Transport apparatus for temperature-controlled NMR test samples having a double tube system

Abstract

Transport apparatus pneumatically conveying NMR test samples (2) from or to an NMR spectrometer (1) through a tubular transport channel (3) includes a device (4) generating positive pressure in the end of the transport channel that is remote from the spectrometer. The transport channel has a tube system which has a gas-tight outer tube (5) having an outer diameter D.sub.a and an inner diameter d.sub.a and an inner tube (6), arranged coaxially with respect to the outer tube, having an outer diameter D.sub.i<d.sub.a and an inner diameter d.sub.i. The inner diameter d.sub.i of the inner tube is greater than or equal to the outer diameter D.sub.P of the test samples, and the inner tube includes mutually spaced cross-holes (7) designed as through-holes. This provides accurate current position determinations for the sample in the transport channel, and reduced risk of damaging the sample during transport.

Claims

1. Transport apparatus for pneumatically conveying a nuclear magnetic resonance (NMR) test sample having an outer diameter D.sub.P from and/or to a region outside an NMR spectrometer into and/or out of the NMR spectrometer, comprising: a tubular transport channel configured to convey the test sample, a device producing positive pressure in an end of the tubular transport channel that is remote from the NMR spectrometer, wherein the tubular transport channel comprises a tube system which comprises a gas-tight outer tube having an outer diameter D.sub.a and an inner diameter d.sub.a and an inner tube, arranged coaxially with respect to the outer tube, having an outer diameter D.sub.i<d.sub.a and an inner diameter d.sub.i, wherein the inner diameter d.sub.i of the inner tube is greater than or equal to the outer diameter Dr of the NMR test sample, and wherein the inner tube comprises plural cross-holes that are mutually spaced apart along an axial direction of the inner tube and that are configured as through-holes.

2. Transport apparatus according to claim 1, wherein the cross-holes are arranged spaced equidistantly apart from one another along the axial direction of the inner tube.

3. Transport apparatus according to claim 1, further comprising a thermal insulator surrounding the outer tube.

4. Transport apparatus according to claim 1, further comprising a protective sleeve surrounding the tube system.

5. Transport apparatus according to claim 1, further comprising a device producing negative pressure in an end of the tubular transport channel that is nearer to the NMR spectrometer than is the remote end.

6. Transport apparatus according to claim 1, wherein the tube system is arranged radially inside a transport tube.

7. Transport apparatus according to claim 1, wherein the tube system has the following dimensions: outer diameter D.sub.a of the outer tube: 15 mmD.sub.a30 mm; inner diameter d.sub.a of the outer tube: 10 mmd.sub.a25 mm; outer diameter D.sub.i of the inner tube: 7.5 mmD.sub.i15 mm; inner diameter d.sub.i of the inner tube: 5 mmd.sub.i10 mm; axial distance A.sub.Q between the cross-holes: 50 mmA.sub.Q300 mm.

8. Transport apparatus according to claim 7, wherein the tube system has the following dimensions: outer diameter D.sub.a of the outer tube: 18 mmD.sub.a26 mm; inner diameter d.sub.a of the outer tube: 15 mmd.sub.a20 mm; outer diameter D.sub.i of the inner tube: 10 mmD.sub.i12 mm; inner diameter d.sub.i of the inner tube: 8.5 mmd.sub.i9.5 mm.

9. Transport apparatus according to claim 1, wherein, during operation, the NMR test sample is surrounded by a transport container having a mass M.sub.T<<50 g.

10. Transport apparatus according to claim 9, wherein the transport container has a mass M.sub.T25 g.

11. Transport apparatus according to claim 1, wherein, during the conveying, a plurality of the NMR test samples are each located in a respective cylindrical sample test tube having an outer diameter D.sub.PR, and during the conveying, the sample test tubes are each sealed in a fluid-tight manner by respective closure caps, which are attached at one end and have a maximum outer diameter D.sub.VK.

12. Transport apparatus according to claim 11, wherein the sample test tubes and the closure caps are dimensioned such that: d.sub.iD.sub.VK>D.sub.PR.

