• 专利附录
  • 专利说明
  • 权利要求
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    • 专利摘要:
    The invention relates to an NMR measuring arrangement with tempering device for a sample tube (1) surrounded by a temperature control fluid (8), which is tempered in the inflow to the measuring space (14) by a controlled heater (12), wherein a temperature sensor (9) is provided, whose measuring head protrudes spatially adjacent to the sample tube into the measuring chamber, while the supply lines to the measuring head of the temperature sensor are arranged in a space separated from the measuring space. The temperature sensor together with supply lines is surrounded by a sensor tube (15) at a radial distance, which is connected to the measuring chamber via a sensor flow inlet (26) such that a partial flow of the tempering fluid as tempering flow (16) into the free space (17) between the temperature sensor and the inner wall of the sensor tube flows along the supply lines and flows out of the sensor tube via a sensor flow outlet (18) at the opposite end of the sensor tube. This minimizes both temperature penetration and the difference between sensor and sample temperature (ΔTp).
    公开号:CH706981B1
    申请号:CH01534/13
    申请日:2013-09-09
    公开日:2017-08-15
    发明作者:Gisler Philipp；Wilhelm Dirk；Pfenninger Christoph
    申请人:Bruker Biospin Ag；
    IPC主号:
    专利说明:

    Description: The invention relates to an NMR measuring arrangement with a tempering device for a solid and / or liquid sample substance filled NMR sample tube, which is arranged in a measuring position in an NMR spectrometer in a measuring space surrounded by NMR coils and of a Tempering fluid is flowed around, which is tempered in the influx to the measuring chamber by a controlled heater, wherein at least one temperature sensor is provided, the temperature-sensitive measuring head is positioned in spatial proximity to the NMR sample tube and at least partially projects into the measuring space, while the leads to the measuring head of the temperature sensor are arranged in a space separated from the measuring space.
    Such an NMR measuring arrangement has become known from US-A 4,266,194 (= reference [1]).
    A powerful method of instrumental analysis is the nuclear magnetic resonance (= NMR) spectroscopy. In NMR spectroscopy are radiated in a measurement sample, which is arranged in a strong static magnetic field, radio frequency ^ RF) pulses, and the HF reaction of the sample is measured. The information is obtained integrally over a certain range of the test sample, the so-called active volume. The sample is picked up by the probe.
    The temperature of the sample (Tprobe) basically influences the results of the NMR measurements. For high-quality measurements, the temperature is typically set with the aid of a temperature control unit and kept as constant as possible spatially and temporally over the active measurement volume. NMR measurements are typically performed on both heated and cooled samples. (If the sample is to be cooled below room temperature, a sufficiently cold tempering fluid stream will be conducted in the feed tube and heated to the set temperature by the heater.) The spatial temperature gradient across the active sample volume and the sample temperature stability over time have a significant impact on the quality of the sample NMR measurements.
    From DE 10 2010 029 080 A1 [2] and DE 4 018 734 C2 [3] tempering units for minimizing the temperature gradient in the active measuring volume are known.
    The temperature of the tempering fluid is measured by means of one or more temperature sensors. These sensor temperatures (Tsensor) are processed in a control. This control controls the heating power of the heater, which is located in the feed pipe of the tempering.
    The aim of the scheme is to set as well as possible the desired target temperature in the NMR sample. In the prior art ([1], [3]), the temperature sensors are outside the sample tube. Therefore, the temperature sensors do not measure the sample temperature, but the temperature of the gas flowing around it. The difference between sample temperature and sensor temperature (ΔΤρ) is compensated with a suitable calibration (where ΔΤρ = Tprobe-Tsensor). However, the calibration is not universal for the entire temperature range of the sample, which is typically -200 ° C to +200 ° C. Therefore, it is desirable to minimize the deviation ΔΤρ over the entire temperature range of the sample.
