DE102020209596A1 - Pressure measuring device and method for non-invasively measuring a pressure in an elongate cylindrical container - Google Patents

Abstract

Non-invasive pressure measuring device (1) for measuring a pressure inside an elongated cylindrical container (2), with a disc-shaped or ring-shaped spring body (4), which is arranged equidistantly from at least three in a circle and fixed on an outer wall (3) of the support elements (5) that can be mounted on the container (2), with at least three strain sensors that are designed and arranged to detect radial deformations of the spring body (4), and with an evaluation device (8) to which the strain sensors are connected and which is designed to use different deformations of the spring body (4) in the longitudinal direction (7) and circumferential direction (6) of the container (2) to differentiate between pressure- and temperature-related deformation components and to obtain a measurement result (9) for the pressure in the pressure-related deformation components from the pressure-related deformation components To determine and output the interior of the container (2).

Description

The invention relates to a non-invasive pressure measuring device for measuring a pressure inside an elongated cylindrical container.

The invention also relates to a method for non-invasively measuring a pressure inside an elongate cylindrical container

An elongated cylindrical container is to be understood here in particular as a tube, which is why terms such as “container wall” and “tube wall”, if used, are interchangeable.

In process or supply technology, the measurement or monitoring of pressures in containers or pipelines is usually invasive through process openings in the containers, pipes or in flange adapters installed between pipes. The introduction of suitable openings in existing containers or pipes is expensive and often not desirable. The installation of flange spacers in the course of pipelines is also expensive. In addition, since direct contact between the media contained or carried in the containers or pipelines and the invasive pressure gauges can be a disadvantage, non-invasive, contactless pressure measurement is desirable, particularly in cases where high measurement accuracy is not required.

From the U.S. 2005/235755 A1 a non-invasive pressure measuring device with a pipe clamp that is placed around a pipe is known. The pipe clamp consists of two halves which are connected to one another by a hinge on one side and a clamping screw on the other side. Strain sensors are attached to the clamping screw. Changes in pressure inside the pipe cause changes in the diameter of the pipe and thus changes in length of the clamping screw, which are detected by means of the expansion sensors and evaluated in an evaluation device to give a measured value for the pressure inside the pipe.

In the WO 2017/097888 A1 it is proposed to place a joint chain around the pipe instead of a pipe clamp, with a force measuring pin being arranged in a joint between two chain links, which is also used for the pivotable connection of the two chain links.

Since in the cases mentioned the changes in the pipe diameter are transmitted indirectly to the force sensors via mobile transmission devices such as pipe clamps or link chains, a reasonably reliable pressure measurement is only possible if the pipe wall is sufficiently flexible or the pressure to be measured is sufficiently high.

It is still, for example, from the US 4,399,514A , US 5,585,567A , U.S. 2007/0251325 A1 or EP 0 088 362 A1 , Known to stimulate the wall of a container to vibrate or oscillations and to determine the pressure inside the container by evaluating the frequencies of the generated vibrations or oscillations.

Zhou, H., Lin, W., Ge, X., & Zhou, J. (2016): "A non-intrusive pressure sensor by detecting multiple longitudinal waves", Sensors 2016, 16(8), 1237, describes a Method for determining the pressure in a cylindrical container using the propagation times of ultrasonic waves in the container wall.

The non-invasive pressure measurement based on the sound or vibration evaluation is very dependent on the medium in the container or pipe and the material of the container or pipe wall, so that an application-independent evaluation based on a uniform algorithm is hardly possible.

The invention is therefore based on the object of providing an improved option for non-invasive pressure measurement.

According to the invention, the object is achieved in each case by the non-invasive pressure measuring device specified in claim 1 and the method defined in claim 11 .

Advantageous developments of the non-invasive pressure measuring device are specified in the dependent claims.

The subject matter of the invention is therefore a non-invasive pressure measuring device for measuring a pressure inside an elongated cylindrical container, with a disc-shaped or ring-shaped spring body, which is carried by at least three support elements which are arranged equidistantly in a circle and can be fixedly mounted on an outer wall of the container, with at least three strain sensors, which are designed and arranged to detect radial deformations of the spring body, and with an evaluation device to which the strain sensors are connected and which is designed to use different deformations of the spring body in the longitudinal direction and circumferential direction of the container between pressure - Distinguish between deformation components caused by temperature and from the pressure-related deformation components a measurement result for the Determine and output the pressure inside the container.

