Nuclear magnetic flowmeter
Patent Information
- Application Number
- EP2023786236
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2022-10-07
- Filing Date
- 2023-10-06
- Publication Date
- 2025-08-13
AI Technical Summary
Existing nuclear magnetic flowmeters require extensive work for installing and removing the measuring tube, making them cumbersome and unsuitable for applications where hygiene, purity, and safety are critical, and their measurement accuracy decreases with smaller inner diameters in other types of flowmeters.
A modular nuclear magnetic flowmeter design with a receiving device that allows easy connection and disconnection of the measuring tube, enabling simple assembly and disassembly without requiring extensive work on the flowmeter, and maintaining measurement accuracy even with smaller inner diameters by using a clamp-on configuration and efficient magnetic field generation.
Facilitates easy installation and removal of the measuring tube, maintains measurement accuracy at smaller diameters, and prevents contamination in applications like life sciences and medical industries, while reducing the complexity and cost associated with larger volumes and higher energy consumption.
Smart Images
Figure 1.1
Abstract
Description
[0001] Nuclear magnetic flowmeter
[0002] The invention relates to a nuclear magnetic flowmeter with a measuring tube, a measuring device and a control system.
[0003] The measuring tube has a longitudinal axis. The measuring device comprises a magnetic field generator, an antenna device, and a longitudinal measuring axis. The magnetic field generator is designed to generate a magnetic field extending along the longitudinal measuring axis. The controller is designed to perform nuclear magnetic measurements on a medium in the measuring tube using the antenna device.
[0004] In a nuclear magnetic measurement, a medium is first magnetized by a macroscopic magnetic field. Then, in the presence of the macroscopic magnetic field, the precession of the medium's atomic nuclei is influenced by exciting the atomic nuclei to nuclear magnetic resonances, and the nuclear magnetic resonances are evaluated. Therefore, nuclear magnetic measurements are often referred to as nuclear magnetic resonance measurements or magnetic resonance measurements, and the corresponding measuring instruments are called nuclear magnetic resonance measuring instruments or magnetic resonance measuring instruments. The excitation is achieved by excitation signals, and the resonances are contained in response signals.
[0005] Precession is a property of atomic nuclei of elements that exhibit nuclear spin. One such element is hydrogen. Nuclear spin can be thought of as an angular momentum described by a vector, and accordingly, the magnetic moment caused by nuclear spin can also be described by a vector parallel to the angular momentum vector. The presence of a macroscopic magnetic field causes an excess of atomic nuclei in the medium with magnetic moments aligned parallel to the macroscopic magnetic field, causing the medium to exhibit macroscopic magnetization that can be described in its entirety by a vector. In the presence of a macroscopic magnetic field, the vector of the magnetic moment of an atomic nucleus precesses around the vector of the magnetic field at the location of the atomic nucleus. This is the property of precession.
[0006] An excitation signal generally comprises at least one electromagnetic radio-frequency pulse. For example, an excitation signal comprises an activation pulse and at least one refocusing pulse. An activation pulse causes a nuclear magnetic resonance in the form of a macroscopic magnetization of the medium that is transverse to the magnetic field vector and rotates around the vector of the macroscopic magnetic field. The rotating transverse macroscopic magnetization can be detected as a response signal in the form of a free induction decay and / or, after refocusing, as an echo signal. Thus, a response signal comprises a free induction decay and / or at least one echo signal.Refocusing of the rotating transverse magnetization is necessary when the initial relationship between the precession phases of the individual magnetic moments of the atomic nuclei is disrupted after the activation pulse, for example, by inhomogeneities in the macroscopic magnetic field. Refocusing is achieved by a refocusing pulse, which restores the phase relationship.
[0007] The medium has one or more phases. To determine information about the individual phases, atomic nuclei of the individual phases must be excitable to distinguishable nuclear magnetic resonances. For example, nuclear magnetic resonances differ from one another when longitudinal relaxations of the individual phases have different longitudinal relaxation time constants. Since the multiphase medium produced from oil wells essentially has crude oil and salt water as its liquid phases and natural gas as its gaseous phase, the atomic nuclei of all phases contain hydrogen atom nuclei, and the crude oil and salt water phases in particular are usually characterized by different longitudinal relaxation time constants, nuclear magnetic measuring instruments are well suited for determining information about media produced from oil wells. In principle, nuclear magnetic measuring instruments are suitable for media whose phases contain hydrogen nuclei.
[0008] The nuclear magnetic flowmeter is designed to perform nuclear magnetic measurements on a medium in the measuring tube. A nuclear magnetic measurement provides at least one piece of information about the medium. Such information could be, for example, a property or flow velocity of the medium or a proportion of a phase in the medium if the medium is multiphase. A nuclear magnetic measurement includes, for example, the determination of a longitudinal and / or transverse relaxation time constant and / or a chemical shift.