    There are different types of temperature sensors known. Commonly used are so-called thermocouples, which essentially consist of two lead wires of different material (e.g., type K nickel-chromium and nickel-aluminum or type T copper and constantan), which are connected to a thermojunction. The thermojunction is placed at the location where the temperature is to be measured, the temperature measuring point. The wires and the thermojunction are typically surrounded by an electrically insulating filling material, which has good thermal conductivity, and is surrounded by an electrically conductive jacket. The electrically conductive jacket counteracts the penetration of RF fields of the NMR coil into the interior of the temperature sensor and prevents the thermojunction from being heated directly under the influence of the RF fields, and RF currents as conducted interference along the lead wires up to the Evaluation of the temperature sensor can continue to penetrate. Another function of the electrically conductive jacket is to prevent the ingress of RF interference resulting from e.g. Broadcasting and television broadcasters and other unspecified sources of interference, as well as possible to prevent in the probe by the jacket is preferably connected over its entire length with the mass of the measuring head, with a low-impedance connection with the outer shell of the measuring head is of crucial importance. The electrically conductive jacket typically also has a high thermal conductivity.
    The lead wires and the jacket have a material and geometry dependent thermal longitudinal line. By thermal longitudinal line is meant the vertical to the respective conductor cross-sections thermal conduction. Furthermore, thermal transverse conduction occurs in the radial direction. The temperature sensor protrudes around the immersion depth ET in the measuring space and is surrounded or circulated by the tempering fluid. Due to the thermal longitudinal and transverse conduction and the finite ET temperature sensor measures a mixing temperature of the temperature of the fluid flowing around the sensor tip and the temperature that prevails along the lead wires, especially outside the measuring space. The deviation of the mixing temperature from the temperature of the fluid in the absence of the sensor is undesirable and should be as small as possible. Because when the outside temperature changes, this causes a change in the mixing temperature measured by the sensor. This change is absorbed by the control circuit of the temperature and causes a change of Tin of the fluid flowing into the measuring space and ultimately of the sample temperature Tprobe. The ratio of the changes is indicated by the temperature penetration D from the laboratory temperature to the sample temperature: where:
    ATprobe = temperature change in the test sample ATlab = change in the laboratory temperature.
    A disadvantage of this prior art, however, is that typical values for the temperature penetration are D = 1/10 ... 1/20.
    The temperature penetration D has a direct influence on the quality of the NMR measurements, since changes in the laboratory temperature ATlab the sample temperature by the factor DATlab (this ATlab »ATprobe was assumed). Therefore, it is desired to make D as small as possible.
    One way to minimize the temperature penetration is to lead the thermocouple along with lead wires in the feed pipe (see, prior art in [1], [6]). However, since the feed tube is typically very well thermally isolated outwardly, e.g. by using a glass dewar ([1]), this has large dimensions and therefore the thermocouple is far from the sample. This in turn leads to a big difference between sample temperature (Tprobe) and sensor temperature (Tsensor).
    Another way to minimize D is to attach the temperature sensors in the measuring chamber. This possibility is used in [1]. However, since these temperature sensors are typically not completely non-magnetic, they must maintain a certain distance from the sample tube to avoid magnetic interference. On the one hand, however, the difference between sensor temperature and sample temperature increases with the distance, and, on the other hand, the parts of the supply lines which are not guided in the measuring volume cause a mixing temperature which deviates from the temperature at the temperature measuring point and thus increases the temperature penetration D.
    Another way to minimize D is to minimize the thermal longitudinal conduction of the sensor from the terminal to the thermojunction and to maximize in the field of thermojunction to the medium, while shielding against interference, as shown in [5] , The disadvantage of this method is the relatively complex structure of the sensor. Furthermore, a minimization of the thermal longitudinal conduction also implies a minimization of the thermally relevant cross-sections and the use of materials with low thermal conductivity, which must be considered in addition to the RF shield, the filler and the two lead wires. Depending on further requirements such as the technical temperature range, tolerance and aging resistance of the sensor, an optimal solution can not always be found because the requirements can sometimes be contradictory, but the advantages and disadvantages of different variants must be weighed against each other.
    OBJECT OF THE INVENTION The present invention is based on the object of improving an NMR measuring arrangement of the type described above with the simplest possible technical means so that the temperature penetration is minimal, while minimizing the difference between sensor and sample temperature (ATp ).
