Pressure measuring device, measuring method and computer program product

Abstract

The present invention relates to a pressure measuring device (10) comprising a plurality of housings (12), each housing partially surrounding a fluid-filled pipe (11). The housings (12) are interconnected by stretchable connecting members (14). According to the invention, at least one of the stretchable connecting members (14) has a grating (30) designed to produce a diffraction pattern (39) variable under tensile load (31). The invention also relates to a method (100) for measuring pressure (28) in a fluid-filled pipe (11) using the claimed pressure measuring device (10) and a pressure measuring system (50) including such a pressure measuring device (10). Furthermore, the invention relates to a computer program product (80) by means of which the operational behavior of such a pressure measuring device (10) can be simulated.

Description

Technical Field

[0001] This invention relates to a pressure measuring device for non-invasive pressure measurement of fluids in pipe fittings and a suitable measuring method thereunder. The invention also relates to a corresponding pressure measuring system and a computer program product for simulating the operational behavior of the corresponding pressure measuring device. Background Technology

[0002] Publication WO 2021 / 071859 A1 discloses a pressure sensor for non-invasive measurement of static and dynamic pressure components in a pipe fitting. The strain sensor has a wire made of polyvinylidene fluoride wound around the pipe fitting to measure the variable dynamic pressure components. Furthermore, the pressure sensor also includes a strain gauge to measure the static pressure components. The strain gauge is also wound around the pipe fitting.

[0003] Patent application US 2005 / 0072216 A1 discloses a piezoelectric sensor for measuring variable pressure in a pipe fitting. The piezoelectric sensor includes a cable wound around the pipe fitting, such that the expansion of the pipe fitting caused by a pressure rise can be detected as longitudinal stretching of the cable. Summary of the Invention

[0004] Increasingly, pressure measuring devices for non-invasive pressure measurement are being used in various applications, such as automated systems. There is a desire to manufacture space-saving pressure measuring devices at low cost. Improved measurement accuracy and durability are also needed for reliable use under adverse environmental conditions. The object of this invention is to provide a pressure measuring device that is improved in at least one of the aforementioned aspects.

[0005] The aforementioned objective is achieved by a pressure measuring device according to the invention, by means of which the pressure in a fluid-filled pipe fitting can be measured. The pipe fitting may have any closed cross-section and may, for example, be at least partially filled with a liquid, gas, or a mixture thereof. The fluid in the pipe fitting may exert static and / or dynamic pressure on the pipe fitting wall. The pressure measuring device comprises several housings, each designed to partially enclose the fluid-filled pipe fitting, i.e., each partially surrounds the fluid-filled pipe fitting. For this purpose, the shape of the housings substantially conforms to the shape of the pipe fitting and, in the assembled state, at least partially abuts the outer contour of the pipe fitting. The housings are interconnected by connecting members adapted to absorb tensile loads. The expansion of the pipe fitting due to pressure rise is transmitted as a tensile load to the connecting members by the housings. According to the invention, at least one of the stretchable connecting members has a grating adapted to produce a variable diffraction pattern. The diffraction pattern is variable under the influence of the tensile load present in the connecting member. For this purpose, the grating is connected to or integrated into the connecting member so that the grating also undergoes at least one stretch caused by the tensile load. Therefore, a pressure increase or decrease in a fluid-filled pipe will cause a change in the diffraction pattern at at least one stretchable connecting member. This change in diffraction pattern can be accurately detected in a simple manner, thus enabling precise measurement of the pressure in the fluid-filled pipe. The pressure measuring device according to the invention is designed for non-invasive pressure measurement in fluid-filled pipes. The measurement principle thus achieved is mechanical and optical, and therefore has strong resistance to electrical interference. Therefore, the pressure measuring device according to the invention can be readily applied to complex automated systems where considerable interfering electromagnetic fields exist due to numerous existing devices. Furthermore, such a grating can be compactly formed, for example, in the form of slits, slots, circular holes, rectangular gaps, or other polygonal gaps. Therefore, the pressure measuring device according to the invention can be manufactured in a space-saving manner overall.

[0006] In one embodiment of the pressure measuring device for which protection is sought, the tensile load applied to at least one connecting member during pressure measurement is oriented substantially tangentially to the pipe fitting. This orientation ensures that the expansion of the pipe fitting (i.e., radial increase) is fully converted into a load on the corresponding connecting member. In particular, the bending component of the deformation of at least one connecting member is suppressed. As a result, a substantially uniaxial load condition is generated in at least one connecting member, which ensures improved measurement accuracy.