[0009] The controller is specifically designed to generate excitation signals for the medium and to evaluate reaction signals induced by the excitation signals in the medium. The antenna device is designed to radiate the excitation signals into the medium in the measuring tube and to receive the reaction signals. The magnetic field generator is designed to generate a magnetic field in the medium located in the measuring tube. This is a macroscopic magnetic field. The longitudinal axis of the measuring tube and the longitudinal measurement axis usually coincide. The measuring tube is made of a material that is sufficiently transparent for the magnetic field, the excitation signals, and the reaction signals.
[0010] During operation of the nuclear magnetic flowmeter, a medium is present in the measuring tube. The medium flows, for example, through the measuring tube, with one flow direction of the medium being along the measuring tube's longitudinal axis. However, the medium can also remain stationary in the measuring tube. The medium in the measuring tube is magnetized by the magnetic field generated by the magnetic field generator. The controller performs nuclear magnetic measurements on the magnetized medium in the measuring tube in the magnetic field using the antenna device. For this purpose, nuclear magnetic excitation signals are generated by the controller, transmitted to the antenna device, radiated into the medium by the antenna device, and reaction signals caused by the excitation signals in the medium are received by the antenna device and transmitted to the controller. The controller evaluates the reaction signals.
[0011] In prior art nuclear magnetic flowmeters of the type described, the measuring tube is connected to the rest of the nuclear magnetic flowmeter in such a way that a simple replacement of the measuring tube is not possible. Rather, extensive work on the nuclear magnetic flowmeter, often also on the measuring tube itself, is required to install or remove the measuring tube.
[0012] An object of the present invention is therefore to provide a nuclear magnetic flowmeter of the type described in which the installation and removal of the measuring tube is simplified.
[0013] The problem is solved by a nuclear magnetic flowmeter having the features of patent claim 1.
[0014] The nuclear magnetic flowmeter according to the invention has a receiving device for the measuring tube. The receiving device and the measuring tube can be brought together and separated. When the receiving device and the measuring tube are brought together, the measuring device and the measuring tube can be connected and separated by the receiving device. When the measuring device and the measuring tube are connected, the measuring longitudinal axis and the measuring tube longitudinal axis coincide, and nuclear magnetic measurements can be performed on the medium in the measuring tube by the controller using the antenna device.
[0015] The mounting device thus has connecting means that connect the mounting device and the measuring tube to each other, so that the measuring tube is fixed and aligned within the rest of the nuclear magnetic flowmeter. It is aligned when the measuring axis and the longitudinal axis of the measuring tube coincide. Connecting and disconnecting the connecting means generally only requires work on the connecting means. Therefore, no further work is required on the nuclear magnetic flowmeter. The nuclear magnetic flowmeter is modular, with the measuring tube being one module and the rest of the nuclear magnetic flowmeter being another module.
[0016] The nuclear magnetic flowmeter according to the invention is advantageous because the measuring tube can be easily connected to and detached from the rest of the nuclear magnetic flowmeter.
[0017] This makes it suitable for applications where the measuring tube is already installed in a system, as the measuring tube does not need to be disassembled to install the remaining nuclear magnetic flowmeter; instead, it can be simply joined to the measuring tube by placing it on top of the system. In many applications, disassembling the measuring tube from the system is also very laborious, as the medium in the measuring tube must meet stringent hygiene, purity, and safety requirements.
[0018] Furthermore, the nuclear magnetic flowmeter is also suitable for applications where different media need to be measured and contamination of one medium by another must be avoided. Contamination is avoided by using a measuring tube for each individual medium. Such applications are often found in the life sciences, biotechnology, and medical industries. Such measuring tubes are also referred to as disposable measuring tubes.
[0019] In addition to nuclear magnetic flowmeters, ultrasonic, Coriolis, and electromagnetic flowmeters are also known. What all of these types of flowmeters have in common is that they each have a measuring tube. It has been shown that the measurement accuracy of ultrasonic, Coriolis, and electromagnetic flowmeters decreases with a decreasing inner diameter of the measuring tube, whereas this effect does not occur with nuclear magnetic flowmeters. Therefore, one embodiment of the nuclear magnetic flowmeter provides for an inner diameter of the measuring tube to be less than 9 mm, preferably less than 6 mm, and particularly preferably less than 3 mm.
[0020] The measuring tube and the mounting device can be joined and separated. Joining and separating, or assembly in short, can be done in various ways.
[0021] In one assembly configuration, the mounting device and the measuring tube can be joined and separated by a relative movement along a direction perpendicular to the measuring tube's longitudinal axis. For this purpose, the mounting device typically has a lateral opening through which the measuring tube fits. This configuration is particularly advantageous for a measuring tube already installed in a system, as the remaining core-magnetic flowmeter can be easily attached and removed. This attachment is also referred to as "clamp-on." A core-magnetic flowmeter according to this configuration is also referred to as a clamp-on flowmeter.
[0022] In a further embodiment of the assembly, the mounting device and the measuring tube can be brought together and separated by a relative movement along a direction parallel to the longitudinal measuring axis. For this purpose, the mounting device typically has an opening at the front through which the measuring tube fits.
