U.S. patent application number 09/728470 was filed with the patent office on 2002-05-30 for axial sample conveyer.
Invention is credited to Higgins, James A., Howard, Layne E..
Application Number | 20020063561 09/728470 |
Document ID | / |
Family ID | 24926987 |
Filed Date | 2002-05-30 |
United States Patent
Application |
20020063561 |
Kind Code |
A1 |
Higgins, James A. ; et
al. |
May 30, 2002 |
Axial sample conveyer
Abstract
An axial sample conveyer for transferring samples into an
analysis device such as a nuclear magnetic resonance (NMR) probe of
an NMR spectrometer includes an auger having a helical thread for
axially constraining the samples, and a plurality of guides facing
the auger for laterally constraining the samples to follow a linear
axial path as the auger is rotated. Samples are inserted into the
conveyer through plural input apertures. The samples abut the
helical thread of the auger, and are moved through the conveyer as
the auger is rotated about its axis. The samples exit the conveyer
through corresponding output apertures aligned with the input
apertures. Each guide extends between an input aperture and an
output aperture.
Inventors: |
Higgins, James A.;
(Campbell, CA) ; Howard, Layne E.; (Los Gatos,
CA) |
Correspondence
Address: |
VARIAN, INC.
Legal Department
3120 Hansen Way, M/S D-102
Palo Alto
CA
94304
US
|
Family ID: |
24926987 |
Appl. No.: |
09/728470 |
Filed: |
November 30, 2000 |
Current U.S.
Class: |
324/318 ;
324/322 |
Current CPC
Class: |
G01R 33/307 20130101;
G01N 35/04 20130101 |
Class at
Publication: |
324/318 ;
324/322 |
International
Class: |
G01V 003/00 |
Claims
What is claimed is:
1. A nuclear magnetic resonance spectrometer comprising: a) a
magnet for applying a magnetic field to a plurality of nuclear
magnetic resonance samples; b) a nuclear magnetic resonance probe
positioned in a bore of the magnet, for performing nuclear magnetic
resonance measurements on the samples; and c) an axial multi-sample
conveyer coupled to the probe, for transferring a plurality of
sample containers containing the samples into the probe, the
conveyer comprising: a plurality of input apertures for receiving
the sample containers, a plurality of output apertures positioned
opposite the input apertures and transversely aligned with the
plurality of input apertures, for sequentially transferring the
sample containers to the probe, an axially-rotatable auger
positioned between the input apertures and the output apertures,
for axially constraining a motion of the sample containers between
the input apertures and output apertures, and a plurality of axial
sample guides positioned facing the auger between the input
apertures and the output apertures and transversely aligned with
the input apertures and the output apertures, for transversely
constraining the motion of the sample containers.
2. The spectrometer of claim 1 wherein: a) the conveyer comprises a
lateral casing enclosing the auger; and b) each of the plurality of
guides is formed by a rail attached to an inside surface of the
casing.
3. The spectrometer of claim 1 wherein: a) the conveyer comprises a
lateral casing enclosing the auger; and b) each of the plurality of
guides is formed by an inside surface of the casing.
4. The spectrometer of claim 1 wherein the conveyer further
comprises: a) a fixed input plate comprising an axial input bearing
coupled to the auger, the input apertures being defined in the
input plate; and b) a fixed output plate comprising an axial output
bearing coupled to the auger, the output apertures being defined in
the output plate.
5. The spectrometer of claim 1 further comprising a driving device
coupled to the auger, for rotating the auger.
6. The spectrometer of claim 5 wherein the driving device comprises
a piezoelectric motor coupled to the auger.
7. The spectrometer of claim 5 wherein the driving device comprises
a gas source for providing gas flow coupled to the auger, for
rotating the auger.
8. The spectrometer of claim 1 wherein: a) the sample conveyer is
positioned above the probe; and b) the motion of the sample
containers through the conveyer is driven by gravity.
9. The spectrometer of claim 8 further comprising a funnel
positioned between the output apertures and the probe, for
funneling the sample containers from the output apertures to the
probe.
