Sample catcher for NMR apparatus and method utilizing thereof
View Patent ↗An NMR apparatus, sample contained in a sample holder is ejected from an NMR probe to the top of the magnet region where a sample latching mechanism holds the sample in place without requiring a continuing flow of pressurized gas, electrical power or other outside force. The sample can then be removed and/or exchanged with another sample that is also held in place without the expenditure of gas. When ready the operator depresses a lever arm enabling the exchanged sample to move into the probe.
1. A nuclear magnetic resonance apparatus comprising:
a magnet which produces a magnetic field for applying to a nuclear resonance sample;
a nuclear magnetic resonance probe positioned within a bore of said magnet,
a sample passageway extended via said probe, said passageway comprising a sample exchange region;
a sample holder, which holds and loads the sample into said probe; and
a sample catcher mounted onto the sample passageway within the exchange region latching said sample holder being ejected from said probe for sample removal or reloading, said sample catcher comprising:
a first cylindrical body having a cylindrical bore therein and a slot extending through a wall thereof, and
a latch mechanism disposed within said slot and comprising an arm, a mechanical pivot turning said arm within said slot, and a limit pin, which limits a rotational range of said arm, said arm is moved towards said sample holder under a force of gravity traversing said slot into the sample passageway when the sample holder is ejected to the sample exchange region.
2. The apparatus of claim 1 , further comprising a gas source, which provides a compressed gas flow within said sample passageway for moving said sample holder therein.
3. The apparatus of claim 1 , wherein said sample holder comprises a second cylindrical body that is movable within said cylindrical bore of said first cylindrical body.
4. The apparatus of claim 3 , wherein said first cylindrical body comprises at least one O-ring disposed on the interior thereof which provides a gas tight seal with said sample passageway.
5. The apparatus of claim 1 , wherein said first cylindrical body and said arm are made from a non-magnetic material.
6. The apparatus of claim 5 , wherein said second cylindrical body of said sample holder further comprises a cylindrical shoulder for resting thereon an upper edge of said arm of said sample catcher in a latch position.
7. The apparatus of claim 5 , wherein said first cylindrical body of said sample catcher having a bottom and an upper portions, the diameter of said bottom portion is smaller than the diameter of said upper portion for releasing the compressed gas flow when said sample holder is moved to the exchange region, and said second cylindrical body of said sample holder having a flat bottom portion for resting thereon an upper edge of said arm of said sample catcher in a latch position.
8. The apparatus of claim 1 , wherein said first cylindrical body and said arm are made from different materials.
9. The apparatus of claim 8 , wherein said first cylindrical body is made from aluminum.
10. A sample catcher of a nuclear magnetic resonance apparatus for retaining a sample holder in a sample exchange region comprising:
a hollow cylindrical body forming a chamber for maintaining the sample holder therein in a vertical position;
said chamber having a slot intersecting a wall of said chamber; and
a latch mechanism disposed within said slot, which latches said sample holder within said chamber after a gas flow ejecting said sample holder into a sample exchange region is terminated, said latch mechanism comprising an arm, a mechanical pivot supporting said arm, and a limit pin constraining a rotation of said arm between a first and a second positions where the arm protruding into and clearing out of said chamber respectively.
11. The sample catcher of claim 10 , wherein said mechanical pivot passes through said arm at the location where a distance from said pivot to said cylindrical chamber is greater than a distance from the center of gravity of said arm to said cylindrical chamber.
12. The sample catcher of claim 11 , wherein said chamber and said arm are made from non-magnetic materials.
13. A method of retaining a sample holder within a sample catcher of a nuclear magnetic resonance apparatus comprising the steps of:
providing the sample catcher having a cylindrical hollow body with a slot within a wall thereof and a latch mechanism, which is disposed within the slot and having a movable arm, mechanical pivot and a limit pin constraining the rotation of the arm between a first and a second positions where the arm protruding into and being cleared of the cylindrical hollow body respectively;
mounting the sample catcher at a top portion of a sample passageway within an exchange region;
moving the sample holder by a compression gas flow into the exchange region;
pushing the latch mechanism out of the slot by a body of the sample holder;
terminating the compression gas flow via the sample passageway; and
latching the sample holder within the cylindrical chamber by resting the body of the sample holder on the latch mechanism.
14. The method of claim 13 , wherein a distance from the mechanical pivot passing through the arm to the cylindrical chamber is greater than a distance from the center of gravity of the arm to the cylindrical chamber.
15. The method of claim 14 , further comprising the step of forming a body of the sample holder with a shoulder or with a flat bottom, wherein in a latch position an upper edge of the arm is rested on the shoulder or on the flat bottom.