Hand-Held Measuring Device having an NMR Sensor and Method for the Operation Thereof

Abstract

A mobile measuring device, in particular a hand-held measuring device, comprises a housing, in which at least one sensor device, a control device for controlling the sensor device, an evaluation device for evaluating the measurement signals supplied by the sensor device as well as a device for supplying energy to the measuring device are provided. The sensor device comprises at least one nuclear spin resonance sensor which is provided at least for the detection and/or analysis and/or differentiation of a material characteristic of a workpiece, in particular in a workpiece.

Claims

1. A mobile measuring device, comprising: a housing; a sensor device at least partially located in the housing; a control device configured to control the sensor device; an analysis device configured to analyze measuring signals supplied by the sensor device; and a device for a power supply of the measuring device, wherein the sensor device has at least one nuclear magnetic resonance sensor configured to detect, analyze, and/or differentiate a material characteristic value of a workpiece.

2. The measuring device as claimed in claim 1, further comprising: an input device configured to input operating parameters.

3. The measuring device as claimed in claim 2, further comprising: an output device configured to output operating parameters and/or analysis results.

4. The measuring device as claimed in claim 3, wherein at least one of the input device and the output device is arranged on a first housing side.

5. The measuring device as claimed in claim 1, wherein the nuclear magnetic resonance sensor has a receiving coil configured to detect a magnetic field change.

6. The measuring device as claimed in claim 4, wherein: the nuclear magnetic resonance sensor has a first device configured to generate a first magnetic field and a second device configured to generate a second magnetic field, the second magnetic field is superimposed on the first magnetic field, the control device has at least one control unit configured to control the second device, and the control unit is configured to modify the second magnetic field to generate pulse sequences.

7. The measuring device as claimed in claim 6, wherein: the first magnetic field is aligned substantially in parallel to a second housing side of the measuring device, and the second magnetic field is aligned substantially perpendicularly to the first magnetic field.

8. The measuring device as claimed in claim 6, wherein: at least one of the first device and the second device is at least partially enclosed by at least one magnetic shield, and the nuclear magnetic resonance sensor has at least one homogenizing device configured to homogenize the magnetic fields generated by the first and/or the second device.

9. (canceled)

10. The measuring device as claimed in claim 6, wherein: the second device is implemented as nondestructively replaceable and includes a high frequency coil.

11. The measuring device as claimed in claim 6, wherein the first and second magnetic fields define a sensitive region of the nuclear magnetic resonance sensor extending substantially in parallel to and spaced apart from a second housing side outside the housing of the measuring device.

12. The measuring device as claimed in claim 11, wherein the sensitive region of the nuclear magnetic resonance sensor is displaceable perpendicularly to the second housing side of the measuring device outside the housing by 1 cm to 3 cm.

13. The measuring device as claimed in claim 11, wherein the second housing side of the measuring device is opposite to the first housing side accommodating the input device and/or the output device on a rear side of the device.

14. The measuring device as claimed in claim 6, wherein the analysis device is configured to analyze at least one amplitude and/or the measuring signal supplied by the sensor device resulting from the excitation of the nuclear spins in a workpiece by the second magnetic field.

15. The measuring device as claimed in claim 14, wherein the analysis device analyzes the measuring signals supplied by the sensor device, at least to determine: a relative and/or absolute hydrocarbon content; bonding states of chemical compounds; concentration gradients of a material into the workpiece; chronological-dynamic processes of chemical compounds; a relative and/or absolute moisture content; and/or further construction-relevant parameters including salt content, composition, and/or porosity of the material of the workpiece with depth resolution.

16. The measuring device as claimed in claim 1, further comprising: a position determination device configured to capture at least one instantaneous position and/or alignment of the measuring device in relation to the workpiece; and at least one memory device configured to store measurement results and/or operating parameters.

17. The measuring device as claimed in claim 16, wherein: the analysis device is configured to analyze the measuring signals of the sensor device as a function of a position and/or alignment of the measuring device in relation to the workpiece, and the analysis device is further configured to carry out the detection, the analysis, and/or the differentiation of the material characteristic value based on measuring signals of the sensor device which relatively change as a function of the position and/or the alignment of the measuring device in relation to the workpiece.

