EP1647760A2 - Gas container with membrane - Google Patents

Abstract

Ultra-sound monitoring (5) of the contents of a flexible wall, double-skin (1, 2) gas holder, requires that the upper reflection surface (15) of the internal skin remains reasonable smooth and crease-free. By constructing the internal skin (2) with some lower areas of heavier fabric, the gravitational collapsing of the deflating inner holder, is controlled to maintain the required surface (15) under uniform tension.

Description

The invention relates to a gas storage with a flexible inner membrane and a flexible outer membrane surrounding this at least partially, wherein the inner membrane closes a variable gas storage space, into or out of the inlet and outlet lines to be stored gas is introduced or derivable, and auxiliary gas in the intermediate space formed between the inner membrane and the outer membrane, and wherein a distance measuring device for determining the distance between a measuring section of the outer membrane and a measuring section of the inner membrane is provided.

A gas storage of this kind is e.g. from AT 391 181 B and serves for the intermediate storage of a gas that can be introduced from at least one gas generator in the gas storage and can be removed from at least one gas consumer from this. In this way, an independent power supply e.g. be ensured in gas production by biological processes, which occur for example in the agricultural sector by itself.

Depending on the filling level of the gas reservoir, the shape of the inner membrane changes from a folded state to a fully expanded, wrinkle-free state, which in most cases corresponds to a three-quarter hollow sphere shape. It is becoming more and more important recently to capture the actual memory level metrologically, which is usually done by a distance measuring device, which determines the distance between this and the outer membrane by means of ultrasonic sensor / receiver at the highest point of the inner membrane. When the inner membrane is full, very reliable information on the level is possible, but as soon as the gas storage is emptied slowly, this also affects the shape of the inner membrane, which throws more and more wrinkles in the course of volume reduction, until it folds up on the floor. These cause a scattering of the ultrasonic signal emitted by the ultrasonic signal and increase the uncertainty finally so strong that from a certain level no meaningful measurements are more feasible.

Since the Füllstandsmeßsignal recently used for the control of upstream and downstream processes, it is an object of the invention to provide a gas storage of the type mentioned, softer allows a reliable measurement of the level even with significant volume reduction of the inner membrane.

This is achieved according to the invention by providing means for exerting a clamping force on the inner membrane measuring section, which hold the inner membrane measuring section in a substantially smooth state during a volume reduction process of the gas storage chamber.

Essential to obtaining a unique ultrasonic measurement signal is obtaining the smooth shape of the inner membrane within the measuring section provided for the measuring operation during a reduction in volume in order to reflect the ultrasound impinging on the inner membrane surface in the direction of the ultrasonic receiver. This is achieved by exerting, in accordance with the invention, a clamping force on the inner membrane measuring section which keeps the inner membrane measuring section in a substantially smooth state during a draining operation of the gas storage while the rest of the volume reduction follows.

There are several ways to maintain the smooth, wrinkle-free condition in the area in question. Preference is given to those embodiments which do not require additional elements which jeopardize the undamaged state of the membrane; all angular or separate parts are therefore rather to be avoided.

In a simple way, this can be achieved by a further embodiment of the invention, an uneven basis weight distribution of the inner membrane is formed, so that the inner membrane measuring section during a Volume change operation of the gas storage space is maintained in a substantially smooth state.

This can be achieved in particular by the fact that according to a further embodiment of the invention, the means for exerting a clamping force by providing a deviating from the ball symmetry with respect to the main axis of the filled inner membrane deviating basis weight distribution of the inner membrane.

When fully filled, the gas internal pressure completely compensates for the asymmetric basis weight distribution and the inner membrane assumes the perfectly smooth condition, e.g. in the form of a three-quarter hollow sphere. As the level decreases, the effect of the asymmetric basis weight distribution begins to displace the inner membrane folding process into the zone where the basis weight is higher than the remaining inner membrane, leaving the inner membrane measuring section in a smooth state and the ultrasonic signal in the direction of the Ultrasonic receiver reflected. In this case, the point at which the sound is reflected during the volume reduction process along the inner membrane surface migrate, so that the inner membrane measuring section has a size that takes into account this migration movement.

The inner membrane may be composed of a plurality of segments in a conventional manner, which are connected to each other along Längenkreis sections of the inner membrane, preferably welded, are, so that the inner membrane in the inflated state has a hollow spherical shape.

In this construction, an asymmetric basis weight distribution according to the invention can be achieved in that a part of the inner membrane segments has a higher basis weight than the other inner membrane segments. The heavier segments are first deposited when emptying the inner membrane and due to the still existing gas volume thereby pull the remaining inner membrane surface upwards, whereby the zone of the inner membrane measuring section remains smooth or wrinkle-free and offers a suitable reflection surface for the ultrasonic signal of the distance measuring device.