The subject matter of the invention is also a method for the non-invasive measurement of a pressure inside an elongated cylindrical container, wherein a disk-shaped or ring-shaped spring body is mounted on an outer wall of the container via at least three supporting elements arranged equidistantly in a circle, radial deformations of the spring body are detected and on the basis of different detected deformations of the spring body in the longitudinal direction and circumferential direction of the container, a distinction is made between pressure and temperature-related deformation components and a measurement result for the pressure inside the container is determined from the pressure-related deformation components.

The invention is based on the finding, manifested in the so-called boiler formula, that in rotationally symmetrical bodies subjected to internal pressure, such as pipes or elongated containers, the pressure-related circumferential stress (tangential stress) is ideally twice as great as the stress in the longitudinal direction (axial stress). Therefore, while the tangential stress in the container wall changes twice as much as the axial stress in the event of pressure changes, temperature-related changes in the tangential stress and axial stress take place at the same percentage.

In the pressure measuring device according to the invention, the different mechanical stresses are transmitted via the support elements firmly mounted on the outer wall of the container to the disk-shaped or ring-shaped spring body, whose radial deformations are detected by the strain sensors.

Polar coordinates of the radial deformations are measured with three strain sensors arranged equidistantly on a circle, i.e. at an angular distance of 120°. This conversion can be omitted if four equidistant support elements are provided. In the ideal case, the four equidistant support elements are mounted on the outer wall of the container in an axisymmetric manner with respect to the longitudinal direction and circumferential direction of the container. This can mean that two opposite supporting elements in the circle are mounted along a straight line in the longitudinal direction of the container and two further, also opposite supporting elements are mounted at right angles thereto in the circumferential direction of the container on its outer wall. Alternatively, four support members may be mounted on the container wall such that each of the support members has a support member longitudinally and circumferentially adjacent to the container. In these cases, the deformation of the disk-shaped or ring-shaped spring body in the event of pressure and/or temperature changes in the container takes place axisymmetric to the longitudinal direction and circumferential direction of the container, so that when the deformation of the spring body is detected by means of the strain sensors between deformations in the longitudinal direction and in the circumferential direction and so that, on the basis of the boiler formula, it is possible to distinguish between deformations due to pressure changes in the container and temperature-related deformations.

The spring body can be designed as a membrane on which the strain sensors are applied and which is spanned by the supporting elements carrying them. The membrane with the strain sensors can also be stretched over an elastic ring body, which is carried by the support elements. In this case, the deformation of the ring body leads to a deformation of the membrane. It is also possible to attach the strain sensors directly to the annular body, for example to its inner wall.

Since it can be difficult in practice to mount the support elements on the container in the manner described above so that it is axisymmetric to the longitudinal direction and circumferential direction of the container, the two directions can advantageously also be determined automatically by at least eight strain sensors measuring the deformations of the spring body in different ways detect radial directions. The evaluation device can then identify the direction in which the greatest deformation is detected when the pressure in the container increases as the circumferential direction and/or the direction in which the smallest deformation is detected when the pressure increases in the container as the longitudinal direction.

The support elements of the pressure measuring device can advantageously be materially connected to the outer wall of the container. Cohesive connections are used to connect parts to one another by fusing and by intermolecular or chemical bonding forces, possibly via additives. These connections include, in particular, welded, soldered and glued connections. The support elements themselves can consist of the connecting material, for example a two-component adhesive, which is kneaded on site, shaped and applied to the spring body or the outer wall of the container before the pressure measuring device with the spring body is placed on the outer wall. They are gap-filling two-component epo xidharze known and commercially available, which harden extremely solid and brittle within a few minutes. But it is also possible in principle, with a suitable design of the support elements, these non-positively, z. B. via straps on the container.

• 1 ein Beispiel für eine auf einem Behälter montierte nicht-invasive Druckmesseinrichtung,
• 2 ein Beispiel eines Federkörper als Bestandteil der nicht-invasiven Druckmesseinrichtung in Draufsicht,
• 3 den Federkörper gemäß 2 in einem Längsschnitt,
• 4 den Federkörper in perspektivischer Ansicht,
• 5 einen Rohrabschnitt mit aufmontiertem Federkörper in perspektivischer Ansicht,
• 6 zeigt eine Variante der Anordnung des Federkörpers auf dem Rohrabschnitt und
• 7 eine Befestigungsvariante für den Federkörper mittels des Spanngurten.