[0023] During operation of the nuclear magnetic flowmeter, the magnetic field generator generates the magnetic field that magnetizes the medium in the measuring tube and in which the nuclear magnetic measurements are performed. In one embodiment, the magnetic field generator is designed to generate the magnetic field with a direction parallel to the measuring longitudinal axis. Consequently, the magnetic field then extends along the measuring longitudinal axis and has a direction parallel to the measuring longitudinal axis.
[0024] In a further development of the previously described embodiment, the magnetic field generator has a coil arranged on the measuring tube for generating the magnetic field. The coil is preferably a cylindrical coil arranged around the measuring tube. The magnetic field generator is designed to supply electricity to the coil so that it generates the magnetic field during operation. The cylindrical coil arranged around the measuring tube is, for example, wound around the measuring tube. Furthermore, the measuring tube and the receiving device preferably have an electrical plug connection for the electrical supply of the coil by the magnetic field generator. In particular, the electrical plug connection is designed such that it is connected when the measuring device and the measuring tube are brought together and is separated when the measuring device and the measuring tube are separated.
[0025] In a further embodiment, the magnetic field generator is designed to generate the magnetic field in a direction perpendicular to the longitudinal measuring axis. Consequently, the magnetic field then extends along the longitudinal measuring axis and has a direction perpendicular to the longitudinal measuring axis.
[0026] In a further development of the previously described embodiment, the magnetic field generator comprises permanent magnets that generate the magnetic field. Generating the magnetic field using permanent magnets is advantageous because they do not require electrical current and ensure compact dimensions for the nuclear magnetic flowmeter.
[0027] In one embodiment of the nuclear magnetic flowmeter with permanent magnets, the magnetic field generator has a yoke. The yoke arranges the permanent magnets and guides a magnetic flux of the magnetic field. The arrangement of the permanent magnets by the yoke also means that the yoke holds them in place.
[0028] In a further development of the previously described embodiment, the yoke has an opening along the longitudinal measuring axis. This opening is designed such that the receiving device and the measuring tube can be brought together and separated by a movement relative to one another along the direction perpendicular to the longitudinal measuring tube axis. However, if the yoke does not have an opening, then a combination with the embodiment in which the receiving device and the measuring tube can be brought together and separated by a movement relative to one another along the direction parallel to the longitudinal measuring axis is advantageous.
[0029] In a further embodiment of the nuclear magnetic flowmeter with permanent magnets, the yoke comprises a first sub-yoke, a second sub-yoke, and a hinge. The first sub-yoke and the second sub-yoke are pivotally connected to each other by the hinge and can be pivoted into an open and closed state. In the open state, the holding device and the measuring tube can be brought together and separated, and in the closed state, the yoke conducts the magnetic flux of the magnetic field. This embodiment is preferably combined with the previously described clamp-on design.
[0030] In a further development of the previously described embodiment, the permanent magnets are arranged either in the first partial yoke and the second partial yoke, or only in the first partial yoke. In a further embodiment of the nuclear magnetic flowmeter with permanent magnets, the magnetic field generator has a carrier for permanent magnets, and the carrier arranges the permanent magnets in a Halbach array. The Halbach array efficiently guides the magnetic flux of the magnetic field. Particularly preferred is the carrier's design similar to the previously described yoke.
[0031] In a further embodiment of the nuclear magnetic flowmeter, the antenna device is arranged on the measuring tube. Consequently, the receiving device has a connection device for electrically connecting the antenna device. When the measuring tube with the antenna device and the receiving device are brought together, the antenna device and the connection device are electrically connected to one another. When the measuring tube and the receiving device are separated, the antenna device and the connection device are also electrically separated. The connection device and the measuring tube have a corresponding electrical plug connection. Due to its arrangement on the measuring tube, the antenna device is closer to the medium than if it were arranged on the rest of the nuclear magnetic measuring device.Due to the shorter distance between the antenna device and the medium, the signal-to-noise ratio is improved, which also improves the quality of the nuclear magnetic measurements.
[0032] In a further development of the previously described embodiment, a data carrier is arranged on the measuring tube. Calibration data of the antenna device is stored on the data carrier. The data carrier is preferably an RFID tag, a barcode, or a QR code. The controller is configured to perform nuclear magnetic measurements using the calibration data. Preferably, the controller is also configured to read the calibration data from the data carrier when the receiving device and the measuring tube are brought together. This embodiment is preferably combined with disposable measuring tubes.
[0033] The antenna device is designed to transmit the excitation signals into the medium in the measuring tube and to receive the reaction signals of the medium. The reaction signals are generated by the excitation signals in the medium. For this purpose, in one embodiment of the nuclear magnetic flowmeter, the antenna device has at least one coil for transmitting the excitation signals and / or for receiving the reaction signals. Accordingly, the antenna device has, for example, at least one coil for transmitting the excitation signals and for receiving the reaction signals, or at least one coil for transmitting the excitation signals and at least one coil for receiving the reception signals.
[0034] The at least one coil of the nuclear magnetic flowmeter can be designed in different ways.