    Namely, a high temperature penetration has the disadvantage that the sensor temperature is strongly influenced by the outside temperature. This leads to a negative influence on the temperature control and finally to a change of the sample temperature due to outside temperature changes. Since NMR methods are sensitive to extremely small temperature changes in the range of 10 mK, it is extremely important for stable measurements to achieve temperature gains of the order of 1/100 with a change in the laboratory temperature Tlab by 1 ° C.
    A large temperature difference between the sensor and sample temperature in turn has the disadvantage that the absolute temperature of the sample can not be easily adjusted. It is possible to perform a calibration that will allow the sample temperature to be calculated from the sensor temperature. However, this calibration is not the same for the entire temperature range of the sample, which is usually between -200 ° C and + 200 ° C, so that in each case a locally valid calibration must be created. The object of the invention is to make the local calibration obsolete by minimizing (ATp).
    BRIEF DESCRIPTION OF THE INVENTION This object is achieved in an equally surprisingly simple and effective manner by an NMR measuring device of the type mentioned in the introduction, which is characterized in that the temperature sensor and its supply lines are surrounded by a sensor tube at a radial distance, which is connected via a sensor flow inlet to the measuring chamber in such a way that a partial flow of the tempering fluid flows out of the measuring chamber as a tempering in the free space between the temperature sensor and the inner wall of the sensor tube along the leads of the temperature sensor and at the sensor flow inlet opposite end of the sensor tube via a Sensor flow outlet flows out of the sensor tube or the sensor tube is closed at the opposite end of its sensor flow inlet and the tempering (16) can escape through lateral openings in the wall of the sensor tube (15).
    The tempering fluid is usually a gas, such as air, nitrogen, a nitrogen-oxygen mixture or helium. In the following, we speak of simplification, without restricting the generality, of a tempering gas, although tempering with liquids or liquefied gases, such as liquid nitrogen, are possible.
    The inventive NMR measuring device operates on the principle that the exhaust air flow of the tempering gas is divided. The larger part, as in the prior art, flows along the sample and heats or cools it. A second, smaller portion flows into the sensor tube along the temperature sensor and ultimately from an outlet at the end of the sensor tube. Here, the Temperiergasstrom cooled due to the thermal contact to the sensor tube in the flow direction, because the sensor tube on the outer side assumes the temperature in the probe head and a heat flow from the outside of the sensor tube to internally flowing Temperiergasstrom is present. Since the measuring head of the temperature sensor is located at the input of the sensor tube, the temperature influence of this part of the Temperiergasstromes decreases with the distance to the measuring head. The tempering gas flow in the sensor tube (|> out2) counteracts the thermal longitudinal conduction in the supply wire. It acts as insulation of the temperature sensor along with lead wires to the outside temperature. As a result, the temperature penetration is significantly reduced.
    Advantage over the Prior Art Due to the insulating effect of the gas flow, the sensor tube can be selected with a small diameter. This makes it possible to place the temperature measuring point close to the sample tube, which in turn results in a small difference (ΔΤρ) between sample and Tsensor. At the same time a significantly reduced temperature penetration is achieved.
    PREFERRED EMBODIMENTS OF THE INVENTION In a preferred tempering device for an NMR measuring arrangement of the type according to the invention, it is provided that the heater is arranged in the inflow of the tempering fluid to the measuring space upstream of a flow inlet to the measuring space, preferably in an inflow pipe. In this embodiment, the heating power due to the sensor temperature can be adjusted by means of a control. If a sample temperature is to be reached which is below the laboratory temperature, then a tempering fluid which is cooled considerably below room temperature is passed into the feed pipe and heated by the heater.
    In an advantageous embodiment of this embodiment, it is provided that the measuring space between an insert base and an axially spaced in the NMR sample tube by a holder from the insert base insert insert is included, and that in the insert base of the flow inlet for the influx of the tempering in the Measuring space and in the insert upper part a flow outlet for the outflow of tempering fluid from the measuring space are provided. This has the advantage that the sample tube is in direct thermal contact with the tempering fluid. As a result, rapid heating or cooling to the desired setpoint temperature is achieved.
