 1.

[0042] The fluid container 1 in accordance with the example in FIG. 1 is a so-called type IV container made of composite materials, such as is used, for example, for fuel cells, and has an inner liner. The inner liner is embodied so as to seal the holding space 3 of the fluid container 1 in a gas-tight manner with respect to the outside.

[0043] In accordance with the invention, the method V comprises the step of providing V1 a pressure chamber 2 having a pressure chamber interior 4. The pressure chamber 2 essentially corresponds, in an exemplary manner, to a so-called decompression chamber having a closable access door. Optionally, the pressure chamber 2 can also have a plurality of access doors or openings. Such pressure chambers 2 are furthermore embodied so as to be essentially curved in order to be able to advantageously withstand the mechanical loads that are caused as a result of the pressure differences with respect to the ambient atmosphere. However, this does not exclude regions of the pressure chamber 2 that are embodied as straight in sections. In this case, the pressure chamber interior 4 is approximately 2 m to approximately 4 m high and has a base area in the range from 5 m.sup.2 to 200 m.sup.2, in particular in the range from 10 m.sup.2 to 100 m.sup.2.

[0044] In addition, the method V comprises the step of positioning V2 the fluid container 1 within the pressure chamber interior 4 in such a manner that the holding space 3 of the fluid container 1 is fluidically connected to a vacuum source, either directly or, as a non-limiting example depicted in FIG. 1, via the pressure chamber interior 4. The fluid container 1 lies, for example, in this case on a transport trolley having rollers. The transport trolley can consequently be conveniently pushed into the pressure chamber interior 4 from the outside, while the fluid container 1 remains on the transport trolley. In addition, a controllable multiport valve 7 is fastened to the fluid container 1 in an exemplary manner.

[0045] The method V further comprises the step of evacuating V3 the pressure chamber interior 4 up to a target negative pressure. The evacuation V3 in this case is performed in a manner that due to the fluid coupling, a negative pressure difference initially forms in the pressure chamber interior 4 with respect to the holding space 3. The desired target negative pressure is generated, for example, by means of using a compressor device 6 as a vacuum source, which is for example embodied as a vacuum pump. In accordance with the example in FIG. 1, the step of evacuation V3 is performed/maintained until the desired target negative pressure of at most 0.5 bar abs, in particular in the range from 0.48 bar abs to 0.4 bar abs, is achieved. When the desired target negative pressure is achieved, the compressor device 6 is throttled in such a manner that the negative pressure difference in the pressure chamber interior 4 with respect to the holding space 3 is compensated again.

[0046] Furthermore, for example, at the beginning of the evacuation step V3, a fluidic exchange between the holding space 3 of the fluid container 1 and the pressure chamber interior 4 is not permitted. As a result, in the initial phase of the evacuation step V3, the pressure difference between the holding space 3 and the pressure chamber interior 4 increases. An internal pressure can consequently be applied to the inner liner right at the beginning and, in addition, a leakage test of the inner liner can be performed by measuring and monitoring the internal pressure in the holding space 3.

[0047] In addition, after the evacuation step V3, the method V in accordance with FIG. 1 further comprises the optional step of switching V4 from an evacuation state, in which a fluidic exchange between the holding space 3 of the fluid container 1 and the pressure chamber interior 4 is permitted, into a filling state, in which a fluidic exchange between the holding space 3 of the fluid container 1 and a fluid tank 5 that is fluidically connected to the holding space is permitted. For example, a control device controls the switching V4, wherein the control device uses, inter alia, the pressure in the pressure chamber interior 4 and the pressure in the holding space 3 for this purpose. In this case, the control device sends, by way of example, corresponding control signals in a wired and/or wireless manner to the controllable multiport valve 7.

[0048] In addition, the method V comprises the step of filling V5 the fluid container 1 by introducing a fluid into the holding space 3. For example, the fluid is hydrogen with a purity of at least 99.99% by volume, which is introduced into the holding space 3, from the fluid tank 5, which is fluidically connected to the holding space 3.