[0035] In one embodiment, the at least one coil is a surface coil. If the at least one coil is a surface coil, then a combination with a configuration is advantageous in which the receiving device and the measuring tube can be brought together and separated by a movement relative to one another along the direction perpendicular to the measuring tube axis, since the at least one coil provides the space required for this. The at least one surface coil can be designed in various ways.
[0036] In one embodiment, the at least one surface coil is a Helmholtz coil. Preferably, a conductor of the Helmholtz coil is arranged in a round or rectangular shape. The conductor preferably has one turn.
[0037] In a further embodiment, the at least one surface coil is a spiral coil. Preferably, a conductor of the spiral coil is arranged in a round or rectangular shape.
[0038] In a further embodiment, the at least one surface coil is a stripline. The stripline has at least one strip. Preferably, the at least one strip is a line or a conductor track.
[0039] In a further embodiment of the at least one coil, this is a volume coil. Preferably, the volume coil is a saddle coil, a birdcage coil, or a cylindrical coil. Compared to surface coils, volume coils are more efficient at emitting excitation signals and receiving response signals. If the at least one coil is a volume coil, then a combination with a configuration is advantageous in which the receiving device and the measuring tube can be brought together and separated by a movement relative to one another along the direction parallel to the longitudinal measuring axis. This is because, in a saddle coil, a lateral opening in the receiving device, which enables the receiving device and the measuring tube to be brought together and separated by a movement relative to one another along the direction perpendicular to the longitudinal measuring tube axis, is more difficult to implement than a surface coil.In a further embodiment of the nuclear magnetic flowmeter, the antenna device comprises an additional coil. The coil and the additional coil are arranged opposite one another or stacked one above the other with respect to the measuring tube. The additional coil is preferably designed in the same way as the coil.
[0040] The at least one coil can be either a surface or a volume coil. If there is more than one coil, they can be either all surface coils or all volume coils, or even a combination of surface and volume coils.
[0041] The invention also relates to a nuclear magnetic flowmeter comprising a measuring tube, an antenna device, a magnetic field generator and a controller.
[0042] The measuring tube has a bias section and a measuring section. The antenna device is arranged in the measuring section. The magnetic field generator is designed to generate a magnetic field along a magnetic field path. The bias section and the measuring section are arranged entirely within the magnetic field path. The controller is designed to perform nuclear magnetic measurements on a medium in the measuring section of the measuring tube using the antenna device.
[0043] The quality of nuclear magnetic measurements on a medium in the measuring tube correlates with the magnetization of the medium in the measuring tube. Thus, the signal-to-noise ratio of the nuclear magnetic measurements correlates with the magnetization of the medium. A higher magnetization of the medium results in a higher signal-to-noise ratio in the measurements and, consequently, higher measurement quality.
[0044] In the prior art, it is known to increase magnetization in two different ways.
[0045] According to the first type, the magnetic field strength is increased. The magnetic field is generated in the magnetic field generator either by an electromagnet or by permanent magnets. In both cases, increasing the magnetic field strength requires a larger volume and higher cost of the nuclear magnetic flowmeter. The electromagnet requires even higher energy costs.
[0046] According to the second method, the bias section is extended. However, this also means a lengthening of the core-magnetic flowmeter, resulting in a larger volume and higher costs. An object of the present invention is therefore to provide a core-magnetic flowmeter of the type described, in which the magnetization of the medium is increased, but the volume and costs are lower than those known in the prior art.
[0047] The problem is solved, on the one hand, by a nuclear magnetic flowmeter having the features of patent claim 23. This is characterized in that a length of the measuring tube in the pre-magnetization section is greater than a length of the pre-magnetization section.
[0048] In a first embodiment of the nuclear magnetic flowmeter, the measuring tube has at least one loop in the pre-magnetization section. A loop in the measuring tube causes a medium flowing in the measuring tube to have one direction upstream of the loop and a direction opposite to that direction downstream of the loop.
[0049] In a further embodiment, the measuring tube has at least one bend in the pre-magnetization section.
[0050] The problem is solved, on the other hand, by a nuclear magnetic flowmeter having the features of patent claim 26. This is characterized in that the measuring tube has a larger cross-sectional area in the pre-magnetization section than in the measuring section.