18. (canceled)

19. (canceled)

20. The measuring device as claimed in claim 1, wherein the control device and/or the analysis device has a data communication interface configured for wireless communication to enable the measuring device to transmit and/or to receive measurement results and/or operating parameters.

21. The measuring device as claimed in claim 3, wherein: the control device has a first operating mode, in which specifications on a workpiece are specified by user inputs and/or provided to the measuring device, and the control device has a second operating mode, in which output parameters of the output device are specified and/or provided to the measuring device.

22. (canceled)

23. The measuring device as claimed in claim 1, wherein the sensor device comprises at least one further sensor from a group of sensors which comprises at least sensors sensitive to induction, capacitance, ultrasound, temperature, radiation, inclination, angle, magnetic field, acceleration, rotation rate, and moisture.

24. A method for detecting, differentiating, and/or analyzing a material characteristic value in a workpiece comprising: generating a first magnetic field in the workpiece with a first device arranged in the measuring device; generating high-frequency pulses in the workpiece with a second device of the measuring device, the second device including a high-frequency coil; detecting at least one amplitude and/or a relaxation time of a measuring signal resulting from the excitation of nuclear spins in the workpiece based on an electric current induced in a receiving coil and/or an induced voltage; extracting Larmor frequencies from the measuring signal induced in the receiving coil; and analyzing measuring signals of the nuclear magnetic resonance sensor for the differentiation and/or the analysis of the material characteristic value in the workpiece with an analysis device of the measuring device.

Description

DRAWINGS

[0097] The invention is explained in greater detail in the following description on the basis of exemplary embodiments illustrated in the drawings. The drawings, the description, and the claims contain numerous features in combination. A person skilled in the art will expediently also consider the features individually and combine them to form advantageous further combinations. Identical or similar reference signs in the figures identify identical or similar elements.

[0098] In the figures:

[0099] FIG. 1 shows a perspective illustration of one embodiment of the mobile measuring device according to the invention,

[0100] FIG. 2 shows a view of the first housing side of one embodiment of the measuring device according to the invention,

[0101] FIG. 3 shows a schematic side view of one embodiment of the measuring device according to the invention,

[0102] FIG. 4a shows a schematic and simplified illustration of one embodiment of the components forming the nuclear magnetic resonance sensor and the magnetic fields generated thereby,

[0103] FIG. 4b shows a schematic and simplified illustration of one alternative embodiment of the components forming the nuclear magnetic resonance sensor and the magnetic fields generated thereby,

[0104] FIG. 5 shows a perspective view of the second housing side of one embodiment of the mobile measuring device according to the invention.

DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

[0105] FIG. 1 and FIG. 2 show two views of one exemplary embodiment of the handheld measuring device 10 according to the invention in a perspective illustration and in a simplified, schematic view, respectively.

[0106] The handheld measuring device 10 embodied as an example has a housing 12, an input device in the form of actuating elements 14, suitable for turning the handheld measuring device on and off, for starting and configuring a measuring procedure, and for inputting operating parameters, and an output device for outputting operating parameters and/or analysis results in the form of a display screen 16. The handheld measuring device 10 has a handle 18 for transport and for the guiding thereof. The handle 18, the actuating elements 14, and the display screen 16 are located on a first housing side 20 of the measuring device 10 (also “front side”), which typically faces toward the user during operation of the measuring device.

[0107] For the power supply of the handheld measuring device 10, the device has a recess, which is preferably suitable for accommodating energy accumulators 22 independent of the power network, in particular batteries or rechargeable batteries, on the second housing side 40 (also referred to as the rear side of the measuring device hereafter), which is opposite to the first housing side 20 on the device rear side. The device presented as an example has lithium-ion rechargeable batteries, the high energy density and power density of which is advantageously suitable for the power supply of the measuring device. In one alternative embodiment, the energy accumulator 22 can also be housed in the handle 18 of the measuring device 10. The device for power supply advantageously has a detachable form-fitted and/or friction-locked connection interface, so that the energy accumulator 22 (generally a plurality thereof) can be arranged in a removable and replaceable manner. In addition, the energy accumulator 22 may also be supplied with power from a power network and charged in and/or outside the measuring device.