10. An axial multi-sample conveyer for providing a plurality of
sample containers to a nuclear magnetic resonance probe,
comprising: a) a plurality of input apertures for receiving the
sample containers; b) a plurality of output apertures positioned
opposite the input apertures and transversely aligned with the
plurality of input apertures, for sequentially transferring the
sample containers to the probe; c) an axially-rotatable auger
positioned between the input apertures and the output apertures,
for axially constraining a motion of the sample containers between
the input apertures and output apertures; and d) a plurality of
axial sample container guides positioned facing the auger between
the input apertures and the output apertures and transversely
aligned with the input apertures and the output apertures, for
transversely constraining the motion of the sample containers.
11. The conveyer of claim 10 wherein: a) the conveyer comprises a
lateral casing enclosing the auger; and b) each of the plurality of
guides is formed by a rail attached to an inside surface of the
casing.
12. The conveyer of claim 10 wherein: a) the conveyer comprises a
lateral casing enclosing the auger; and b) each of the plurality of
guides is formed by an inside surface of the casing.
13. The conveyer of claim 10 further comprising: a) a fixed input
plate comprising an axial input bearing coupled to the auger, the
input apertures being defined in the input plate; and b) a fixed
output plate comprising an axial output bearing coupled to the
auger, the output apertures being defined in the output plate.
14. An axial multi-sample conveyer for providing a plurality of
sample containers to a nuclear magnetic resonance probe,
comprising: a) an axial helical thread for engaging the samples and
axially constraining a motion of the samples; and b) a plurality of
axial sample guides each facing the thread, for transversely
constraining the motion of the samples to a linear axial
trajectory.
15. A method of transferring a plurality of sample containers to a
nuclear magnetic resonance probe, comprising the steps of: a)
axially moving the sample containers by engaging the sample
containers with a helical thread and rotating the helical thread;
and b) transversely constraining the sample containers to axial
trajectories by enclosing each sample container with an axial guide
facing the thread.
16. A nuclear magnetic resonance spectrometer comprising: a) a
magnet for applying a magnetic field to a plurality of nuclear
magnetic resonance samples; b) a nuclear magnetic resonance probe
positioned in a bore of the magnet, for performing nuclear magnetic
resonance measurements on the samples; c) an axial multi-sample
conveyer positioned above the probe and facing the probe, for
transferring a plurality of sample tubes containing the samples
into the probe, the conveyer comprising: a plurality of upper input
apertures for receiving the sample tubes, a plurality of lower
output apertures positioned below the input apertures and
transversely aligned with the plurality of input apertures, for
sequentially transferring the sample tubes to the probe, an
axially-rotatable auger positioned between the input apertures and
the output apertures, for axially controlling a downward motion of
the sample tubes between the input apertures and output apertures,
and a plurality of axial sample guides positioned facing the auger
between the input apertures and the output apertures and
transversely aligned with the input apertures and the output
apertures, for transversely constraining the downward motion of the
sample tubes; d) a driving device coupled to the auger, for
rotating the auger; and e) a funnel positioned between the output
apertures and the probe, for funneling the sample tubes from the
output apertures downward into the probe.
17. An axial multi-sample conveyer for transferring a plurality of
sample containers to an analysis device, comprising: a) a plurality
of input apertures for receiving the sample containers; b) a
plurality of output apertures positioned opposite the input
apertures and transversely aligned with the plurality of input
apertures, for sequentially transferring the sample containers to
the analysis device; c) an axially-rotatable auger positioned
between the input apertures and the output apertures, for axially
constraining a motion of the sample containers between the input
apertures and output apertures; and d) a plurality of axial sample
container guides positioned facing the auger between the input
apertures and the output apertures and transversely aligned with
the input apertures and the output apertures, for transversely
constraining the motion of the sample containers.
18. A method of inserting a plurality of sample containers into an
analysis device, comprising the steps of: a) axially moving the
sample containers by engaging the sample containers with a helical
thread and rotating the helical thread; and b) transversely
constraining the sample containers to axial trajectories by
enclosing each sample container with an axial guide facing the
thread.
Description
FIELD OF THE INVENTION
[0001] The invention in general relates to systems and methods for
analyzing samples, and in particular to an axial sample conveyer
for inserting sample tubes into an NMR spectrometer.