It is e.g. already given a sufficient clamping effect by the heavier segments when the inner membrane segments are arranged with the higher basis weight along a quarter-circumferential circle of the inner membrane. The arrangement of the heavier and lighter segments is subject to no limitation in the context of the invention and can be done in any manner.

Finally, the inner membrane - seen in the operating position - in its lower region have a higher basis weight than in the upper region, wherein such a distribution along the entire circumference of the inner membrane can be provided. The asymmetric weight distribution of the inner membrane segments in the height direction has the consequence that - seen in plan view - the outer heavier areas are first deposited during emptying and thus the inner areas are pushed upwards, whereby the measuring section remains smooth and ensures clearly assignable reflection signals, whereby the distance measurement during the entire volume reduction process of the inner membrane with the required measurement reliability is feasible.

• Fig.1 eine teilweise aufgebrochene Schrägrißdarstellung eines bekannten, teilweise geleerten Gasspeichers;
• Fig.2 eine schematische Schnittdarstellung des vollen Gasspeichers gemäß Fig.1;
• Fig.3 eine schematische Schnittdarstellung des halb leeren Gasspeichers gemäß Fig.1;
• Fig.4 eine Ausführungsform des erfindungsgemäßen Gasspeichers in schematischer Schnittdarstellung.
• Fig.5 den halbgeleerten Gasspeicher gemäß Fig.4 in Schnittdarstellung;
• Fig.6 den fast völlig geleerten Gasspeicher gemäß Fig.4;
• Fig.7 die Innenmembran einer weiteren Ausführungsform des erfindungsgemäßen Gasspeichers in schematischer Draufsicht;
• Fig.8 eine weitere Ausführungsform des erfindungsgemäßen Gasspeichers in schematischer Schnittdarstellung;
• Fig.9 die Innenmembran der Ausführungsform gemäß Fig.8 in schematischer Draufsicht und
• Fig. 10 eine schematische Schnittdarstellung einer weiteren Ausführungsform des erfindungsgemäßen Gasspeichers.

The invention will be explained in detail with reference to the embodiments illustrated in the drawings. It shows

• Figure 1 is a partially broken Schräißißdarstellung a known, partially emptied gas storage.
• A schematic sectional view of the full gas storage according to Figure 1;
• 3 is a schematic sectional view of the semi-empty gas storage according to FIG. 1;
• 4 shows an embodiment of the gas reservoir according to the invention in a schematic sectional view.
• 5 shows the half-empty gas storage according to Figure 4 in sectional view;
• Fig.6 almost completely emptied gas storage of Figure 4;
• 7 shows the inner membrane of a further embodiment of the gas reservoir according to the invention in a schematic plan view;
• 8 shows a further embodiment of the gas reservoir according to the invention in a schematic sectional representation;
• 9 shows the inner membrane of the embodiment of Figure 8 in a schematic plan view and
• Fig. 10 is a schematic sectional view of another embodiment of the gas storage device according to the invention.

In the known gas storage shown in Figure 1 is a flexible inner membrane 2, which closes a variable gas storage space 11 inside and in the expanded state a three-quarters hollow sphere (Figure 2), shown in a partially deflated condition, whereby wavy at the top Wrinkles arise. The inner membrane 2 is surrounded by a flexible outer membrane 1. As materials for the outer membrane 1 and the inner membrane 2, plastic or rubber foils, coated textile substrates, e.g. with PVC coated fabric od. Like. Are used. Any other type of flexible sheath may also be used for this purpose, provided it meets the tightness and strength requirements.

Both the outer membrane 1 and the inner membrane 2 are open at the bottom and the lower edges are fixed by corresponding clamping devices 3 on a foundation 9 sealingly against the environment, the lower edge of the outer membrane 1 and the lower edge of the inner membrane 2 are concentric and along their circumference are spaced from each other. Compared to the bottom of the variable gas storage space is sealed by a gas-tight bottom membrane, not shown, so that no leakage losses can occur and no combustible gas can escape from the variable storage space to the outside.

The inner membrane 1 and the outer membrane 2 are coordinated so that between them a gap 9 is formed, in which an auxiliary gas, preferably air, via a supply line 8 and an inlet port 4 under pressure, e.g. by virtue of a compressed air connection 7, can be introduced in order to exert a counterpressure with respect to the gas pressure prevailing in the interior of the inner membrane 2 and to protect it from overstressing.