    In a particularly preferred embodiment of the temperature control device according to the invention, the temperature-sensitive measuring head of the temperature sensor projects into the measuring space with an immersion depth ET <20 mm. This ensures that the temperature-sensitive measuring head is located directly in the Temperierfluidstrom and thus the sensor temperature is very little different from the sample temperature.
    Particularly simple and reliable is an embodiment of the inventive temperature control, in which only a single temperature sensor is provided. This allows a simple and robust control of the heating power (for example P-I-D controller).
    In one embodiment of the inventive tempering is provided that the sensor tube is closed at the opposite end of its sensor flow inlet, and that the tempering can escape through lateral openings in the wall of the sensor tube. By adjusting the size and number of side openings, this allows the RFlow ratio to be optimally adjusted. Where RFlow refers to the ratio of the volume flow {/ out2 of the temperature flow flowing into the free space between sensor and sensor tube to the volume flow {/ in of the temperature gas flowing into the measurement space. The temperature penetration D depends directly on RFlow. Therefore, a precise adjustment of RFlow should be aimed for.
    Also preferred is an embodiment in which the sensor tube is cylindrical and has a circular and / or oval and / or polygonal, in particular rectangular Guerschnitt. Non-round guer cuts are often beneficial to make the most of the space in the sample head. In addition, these forms may be preferred for manufacturing reasons.
    Advantageous developments of this embodiment provide that the clear Guerschnitt of the sensor tube at different axial positions is different in size, in particular that the cross section in the region of the Sensorströmungseinlasses is greater than in the region of Sensorströmungsauslasses (= «nozzle tube») or vice versa (= « diffuser tube "). Depending on the flow conditions in the measuring chamber, the nozzle tube or diffuser tube allows the ratio RFlow to be optimally set for a large range of the volume flow {/ in.
    In a particularly preferred embodiment, the ratio of the inner diameter DtubeJ of the sensor tube to the outer diameter Dsens of the temperature sensor is: 1.02 <DtubeJ / Dsens <5.0. Designate
    DtubeJ and Dsens for non-round cross sections respectively the hydraulic diameters (ie), with dh = 4 A / U. A is the area through which the fluid flows and U is the circumference wetted by the fluid. In this area of DtubeJ / Dsens a very good insulation is achieved by the flow rate |> out2. Furthermore, the space requirement of the sensor tube in the probe head for this ratio is optimal.
    In a further advantageous embodiment, the sensor tube is at least partially constructed of thermally highly insulating material, in particular made of plastic, preferably Peek® or Teflon®, or ceramic. This has the advantage that due to the insulating effect, the gas flow in the sensor tube cools less strongly over the length of the sensor tube.
    Particularly favorable developments of this embodiment are characterized in that the sensor tube has an acting as an RF shield, electrically conductive layer or film. This has the advantage that high-frequency currents can not propagate within the sensor tube on the RF shield of the temperature sensor. This prevents currents on the RF shield from affecting the tuning networks and the NMR coil, which may affect the electrical parameters (quality, tuning, resonant frequency of the tuning circuits) of the probe.
    Also advantageous is an embodiment in which the sensor tube is at least partially constructed of thermally highly conductive material, in particular of metal, preferably with a thin wall thickness. Since metal can be processed very well and is very dimensionally stable, it is preferred for mechanical stability reasons compared to plastics.
    Alternatively or additionally, in other embodiments of the inventive tempering is provided that the sensor tube in the (upper) region of the Sensorströmungseinlasses of good thermal insulating material, in particular acting as an RF shield, electrically conductive layer or film, and in (lower ) Region of the sensor flow outlet of thermally highly conductive material, in particular of metal, preferably with a thin wall thickness, is constructed. This construction achieves good insulation with respect to the inside of the probe head with a less dimensionally stable plastic in the critical upper region, and a dimensionally stable metal tube is located in the lower part. The RF shield is achieved by the continuous conductive surface of metal tube and conductive layer or foil connected thereto.
    Also preferred are embodiments of the invention in which for the flow fraction RFlow f> out2 / f> in: RFlow = t> out2 / {/ in <0.5, in particular RFlow <0.3, preferably 0.02 <RFlow <0.2.
    The temperature penetration decreases monotonically with increasing RFlow. In the range of RFlow> 0.2, however, no further significant improvement is achieved, so the range given above is optimal.