The invention is explained below using exemplary embodiments and with reference to the figures of the drawing; show in detail:

• 1 an example of a non-invasive pressure measuring device mounted on a container,
• 2 an example of a spring body as part of the non-invasive pressure measuring device in plan view,
• 3 according to the spring body 2 in a longitudinal section,
• 4 the spring body in a perspective view,
• 5 a perspective view of a pipe section with spring body mounted on it,
• 6 shows a variant of the arrangement of the spring body on the pipe section and
• 7 a fastening variant for the spring body using the tension belts.

The same reference symbols have the same meaning in the different figures. The illustrations are purely schematic and do not represent any proportions.

1 1 shows a pressure measuring device 1 mounted on an outer wall 3 of the container 2 for non-invasively measuring a pressure inside an elongate cylindrical container 2 . The container 2 can contain a medium or, in the case of the tube shown here, the medium can flow through it.

The pressure measuring device 1 has a disk-shaped or ring-shaped spring body 4 which is carried by support elements 5 which can be fixedly mounted on the outer wall 3 of the container 2 . For this purpose, in the example shown, the support elements 5 of the pressure measuring device 1 are bonded to the outer wall 3 of the container 2 by gluing. The support elements 5 themselves can consist of the connecting material, for example a two-component adhesive, which is kneaded on site, shaped and applied to the spring body 4 or the outer wall 3 of the container 2 before the pressure measuring device 1 is attached to the spring body 4 on the Outer wall 3 is placed.

$${\mathrm{\sigma }}_{\text{a}}=\left(\text{p}\cdot \text{D}\right)/4\text{s}\text{,}$$

wobei σ_t die Tangentialspannung in Umfangsrichtung 6 des Rohres 2, σ_a die Axialspannung in Längsrichtung 7 des Rohres 2, p den Innendruck, D den mittleren Innendurchmesser und s die Wanddicke des Rohres 2 bezeichnen.The so-called boiler formula specifies the mechanical stresses in rotationally symmetrical bodies loaded by internal pressure, such as those found in pipes or pressure vessels. The boiler formula is particularly simple for a thin-walled tube 2 subjected to internal pressure: $${\mathrm{\sigma }}_{\text{t}}=\left(\text{p}\cdot \text{D}\right)/2\text{s}$$

$${\mathrm{\sigma }}_{\text{a}}=\left(\text{p}\cdot \text{D}\right)/4\text{s}\text{,}$$

where σ _t is the tangential stress in the circumferential direction 6 of the tube 2, σ _a is the axial stress in the longitudinal direction 7 of the tube 2, p is the internal pressure, D is the mean inside diameter and s is the wall thickness of the tube 2.

$$\Delta {\mathrm{\sigma }}_{\text{a}}=\text{k}1\cdot \Delta \text{p + k2}\cdot \Delta \text{T}\text{,}$$

wobei k1 und k2 Proportionalitätskonstanten für die druck- bzw. temperaturbedingten Spannungsanteile sind. Daraus ergibt sich für die Druckänderungen Δp: $$\Delta \text{p}=\left(\Delta {\mathrm{\sigma }}_{\text{t}}-\Delta {\mathrm{\sigma }}_{\text{a}}\right)/\text{k}1.$$

So while the tangential stress σ _t in the container wall changes twice as much as the axial stress σ _a in the case of pressure changes Δρ, the tangential stress σ _t and the axial stress σ _a change in equal percentages in the case of temperature changes ΔT: $$\Delta {\mathrm{\sigma }}_{\text{t}}=2\text{k}1\cdot \Delta \text{p + k2}\cdot \Delta \text{T}$$

$$\Delta {\mathrm{\sigma }}_{\text{a}}=\text{k}1\cdot \Delta \text{p + k2}\cdot \Delta \text{T}\text{,}$$

where k1 and k2 are constants of proportionality for the pressure and temperature-related stress components. This results in the pressure changes Δp: $$\Delta \text{p}=\left(\Delta {\mathrm{\sigma }}_{\text{t}}-\Delta {\mathrm{\sigma }}_{\text{a}}\right)/\text{k}1.$$