13. Method for operating a transport apparatus as claimed in claim 1, comprising: (a) supplying an NMR test sample acquired from a feed point outside the NMR spectrometer through external parts of the transport channel to an entry point into the NMR spectrometer; (b) moving the NMR test sample into a spatial position for further transport into NMR magnets; (c) introducing the NMR test sample through an internal part of the transport channel into a magnet center of the NMR spectrometer in a pneumatically controlled manner; (d) carrying out an NMR measurement on the NMR test sample; and (e) pneumatically transporting the NMR test sample back out of the magnet center to outside the NMR spectrometer.

14. Method according to claim 13, further comprising transporting the measured NMR test sample through the external parts of the transport channel back to the feed point.

15. Method according to claim 13, further comprising: spacing the cross-holes equidistantly in the axial direction of the inner tube, and calculating a current axial position of the NMR test sample from a ratio of air escaping from the cross-holes to a total volumetric flow rate and a direct relationship that exists between the total volumetric flow rate and the axial position of the NMR test sample in the transport channel.

16. Method according to claim 13, further comprising maintaining the inner tube at a constant temperature during the NMR measurement using a thermal insulator surrounding the outer tube, wherein the constant temperature is thermally insulated from an unregulated temperature of the transport channel.

17. Method according to claim 13, wherein said carrying out of an NMR measurement comprises suctioning the NMR test sample into the NMR spectrometer with a device that produces a negative pressure in the tubular transport channel, and blowing at the NMR test sample with the device producing the positive pressure.

18. NMR spectrometer comprising a transport apparatus according to claim 1.

19. Transport apparatus according to claim 1, wherein the cross-holes are arranged in groups which are spaced equidistantly apart from one another along the axial direction of the inner tube.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention is shown in the drawings and will be described in greater detail with reference to embodiments.

(2) In the drawings:

(3) FIG. 1 is a schematic, partial, vertical sectional view of an embodiment of the transport apparatus according to the invention having an NMR test sample without a transport container, but with a closure cap;

(4) FIG. 2 is a schematic vertical sectional view of a transport apparatus according to the prior art;

(5) FIG. 3 is a partially transparent vertical sectional view of an NMR spectrometer having a transport apparatus according to the prior art;

(6) FIG. 4 shows the relationship between the distance covered by the NMR test sample in a transport apparatus according to the prior art and the magnitude of the gas flow, and a corresponding error bar for the axial position of the NMR test sample; and

(7) FIG. 5 shows the relationship from FIG. 4 in a transport apparatus according to the invention.

DETAILED DESCRIPTION

(8) In general, the present invention concerns a modified transport apparatus of test samples to and from an NMR spectrometer 1. Advantages of the invention can, however, also be used in a spectrometer that uses a different physical measuring technology, it thus being possible that corresponding appropriate modifications have to be carried out.

(9) In the prior art, a transport apparatus of this kind for pneumatically conveying NMR test samples 2 from a region outside an NMR spectrometer 1 through a tubular transport channel 3 into the NMR spectrometer 1 and, from there, optionally after an NMR measurement has been carried out on the NMR test samples 2, back outside the NMR spectrometer 1 already comprises a device 4 for generating positive pressure in the end of the tubular transport channel 3 that is remote from the NMR spectrometer.

(10) In contrast, the transport apparatus according to the invention is characterized in that the tubular transport channel 3 has a tube system which comprises a gas-tight outer tube 5 having an outer diameter D.sub.a and an inner diameter d.sub.a and an inner tube 6, arranged coaxially with respect to said outer tube, having an outer diameter D.sub.i<d.sub.a and an inner diameter d.sub.i, the inner diameter d.sub.i of the inner tube 6 being selected so as to be greater than or equal to the outer diameter D.sub.P of the NMR test samples 2, and in that the inner tube 6 comprises cross-holes 7 that are mutually spaced in the axial direction and are designed as through-holes.

(11) In principle, the cross-holes 7 can be provided at any desired axial positions of the inner tube 6. In the embodiment of the invention shown in FIG. 1, however, said cross-holes are arranged equidistantly in the axial direction of the inner tube 6.

(12) In this embodiment, there is furthermore a thermal insulator 8 surrounding the outer tube 5. In addition, a protective sleeve 9 surrounds the tube system 5, 6 in this case. Finally, in this embodiment of the invention the transport apparatus comprises a device 10 for generating negative pressure in the end of the tubular channel 3 that is nearer the NMR spectrometer. The pseudo-conical double tube system 5, 6 can therefore be both blown into with the device 4 and evacuated with the device 10.