[0108] The position determination device of the handheld measuring device comprises, in the exemplary embodiment, four wheels 24, by means of which the handheld measuring device 10 can be moved along the surface 44 of a workpiece 42 (cf. FIG. 3). Sensors which are sensitive to a rotation of the wheels capture a movement of the measuring device 10 and therefore enable measurement results to be related to a position of the measuring device, in particular in relation to the workpiece 42. In one alternative embodiment of the measuring device 10, the position determination device can have an optical distance transducer instead of the wheels, for example. For more precise position determination, in addition further sensors can also be provided, in particular sensors sensitive to inclination, angle, translation, acceleration, and rotation rate. After placing the handheld measuring device 10 on the surface 44 of a workpiece 42 to be measured, for example, on a wall or on a concrete floor, the position change of the handheld measuring device as a consequence of a movement of the device on the workpiece is ascertained. These position data are relayed to an analysis device 30 for further analysis.

[0109] Further components of the measuring device, in particular a sensor device 32 having a nuclear magnetic resonance sensor 32′, a control device 28 for controlling the sensor device 32, an analysis device 30 for analyzing measuring signals supplied by the sensor device 32, and a data communication interface 54 connected to the control and/or analysis device are housed on a carrier element 26, in particular a system circuit board or printed circuit board inside the housing 12 (see in particular FIG. 2).

[0110] The nuclear magnetic resonance sensor 32′, which is explained in detail in FIGS. 4a and 4b, is provided for exciting nuclear magnetic resonance in atomic nuclei of the material of the workpiece 42. According to the invention, the measured resonance signal is used at least for the nondestructive detection and/or analysis and/or differentiation of a material characteristic value, in particular of material inclusions 60, 60′, 60″, in the workpiece 42, i.e., for ascertaining items of information which relate, inter alia, to a relative and/or absolute hydrocarbon content and/or bonding states of chemical compounds and/or concentration gradients of a material into the workpiece and/or chronological-dynamic processes of chemical compounds and/or a relative and/or absolute moisture content and/or further construction-relevant parameters, in particular salt content, composition, and/or porosity of the material of the workpiece. The control device 28 has a control electronics unit comprising means for communication with the other components of the measuring device, for example, means for controlling and regulating the sensor device 32 and the measuring device. The control device 28 comprises in particular a unit having a processor unit, a memory unit, and an operating program stored in the memory unit. The control device 28 is provided for the purpose of setting at least one operating functional parameter of the measuring device depending on at least one input by the user, by the analysis device, and/or by the data communication interface.

[0111] The analysis device 30 for analyzing measuring signals supplied by the sensor device 32, optionally also for analyzing measuring signals of further sensor devices of the handheld measuring device 10, has in particular an information input, an information processing unit, and an information output. The analysis device 30 advantageously at least consists of a processor, a memory having an operating program stored and executable thereon, and enables at least one measuring signal of the nuclear magnetic resonance sensor 32′ to be analyzed and items of information to be determined with respect to the detection and/or analysis and/or differentiation of material inclusions 60, 60′, 60″ in a workpiece. The analysis device particularly advantageously has stored correction and/or calibration tables, which enable the analysis results to be interpreted, converted, interpolated and/or extrapolated, and also the measuring device, in particular the analysis routines, to be calibrated with respect to a workpiece material. The analysis results are output by the analysis device 30 for further use via the control device 28 either directly to a user of the measuring device 10 or for transmitting the data to the data communication interface 54.