[0007] Furthermore, a variable diffraction pattern can be generated by irradiating a grating radially onto the pipe fitting. This irradiation can be achieved using visible light, ultraviolet radiation, and / or infrared radiation. For this purpose, the pressure measuring device can be equipped with a light source fixed to it. The light source is designed to work in conjunction with the grating to produce a measurable, technically usable, variable diffraction pattern. For this purpose, the light source can, for example, be designed to emit monochromatic radiation. Therefore, depending on the existing installation space on the corresponding pipe fitting, different light sources whose radiation is unaffected by electromagnetic fields can be used. Changes in the variable diffraction pattern can be easily identified through radial irradiation. Such irradiation can be continuous or temporary. Even with continuous irradiation, there is no reaction on the pipe fitting or the fluid within it. Therefore, no reaction needs to be considered when designing the pressure measuring device for protection, making design and manufacturing simple and cost-effective. Temporary irradiation further reduces the energy requirements of the pressure measuring device during operation. This makes it possible for the pressure measuring device for protection to operate for extended periods using energy storage devices (e.g., batteries). In particular, this allows for the advantageous design of the pressure measuring device as a wireless device that transmits measurement data via a radio connection. This effect can be further enhanced by designing the light source, for example, as an LED.

[0008] In another embodiment of the pressure measuring device for which protection is sought, the grating has at least one gap designed to produce a direction-dependent variable diffraction pattern. In this case, with reference to the pipe, the circumferential variation of the diffraction pattern can be distinguished from the axial variation. For this purpose, the at least one gap can be designed, for example, as a diffraction slit oriented circumferentially or tangentially along the pipe or axially. Alternatively or supplementary, the at least one gap can also be polygonal, particularly rectangular or square. The grating can also have several gaps of the above types or combinations thereof. This allows, for example, the differentiation between diffraction pattern changes caused by pipe temperature variations and those caused by pressure variations. In this way, the pressure measuring device for which protection is sought will be conveniently adapted for temperature-compensated pressure measurements. Furthermore, the pipe can be designed as a thin-walled pipe. In the case of thin-walled pipes, it can be considered that when subjected to pressure loads, their circumferential stretch is twice that in the longitudinal direction. Thin-walled pipes are defined as pipes with an outer diameter to inner diameter ratio of less than 1.2.

[0009] Furthermore, the pressure measuring device for which protection is sought can have a detection element positioned in a region of the grating, designed to detect variable diffraction patterns. The detection element can be arranged such that at least one connecting member with the grating is located between the light source and the detection element. For this purpose, the at least one connecting member with the grating can be designed, for example, as a sheet or strip, thus providing sufficient space between the connecting member and the pipe to mount the detection element or the light source. When installed correctly, the expansion of the pipe will be substantially entirely converted into a tensile load on the connecting member. Therefore, the pressure measuring device for which protection is sought is particularly easy to assemble overall, thereby enabling reliable and accurate measurement operations.

[0010] The sensing element can be designed as an array, particularly a photodiode array or a photoresistor array. Array or mesh layouts allow for the detection of at least a two-dimensional resolution image of the variable diffraction pattern with relatively low hardware investment. Furthermore, photoresistors are virtually unaffected by aging, making them particularly suitable for continuous operation. Alternatively or as a supplement, the sensing element can also be designed as an image sensor, such as a CMOS sensor or a CCD sensor. These image sensors are particularly compact and offer higher resolution, thus enabling more accurate detection of changes in the diffraction pattern. Therefore, the pressure measuring device under protection can be implemented with cost-effective components and achieves higher accuracy and compactness. Consequently, the pressure measuring device under protection can also be used on pipe fittings with limited surrounding installation space. Therefore, the pressure measuring device under protection has a wide range of applications.

[0011] Furthermore, the pressure measuring device for which protection is sought can be designed to be non-destructively detachable from the pipe fitting. For this purpose, at least one connecting member can be connected to one of the housings in a non-destructive, detachable manner, particularly by screwing. Specifically, the non-destructive separation of the pressure measuring device from the pipe fitting is ensured by the absence of a material-bonding connection (e.g., adhesive or welded connection) between them. Therefore, the pressure measuring device for which protection is sought can be easily installed on pipe fittings with any surface finish. In particular, it is not necessary to use measuring pipe fittings with specially treated (i.e., machined) surfaces. In this way, the pressure measuring device for which protection is sought can be installed in existing equipment in a cost-effective manner during retrofitting. Furthermore, the housings can be designed to be mounted on the pipe fitting without being affected by fitting tolerances. Each housing can have at least one externally adjustable clamping block. This allows the installation of the pressure measuring device to be adjusted so that, for example, the required preload can be set in at least one stretchable connecting member.