[0051] The nuclear magnetic flowmeter can be designed and developed in a variety of ways. Reference is made, on the one hand, to the patent claims subordinate to the independent patent claims and, on the other hand, to the following description of preferred embodiments in conjunction with the drawing. The drawing shows, in an abstract and schematic manner,
[0052] Figure 1 shows a first embodiment of a nuclear magnetic flowmeter in a first state,
[0053] Figure 2 shows the first embodiment in a second state,
[0054] Figure 3 shows a second embodiment of a nuclear magnetic flowmeter in a first state,
[0055] Figure 4 shows the second embodiment in a second state,
[0056] Figure 5 shows a third embodiment of a nuclear magnetic flowmeter with a yoke,
[0057] Figure 6 shows a fourth embodiment of a nuclear magnetic flowmeter with a yoke with an opening,
[0058] Figure 7 shows a fifth embodiment of a nuclear magnetic flowmeter with a two-part yoke, Figure 8 shows a sixth embodiment of a nuclear magnetic flowmeter with a two-part yoke,
[0059] Figure 9 shows a seventh embodiment of a nuclear magnetic flowmeter with a carrier for permanent magnets,
[0060] Figure 10 shows a first embodiment of an antenna device, Figure 11 shows a second embodiment of an antenna device, Figure 12 shows a third embodiment of an antenna device, Figure 13 shows a fourth embodiment of an antenna device, Figure 14 shows a fifth embodiment of an antenna device, Figure 15 shows a sixth embodiment of an antenna device, Figure 16 shows a seventh embodiment of an antenna device, Figure 17 shows an eighth embodiment of an antenna device, Figure 18 shows a ninth embodiment of an antenna device, Figure 19 shows a first embodiment of a measuring tube, Figure 20 shows a second embodiment of a measuring tube and Figure 21 shows a third embodiment of a measuring tube.
[0061] Figure 1 shows a first embodiment of a nuclear magnetic flowmeter 1 in a perspective view in a first state. The nuclear magnetic flowmeter 1 comprises a measuring tube 2, a measuring device 3, and a control unit 4. The measuring tube 2 has a longitudinal axis 5 and an inner diameter of 3 mm.
[0062] The measuring device 3 comprises a magnetic field generator 6, an antenna device 7, a longitudinal measuring axis 8, and a receiving device 9. The receiving device is divided into two parts. The magnetic field generator 6 is designed to generate a magnetic field 10 with a direction 11 perpendicular to the longitudinal measuring axis 8 and extending along the longitudinal measuring axis 8. It has permanent magnets 12 for generating the magnetic field 10. The controller 4 is designed to perform nuclear magnetic measurements on a medium 13 in the measuring tube 2 using the antenna device 7.
[0063] The mounting device 9 and the measuring tube 2 can be joined and separated. The mounting device 9 and the measuring tube 2 can be joined and separated by a movement relative to one another along a direction 14 perpendicular to the measuring tube's longitudinal axis 5. For this purpose, the mounting device 9 has a lateral opening 15 through which the measuring tube 2 fits. In this exemplary embodiment, the measuring tube 2 is already mounted in a system (not shown), and the remaining nuclear magnetic flowmeter 1 can be placed on and removed from the measuring tube 2. This is therefore a clamp-on flowmeter.
[0064] When the receiving device 9 and the measuring tube 2 are brought together, the measuring device 3 and the measuring tube 2 can be connected and detachable by the receiving device 9. When the measuring device 3 and the measuring tube 2 are connected, the measuring longitudinal axis 8 and the measuring tube longitudinal axis 5 coincide, and the controller 4 can perform nuclear magnetic measurements on the medium 13 in the measuring tube 2 using the antenna device 7.
[0065] The first state of the nuclear magnetic flowmeter 1 is characterized by the fact that it is not in operation and is separated from the measuring tube 2. Figure 2 shows the nuclear magnetic flowmeter 1 in a second state. This state is characterized by the fact that it is in operation and is mounted on the measuring tube 2. The medium 13 flows through the measuring tube 2, and the controller 4 performs nuclear magnetic measurements on the medium 13 in the measuring tube 2 using the antenna device 7.
[0066] Further examples of nuclear magnetic flowmeters and components such as antenna devices and measuring tubes are presented below. However, only the differences between the examples are described. Otherwise, the corresponding statements apply.
[0067] Figure 3 shows a second embodiment of a nuclear magnetic flowmeter 1 in a perspective view in a first state and Figure 4 in a second state.
[0068] The second embodiment differs from the first embodiment in that the remaining core-magnetic flowmeter 1 cannot be attached to or removed from the measuring tube 2, but rather the measuring tube 2 can be inserted into and removed from the remaining core-magnetic flowmeter 1. Thus, the core-magnetic flowmeter 1 is stationary, while the measuring tube 2 is movable. The measuring tube 2 is, for example, a disposable measuring tube.
[0069] Figure 5 shows a third embodiment of a nuclear magnetic flowmeter 1. In this embodiment, the magnetic field generator 6 additionally has a yoke 16. The yoke 16 arranges the permanent magnets 12 and guides a magnetic flux of the magnetic field 10. Since the yoke 16 is closed all around, the receiving device 9 and the measuring tube 2 can be brought together and separated by a movement relative to one another along a direction 17 parallel to the longitudinal measuring axis 8.
[0070] Figure 6 shows a fourth embodiment of a nuclear magnetic flowmeter 1. In this embodiment too, the magnetic field generator 6 has a yoke 16. In this embodiment, however, the yoke 16 has an opening 18 along the measuring longitudinal axis 8 compared to the third embodiment. As a result, the receiving device 9 and the measuring tube 2 can be brought together and separated by a movement relative to one another along the direction 14 perpendicular to the measuring tube longitudinal axis 5.