The pressure measuring device 1 contains an evaluation device 8 to which strain sensors (not shown here) are connected, which detect deformations of the spring body 4 . The evaluation device 8 is designed to use different deformations of the spring body 4 in the longitudinal direction 7 and circumferential direction 6 of the container 2 to distinguish between pressure and temperature-related deformation components and to determine a measurement result 9 for the pressure inside the container 2 from the pressure-related deformation components and to spend

As 1 shows, the measurement result 9 can be output, for example, via a line 10 to a neighboring device 11, which is here z. B. a mounted on the tube 2 sensor (multi-sensor) with different sensors not shown here for measuring, for example, vibrations (acceleration), temperature, humidity, air pressure, etc. can act. Such a sensor is z. B. from the WO 2020/058497 A1 known. The non-invasive pressure measuring device 1 forms a further, external sensor of the measuring transducer 11, which has its own evaluation device 12 and an energy source 13, e.g. B. battery contains. The evaluation device 12 of the measuring sensor 11 can use partial radio take over functions of the evaluation device 8 of the pressure measuring device 1 and the measurement result 9 possibly together with measurement results of the other sensors of the measuring transducer 11 wirelessly via a radio interface 14 to a remote location 15, z. B. to a mobile communication terminal or by means of a gateway in a cloud. The pressure measuring device 1 can be supplied with power via the line 10 from the energy source 13 of the measuring transducer 11 and in this case does not require its own energy source. The pressure measuring device 1 itself can also be equipped with a radio interface 16 for the wireless transmission of the measurement result to the remote location 15 . Finally, the pressure measuring device 1 can be designed as a self-sufficient measuring transducer and can be provided with its own energy source (solar cell, battery, etc.) 17 . The evaluation device 8, optionally with the radio interface 16, and optionally the energy source 17 are accommodated in a housing part 18, which is mounted on the spring body 4 via an elastic intermediate part 20 that does not impair the deformability of the spring body 4. The pressure measuring device 1 can also be an integral part of the multisensor 11 as a further sensor, the spring body 4 with the support elements 5 and the intermediate part 20 serving to fasten the multisensor 11 on the pipe 2 . The evaluation device 18 of the pressure measuring device 1 is then part of the evaluation device 12 of the multisensor 11.

2 shows an example of the spring body 4 with the support elements 5 in plan view, 3 the same spring body 4 in a longitudinal section and 4 in perspective view. In the example shown, the spring body 4 consists of a membrane 21, which consists of an elastic ring body 22 made of z. B. steel is clamped. The ring body 22 is carried by segment-shaped support elements 5, which are arranged equidistantly on a circle. Instead of the four supporting elements 5 here, more, e.g. B. eight, equidistant support elements can be provided. In the example shown, the elastic annular body 22, the membrane 21 and the supporting elements 5 are formed in one piece, so that the elastic annular body 22 is mounted with its supporting elements 5 on the outer wall 3 of the container 2, e.g. B. can be glued. As already mentioned above, the support elements 5 themselves can be kneaded and shaped from a two-component adhesive and applied to the annular body 22 or the outer wall 3 of the container 2 before the annular body 22 is placed on the outer wall 3 . Since the membrane 21 is comparatively thin, the majority of the surface of the support elements 5 should be located under the annular surface of the annular body 22 so that the membrane 21 is not plastically deformed by being pressed on the pipe 2 during assembly.

Four strain sensors 23, for example in the form of piezoresistive measuring elements, are arranged on the membrane 21 opposite the supporting elements 5 and contacted with an integrated circuit on a chip 24, which in turn is connected to the evaluation device 8 in the housing part 18 ( 1 ) is connected or may contain it, so that the housing part 18 can be omitted. The temperature influence on the strain sensors 23 can be minimized by factory calibration, for which purpose the signal from an additional temperature sensor 25 on the chip 24 can be used.

5 shows a section of the tube 2 with the mounted spring body 4 in a perspective view. The spring body 4 is aligned in such a way that two strain sensors 23 measure the axial stress σ _a in the longitudinal direction 7 of the tube 2 and the other two strain sensors 23 measure the tangential stress σ _t in the circumferential direction 7 . For this purpose, in the example shown, support elements 5 are in the longitudinal direction 7 of the pipe 2 and the other two support elements 5 are opposite one another at right angles thereto in the circumferential direction 7 of the pipe 2 .