    Finally, in advantageous embodiments of the inventive tempering the at least one temperature sensor, a thermocouple, in particular of the type K, E, T, J, N, S, R and / or a resistance thermometer, in particular PT 100, PT 1000, PTC type 201 , NTC type 101 to 105 and / or a semiconductor temperature sensor, in particular with silicon or GaAlAs diodes. The tempering device according to the invention can thus be used very widely for the common temperature sensors.
    Further advantages of the invention will become apparent from the description and the drawings. Likewise, according to the invention, the above-mentioned features and those which are still further developed can each be used individually for themselves or for several in any desired combinations. The embodiments shown and described are not to be understood as exhaustive enumeration, but rather have exemplary character for the description of the invention.
    DETAILED DESCRIPTION OF THE INVENTION AND DRAWING The invention is illustrated in the drawing and will be explained in more detail by means of exemplary embodiments. FIG. 1 shows an embodiment of the inventive NMR measuring device in a schematic vertical section; FIG. Fig. 2 is a schematic vertical cross-sectional view of a prior art NMR measuring device; 3 shows a schematic, vertical cross-sectional view of a tempering device according to the prior art; FIG. 4 shows a schematic horizontal section through the tempering device according to the prior art from FIG. 3; FIG. 5 shows a schematic, axial cross-sectional illustration of a tempering device according to the invention, with temperature sensor, sensor tube and free space; Fig. 6: the embodiment of Figure 1 with schematically drawn temperatures. FIG. 7 shows the embodiment according to FIG. 1 with schematically indicated volume flows; FIG. FIG. 8 shows the profile of the temperature penetration D as a function of RFflow for immersion depths ET = 1.5 mm, curve 24 and ET = 3 mm, curve 25; FIG. and FIG. 9: RFlow as a function of the volumetric flow {/ in.
    The invention relates to the temperature control of NMR sample tubes with minimal temperature penetration while minimizing the temperature difference between the NMR sample temperature and sensor temperature.
    NMR test tubes are usually operated (measured) at a defined temperature, which is adjusted via the NMR spectrometer and is to be kept stable. Such a constant temperature is necessary because the spectra generated in the NMR show a dependence on the temperature of the sample substance (sample), which means that changes in the ambient temperature ultimately go into the measurement result (shift of individual frequency lines). Depending on the experiment, these effects are disturbing and distort the picture.
    The invention is characterized in that at least one temperature sensor, including supply lines, is located in a sensor tube. The sensor protrudes around the immersion depth ET into the measuring room. Typical value for ET are 0 mm to 10 mm. The sensor tube is open on both sides. On one side it is connected to the measuring room. The tempering gas flow in the sensor tube (|> out2) counteracts the thermal longitudinal conduction in the supply wire. It acts as insulation of the temperature sensor along with lead wires to the outside temperature. As a result, the temperature penetration is significantly reduced.
    The sensor tube can, due to the insulating effect of the gas flow, be selected with a small diameter. This makes it possible to place the temperature measuring point close to the sample tube, which in turn results in a small difference (ΔΤρ) between sample and Tsensor.
    FIG. 1 shows the device according to the invention for sample head temperature control. In this case, the volume flow {/ in the inflow pipe 11 is heated by the heater 12. The inflow of the tempering gas 8 flows through the flow outlets 10 in the insert lower part 13 into the measuring space 14, which is surrounded by the holder 7. Part of the volume flow flows along the temperature sensor 9 to the sample 1 and heats (or cools) this to the temperature Tprobe. Another part flows along the NMR coil 5, which is located on the bobbin 6 along. These two partial streams leave the measuring chamber through the flow outlet 2 in the insert upper part 4. Together they form the outflow 1 (designated by 3).