[0012] In another embodiment of the pressure measuring device for which protection is sought, the device has at least two stretchable connecting members, each having a grating. Variable diffraction patterns can be detected on these gratings. By individually evaluating these variable diffraction patterns, different deformations within the respective stretchable connecting member regions can be identified. For example, this can identify bending in a fluid-filled pipe, thus distinguishing the bending from pressure changes in the fluid. Therefore, the pressure measuring device for which protection is sought is highly resistant to unintended influences and has a wide range of potential applications.

[0013] The aforementioned objective is also achieved by a method according to the invention for measuring pressure in a fluid-filled pipe fitting. The method includes a first step of providing a fluid-filled pipe fitting whose pressure (i.e., pressure existing inside the fitting in both static and dynamic forms) needs to be measured. In the first step, a pressure measuring device is also provided to the fluid-filled pipe fitting to be used for pressure measurement. For this purpose, the pressure measuring device is mounted on the fluid-filled pipe fitting. The pressure measuring device includes several housings interconnected by stretchable connecting members. The stretchable connecting members can be pre-tightened in an assembled state. In the assembled state, the expansion of the pipe fitting due to internal pressure changes translates into an increase in the tensile load on the stretchable connecting members. The method further includes a second step of irradiating at least one stretchable connecting member with a light source. The at least one stretchable connecting member includes a grating, which is irradiated by the light source in the second step. A diffraction pattern is generated by irradiating the grating.

[0014] Furthermore, the method according to the invention includes a third step: detecting the current diffraction pattern generated in the second step. In the third step, the detected diffraction pattern is further compared with a reference diffraction pattern, and the difference between the two is determined. The reference diffraction pattern may, for example, be a diffraction pattern generated at a known ambient temperature, a known fluid temperature, and a known ambient pressure after the pipe pressure has been calibrated. The method further includes a fourth step: determining the pressure present in the fluid-filled pipe based on the difference determined in the third step. This pressure may include both static and dynamic pressure. That is, the difference determined in the third step is a scale used to measure the pressure present in the fluid-filled pipe. For this purpose, the difference can be evaluated using a value table, algorithm, or artificial intelligence (e.g., a neural network) to ultimately determine the current pressure in the pipe. The method according to the invention is essentially optical; therefore, electromagnetic influences (e.g., magnetic or electric fields) do not interfere with the diffraction pattern generated at at least one connecting member. Furthermore, the diffraction pattern is continuously variable; therefore, the achievable measurement accuracy is essentially limited only by the accuracy achievable when detecting a variable diffraction pattern. Even simple detection components, such as photodiode arrays, CMOS sensors, or CCD sensors, can provide higher accuracy. The method according to the invention is suitable for further improving the achievable measurement accuracy in pressure measurement by incorporating future higher-resolution CMOS sensors, CCD sensors, or similar functional components. Therefore, the method according to the invention can also be used to rapidly develop the future technological potential of corresponding detection components.

[0015] In one embodiment of the method for which protection is sought, the grating can be oriented substantially tangentially to the pipe fitting. For this purpose, the grating can be fixedly connected to at least one stretchable connecting member. In this way, the load present in the at least one stretchable connecting member can be substantially entirely converted into deformation of the grating. With the grating oriented tangentially to the pipe fitting, higher measurement accuracy is generally achieved.

[0016] Furthermore, in the method for claiming protection, the circumferential deformation of the grating can be measured in the third step. As an alternative or supplementary method, the axial deformation of the grating can be measured. For this purpose, the grating can be designed to display changes that can be distinguished between the circumferential and axial directions. The pressure measuring device can particularly be equipped with a detection component capable of identifying two-dimensional changes in the diffraction pattern. The axial stretching of the pipe fitting is usually caused by thermal expansion, i.e., a rise in temperature. Simultaneously, this thermal expansion also causes radial expansion of the pipe fitting. This causes a change in the diffraction pattern at the grating, similar to the effect of a pressure increase within the pipe. The axial effect of the pressure increase on the pipe fitting is negligible. Temperature compensation for the pipe fitting can be performed by comprehensively measuring the circumferential and axial deformation of the grating. The fluid temperature can also be measured based on information such as the outer diameter, wall thickness, pipe material specifications, and / or ambient temperature.