[0071] Figure 7 shows a fifth embodiment of a nuclear magnetic flowmeter 1. In this embodiment, the magnetic field generator 6 has a yoke 16, which has a first partial yoke 19, a second partial yoke 20, and a hinge 21. Consequently, the yoke 16 is divided into the first partial yoke 19 and the second partial yoke 20. The first partial yoke 19 and the second partial yoke 20 are pivotally connected to one another by the hinge 21 and can be pivoted into an open state and a closed state. Figure 7 shows the yoke 16 in the open state. In the open state, the receiving device 9 and the measuring tube 2 can be brought together and separated, and in the closed state, the yoke 16 conducts the magnetic flux of the magnetic field 10. The permanent magnets 12 are arranged in the first partial yoke 19 and the second partial yoke 20.
[0072] Figure 8 shows a sixth embodiment of a nuclear magnetic flowmeter 1. In this embodiment, too, the magnetic field generator 6 has a yoke 16, which comprises a first partial yoke 19, a second partial yoke 20, and a hinge 21. In contrast to the fifth embodiment, however, the permanent magnets 12 are arranged only in the first partial yoke 19. Figure 8 shows the yoke 16 in the open state.
[0073] Figure 9 shows a seventh embodiment of a nuclear magnetic flowmeter 1. The magnetic field generator 6 has a carrier 22 in which the permanent magnets 12 are arranged in a Halbach array. In this embodiment, the carrier 22 is additionally designed similarly to the yoke 16. Specifically, the carrier 22 has a first sub-carrier 23, a second sub-carrier 24, and a hinge 25. The first sub-carrier 23 and the second sub-carrier 24 are pivotally connected to one another by the hinge 25 and can be pivoted into an open state and a closed state. In the open state, the receiving device 9 and the measuring tube 2 can be brought together and separated, and in the closed state, the permanent magnets 12 form the Halbach array.
[0074] Figure 9 shows the carrier 22 in the open state.
[0075] The following presents exemplary embodiments of an antenna device 7 of a nuclear magnetic flowmeter 1. The exemplary embodiments of the antenna device 7 comprise surface coils and / or volume coils. First, exemplary embodiments are described which comprise a first coil 26 and a second coil 27, both of which are designed as surface coils.
[0076] Figure 10 shows a first embodiment of an antenna device 7 with a first coil 26 and a second coil 27, each of which is a surface coil, specifically a Helmholtz coil. The first coil 26 and the second coil 27 are arranged opposite one another with respect to a measuring tube 2. In this embodiment, a conductor 28 of each of the two coils 26, 27 is arranged in a round shape.
[0077] Figure 11 shows a second embodiment of an antenna device 7. It differs from the first embodiment in that a conductor 28 of each of the two coils 26, 27 is arranged in a square shape.
[0078] Figure 12 shows a third embodiment of an antenna device 7 with a first coil 26 and a second coil 27, each of which is a surface coil, specifically a spiral coil. The first coil 26 and the second coil 27 are arranged opposite one another with respect to a measuring tube 2. In this embodiment, a conductor 28 of each of the two coils 26, 27 is arranged in a round shape.
[0079] Figure 13 shows a fourth embodiment of an antenna device 7. It differs from the third embodiment in that a conductor 28 of each of the two coils 26, 27 is arranged in a square shape.
[0080] Figure 14 shows a fifth embodiment of an antenna device 7 with a first coil 26 and a second coil 27, each of which is a surface coil, specifically a stripline with a strip 29. The first coil 26 and the second coil 27 are arranged opposite one another with respect to a measuring tube 2. The strip 29 is a conductor track.
[0081] Figure 15 shows a sixth embodiment of an antenna device 7. It differs from the fifth embodiment in that the strip lines each have three strips 29.
[0082] Following the exemplary embodiments of an antenna device 7 having surface coils, exemplary embodiments having one or two volume coils are described below. Figure 16 shows a seventh exemplary embodiment of an antenna device 7 with a first coil 26 and a second coil 27, each of which is a volume coil, specifically a saddle coil. The first coil 26 and the second coil 27 are arranged opposite one another with respect to a measuring tube 2.
[0083] Figure 17 shows an eighth embodiment of an antenna device 7 with a first coil 26, which is a volume coil, namely a birdcage coil.
[0084] Figure 18 shows a ninth embodiment of an antenna device 7 with a first coil 26, which is a volume coil, namely a cylindrical coil.
[0085] In the following, embodiments of a measuring tube 2 of a nuclear-magnetic flowmeter 1 are presented, which increase a magnetization of a medium 13.
[0086] Figure 19 shows a first embodiment of a measuring tube 2 of a nuclear magnetic flowmeter 1. The nuclear magnetic flowmeter 1 also has an antenna device 7, a magnetic field generator 6 and a controller 4.
[0087] The measuring tube 2 has a bias section 30 and a measuring section 31, and the antenna device 7 is arranged in the measuring section 31. The magnetic field generator 6 is designed to generate a magnetic field 10 along a magnetic field path 32, and the bias section 30 and the measuring section 31 are arranged entirely in the magnetic field path 32. The controller 4 is designed to perform nuclear magnetic measurements on a medium 13 in the measuring section 31 of the measuring tube 2 using the antenna device 7.