    In the inventive device, the temperature sensor 9 is surrounded by a sensor tube 15 and between 9 and 15 is the free space 17. Now flies another part 18 of the gas flowed into the measuring chamber along the temperature sensor 9 in the flow inlet 28 of the sensor tube. It flows in free space between the temperature sensor and the sensor tube and leaves the sensor tube at the flow outlet of the sensor tube 18th
    The temperature sensor 9 measures the temperature Tsensor on the measuring head. Due to the heat conduction in the longitudinal direction, however, the temperature is not measured selectively at the measuring head, but a mixing temperature from the temperature of the supply lines and the temperature at the measuring head. The device according to the invention makes it possible to minimize the difference between the temperature of the gas flowing around the measuring head and the temperature measured in the measuring head. This happens because the tempering gas flow flowing into the free space cools down in the flow direction due to the thermal contact with the sensor tube because the sensor tube on the outer side assumes the temperature in the sample head and a heat flow from the outside of the sensor tube to the internally flowing tempering gas flow is present. Since the measuring head of the temperature sensor is located at the input of the sensor tube, however, the temperature influence of this part of the Temperiergasstroms decreases with the distance to the measuring head. The Temperiergasstrom in the sensor tube counteracts the thermal longitudinal line in the supply wire. It acts as insulation of the temperature sensor along with lead wires to the outside temperature. As a result, the temperature penetration is significantly reduced.
    In Fig. 2, a temperature control device according to the prior art is shown, wherein no free space between the temperature sensor and sensor tube exists, could escape through which a part of the gas 8 which has flowed into the measuring space.
    Fig. 3 shows a typical prior art temperature sensor. It is composed of a lead wire of material 1 (designation 19) and a lead wire of material 2 (designation 23) connected to the thermojunction 20. These wires are surrounded by the electrically insulating filling material 21, which in turn is surrounded by the RF shield.
    Fig. 4 shows the temperature sensor of Fig. 3 in a cross-section below the thermojunction.
    The temperature sensor 9 is surrounded by the sensor tube 15 in the inventive arrangement. Fig. 5 shows this arrangement in cross section. The sensor tube and the sensor preferably each have a round, polygonal or oval cross-section. A mixture of different cross sections (for example sensor round, sensor tube oval) is possible. Typical values for the sensor diameter Dsens are 0.5 to 5 mm and for the inner diameter DtubJ 0.55 to 8 mm. Where Dsens and Dtube are defined as non-circular cross-sections as hydraulic diameters [4]. Typical lengths of the sensor tube Lsens are 10 mm to 100 mm.
    The sensor tube consists either of a thermal insulator (eg plastic such as Peek®, Teflon® etc.) or a non-magnetic, thin-walled thermal conductor (metal such as copper, aluminum, bronze, etc.) or on the outside with a conductive Coating or conductive foil provided insulator. Also advantageous is a two-part sensor tube, in which the inlet (upper) part of the sensor tube consists of a thermal insulator (e.g., plastic) and the outlet (lower) part of a thermal conductor (metal). The insulator may be surrounded for better RF shielding with a thin conductive layer or a conductive film on the outside. The structure has the advantage that the upper part offers a good thermal insulation. In addition, if the coating or foil for high-frequency signals is conductively connected to the metal tube in a highly conductive manner, it is also largely suppressed that high-frequency currents can propagate on the HF shield of the temperature sensor. In order to further restrict the range on which high-frequency currents can propagate on the RF shield, the RF shield can be electrically connected to the metallic sensor tube and the sensor tube can also be electrically connected to the mass of the measuring head. This prevents high-frequency currents from propagating along the entire length of the RF shield. This is undesirable because currents on the RF shield may affect the tuning networks and the NMR coil and thus affect the electrical parameters (quality, tuning, resonant frequency of the tuning circuits) of the probe.
    Between the temperature sensor and the sensor tube is a free space which is constructed so that a part of the tempering gas can flow from the measuring space through this free space. In this free space, the flow cross section is defined as a surface of the free space perpendicular to the flow direction. The flow cross section does not have to be constant over the length Lsens, but may change in shape and size. For example, nozzle-shaped sensor tubes are possible in which the cross section of the sensor tube downstream decreases or diffuser-type sensor tubes, which have a widening of the sensor tube cross-section in the flow direction. Also, sudden extensions or narrowing of the flow cross section are possible. The sensor tube may also be composed of several sections, wherein the materials used may be different. It is possible to place several temperature sensors of the type described above in the measuring space. The measured values of the sensors are then processed using a corresponding control algorithm.