[0017] Furthermore, in the method for which protection is sought, the total intensity of the diffraction pattern, the width of the central maximum value, the number of secondary maximum values, the circumferential position of the secondary maximum values, the number of secondary minimum values, and / or the circumferential position of the secondary minimum values ​​can be detected in the third step. Based on these variables, the deformation of the stretchable connecting member along the circumference of the pipe can be detected in a simple manner. When detecting the number of secondary maximum or minimum values, those secondary maximum or minimum values ​​that are adjacent to each other in the circumferential direction are detected. These are variables that can be accurately determined in a simple manner for the diffraction pattern. By combining at least two of these variables, the verisimilitude of the pipe expansion derived from individual variables can also be cross-checked. This allows for the identification of damage to at least one stretchable connecting member, but is not limited to this. Damage can include plastic deformation, such as plastic deformation due to relaxation. When measuring the pipe expansion and thus the pressure in the fluid, variables that no longer have sufficient explanatory power on the diffraction pattern can be intentionally ignored. Therefore, the method for which protection is sought is highly resistant to the deterioration of the stretchable connecting member. As a result, the pressure measuring device used in this method will have a technically longer service life.

[0018] The aforementioned objective is further achieved by a pressure measurement system according to the invention, designed to measure the pressure in a fluid-filled pipe fitting. The pressure measurement system includes a pressure measuring device connectable to a light source. The light source is used to measure pressure during a predetermined operation of the pressure measuring device. The pressure measuring device is coupled to an evaluation unit to forward the measurement signal generated by the pressure measuring device to the evaluation unit. The measurement signal may be generated directly by the detection element of the pressure measuring device, or may have been at least partially processed. The evaluation unit is designed to evaluate the measurement signal in order to determine the pressure present in the fluid-filled pipe fitting. For this purpose, the pressure measuring device can be designed according to one of the aforementioned embodiments. As an alternative or supplementary solution, the evaluation unit can be designed to implement at least one embodiment of the above-described method. For this purpose, the evaluation unit can be equipped with a control program product of a corresponding design, having a corresponding chip, or a combination of both. The pressure measurement system according to the invention makes it possible to achieve, to a certain extent, the technical advantages of the aforementioned pressure measuring device and / or the described method. The pressure measurement system according to the invention can be easily installed in existing applications such as automation systems during retrofitting.

[0019] Furthermore, the objective stated at the outset is also achieved by a computer program product according to the present invention, which is designed to simulate the operational behavior of a pressure measuring device arranged on a fluid-filled pipe fitting. The pressure measuring device is configured to measure the pressure present in the fluid-filled pipe fitting. The pressure measuring device to be simulated in terms of operational behavior is designed according to one of the above-described embodiments. The operational behavior of the pressure measuring device includes the radial expansion of the fluid-filled pipe fitting as its internal pressure increases, and the force exerted by the pipe fitting on the pressure measuring device. Similarly, the expansion of the pipe fitting as the ambient temperature of the pipe fitting or the temperature of the fluid inside the pipe increases can also be considered operational behavior of the pipe fitting. Furthermore, the elastic deformation behavior of the stretchable connecting member can be considered operational behavior caused by the force exerted by the pipe fitting. The elastic deformation behavior of the stretchable connecting member can also cause changes in the grating at the stretchable connecting member, which can also be considered operational behavior of the pressure measuring device. Further, the operational behavior can also include changes in the diffraction pattern caused by changes in the diffraction pattern. The detection behavior of the detection member and the measurement signal of the detection member can also be considered operational behavior of the pressure measuring device.

[0020] The computer program product may further have a data interface through which users, algorithms, and / or other simulation-oriented computer program products specify parameters for setting operational behavior. The computer program product may also have a data interface for outputting simulation results to users and / or other simulation-oriented computer program products. The computer program product according to the invention has an image of a pressure measuring device to be simulated, which can be executed in the physical module of the computer program product. By executing the image in the physical module, the operational behavior of the pressure measuring device can be simulated. For this purpose, the image of the pressure measuring device in the physical module can be a spatially accurate image of the pressure measuring device to be simulated, or it can be a purely computational model that reproduces its operational behavior in an abstract form. Similarly, the physical module containing the image of the pressure measuring device can also be designed as a combination of the above two. The computer program product can in particular be designed as a so-called digital twin, for detailed description in publication US 2017 / 286572 A1, etc. The disclosure of US 2017 / 286572 A1 is incorporated herein by reference.