Via an inlet and outlet 6 and a centrally located bottom inlet (not shown), the gas to be stored in the variable gas storage chamber 11 is introduced or removed from this, so depending on the degree of filling the gas storage space 11 upwards final inner membrane 2 an irregular curved surface forms, as indicated in Figure 1, or inflates and then assumes the shape of a three-quarters hollow sphere (Figure 2). In the context of the invention, membrane shapes deviating from the hollow spherical shape are also applicable.

Due to the overpressure in the intermediate space 9, the outer membrane 1 can be kept dimensionally stable within wide limits. A wind pressure acting on the outer membrane 1 or e.g. a snow load thus remain without significant influence on the gas pressure in the variable gas storage space eleventh

The structure of the outer membrane 1 and the inner membrane 2 and the materials used therefor, as well as the attachment of the membranes to the substrate may vary within the scope of the invention.

Air is preferably used as auxiliary gas, although other gases, for example inert gases, could also be used. By-pass gas is therefore understood to mean any kind of gas or gas mixtures suitable for the purpose of interstitial filling. The introduction of the auxiliary gas in the outer membrane 1 at only one point, as shown for example in Figure 1, but is not mandatory but can also in other ways done without thereby having an effect on the effect of the invention.

For measuring and controlling the degree of filling of the inner membrane 2, a distance measuring device 5 is arranged at the uppermost point of the outer membrane 1, via which the respective distance between a measuring section 15 of the inner membrane 2 and a measuring section of the outer membrane 1 at this point converted into a measuring signal and to a non shown control device is passed. The distance measuring device 5 comprises an ultrasonic transmitting and receiving device and operates on the echosounding principle.

As shown in Figure 2, the highest point 13 in the expanded state of the inner membrane 2 is exactly opposite the distance measuring device 5. The main axis of symmetry 16 of the filled inner membrane 2 also extends through this point. The ultrasound reflected at point 13, which was emitted by the ultrasound transmitting device, returns to the ultrasound receiving device and generates a detectable reflection pulse, from which distance information is obtained.

In known gas storage results by material fabrication and additional facilities in the upper region of the inner membrane 2, a higher basis weight than in the lower region, so that in a volume reduction process, the upper portion of the inner membrane 2 begins to fold first and therefore the folding takes place exactly in the measuring section where the Ultrasound signal is reflected. The consequence of this can be seen in Figure 3, there is no direct return reflection in the direction of the ultrasound receiving device, resulting in a falsified distance information or due to multiple reflections or scattering an ambiguous result that leads to misinterpretation.

To remedy this, according to the invention means are provided for exerting a clamping force on the inner membrane measuring section 15, which means the inner membrane measuring section 2 during a volume reduction process of the gas storage space 11 in a substantially smooth state. Smooth in this context means substantially wrinkle-free, so that an undisturbed reflection of the ultrasonic signal can take place.

For the implementation of Spannkrafimittei invention there are several possibilities. Thus, a suitably sized elastic band can act on the surface of the inner membrane 2, which tensions it so that the inner membrane measuring portion 15 remains wrinkle-free during a draining process. The inner membrane measuring section 15 results as that imaginary region within whose limits the point of impact of the ultrasound emitted by the ultrasonic transmitting device can move during level changes and is indicated in FIG. 4 by a surface surrounded by a dashed line.

For reasons of reliability and ease of assembly, an influence of the basis weight of the inner membrane 2 is used as a clamping force in practice. Thus, e.g. the means for exerting a clamping force by an uneven basis weight distribution of the inner membrane 2 may be formed.

For this purpose, for example, the means for exerting a clamping force by providing a deviating from the ball symmetry with respect to the main axis 16 of the filled inner membrane 2 different basis weight distribution of the inner membrane 2, as shown schematically in Figure 4 in cross section. The part 30 of the inner membrane 2 has a higher weight per unit area than the part 33. As a result, the part 30 sinks to the bottom and the inner membrane 2 contracts on the side of the part 30 in the area 34, while the part 33 is raised slightly, whereby the measuring section 15 remains smooth or wrinkle-free. As a result, the originally highest point 13 migrates somewhat to the side of the heavy part 30, but the point of impact for the ultrasound signal remains in a strained zone of the inner membrane and can therefore emit a clearly detectable reflection signal.

5 and 6 show the further course of the emptying process, during which the collapsed area 34 of the inner membrane 2 becomes ever more extensive while the inner membrane measuring section 15 sinks in a smooth or wrinkle-free state and constantly delivers a usable ultrasonic measurement signal.