(13) Typically, the NMR test samples 2 are each located, during operation, in a preferably cylindrical sample test tube 2 having an outer diameter D.sub.PR. During operation, these sample test tubes 2 are each sealed in a fluid-tight manner by a closure cap 2 which is attached at one end and has a maximum outer diameter D.sub.VK. The sample test tubes 2 and the closure caps 2 are dimensioned in this case such that: d.sub.iDYK>D.sub.PR.

(14) FIG. 2 shows a transport apparatus according to the prior art. In this case, therefore, the double tube system 5, 6 according to the invention is omitted. Instead, the sample test tube 2 and its closure cap 2 are surrounded by a transport container 12, the outer contour of which is guided radially inside a standard transport tube 11.

(15) In other embodiments (not shown individually in the present drawings) of the invention, the double tube system 5, 6 of the transport apparatus according to the invention may, however, also be arranged radially inside an existing conventional standard transport tube 11 according to the prior art, ensuring downward compatibility with existing apparatuses. In addition, in embodiments of the invention, the NMR test samples 2 are also surrounded by a transport container 12 during operation. However, said container usually has a significantly smaller mass M.sub.T than the transport container that is conventional in the prior art, i.e. M.sub.T<<50 g, in particular M.sub.T<40 g, preferably M.sub.T25 g.

(16) FIG. 3 shows an NMR spectrometer 1 having a transport apparatus according to the prior art, which apparatus could, however, instead be exchanged for a transport apparatus according to the invention.

(17) FIG. 4 is a diagram of the relationship between the distance covered by the NMR test sample in a transport apparatus according to the prior art and the magnitude of the gas flow, and a corresponding error bar for the axial position of the NMR test sample. In the currently-used transport systems according to the prior art, there is a large degree of uncertainty regarding the precise current position of the NMR test sample in the transport channel. This can be clearly seen from the constantly and somewhat significantly increasing height of the error bar in FIG. 4.

(18) Finally, FIG. 5 shows the relationship between the distance covered by the NMR test sample in a transport apparatus according to the invention and the magnitude of the gas flow, and a corresponding error bar for the axial position of the NMR test sample.

(19) The above-described modification according to the invention of the transport apparatus results in a fixed relationship between the gas flow and the position of the NMR test sample 2 in the transport channel 3, which is shown in FIG. 5 as a stepped curve. Each step corresponds to a position with the cross-holes 7 in the inner transport tube 6. As can be clearly seen, the height of the error bar in FIG. 5 remains the same over the entire transport distance. The relevant current position of the NMR test sample 2 during the transport thereof is therefore always fairly accurately defined.

(20) As a result of completely omitting the transport carrier 12 or at least significantly reducing the size thereof, the total mass of the NMR test sample 2 to be transported is very small. A greater dynamic can therefore be achieved whilst there is simultaneously the smallest risk of damage to the NMR test sample. The potential total omission of the transport carrier additionally allows the inner tube 6, and therefore also the transport channel 3, to have the smallest possible dimensions (typically 9 mm instead of 26 mm as before). This produces a large amount of additional installation space, which can be used, for example, for thermal insulation 8 against the NMR magnet and for an additional protective sleeve 9. As a result, undesired changes in temperature in the NMR test sample 2 can be further reduced during transport into the NMR spectrometer 1.

LIST OF REFERENCE SIGNS

(21) 1 NMR spectrometer 2 NMR test sample 2 Sample test tubes 2 Closure cap 3 Transport channel 4 Device for generating positive pressure 5 Outer tube 6 Inner tube 7 Cross-holes 8 Thermal insulator 9 Protective sleeve 10 Device for generating negative pressure 11 Standard transport tube 12 Transport container

LIST OF REFERENCES

(22) Publications taken into consideration for the assessment of patentability: [1] DE 37 29 819 C2 [2] Company brochure Z31123: Bruker Sample Transport. BST Installation and Technical Manual Version 002, Bruker BioSpin AG (21 Nov. 2008) [3] EP 2 199 816 B1; U.S. Pat. No. 8,217,655 B2 [4] DE 10 2013 212 312 B4 [5] U.S. Pat. No. 6,768,305 B1 [6] DE 10 2014 201 076 B3 [7] DE 10 2018 201 226.1 (not yet published as of 13 Apr. 2018)