[0088] The measuring tube 2 has a loop 33 in the pre-magnetization section 30, whereby a length of the measuring tube 2 in the pre-magnetization section 30 is greater than a length of the pre-magnetization section 30.
[0089] Figure 20 shows a second embodiment of a measuring tube 2. This differs from the first embodiment in that the measuring tube 2 has a plurality of bends 34 in the pre-magnetization section 30, whereby a length of the measuring tube 2 in the pre-magnetization section 30 is greater than a length of the pre-magnetization section 30.
[0090] Figure 21 shows a third embodiment of a measuring tube 2. This differs from the two preceding embodiments in that the measuring tube 2 has a larger cross-sectional area in the pre-magnetization section 30 than in the measuring section 31. The measuring tube 2 of the second embodiment of a nuclear magnetic flowmeter, see Figures 3 and 4, is designed in the same way.
[0091] Reference symbol
[0092] 1 core magnetic flow meter
[0093] 2 measuring tube
[0094] 3 Measuring device
[0095] 4 Control
[0096] 5 Me s srohrläng sachs e
[0097] 6 Magnetic field generator
[0098] 7 Antenna device
[0099] 8 Measuring longitudinal axis
[0100] 9 Mounting device
[0101] 10 Magnetic field
[0102] 11 Direction perpendicular to the measuring longitudinal axis
[0103] 12 permanent magnet
[0104] 13 Medium
[0105] 14 Direction perpendicular to the measuring tube longitudinal axis
[0106] 15 Opening of the receiving device
[0107] 16 yoke
[0108] 17 Direction parallel to the measuring longitudinal axis
[0109] 18 Opening of the yoke
[0110] 19 first partial yoke
[0111] 20 second partial yoke
[0112] 21 Hinge
[0113] 22 carriers
[0114] 23 first sub-carrier
[0115] 24 second sub-carrier
[0116] 25 hinge
[0117] 26 first coil
[0118] 27 second coil
[0119] 28 ladders
[0120] 29 stripes
[0121] 30 Premagnetization section
[0122] 31 measuring section
[0123] 32 magnetic field section
[0124] 33 Loop
[0125] 34 Bend
Claims
Patent claims 1. Nuclear magnetic flowmeter (1) with a measuring tube (2), a measuring device (3) and a controller (4), wherein the measuring tube (2) has a measuring tube longitudinal axis (5), wherein the measuring device (3) has a magnetic field generator (6), an antenna device (7) and a measuring longitudinal axis (8), wherein the magnetic field generator (6) is designed to generate a magnetic field (10) extending along the measuring longitudinal axis (8), and wherein the controller (4) is designed to carry out nuclear magnetic measurements on a medium (13) in the measuring tube (2) using the antenna device (7), characterized in that the measuring device (3) has a receiving device (9) for the measuring tube (2), that the receiving device (9) and the measuring tube (2) can be brought together and separated, that the measuring device (3) and the measuring tube (2), when the receiving device (9) and the measuring tube (2) are merged,are connectable and detachable from one another by the receiving device (9) and that, when the measuring device (3) and the measuring tube (2) are connected to one another, the measuring longitudinal axis (8) and the measuring tube longitudinal axis (5) coincide and nuclear magnetic measurements can be carried out by the controller (4) on a medium (13) in the measuring tube (2) using the antenna device (7).
2. Nuclear magnetic flowmeter (1) according to claim 1, characterized in that an inner diameter of the measuring tube (2) is less than 9 mm, preferably less than 6 mm and particularly preferably less than 3 mm.
3. Nuclear magnetic flowmeter (1) according to claim 1 or 2, characterized in that the receiving device (9) and the measuring tube (2) can be brought together and separated by a movement relative to each other along a direction (14) perpendicular to the measuring tube longitudinal axis (5).
4. Nuclear magnetic flowmeter (1) according to one of claims 1 to 3, characterized in that the receiving device (9) and the Measuring tubes (2) can be brought together and separated by a movement relative to one another along a direction (17) parallel to the measuring longitudinal axis (8).
5. Nuclear magnetic flowmeter (1) according to one of claims 1 to 4, characterized in that the magnetic field generator (6) for generating the magnetic field (10) is designed with a direction (17) parallel to the measuring longitudinal axis.
6. Nuclear magnetic flowmeter (1) according to claim 6, characterized in that the magnetic field generator (6) has a coil arranged on the measuring tube (2) for generating the magnetic field (10) and that the coil is preferably a cylindrical coil arranged around the measuring tube (2).
7. Nuclear magnetic flowmeter (1) according to one of claims 1 to 4, characterized in that the magnetic field generator (6) is designed to generate the magnetic field (10) with a direction (11) perpendicular to the measuring longitudinal axis 8. Nuclear magnetic flowmeter (1) according to claim 7, characterized in that the magnetic field generator (6) has permanent magnets (12) for generating the magnetic field (10).
9. Nuclear magnetic flowmeter (1) according to claim 8, characterized in that the magnetic field generator (6) has a yoke (16) and that the yoke (16) arranges the permanent magnets (12) and guides a magnetic flux of the magnetic field (10).