[0021] The computer program product according to the invention is primarily based on the following unexpected discovery: the mechanism of action upon which the pressure measuring device according to the invention is based can be calculated in a simple manner. In particular, the use of computationally intensive finite element calculations can be minimized. Accordingly, the operational behavior of the pressure measuring device according to the invention is not difficult to simulate. The pressure measuring device is designed for non-invasive pressure measurement; therefore, there is a relatively complex chain of action between the measured variable (i.e., the pressure in a pipe containing fluid) and the measured signal. Despite this complex chain of action, the computer program product according to the invention can still provide a higher degree of realism in simulating operational behavior. Therefore, the computer program product according to the invention is also based on the following unexpected discovery: the construction of the pressure measuring device according to the invention provides such enhanced realism. In many applications, such as in automation systems, numerous devices and measuring instruments are used that require reproduction of their operational behavior in process simulations at control stations (so-called operator consoles). The computer program product according to the invention makes it possible to create accurate process simulations with reduced hardware investment. Furthermore, the computer program product according to the invention can be used to perform plausibility testing on the measurement signals generated by the pressure measuring device in order to identify defects in the simulated pressure measuring device itself or defects in other equipment in the automation system. The computer program product according to the present invention generally helps to improve the operational reliability of applications using simulated pressure measuring devices. Furthermore, the computer program product according to the present invention can also test and / or optimize pressure measuring devices in a simulated manner. The computer program product can be a monolithic design, meaning it can be executed entirely on a single hardware platform. Alternatively, the computer program product can be a modular design, comprising several subroutines that can execute on several separate hardware platforms and interact via a communication data connection. This communication data connection can be a network connection or an internet connection. In particular, the computer program product can be designed to execute in a computer cloud. Attached Figure Description

[0022] The present invention will now be described in detail with reference to the embodiments shown in the accompanying drawings. These drawings should be understood as complementary, as the same reference numerals in different drawings have the same technical meaning. Features of the various embodiments can also be combined with each other. Furthermore, the embodiments shown in the drawings can be combined with the foregoing features. Wherein:

[0023] Figure 1 Longitudinal cross-section of a first embodiment of a pressure measuring device for which protection is sought;

[0024] Figure 2 A perspective view of a first embodiment of a pressure measuring device for which protection is sought;

[0025] Figure 3 A detailed schematic diagram of a first embodiment of a pressure measuring device for which protection is sought;

[0026] Figure 4 A detailed schematic diagram of a second embodiment of a pressure measuring device for which protection is sought;

[0027] Figure 5 This is a stage in one implementation of a pressure measurement method for which protection is sought. Detailed Implementation

[0028] Figure 1 A longitudinal section of a first embodiment of the pressure measuring device 10 for which protection is sought is shown. The pressure measuring device 10 is mounted on a pipe fitting 11, in which at least partially a fluid 25 adapted to flow along a pipe fitting axis 15, which defines an axial direction 29. The fluid 25 is subjected to a pressure 28, which includes a static pressure and, in the presence of a flow rate 27, a dynamic pressure. The current pressure 28 exerts an expansion force on the pipe fitting 11. The pressure measuring device 10 includes a housing 12 that partially surrounds the pipe fitting 11 to transfer the expansion force acting on the pipe fitting 11 radially 23 to the housing 12. The pressure measuring device 10 also includes two stretchable connecting members 14 subjected to tensile loads due to the presence of pressure 28 in the pipe fitting 11. At least one of the stretchable connecting members 14 has a grating 30 that can be illuminated by a light source 20. In addition, a detection member 16 is provided in the area of ​​the stretchable connecting member 14. The detection member is designed to detect a diffraction pattern 39, which is not shown in detail in the figure. The diffraction pattern is generated by the grating 30 being irradiated 22 by the light source 20. Figure 1 The assembly state shown is the first step 110 of the pressure measurement method 100, which can be implemented using the pressure measuring device 10. In this assembly state, a pipe fitting 11 with fluid 25 is provided, and the pressure measuring device 10 is mounted on the pipe fitting. The first step 110 represents an initial state, followed by a second step 120, in which a grating 30 is illuminated by a light source 20. The diffraction pattern 39 detected by the detected component 16 is forwarded as a measurement signal 45 to an evaluation unit 40, which is at least functionally coupled to the pressure measuring device 10. In this case, the measurement signal 45 can be transmitted wired or wirelessly. To determine the pressure 28 in the pipe fitting 11, the third step 130 and the fourth step 140 of the method 100 are also implemented on the evaluation unit 40. Furthermore, the evaluation unit 40 is adapted to control the light source 20 via control commands 47. The pressure measuring device 10 and the evaluation unit 40 together form a pressure measurement system 50. Furthermore, the pressure measuring device 10 is mapped in a computer program product 80, which is designed to simulate the operational behavior of the pressure measuring device 10. For this purpose, the computer program product 80 was designed as a digital twin.