[0049] The method V optionally further comprises the step of reducing V6 the negative pressure difference in the pressure chamber interior 4 in comparison with an ambient atmosphere that surrounds the pressure chamber 2 until the pressure in the pressure chamber interior 4 corresponds to the pressure of the ambient atmosphere. In particular, the step of reducing V6 the negative pressure difference is performed during the step of filling V5 the fluid container 1. In this case, the pressure in the pressure chamber interior 4 always comprises at most the pressure in the holding space 3, so that damage to the inner liner is avoided.

[0050] FIG. 2 illustrates in an exemplary manner a schematic view of a system 10 for filling fluid containers 1.

[0051] In accordance with the invention, the system 10 has a fluid container 1, a pressure chamber 2 and a compressor device or vacuum source 6. In addition, the system 10 that is illustrated in an exemplary manner contains an optional fluid tank 5 and an optional controllable multiport valve 7.

[0052] The pressure chamber 2 comprises a pressure chamber interior 4 that is embodied to be fluid-tight. The pressure chamber 2 is embodied in an exemplary manner as essentially cylindrical. The pressure chamber 2 further has at least one access door. In this case, the pressure chamber interior 4 comprises an inner height of approximately 2 m to approximately 4 m, a base area in the range from 5 m.sup.2 to 200 m.sup.2, in particular in the range from 10 m.sup.2 to 100 m.sup.2. The pressure chamber 2 in accordance with the example in FIG. 2 can likewise also be combined with features of the pressure chamber 2 in accordance with the example in FIG. 1.

[0053] The fluid container 1 is positioned within the pressure chamber interior 4. In addition, the holding space 3 of the fluid container 1 can be fluidically connected to the pressure chamber interior 4. By way of example, the fluid container 1 has an outlet opening 8, which extends into the pressure chamber interior 4 and can be closed. Alternatively, the outlet opening may be connected directly to the same or to an additional vacuum source. In the example in FIG. 2, the fluid container 1 is made of a steel or a steel alloy.

[0054] The compressor device 6 is arranged, by way of example, outside the pressure chamber 2 and is fluidically coupled to the pressure chamber 2. The compressor device 6 is further embodied so as to generate a negative pressure difference in the pressure chamber interior 4 with respect to the holding space 3 of the fluid container 1. As an alternative or in addition, the compressor device 6 is embodied so as to generate a negative pressure in the pressure chamber interior 4 in comparison with the ambient atmosphere that surrounds the pressure chamber 2.

[0055] The fluid tank 5 is arranged, by way of example, outside the pressure chamber 2 and can be fluidically connected to the holding space 3. In this case, the fluid tank 5 is fluidically connected to the holding space 3, by way of example via a hose line device 9, wherein hoses of the hose line device 9 are embodied in particular as a dimensionally stable hose. Alternatively or additionally, the fluid tank 5 can be connected to the holding space 3 via a pipeline system. In addition, the fluid tank 5 is embodied so as to introduce a fluid into the holding space 3.

[0056] In FIG. 2, the controllable multiport valve 7 is, by way of a non-limiting example only, fluidically connected to a plurality of fluid containers 1 and is able to switch between an evacuation state and a filling state. In the evacuation state, a fluidic exchange between the holding space 3 of the fluid containers 1 and the pressure chamber interior 4 or vacuum source 6 or an additional vacuum source is permitted. In the filling state, a fluidic exchange between the holding space 3 of the fluid containers 1 and the fluid tank 5 is permitted.

[0057] By way of example, the fluid is liquid hydrogen, which is stored in the fluid tank 5 at about 200 bar to 300 bar and, in the filling state, the fluid container 1 comprises a direction of flow into the holding space 3 as a result of the pressure difference with respect to the holding space 3.

[0058] In accordance with the invention, the system 10 that is illustrated in FIG. 2 is embodied so as to implement the method V in accordance with the example in FIG. 1 or in accordance with a method V that is not described in detail and comprises at least the method features of the present invention.

[0059] Although the present invention has been fully described above on the basis of exemplary embodiments, it is not limited thereto, but can be modified in a variety of ways.