Device for determining a volume of gas in a sample
The invention relates to a device for determining a volume of gas in a sample contained in a vessel, the device comprising: a frame configured to attach the vessel; a needle having a longitudinal axis, comprising a proximal part and a distal part, the distal part being configured to pierce the vessel and the proximal part comprising a lumen; and an analysis compartment comprising a cell in fluid communication with the lumen of the proximal part of the needle. The invention also relates to a method for determining a volume of gas in a sample contained in a vessel.
1. A device for determining a volume of gas in a sample contained in a vessel ( 4 ), the device comprising:
a frame ( 11 ) configured to attach the vessel ( 4 );
a needle ( 1 ) having a longitudinal axis, comprising a proximal part ( 2 ) defined as a part of the needle connected to an analysis compartment and a distal part ( 3 ) defined as a part of the needle opposite the proximal part, the distal part ( 3 ) being configured to pierce the vessel ( 4 ) and the proximal part ( 2 ) comprising a lumen; and
the analysis compartment comprising a cell in fluid communication with the lumen of the proximal part ( 2 ) of the needle ( 1 ), and a piston slidable in the cell and sealing the cell in a gas-tight manner.
2. The device according to claim 1 , wherein the distal part ( 3 ) of the needle ( 1 ) is tapered.
3. The device according to claim 1 , wherein at least one of: the lumen is in fluid communication with an opening ( 13 ) on a peripheral surface of the needle ( 1 ) and the lumen does not extend to a distal end of the needle ( 1 ).
4. The device according to claim 1 , wherein the device is configured to provide a relative longitudinal movement of the needle ( 1 ) and the frame ( 11 ).
5. The device according to claim 1 , comprising an actuating member ( 12 ) connected to the frame ( 11 ) and configured to longitudinally move the frame ( 11 ) relative to the needle ( 1 ).
6. The device according to claim 1 , comprising a sheath ( 5 ) surrounding at least part of the needle ( 1 ) and having a proximal end ( 6 a ) and a distal end ( 6 b ), the device being configured to provide a relative longitudinal movement of the needle ( 1 ) and the sheath ( 5 ).
7. The device according to claim 6 , comprising an actuating member ( 9 ) connected to the proximal end ( 6 a ) of the sheath ( 5 ) and configured to longitudinally move the sheath ( 5 ).
8. The device according to claim 6 , comprising a seal ( 10 ) located at the distal end ( 6 b ) of the sheath ( 5 ) and configured to press against the vessel ( 4 ).
9. The device according to claim 1 , wherein at least one of: (i) the cell comprises at least one of a pressure sensor and a temperature sensor, and (ii) the device does not comprise a Toepler pump.
10. A method for determining a volume of gas in a sample contained in a vessel ( 4 ), the method comprising the steps of:
attaching the vessel ( 4 ) to a frame ( 11 ) of a device, the device having:
the frame ( 11 ) configured to attach the vessel ( 4 );
a needle ( 1 ) having a longitudinal axis, comprising a proximal part ( 2 ) defined as a part of the needle connected to an analysis compartment and a distal part ( 3 ) defined as a part of the needle opposite the proximal part, the distal part ( 3 ) being configured to pierce the vessel ( 4 ) and the proximal part ( 2 ) comprising a lumen; and
the analysis compartment comprising a cell in fluid communication with the lumen of the proximal part ( 2 ) of the needle ( 1 );
piercing the vessel ( 4 ) with the needle ( 1 ) of the device;
transferring gas present in the sample from the vessel ( 4 ) to the cell of the device; and
determining compressibility of the gas within the cell.
11. The method according to claim 10 , wherein at least one of: piercing is achieved by longitudinally moving the frame ( 11 ) towards the needle ( 1 ), and moving the frame ( 11 ) towards the needle ( 1 ) is carried out by rotating an actuating member ( 12 ).
12. The method according to claim 10 , wherein the device comprises a sheath ( 5 ) surrounding at least part of the needle ( 1 ), and the method comprises retracting the sheath ( 5 ) proximally upon piercing.
13. The method according to claim 12 , wherein retracting the sheath ( 5 ) is carried out by rotating an actuating member ( 9 ).
14. The method according to claim 10 , wherein the lumen of the needle ( 1 ) is in fluid communication with an opening ( 13 ) on a peripheral surface of the needle ( 1 ), and during the step of transferring gas, the opening ( 13 ) is located in the vessel ( 4 ).
15. The method according to claim 10 , wherein during the step of piercing the vessel ( 4 ) and during the step of transferring gas, there is a gas-tight connection between the vessel ( 4 ) and the needle ( 1 ).
16. The method according to claim 10 , wherein the compressibility of the gas in the cell is determined by measuring pressure in the cell as a function of volume of the cell.
17. The method according to claim 10 , wherein the volume of gas in the vessel ( 4 ) is calculated based on the compressibility of the gas and known dead volumes within the device.
18. The method according to claim 10 , further comprising a step of performing pyrolysis of a source rock sample in the vessel ( 4 ), prior to attaching the vessel ( 4 ) to the frame ( 11 ).
19. The method according to claim 10 , wherein the gas in the sample derives from pyrolysis of a source rock sample.