10. Nuclear magnetic flowmeter (1) according to claim 9, characterized in that the yoke (16) has an opening (15) along the measuring longitudinal axis (8) so that the receiving device (9) and the measuring tube (2) can be brought together and separated by a movement relative to one another along the direction (14) perpendicular to the measuring tube longitudinal axis (5).
11. Nuclear magnetic flowmeter (1) according to claim 9 or 10, characterized in that the yoke (16) has a first partial yoke (19), a second partial yoke (20) and a hinge (21), that the first partial yoke (19) and the second partial yoke (20) are pivotally connected to one another by the hinge (21) and can be pivoted into an open state and a closed state, that in the open state the receiving device (9) and the measuring tube (2) can be brought together and separated and that in the closed state the yoke (16) conducts the magnetic flux of the magnetic field (10).
12. Nuclear magnetic flowmeter (1) according to claim 11, characterized in that the permanent magnets (12) are arranged either in the first partial yoke (19) and in the second partial yoke (20) or only in the first partial yoke (19).
13. Nuclear magnetic flowmeter (1) according to claim 8, characterized in that the magnetic field generator (6) has a carrier (22) for the permanent magnets (12) and that the carrier (22) arranges the permanent magnets (12) in a Halbach array.
14. Nuclear magnetic flowmeter (1) according to one of claims 1 to 13, characterized in that the antenna device (7) is arranged on the measuring tube (2).
15. Nuclear magnetic flowmeter (1) according to claim 14, characterized in that a data carrier is arranged on the measuring tube (2), that calibration data of the antenna device (7) are stored on the data carrier and that preferably the data carrier is an RFID tag, a barcode or a QR code.
16. Nuclear magnetic flowmeter (1) according to one of claims 1 to 15, characterized in that the antenna device (7) has at least one coil (26, 27) for transmitting energization signals and / or for receiving reaction signals caused by the energization signals.
17. Nuclear magnetic flowmeter (1) according to claim 16, characterized in that the at least one coil (26, 27) is a surface coil.
18. Nuclear magnetic flowmeter (1) according to claim 17, characterized in that the at least one coil (26, 27) is a Helmholtz coil, that preferably a conductor (28) of the Helmholtz coil is arranged in a round or oval or elliptical or rectangular shape and that preferably the conductor has a single turn.
19. Nuclear magnetic flowmeter (1) according to claim 17, characterized in that the at least one coil (26, 27) is a spiral coil and that preferably a conductor (28) of the spiral coil is arranged in a round or rectangular shape.
20. Nuclear magnetic flowmeter (1) according to claim 16, characterized in that the at least one coil (26, 27) is a strip line, that the strip line has at least one strip (29) and that preferably the at least one strip (29) is a line or a conductor track.
21. Nuclear magnetic flowmeter (1) according to claim 16, characterized in that the at least one coil (26, 27) is a volume coil and that preferably the volume coil is a saddle coil, a birdcage coil or a cylinder coil.
22. Nuclear magnetic flowmeter (1) according to one of claims 16 to 21, characterized in that the antenna device (7) has a further coil (27) and that the coil (26) and the further coil (27) are arranged opposite one another or stacked one above the other with respect to the measuring tube (2).
23. Nuclear magnetic flowmeter (1) with a measuring tube (2), an antenna device (7), a magnetic field generator (6) and a controller (4), wherein the measuring tube (2) has a bias section (30) and a measuring section (31) and the antenna device (7) is arranged in the measuring section (31), wherein the magnetic field generator (6) is designed to generate a magnetic field (10) along a magnetic field path (32) and the bias section (30) and the measuring section (31) are arranged completely in the magnetic field path (32), and wherein the controller (4) is designed to carry out nuclear magnetic measurements on a medium (13) in the measuring section (31) of the measuring tube (2) using the antenna device (7), characterized in that a length of the measuring tube (2) in the bias section (30) is greater than a length of the bias section (30).
24. Nuclear magnetic flowmeter (1) according to claim 23, characterized in that the measuring tube (2) has at least one loop (33) in the pre-magnetization section (30).
25. Nuclear magnetic flowmeter (1) according to claim 23 or 24, characterized in that the measuring tube (2) has at least one bend (34) in the pre-magnetization section (30).
26. Nuclear magnetic flowmeter (1) with a measuring tube (2), an antenna device (7), a magnetic field generator (6) and a control (4), wherein the measuring tube (2) has a bias section (30) and a measuring section (31) and the antenna device (7) is arranged in the measuring section (31), wherein the magnetic field generator (6) is designed to generate a magnetic field (10) along a magnetic field path (32) and the bias section (30) and the measuring section (31) are arranged completely in the magnetic field path (32), and wherein the controller (4) is designed to carry out nuclear magnetic measurements on a medium (13) in the measuring section (31) of the measuring tube (2) using the antenna device (7), characterized in that the measuring tube (2) has a larger cross-sectional area in the bias section (30) than in the measuring section (31).