[0029] Figure 2 As shown Figure 1 The diagram shows a perspective view of a first embodiment of the pressure measuring device 10 for which protection is sought. The pressure measuring device 10 has two generally C-shaped or arc-shaped housings 12 that, in the assembled state, partially surround a tube 11 (not shown). The radial expansion 23 of the tube 11, i.e., expansion perpendicular to the tube axis 15, is converted into pressure acting on the inner surface 13 of the housings 12, which, in the assembled state, rest against the tube 11 with said inner surface. The housings 12 are interconnected by stretchable connecting members 14, which are secured to the housings by fixing members 21 designed as screws. In this way, the stretchable connecting members 14 are detachably connected to the housings 12. Viewed from the tube axis 15, the stretchable connecting members 14 are oriented substantially tangentially. The axial direction 24 and circumferential direction 26 are defined by the tube axis 15. Furthermore, the stretchable connecting members 14 are designed as sheets or strips. Therefore, the expansion of the tube 11 is converted into a substantially planar stress state, under which the bending of the stretchable connecting members 14 is minimized. In particular, the expansion of the pipe fitting 11 translates into a tensile load 31 on the stretchable connecting member 14, which affects the grating 30 formed on at least one of the stretchable connecting members 14. The deformation of the stretchable connecting member 14 due to the tensile load 31 is an operational behavior of the pressure measuring device 10 and can be reproduced in the computer program product 80 that maps the pressure measuring device.

[0030] Figure 3A detailed view of the stretchable connecting member 14 according to a first embodiment of the pressure measuring device 10 for which protection is claimed is shown. The stretchable connecting member 14 is irradiated according to the second step 120 of the pressure measuring method 100. Irradiation 22 is indicated here by a broken line. Slits 24, substantially oriented along the axial direction 24, are formed side-by-side in the stretchable connecting member 14, through which a grating 30 is formed. Due to a tensile load 31 along the circumferential direction 26, the stretchable connecting member 14 deforms relative to the unloaded state, and the grating 30 also changes due to this deformation. Under the action of the tensile load 31, the slits 24 forming the grating 30 are widened and stretched, i.e., at least one slit spacing 36 increases. The tensile load 31 also causes a lateral contraction 33 along the axial direction 24, which can be quantified, for example, by the so-called Poisson's ratio. The deformation of the stretchable connecting member 14 occurs substantially within the elastic range; therefore, the effects of the increased slit spacing 36 and the lateral contraction 33 can be reversed by reducing the tensile load 31. The deformation of the stretchable connecting member 14 is further superimposed on the thermal expansion 35 of the stretchable connecting member 14. The thermal expansion 35 depends on the current temperature 32 of the stretchable connecting member 14. The thermal expansion 35 occurs uniformly in all directions and also acts on the grating 30. Overall, at the stretchable connecting member 14, the current temperature 32 and the pressure 28 present in the tube 11 induce deformation of the grating 30. The grating 30 produces a diffraction pattern 39 on the side of the stretchable connecting member 14 away from the light source 20 due to irradiation 22. This diffraction pattern 39 can be used, for example... Figure 1 The detection component 16 shown is used to detect and determine the current pressure 28. The aforementioned deformation behavior can be calculated in a simple way and belongs to the category of... Figure 3 The operation of the pressure measuring device 10 is described. The mapping and simulation of the stretchable connecting member 14 is described in a computer program product 80 (not shown in the figure), which can be used to simulate the operation of the pressure measuring device 10.