BACKGROUND OF THE INVENTION
[0002] Nuclear magnetic resonance (NMR) spectrometers typically
include a superconducting magnet for generating a static magnetic
field Bo, an NMR probe positioned in a longitudinal bore of the
magnet, and a longitudinal guide structure for guiding individual
samples of interest into and out of the probe. The direction of the
static magnetic field B.sub.0 is commonly denoted as the z-axis,
while the plane perpendicular to the z-axis is commonly termed the
x-y or .theta.-plane. The terms "longitudinal" and "axial" are used
to refer to the z-direction, while the term "transverse" is used to
refer to the .theta.-direction.
[0003] Conventional NMR spectrometers typically employ an
air-driven system for inserting and ejecting samples in and out of
the NMR probe. For a description of a prior art air-driven ejector
see for example U.S. Pat. No. 3,512,078, "Gyromagnetic Resonance
Spectrometer Employing Air Pressure for Ejecting Samples from the
Magnet," by Hall. Such conventional systems can be limited in their
sample throughputs.
[0004] Improved throughputs for inserting samples into analysis
devices can be of use in analysis applications other than NMR
spectroscopy, such as for example IR and UV spectroscopy.
SUMMARY OF THE INVENTION
[0005] The present invention provides a nuclear magnetic resonance
spectrometer including: a magnet for applying a magnetic field to a
plurality of nuclear magnetic resonance samples; a nuclear magnetic
resonance probe positioned in a bore of the magnet, for performing
nuclear magnetic resonance measurements on the samples; an axial
multi-sample conveyer coupled to the probe, for transferring a
plurality of sample containers containing the samples into the
probe; and a driving device coupled to the conveyer, for
controlling the motion of the sample containers through the
conveyer.
[0006] The axial sample conveyer includes: a plurality of input
apertures for receiving the sample containers; a plurality of
output apertures positioned opposite the input apertures and
transversely aligned with the plurality of input apertures, for
sequentially transferring the sample containers to the probe; an
axially-rotatable auger positioned between the input apertures and
the output apertures, for axially constraining a motion of the
sample containers between the input apertures and output apertures;
and a plurality of axial sample guides positioned facing the auger
between the input apertures and the output apertures and
transversely aligned with the input apertures and the output
apertures, for transversely constraining the motion of the sample
containers.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] The foregoing aspects and advantages of the present
invention will become better understood upon reading the following
detailed description and upon reference to the drawings where:
[0008] FIG. 1 is a schematic diagram of a nuclear magnetic
resonance (NMR) spectrometer according to the preferred embodiment
of the present invention.
[0009] FIG. 2 shows an isometric view of an axial sample conveyer
of the spectrometer of FIG. 1 according to the preferred embodiment
of the present invention.
[0010] FIG. 3-A shows a longitudinal sectional view of the conveyer
of FIG. 2.
[0011] FIG. 3-B shows a top view of the conveyer of FIG. 3-A with
its input plate removed.
[0012] FIG. 3-C shows a transverse sectional view of the input
plate of the conveyer of FIG. 3-A.
[0013] FIG. 4 shows a front view of an auger of the conveyer of
FIG. 2, according to the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0014] The following description illustrates embodiments of the
invention by way of example and not necessarily by way of
limitation.
[0015] FIG. 1 is a schematic diagram illustrating a nuclear
magnetic resonance (NMR) spectrometer 12 according to the present
invention. Spectrometer 12 comprises a magnet 16 for applying a
static longitudinal magnetic field B.sub.0 to samples of interest.
An NMR probe 20 is positioned in a bore of magnet 16. Probe 20
holds one sample container (test tube) at a time within an analysis
location situated generally at the center of magnet 16. Each sample
container holds a sample of interest. Probe 20 includes one or more
radio-frequency (RF) coils for applying radio-frequency transverse
magnetic fields B.sub.1 to the samples of interest, and/or for
measuring the response of the samples to the applied magnetic
fields.
[0016] A control/acquisition system 18 is electrically connected to
magnet 16 and each RF coil of probe 20, and fluidically connected
to probe 20. Control/acquisition system 18 applies desired
radio-frequency pulses to probe 20, controls the temperature of
probe 20, and acquires data indicative of the nuclear magnetic
resonance properties of the samples within probe 20.
Control/acquisition system 18 is further electrically connected to
a driving device 25, described in more detail below, for
controlling the operation of driving device 25. Driving device 25
is preferably a non-magnetic device, such that the driving device
does not produce magnetic fields which could otherwise disturb NMR
measurements performed on samples within probe 20. Suitable
non-magnetic driving devices include piezo-electric motors and
devices employing fluid flow.