1. 1. Zunächst wird in den Rohr 2 ein definierter Referenzdruckruck, z. B. Umgebungsdruck, hergestellt, um eine Nullpunktkalibrierung durchzuführen.
2. 2. Danach werden die Dehnungssensoren 23 einzeln gemessen.
3. 3. Die von den Dehnungssensoren 23 erhaltenen Einzelwerte werden in der Auswerteeinrichtung 8 durch Multiplikation mit individuellen ersten Faktoren automatisch so korrigiert, dass ihre Beträge gleich dem Mittelwert der Einzelwerte sind (Koordinatendrehung).
4. 4. Danach wird der Druck im Inneren des Rohres 2 erhöht. Die jetzt gemessenen Einzelwerte werden wiederum durch Multiplikation mit individuellen zweiten Faktoren so korrigiert, dass die jeweils gegenüberliegenden Dehnungssensoren 23 den gleichen Wert liefern, wobei die Werte der in Umfangsrichtung 6 einander gegenüberliegenden Dehnungssensoren 23 doppelt so groß sind wie die Werte der in Längsrichtung 7 einander gegenüberliegenden Dehnungssensoren 23 (Koordinatendrehung).

On site, it can be difficult to carry out the optimal alignment of the pressure measuring device 1 with the spring body 4 on the pipe 2, which is necessary for the temperature compensation described. After a rough alignment, a mathematical fine adjustment can be made by means of signal processing according to the following steps.

1. 1. First, a defined reference pressure, z. B. ambient pressure, prepared to perform a zero calibration.
2. 2. The strain sensors 23 are then measured individually.
3. 3. The individual values obtained from the strain sensors 23 are automatically corrected in the evaluation device 8 by multiplication with individual first factors in such a way that their amounts are equal to the mean value of the individual values (coordinate rotation).
4. 4. Thereafter, the pressure inside the tube 2 is increased. The individual values now measured are in turn corrected by multiplication with individual second factors in such a way that the strain sensors 23 lying opposite one another deliver the same value, with the values of the strain sensors 23 lying opposite one another in the circumferential direction 6 being twice as great as the values of those lying opposite one another in the longitudinal direction 7 Strain sensors 23 (coordinate rotation).

However, this calculated temperature correction is accompanied by a loss of sensitivity of the measured values. This can be circumvented by using more than four, e.g. B. eight, strain sensors 23 are provided, which are arranged equidistantly on the membrane 21 in a circle. As already mentioned, more than four equidistant support elements 5 can also be provided as a result. This makes it possible to measure the mechanical stresses in the outer wall 3 of the tube 2 in different radial directions or to interpolate between the measured values. The two directions in which the stresses detected in this way change the most or least when the pressure in the tube 2 increases correspond to the directions of the tangential stress and the axial stress, ie the circumferential direction 6 and the longitudinal direction 7 of the container 2. After a single Determination of the directions of the tangential stress and the axial stress, the further pressure measurement can be carried out with only four strain sensors 23, whose measured values can be corrected by transformation to the directions of the tangential stress and the axial stress.

The membrane 21 represents only one possible location at which the strain sensors 23 can be arranged in order to detect radial deformations of the spring body 4 . So the strain sensors 23 z. B. also on the inner wall 26 of the elastic ring body 22 are attached. Furthermore, the membrane 21 can essentially be spanned by the supporting elements 5 carrying it, in which case the ring body 22 then has more of a partial function of the housing part 18 ( 1 ) meets by forming a space for accommodating the strain sensors 23. In principle, the spring body 4 can be of different shapes, the only decisive factor being that it is supported by at least four support elements 5 arranged equidistantly in a circle and can be fixedly mounted on the outer wall 3 of the container 2 and is provided with at least four strain sensors 23 .

6 1 shows a variant of the spring body 4 in which the four support elements 5 are mounted on the container wall in such a way that each of the support elements 5 has a support element adjacent in the longitudinal direction 7 and in the circumferential direction 6 of the container 2 . Here, too, the deformation of the spring body 4 in the event of pressure and/or temperature changes in the container 2 takes place axisymmetric to the longitudinal direction 7 and circumferential direction 6 of the container 2, so that when the deformation of the spring body 4 is detected by means of the strain sensors 23, between deformations in the longitudinal direction 7 and can be distinguished in the circumferential direction 6 and thus on the basis of the boiler formula between pressure-related and temperature-related deformations. The strain sensors 23 are each mounted on the membrane 21 in the middle between two adjacent support elements 5 . In this variant, the spring body 4 can be aligned in a simple manner with the aid of a belt 27, which is placed around the pipe between the support elements 5 and can be removed again after the pressure measuring device has been installed.