    In Fig. 6, the temperatures of the inventive arrangement are designated. The tempering device is part of an NMR device that is located in the laboratory at the laboratory temperature Tlab. Within the probe head the temperature Tmessk prevails. This differs from the temperature of the gas Tin flowing into the measuring chamber. The gas flowing around the sensor has the temperature Tflow2 and the measuring head of the sensor assumes the temperature Tsensor. Tsensor serves as input for controlling the heating power. In the sample, the temperature Tprobe occurs.
    In Fig. 7, the volume flows are shown. The volume flow Fin flowing into the measuring space is divided into the volume flow Foutl flowing out of the flow outlet and into the volume flow Fout2 flowing through the free space 17. The temperature sensor is immersed by the length ET in the measuring space and it is located in the sensor tube of length Lsens.
    FIG. 8 shows the temperature penetration D as a function of the volume flow ratio RFlow from inflowing gas 1 in and gas flowing through the sensor tube 11 for a typical NMR probe head, ie
    Here, the case RFlow = 0 corresponds to the prior art. The cases with RFlow> 0 are achieved by the arrangement according to the invention. With a proportion of 6% to 15% of volume flowing through the sensor tube to the inflowing volume, a considerable reduction in the temperature penetration is achieved. The ratio RFlow depends on the parameters listed below and can be adjusted accordingly.
    The flow ratio RFlow depends on the flow cross section in the free space 17, which is formed by the sensor and the sensor tube. The larger the flow cross-section in free space, the larger becomes RFlow (if all other parameters remain unchanged). - Furthermore, RFlow depends on the length of the sensor tube. The longer the sensor tube is at a given flow area, the smaller becomes RFlow (due to the friction on the inner wall of the sensor tube and the outer shell of the temperature sensor). - Furthermore, RFlow depends on the volume flow of the inflowing tempering gas (Fin), i. RFlow increases approximately linearly with Fin, as shown in FIG. Fin is typically varied in the range of 0 liter per hour (l / h) to 2000 l / h.
    Reference List [1] L.F. Hlavaka, US 4,266,194
    权利要求:
    Claims (14)
    [1]
    [2] Grossniklaus, F. Rafia, M. Mayer, D. Wilhelm, DE 10 2010 029 080 A1 [3] PB Hepp, WH Tschopp, M. Rindlisbacher, 0 Schett, DE 4 018 734 C2 [4] W. Wagner, fluid mechanics and pressure loss calculation, 1990, bird textbooks, Würzburg [5] OK Fiedler, H.-D. Drees, DE 4 017 079 A1 [6] D. Marek, DE 10 006 317 C1
    1. NMR measuring arrangement with a tempering device for a filled with solid and / or liquid sample substance NMR sample tube (1), which is arranged in a measuring position in an NMR spectrometer in one of NMR coils (5) surrounded measuring space (14) and by a tempering fluid (8) is flowed around, which is tempered in the influx to the measuring chamber (14) by a controlled heater (12), wherein at least one temperature sensor (9) is provided, the temperature-sensitive measuring head in spatial proximity to the NMR sample tube (1) is positioned and at least partially into the measuring space (14) protrudes, while the supply lines to the measuring head of the temperature sensor (9) in a space separated from the measuring space (14) are arranged, characterized in that the temperature sensor (9) and its supply lines surrounded by a sensor tube (15) at a radial distance, which is connected via a sensor flow inlet (26) with the measuring space (14) such that a partial flow of the tempering fluid (8) from the measuring space (14) as tempering (16) in the free space (17) between the temperature sensor (9) and the inner wall of the sensor tube (15) along the leads of the temperature sensor (9) flows and at the Sensor flow inlet (26) opposite end of the sensor tube (15) via a Sensorströmungsauslass (18) flows out of the sensor tube (15) or the sensor tube (15) at its sensor flow inlet (26) opposite end is closed and the tempering (16) through lateral openings in the wall of the sensor tube (15) can escape.
    [2]
    2. NMR measuring arrangement according to claim 1, characterized in that the heater (12) in the inflow of tempering fluid (8) to the measuring chamber (14) in the flow direction in front of a flow inlet (10) to the measuring chamber (14), preferably in an inflow pipe (11 ) is arranged.