[0017] An axial multi-sample conveyer 22 is coupled to probe 20,
for sequentially transferring a plurality of sample containers to
probe 20. Conveyer 22 is preferably positioned above probe 20, such
that samples exiting conveyer 22 drop into probe 20 due to gravity.
Conveyer 22 is connected to probe 22 through a funnel 24 positioned
underneath conveyer 22, between conveyer 22 and probe 20. Funnel 24
is positioned with a larger input aperture facing conveyer 22 and a
smaller output aperture facing probe 20. The input aperture of
funnel 24 is sufficiently large to capture all sample containers
exiting conveyer 22. The diameter of the output aperture of funnel
24 is preferably comparable to or slightly larger than the diameter
of each sample container, such that each sample container is
accurately directed into the analysis location of probe 20.
[0018] FIG. 2 shows an isometric view of conveyer 22 according to
the preferred embodiment of the present invention. Conveyer 22
comprises a fixed output (base) plate 32, a lateral cylindrical
casing 30 mounted on base plate 32, a fixed input (top) plate 34
mounted on casing 30 opposite output plate 32, and an
axially-rotatable rigid shaft 36 mounted through bearings on plates
32 and 34.
[0019] FIG. 3-A shows a longitudinal sectional view of conveyer 22,
while FIG. 3-B shows a top view of conveyer 22 with its input plate
34 removed. As illustrated in FIG. 3-A, output plate 32 has a
plurality of axial sample output apertures 40a defined
therethrough, for allowing sample containers to pass from conveyer
22 into funnel 24 (shown in FIG. 1). Referring to FIG. 3-A, output
apertures 40a are arranged along output plate 32 at the same radial
distance from the longitudinal axis of conveyer 22.
[0020] Input plate 34 has a corresponding plurality of axial sample
input apertures 40b defined therethrough, for allowing sample
containers into the interior of conveyer 22. Each input aperture
40b is transversely aligned with and of the same size as a
corresponding output aperture 40a. Each input aperture 40b is
positioned above a corresponding output aperture 40a.
[0021] The transverse cross-section of each aperture 40a-b is
preferably circular, as illustrated by the transverse cross-section
of input plate 34 shown in FIG. 3-C. The size of each aperture
40a-b is preferably comparable to the diameter of each sample
container 54, such that each sample container 54 fits axially
through apertures 40a-b.
[0022] Casing 30 is attached to input and output plates 32, 34
along annular longitudinal overlap regions 55a-b, respectively.
Casing 30 overlaps with input plate 32 over region 55a, and with
output plate 34 over region 55b. Input and output plates 32, 34
laterally enclose casing 30 along overlap regions 55a-b,
respectively. Transverse (radial) screws can be inserted through
casing 30 and plates 32, 34 along overlap regions 55a-b, for
attaching plates 32, 34 to casing 30.
[0023] Referring back to FIG. 3-A, shaft 36 is mounted on bearings
46a-b, which form parts of plates 32, 34 respectively. Shaft 36
extends axially through plates 32, 34. Shaft 36 is further
connected to driving device 25, for rotating shaft 36 around its
longitudinal axis.
[0024] An axial auger (Archimedes screw) 50 is mounted on shaft 36.
Auger 50 extends between input plate 34 and output plate 32. Auger
50 has a helical thread or flange 52 extending away from the
central body of auger 50, for axially (vertically) constraining a
plurality of sample containers 54. Thread 52 is illustrated in a
lateral view in FIG. 4. Referring back to FIG. 3-A, the transverse
extent of thread 52 is less than the full diameter of each sample
container 54, such that at least part of each sample container 54
extends outside of thread 52.
[0025] The transverse extent of thread 52 is at the same time
sufficiently large to support and axially constrain each sample
container 54. The axial separation or period D of thread 52 is
larger than the axial extent of each sample container 54, such that
each sample container 54 fits between consecutive turns of thread
52.