[0112] For the measurement of a nuclear magnetic resonance signal of a workpiece 42, in particular for the detection and/or analysis and/or differentiation of material inclusions 60, 60′, 60″ in this workpiece, the measuring device 10 is positioned having its second housing side 40, i.e., the device rear side, in a planar manner in the immediate vicinity of the workpiece 42, in particular in contact with the surface 44 thereof. In this case, the magnetic fields 34, 36 generated by the nuclear magnetic resonance sensor 32′ penetrate through the second housing side 40 out of the measuring device 10 and into the workpiece 42, wherein the sensitive region 38 comes to rest in the workpiece (see in particular FIG. 3). Magnetic field changes as a result of a nuclear magnetic resonance effect of the nuclear spins of the atomic nuclei excited in the material of the workpiece 42, i.e., caused by absorption and/or emission of electromagnetic fields by the atomic nuclei accompanied by a change of the energy states thereof, can be detected by means of a receiving coil 68 of the nuclear magnetic resonance sensor 32′. This measuring signal, in particular the amplitude and relaxation times thereof, is relayed to the analysis device 30, by which it is analyzed and prepared by means of analysis routines and relayed to an output device 16. The analyzed measurement result is displayed to the user on the display screen 16 and can alternatively be transmitted via the data communication interface 54 to a further data processing device. The output on the display screen 16 can be graphic, numeric, and/or alphanumeric, for example, in the form of a measured value, a measuring curve, a signal curve, a time curve, as image data, or in a gradient representation and also in a combination thereof. Alternatively or additionally, a display is possible by means of a signal display, in particular, for example, a light-emitting diode which evaluates a target variable via a color coding, for example (for example, red, yellow, green).

[0113] The positioning of the measuring device 10, in particular the nuclear magnetic resonance sensor 32′ contained therein, in the immediate vicinity of the workpiece surface enables the detection and/or analysis and/or differentiation of material inclusions 60, 60′, 60″ to a material depth of several centimeters into the workpiece 42.

[0114] FIG. 3 shows the embodiment according to the invention of the handheld measuring device 10 of FIGS. 1 and 2 in a simplified schematic side view. The nuclear magnetic resonance sensor 32′ comprises two devices for generating magnetic fields, in particular a permanent magnet arrangement 46, 46′ (cf. FIG. 4a), which generates a first magnetic field 34, and a high-frequency coil 48 (cf. FIG. 4a), which generates a second magnetic field 36. The nuclear magnetic resonance sensor 32′ is configured such that the first magnetic field 34 is aligned substantially in parallel to the second housing side 40, while the second magnetic field 36 is aligned substantially perpendicularly to the magnetic field lines of the first magnetic field 34. The two magnetic fields are superimposed in an extended region in which in particular the sensitive region 38 of the nuclear magnetic resonance sensor 32′ is also located, as a layered region in particular. The handheld measuring device 10 is positioned having the second housing side 40 in the immediate vicinity of a workpiece 42 to be examined, so that the distance between the second housing side 40 and the workpiece surface 44 is minimized. In this manner, the magnetic fields 34, 36 penetrate into the workpiece and the sensitive region 38 comes to rest in the workpiece 42.

[0115] By variation of the second magnetic field 36 generated by the second device, i.e., in particular by variation of the high-frequency coil 48 and/or variation of the frequency and/or variation of the current and/or variation of the voltage in the high-frequency coil 48, it is possible to change the sensitive region 38 in its distance to the second housing side 40 and therefore to modify the distance of the sensitive region 38 in the workpiece to the workpiece surface 44 thereof. Alternatively and/or additionally, the nuclear magnetic resonance sensor 32′ can be repositioned in the housing 12 of the handheld measuring device 10 such that the distance of the nuclear magnetic resonance sensor 32′ to the second housing side 40 is changed and therefore the distance of the sensitive region 38 in the workpiece 42 to the workpiece surface 44 thereof is also changed. In this manner, depth profiles of the parameters to be analyzed, in particular material concentration depth profiles, may be particularly advantageously prepared. For example, it is possible to make a statement about the permissible drilling depth into the workpiece 42 via a depth profile of a material inclusion 60, 60′, 60″ to be detected in a workpiece 42, before the material inclusion 60, 60′, 60″ is encountered.