[0031] Figure 4 A second embodiment of the stretchable connecting member 14 for which protection is sought is shown in detailed view. According to... Figure 4 The implementation method can be based on Figure 1 and Figure 2 The structures are combined, but not limited to. According to Figure 4The stretchable connecting member 14 has a grating 30 formed by rectangular openings 34 arranged in a grid or array. In the second step 120 of the claimed pressure measurement method 100, the grating 30 is illuminated by a light source 20. Illumination 22 causes the grating 30 to produce a diffraction pattern 39 on the side of the stretchable connecting member 14 away from the light source 20. The grating 30 and the corresponding diffraction pattern 39 are affected by the deformation of the stretchable connecting member 14. This deformation is mainly caused by a tensile load 31, which is generated by the expansion of the tube 11 (not shown) due to the increased pressure 28 present inside it. Viewed axially 24, this results in a larger gap spacing 36 and a wider rectangular opening 34. Furthermore, the tensile load 31 also induces a lateral contraction 33 in the stretchable connecting member 14, which, viewed circumferentially 26, narrows the rectangular opening 34 and correspondingly reduces the gap spacing 36. Figure 4 The state shown is also superimposed on the thermal expansion 35 of the stretchable connecting member 14. Thermal expansion 35 is caused by the current temperature 32 of the stretchable connecting member 14, which increases the gap spacing 36 in both the axial and circumferential directions 24 and 26. Similarly, thermal expansion 35 widens the rectangular opening 34 in both the axial and circumferential directions 24 and 26. Therefore, deformation occurs at the grating 30, and the components of this deformation in the axial and circumferential directions 24 and 26 can be distinguished and quantified by the corresponding changes in the diffraction pattern 39 along these two directions. This allows for the quantification of the effects of the tensile load 31 caused solely by the pressure 28 present in the fitting 11 and the effects of thermal expansion 35. This facilitates temperature compensation when implementing the pressure measurement method 100. The aforementioned deformation behavior can be calculated in a simple manner and belongs to the category of... Figure 3 The operation of the pressure measuring device 10 is described. The mapping and simulation of the stretchable connecting member 14 is described in a computer program product 80 (not shown in the figure), which can be used to simulate the operation of the pressure measuring device 10.

[0032] Figure 5 This illustration shows a stage of one embodiment of the claimed method 100, which is used to measure pressure 28 in a pipe fitting 11 that is at least partially filled with fluid. Specifically, Figure 5 Figure 70 is shown as comprising two subfigures 70.1 and 70.2. Each of the first subfigure 70.1 and the second subfigure 70.2 has a vertical variable axis that displays the intensity of the diffraction pattern 39. 72. Sub-figures 70.1 and 70.2 also have corresponding horizontal position axes 74, which respectively show the position along the circumferential direction 26 of the fitting 11, for example as... Figure 3 or Figure 4As shown. First subfigure 70.1 shows the intensity distribution 41 produced by the diffraction pattern 39, which is used as a reference diffraction pattern 37. The reference diffraction pattern 37 is detected when the associated tensile connection member 14 is under defined mechanical and thermal load conditions. The reference diffraction pattern 37 includes a central maximum value 42 with a width 43. The width 43 is formed by points 76 on the intensity distribution 41, which are 50% of the maximum amplitude 75 at the central maximum value 42. Following the central maximum value 42 are alternating secondary minimum values ​​44 and secondary maximum values ​​46, whose circumferential positions 77 are stored in the reference diffraction pattern 37.

[0033] The second subfigure 70.2 shows the intensity distribution 41 of the reproduced diffraction pattern 39, which is generated at the grating 30 of the stretchable connecting member 14 subjected to tensile load 31. The diffraction pattern 39 is detected in the third step 130 of the pressure measurement method 100. Compared to the reference diffraction pattern 37, the diffraction pattern 39 has a reduced central maximum value 42 with a width 43. The deviation of the width 43 of the central maximum value 42 between the reference diffraction pattern 37 and the diffraction pattern 39 can be detected in the third step 130. Alternatively or supplementarily, the circumferential positions 77 of the corresponding secondary minimum values ​​44 and / or secondary maximum values ​​46 in the diffraction pattern 39 and the reference diffraction pattern 37 can also be detected. In this case, such secondary minimum values ​​44 or secondary maximum values ​​46 in the diffraction pattern 39 and the reference diffraction pattern 37 will be classified as, from the perspective of the central maximum value 42, the first, second, and third secondary minimum values ​​44 or secondary maximum values ​​46, etc. Furthermore, within the scope covered by sub-figures 70.1 and 70.2, a certain number of secondary minimum values ​​44 and / or secondary maximum values ​​46 can be detected in a simple manner. Therefore, many possible features exist, based on which the current diffraction pattern 39 can be compared with the reference diffraction pattern 37 in the third step 130, particularly a quantifiable comparison. In the third step 130, the deviation between the reference diffraction pattern 37 and the diffraction pattern 39 is detected, and in the fourth step 140, the deviation is used to determine the pressure 28 present in the pipe fitting 11. The fourth step 140 can, for example, be implemented in the software of the evaluation unit 40 of the pressure measurement system 50, to which the pressure measuring device 10 is also subordinate. In the fourth step 140, the current pressure 18 is determined, for example, based on value tables, algorithms, and / or artificial intelligence. The result determined for pressure 28 in the fourth step 140 is considered part of the operational behavior of the pressure measuring device 10. The third and fourth steps 130 and 140 can also be mapped into a computer program product 80 for simulating the operational behavior of the pressure measuring device 10. Similarly, Figure 5 The operation shown is also feasible for more complex diffraction patterns 39 and / or diffraction patterns 39 oriented along axis 24 of horizontal position axis 74.