[0026] As shown in FIGS. 3-A and 3-B, conveyer 22 further includes
a plurality of axial guides 60 extending between input plate 34 and
output plate 32. For ease of manufacturing, guides 60 are
preferably formed by discrete rails attached by screws to the
inside surface of casing 30. Guides 60 can also be integrally
formed as depressions along the inside surface of casing 30. Each
guide 60 has a guiding surface 62 facing auger 50, for transversely
constraining sample containers 54 to follow a linear axial path
along guide 60 as auger 50 is rotated. The transverse cross-section
of each guiding surface 62 can be flat or curved, e.g. shaped as an
arc of a circle. Each guiding surface 62 laterally encloses and
constrains containers 54. A passage 58 is defined between each
guiding surface 62 and the central portion of auger 50. Each
passage 58 connects an input aperture 40b to a corresponding output
aperture 40a, for allowing passage of sample containers 54 from
input aperture 40b to output aperture 40a. connects an input
aperture 40b to a corresponding output aperture 40a, for allowing
passage of sample containers 54 from input aperture 40b to output
aperture 40a.
[0027] Funnel 24 and the various components of axial sample
conveyer 22 are made of nonmagnetic materials that do not affect
NMR measurements taken on samples within probe 20 (shown in FIG.
1). As is apparent to the skilled artisan, suitable non-magnetic
materials can include plastics, glasses, aluminum, and stainless
steel. In a present implementation, shaft 36 is made of aluminum,
auger 50 is made of white nylon, and casing 30, input plate 34,
output plate 32 and guides 60 are made of clear acrylic.
[0028] The loading of sample containers 54 into probe 20 will now
be described with reference to FIGS. 1 and 3-A. During the
operation of spectrometer 20, multiple sample containers 54 are
transferred into conveyer 22 through input apertures 40b, shown in
FIG. 3-A. Sample containers 54 entering conveyer 22 then rest onto
thread 52. Thread 52 axially constrains sample containers 54, and
controls the passage of containers 54 through conveyer 22.
[0029] To move containers 54 down through conveyer 22, driving
device 25 is used to rotate shaft 36 at a desired rate. The
rotation of shaft 36 causes the rotation of auger 50. As auger 50
is rotated, the z-coordinate of thread 52 at each guide (.theta.-)
location decreases at a constant rate. Sample containers 54 move
down along a linear, vertical trajectory defined by guides 60 at a
rate controlled by the rotation of auger 50. Sample containers 54
exit sequentially through output apertures 46a, and one by one pass
through funnel 24 (shown in FIG. 1) and into an analysis location
within probe 20. The analysis location holds one sample container
at a time. The insertion of each sample container 54 into probe 20
is controlled by the rotation of auger 50. Desired NMR measurements
are performed on each individual sample within probe 20. After each
360.degree. rotation of auger 50, a new set of six sample
containers 54 is inserted into conveyer 22. Each sample container
54 is transversely constrained by a corresponding guide 60 to
follow a linear axial trajectory corresponding to a fixed
.theta.-location. Used sample containers are allowed to fall out of
probe 20 through the bottom in a conventional manner.
[0030] The above-described system and methods allow relatively high
throughputs for transferring samples in and out of the measurement
location of the spectrometer. New sample containers 54 can be
inserted into probe 20 at intervals ranging from seconds to minutes
or longer. In a presently-envisioned application, a new sample
container 54 is inserted into probe 20 every 30 seconds.
[0031] Conveyer 20 is preferably assembled from manufactured
components as described below with reference to FIG. 3-A. Auger 50
is attached to shaft 36 using screws. Each guide 60 is using
screws. Shaft 36 is then fitted through the central aperture and
bearing 46a of output plate 32. Input plate 34 is slipped onto
shaft 36 through its central aperture and bearing 46b.
[0032] It will be clear to one skilled in the art that the above
embodiments may be altered in many ways without departing from the
scope of the invention. For example, the number of sample container
conduits/guides can be higher or lower than the number six
illustrated above. The sample container guides can be formed
integrally in the interior surface of a casing, rather than as
individual rails. A sample storage enclosure can be positioned
above the sample conveyer, opposite the probe relative to the
conveyer. The sample storage enclosure can include plural axial
bores aligned with the input apertures of the conveyer, for storing
sample containers and transferring the sample containers into the
conveyer. The sample conveyer can be placed underneath the probe,
or can form part of the probe. Suitable applications of the
conveyer may include applications other than NMR and other
spectroscopy applications. Accordingly, the scope of the invention
should be determined by the following claims and their legal
equivalents.
* * * * *