[0116] FIG. 4a shows a simplified and schematic illustration of the components of one embodiment of the nuclear magnetic resonance sensor 32′ according to the invention. Two permanent magnets 46, 46′, which are arranged perpendicularly to the second housing side 40 and antiparallel to one another, generate a first, in particular static magnetic field 34, which extends substantially in parallel to the surface of the second housing side 40. This first magnetic field, which is provided for aligning the nuclear spins of the atomic nuclei provided in the material sample, has, for example, in particular a magnetic field strength of 0.5 Tesla, wherein the permanent magnets are produced from a neodymium-iron-boron alloy. The second device for generating the second magnetic field is formed in this exemplary embodiment by a high-frequency coil 48. As soon as current flows through this coil, an electromagnetic field, in particular the second magnetic field 36, is induced. The two magnetic fields are superimposed in a region which is located substantially outside the housing 12 of the measuring device 10. The sensitive region 38 of the nuclear magnetic resonance sensor 32′ is also in the superposition field of the magnetic fields 34 and 36. As a function of the frequency of the irradiated electromagnetic field 36 and the static magnetic field strength of the first magnetic field 34, the sensitive region is defined in the ideal case by an area, on which the magnetic field strength of the first magnetic field 34 is constant and in particular has a defined absolute value. In reality, the area is actually layered as a result of inexact frequencies. Because the magnetic field lines 34 do not extend exactly in parallel to the second housing side 40, the sensitive region 38 is therefore also curved in accordance with the magnetic field lines. The curvature and formation of the first magnetic field 34 and therefore of the sensitive region 38 can be influenced and in particular homogenized using further means, for example, a shim coil 56 and a magnetic shield 58.

[0117] FIG. 4b shows a simplified and schematic illustration of the components of an alternative embodiment of the nuclear magnetic resonance sensor 32′ according to the invention. In this case, the first, in particular static magnetic field 34, which is generated by the first device, two permanent magnets 46, 46′ arranged in parallel to the second housing side and collinearly here (in north-south/north-south sequence), is aligned substantially in parallel to a second housing side 40 of the measuring device 10 and the second magnetic field 36, which is generated by the second device, a high-frequency coil 48 here, is aligned substantially perpendicularly to the first magnetic field 34. A high-frequency coil 48, the winding plane of which is collinear to the extension direction of the permanent magnets 46, 46′ and parallel to the second housing side 40, is located between the two permanent magnets 46, 46′. This arrangement is positioned in the immediate vicinity of the second housing side 40. As soon as current flows through this coil, an electromagnetic field, in particular the second magnetic field 36, is induced. The two magnetic fields are superimposed in a region which is located substantially outside the housing 12 of the measuring device 10. The sensitive region 38 of the nuclear magnetic resonance sensor 32′ is also located in the superposition field of the magnetic fields 34 and 36. As a function of the frequency of the irradiated electromagnetic field 36 and the static magnetic field strength of the first magnetic field 34, the sensitive region is defined in the ideal case by an area, on which the magnetic field strength of the first magnetic field 34 is constant and in particular has a defined absolute value. In reality, the area is actually layered as a result of inexact frequencies. Because the magnetic field lines 34 do not extend exactly in parallel to the second housing side 40, the sensitive region 38 is therefore also curved in accordance with the magnetic field lines. The curvature and formation of the first magnetic field 34 and therefore of the sensitive region 38 can be influenced and in particular homogenized using further means, for example, a shim coil 56 and a magnetic shield 58.

[0118] FIG. 5 shows a perspective, simplified illustration of a top view of the second housing side 40, i.e., the rear side of the handheld measuring device 10. The receptacle of the energy accumulator 22, in particular a battery or a rechargeable battery, is directly accessible under a housing flap (dashed lines) on this second housing side 40. A second housing flap 52, shown open in the figure, enables the access to the high-frequency coil 48. The connection plugs 50 of the high-frequency coil 48 are particularly advantageously embodied as detachable, i.e., in particular nondestructively disconnectable. In this manner, the high-frequency coil 48 is replaceable with high-frequency coils having a different characteristic, i.e., which differ in particular with respect to the number of turns, type of turns, geometry, and wire thickness thereof. This possibility for the variation of the high-frequency coil 48 advantageously enables the second magnetic field 36 generated by the high-frequency coil 48 to be modified and in particular to be adapted and optimized to the conditions of the workpiece material. In this simplified illustration, the further components of the nuclear magnetic resonance sensor 32′ from FIG. 4a are not shown.