7 Finally, in a very schematic illustration, FIG. As this example also shows, the support elements 5 can have foot-shaped projections 28 in order to fasten the pressure measuring device to the container 2 using tensioning straps 29 .

Since the tangential stress and axial stress are perpendicular to each other, as explained in the previous examples, preferably four (or eg eight) support elements and strain sensors are used so that the tangential stress and axial stress can be recorded in a Cartesian coordinate system. Alternatively, the tangential stress and axial stress can be recorded in a polar coordinate system using three (or, for example, six) equidistant supports and strain sensors, and then converted to Cartesian coordinates.

QUOTES INCLUDED IN DESCRIPTION

This list of the documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• US2005235755A1 [0005]
• WO 2017/097888 A1 [0006]
• US4399514A [0008]
• US5585567A [0008]
• US 2007/0251325 A1 [0008]
• EP 0088362 A1 [0008]
• WO 2020/058497 A1

Claims (11)

Non-invasive pressure measuring device (1) for measuring a pressure inside an elongated cylindrical container (2), with a disc-shaped or ring-shaped spring body (4), which is arranged equidistantly from at least three in a circle and fixed on an outer wall (3) of the Support elements (5) mountable on the container (2), with at least three expansion sensors (23) which are designed and arranged to detect radial deformations of the spring body (4), and with an evaluation device (8) on which the expansion sensors ( 23) are connected and which is designed to distinguish between pressure and temperature-related deformation components based on different deformations of the spring body (4) in the longitudinal direction (7) and circumferential direction (6) of the container (2) and to generate a measurement result ( 9) for the pressure inside the container (2) to be determined and output. Pressure measuring device (1) according to claim 1 , characterized in that the spring body (4) has a membrane (21) on which the strain sensors (23) are applied and which is spanned by the supporting elements (5) carrying them. Pressure measuring device (1) according to claim 2 , characterized in that the spring body (4) also has an elastic ring body (22) which is carried by the support elements (5) and over which the membrane (21) is stretched. Pressure measuring device (1) according to claim 1 , characterized in that the spring body (4) has an elastic ring body (22) which is carried by the support elements (5) and on the inner wall 26 of which the strain sensors (23) are attached. Pressure measuring device (1) according to one of the preceding claims, characterized in that the supporting elements (5) are connected to the outer wall (3) of the container (2) in a materially bonded manner. Pressure measuring device (1) according to claim 5 , characterized in that the supporting elements (5) are formed from a brittle curable adhesive mass, in particular a two-component epoxy resin kneaded mass. Pressure measuring device (1) according to one of Claims 1 until 5 , characterized in that the support elements (5) have foot-shaped projections (28) in order to fasten the pressure measuring device (1) to the container (2) via tensioning straps (29). Pressure measuring device (1) according to one of the preceding claims, characterized in that at least eight strain sensors (23) are provided, which detect the deformations of the spring body (4) in different radial directions, and that the evaluation device (8) is also designed to Direction in which the greatest deformation is detected when the pressure in the container (2) increases as the circumferential direction (6) and/or that direction in which the smallest deformation is detected when the pressure in the container (2) increases as the Identify longitudinal direction (7). Pressure measuring device (1) according to claim 8 , characterized in that at least eight supporting elements (5) arranged equidistantly on the circle are provided corresponding to the number of strain sensors (23). Pressure measuring device (1) according to one of the preceding claims as part of a measuring sensor (11) mounted on the pipe (2) with different sensors for measuring at least one of the parameters vibration, temperature, air humidity, air pressure. Method for the non-invasive measurement of a pressure inside an elongated cylindrical container (2), wherein a disk-shaped or ring-shaped spring body (4) is supported on an outer wall (3) of the container (2 ) is mounted, radial deformations of the spring body (4) are detected, and on the basis of different detected deformations of the spring body (4) in the longitudinal direction (7) and circumferential direction (6) of the container (2) a distinction is made between pressure and temperature-related deformation components and from the pressure-related deformation components, a measurement result (9) for the pressure inside the container (2) is determined.

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