Claims

1. A pressure measuring device (10) comprising several housings (12) for partially enclosing a fluid containing tube (11) each and being connected to each other by stretchable connecting members (14), characterized in that, At least one of the stretchable connecting members (14) has a grating (30) designed to produce a diffractive pattern (39) that is variable under a tensile load (31), The change in the diffraction pattern (39) in the circumferential direction is distinguished from the change in the diffraction pattern in the axial direction The stretching load (31) is oriented tangentially to the tube (11). .

2. The pressure measuring device (10) according to claim 1, characterized in that The variable diffraction pattern (39) can be generated by irradiating (22) the grating (30) in the radial direction (23) of the tube (11).

3. The pressure measuring device (10) according to claim 1 or 2, characterized in that The grating (30) has at least one gap (24, 34) which is designed to generate a direction-dependent variable diffraction pattern (39).

4. The pressure measuring device (10) according to any one of claims 1 to 3, characterized in that A detection means (16) for detecting the diffraction pattern (39) is provided in a region of the grating (30).

5. The pressure measuring device (10) according to any one of claims 1 to 4, characterized in that The detection means (16) are designed as an array, in particular as a photodiode array, or as an image sensor.

6. The pressure measuring device (10) according to claim 5, characterized in that The pressure measuring device (10) is designed to be detachable from the tube (11) in a non-destructive manner.

7. The pressure measuring device (10) according to any one of claims 1 to 6, characterized in that The pressure measuring device (10) comprises at least two stretchable connection means (14) each having a grating (30) for identifying a bend of the fluid-filled tube (11).

8. The pressure measuring device (10) according to any one of claims 1 to 7, characterized in that 9. A method (100) for measuring a pressure (28) in a fluid-filled tube (11), comprising the following steps: a) providing the fluid-filled tube (11) and equipping the fluid-filled tube (11) with a pressure measuring device (10) comprising several housings (12) which are connected to one another by stretchable connection means (14); b) irradiating at least one stretchable connection means (14) having a grating (30) with a light source (20); c) detecting a diffraction pattern (39) generated by the irradiation (22) in step b) and determining a difference between the detected diffraction pattern (39) and a reference diffraction pattern (37); d) determining the pressure (28) present in the fluid-filled tube (11) on the basis of the difference detected in step c); wherein in step c) a deformation of the grating (30) in the circumferential direction (26) and / or a deformation of the grating (30) in the axial direction (24) is determined. The grating (30) is oriented tangentially to the tube (11).

10. The method (100) according to claim 9, characterized by In step c) the total intensity of the diffraction pattern (39), the width (43) of the central maximum (42), the intensity of the central maximum (42), the number of secondary maxima (46), the circumferential position (77) of the secondary maxima (46), the number of secondary minima (44) and / or the circumferential position (77) of the secondary minima (44) are detected.

11. The method (100) according to any one of claims 9 to 10, characterized by, The pressure measuring device (10) is designed according to any one of claims 1 to 8 and / or the evaluation unit (40) is designed to carry out the method (100) according to any one of claims 9 to 11.

12. Pressure measuring system (50) for measuring a pressure (28) in a fluid-filled tube (11), comprising a pressure measuring device (10) connectable to a light source (20), the pressure measuring device being coupled to an evaluation unit (40), characterized in that The pressure measuring device (10) is designed according to any one of claims 1 to 8.

13. A computer program product (80) for simulating the operating behaviour of a pressure measuring device (10) arranged on a fluid-filled pipe (11), characterized in that ​

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