    [3]
    3. NMR measuring arrangement according to claim 2, characterized in that the measuring space (14) between an insert lower part (13) and in the axial direction of the NMR sample tube (1) by a holder (7) from the insert lower part (13 ) spaced insert upper part (4) is included, and that in the insert lower part (13) of the flow inlet (10) for the inflow of the tempering (8) into the measuring space (14) and in the insert upper part (4) or in the insert lower part (13) a flow outlet ( 2) are provided for the outflow (3) of tempering fluid (8) from the measuring space (14).
    [4]
    4. NMR measuring arrangement according to claim 3, characterized in that the temperature-sensitive measuring head of the temperature sensor (9) with an insertion depth ET <20 mm beyond the upper edge of the insert lower part (13) protrudes into the measuring space (14).
    [5]
    5. NMR measuring arrangement according to one of the preceding claims, characterized in that only a single temperature sensor (9) is provided.
    [6]
    6. NMR measuring arrangement according to one of the preceding claims, characterized in that the sensor tube (15) is cylindrical and has a circular or oval or polygonal, in particular rectangular cross-section.
    [7]
    7. NMR measuring arrangement according to claim 6, characterized in that the clear cross section of the sensor tube (15) is different in size at different axial positions, in particular that the cross section in the region of the sensor flow inlet (26) is greater than in the region of the sensor flow outlet (18). or the other way around.
    [8]
    8. NMR measuring arrangement according to one of the preceding claims, characterized in that for the ratio of the inner diameter DtubeJ of the sensor tube (15) to the outer diameter Dsens of the temperature sensor (9), the following applies: 1.02 <DtubJ / Dsens <5.0 where DtubJ and Dsens for non-round cross sections respectively denote the hydraulic diameters dh = 4A / U, where A is the area through which flows and U the circumference wetted by the temperature control fluid (8).
    [9]
    9. NMR measuring arrangement according to one of the preceding claims, characterized in that the sensor tube (15) at least partially made of thermally insulating material, in particular made of plastic, preferably polyetheretherketone or polytetrafluoroethylene, or ceramic.
    [10]
    10. NMR measuring arrangement according to claim 9, characterized in that the sensor tube (15) has an RF shielding acting as an electrically conductive layer or film.
    [11]
    11. NMR measuring arrangement according to one of the preceding claims, characterized in that the sensor tube (15) is at least partially constructed of thermally conductive material, in particular of metal.
    [12]
    12. NMR measuring arrangement according to one of the preceding claims, characterized in that the sensor tube (15) in the region of the sensor flow inlet (26) of thermally insulating material, in particular acting as an RF shield, electrically conductive layer or foil, and in the field the sensor flow outlet (18) is made of thermally conductive material, in particular of metal.
    [13]
    13. NMR measuring arrangement according to claim 3 and one of claims 4 to 12, characterized in that for the flow fraction RFlow, defined by the ratio of the volume flow voul.2 of in the free space (17) flowing tempering (16) to the flow f / in the tempering fluid (8) flowing into the measuring space (14), RFlow = {> out2 / | / in <0.5, in particular RFlow <0.3, preferably 0.02 <RFlow <0.2.
    [14]
    14. NMR measuring arrangement according to one of the preceding claims, characterized in that the at least one temperature sensor (9) is a thermocouple, in particular of the type K, E, T, J, N, S, R and / or a resistance thermometer, in particular PT 100th , PT 1000, PTC type 201, NTC type 101 to 105 and / or a semiconductor temperature sensor, in particular with silicon or GaAlAs diodes.
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    GB2507181A|2014-04-23|
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    JP2014089178A|2014-05-15|
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    法律状态:
    2019-10-31| PFA| Name/firm changed|Owner name: BRUKER SWITZERLAND AG, CH Free format text: FORMER OWNER: BRUKER BIOSPIN AG, CH |
    优先权:
    申请号 | 申请日 | 专利标题
    DE102012217601.2A|DE102012217601B4|2012-09-27|2012-09-27|NMR measuring device with tempering device for a sample tube|
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