For reasons of production technology, the inner membrane 2 is composed of a plurality of segments 21, 22 (FIG. 7), which are joined together along longitudinal segments of length, preferably welded, so that the inner membrane 2, when inflated, has a three-quarter hollow spherical shape, the advantages with respect to the stability and the foundation diameter has. In principle, however, the inner membrane 2 can also be a different one within the scope of the invention, e.g. take up a hollow cylindrical shape.

The connection of the segments 21, 22 can also be performed by gluing, sewing or the like. Downwardly form the interconnected segments 21, 22 together an edge which is clamped by means of the clamping means on the foundation 9. Towards the top, the tapered segments 4 converge at a point or in an opening into which the distance measuring device 5 is inserted.

In the embodiment of the invention shown in FIG. 7, a portion 22 of the inner membrane segments has a higher basis weight than the remaining inner membrane segments 21, with the inner membrane segments 22 having the higher basis weight being disposed along a quarter circle of the inner membrane 2. Thus, in the same manner as in the embodiment of FIGS. 4 to 6 deviating from the ball symmetry basis weight distribution is achieved, which causes the side of the inner membrane 2 with the heavier inner membrane segments 22 during an emptying process first deposits and thereby the measuring section 15 stretched or kept wrinkle free. The higher basis weight can be achieved either by a specific heavier material or eg by double occupancy of the segments 22 become.

It can be chosen any other Konfektionen the inner membrane 2, which provide the same end result. For example, the basis weight distribution can be influenced by suitably selecting the cut and / or the overlapping zones for the segments 21, 22 in such a way that an asymmetrical weight distribution results without different basis weights of the segments 21, 22.

Finally, FIG. 8 and FIG. 9 show a further embodiment of the invention in which the inner membrane 2 has a higher weight per unit area in its lower area than in the upper area, which is caused by inner membrane segments 20 in the lower one Area 40 have a higher basis weight than in the upper area, whereby an asymmetric weight distribution along the main axis 16 is formed. Thereby, the lower part of the inner membrane 2 is heavier than the upper part thereof, whereby when emptying the inner membrane 2, first the outer lower part is collapsed, while the inner upper part of the inner membrane is pushed up and the measuring section 15 remains smooth or wrinkle-free and provides a clearly identifiable ultrasonic reflection signal during the draining process. The lower heavier part may e.g. up to a height which is 2/3 of the total height of the inner membrane 2, be formed.

As shown in the embodiment of Fig. 10, which is similar to that shown in Figs. 8, 9, by increasing the basis weight in the lower part along the entire circumference of the inner membrane 2, a centered lowering of the inner membrane 2 can be effected so that the impact point the ultrasonic signal remains unchanged during a discharge process. In addition to the heavier lower zone 40, it is also possible to provide any other specially prepared basis weights 41 with the aid of which an additional possibility of influencing the tensioning effect on the measuring section 15 exists.

Claims (7)

Gas storage with a flexible inner membrane (2) and an at least partially surrounding flexible outer membrane (1), wherein the inner membrane (2) closes a variable gas storage space (11) into and out of the supply and discharge lines to be stored gas introduced and auxiliary gas can be introduced into the intermediate space (9) formed between the inner membrane (2) and the outer membrane (1), and wherein a distance measuring device (5) for determining the distance between a measuring section of the outer membrane (1) and a Measuring section (15) of the inner membrane (2) is provided, characterized in that means for exerting a clamping force on the inner membrane measuring section (15) are provided, which the inner membrane measuring section (15) during a volume reduction process of the gas storage space (11) in a maintain a substantially smooth state. Gas store according to claim 1, characterized in that the means for exerting a clamping force by an uneven basis weight distribution of the inner membrane (2) are formed, so that the inner membrane measuring section (15) during a volume change operation of the gas storage space (11) held in a substantially smooth state becomes. Gas accumulator according to claim 1 or 2, characterized in that the means for exerting a clamping force by providing one of the ball symmetry with respect to the main axis (16) of the filled inner membrane (2) deviating basis weight distribution of the inner membrane (2) are formed. Gas storage device according to claim 1, 2 or 3, characterized in that the inner membrane (2) is composed in a manner known per se of a plurality of segments (20, 21, 22) which are connected to each other along longitudinal segments of the inner membrane (2), preferably welded, are, so that the inner membrane (1) in the inflated state has a hollow spherical shape. Gas storage according to claim 3 and 4, characterized in that a part (22) of the inner membrane segments has a higher basis weight than the other inner membrane segments (21). Gas storage according to claim 5, characterized in that the inner membrane segments (22) are arranged with the higher basis weight along a quarter-circle of the inner membrane (2). Gas reservoir according to claim 1 or 2, characterized in that the inner membrane (2) - seen in the operating position - in its lower region (40) has a higher basis weight than in the upper region.

Images