Method and apparatus for dispensing powder samples

1. Apparatus for parallel dispensing powder samples comprising:

at least two sample holders for containing powder samples, each said sample holder having a through passage with an axis, the through passage comprising:

a first aperture through which a powder sample is introduced into said passage,

a second aperture through which a powder sample flows from said passage,

flow control means for controlling flow of powder through each said second aperture and into a respective receptacle, and

an agitator means in each said sample holder for agitating a powder sample during flow of powder through each second aperture,

wherein said flow control means for each said sample holder comprises a resilient film sealing each said second aperture.

2. Apparatus according to claim 1 wherein each through passage of each sample holder generally tapers from the first aperture to the second aperture thereof.

3. Apparatus according to claim 1 comprising more than two sample holders.

4. Apparatus according to claim 1 wherein said agitator means comprises perforator means for perforating said resilient film and is mounted for axial movement through said passage whereby said film is perforable by it.

5. Apparatus according to claim 1 wherein said agitator means is contactable with a wall defining said passage.

6. Apparatus according to claim 1 wherein said agitator means are each mounted on a common support member reciprocal movement of which relative to a dispense location of said sample holders effects simultaneous reciprocal movement of each agitator means relative to the sample holders.

7. Apparatus according to claim 1 wherein each said agitator means comprises stirrer mechanisms each comprising at least one spring wire mounted for rotation about an axis that aligns substantially coaxially with the axis of each through passage, said at least one wire being mounted in a plane including said axis of rotation.

8. Apparatus according to claim 7 wherein said at least one wire has an unstrained position in which at least a part of the wire is at a radius from said axis that is greater than a radius of the first aperture of the passage of the sample holder and wherein said apparatus further comprises constraint means which in a first position constrains said at least one wire in a strained position in which all of said at least one wire is located at a radius from said axis which is less than the radius of said first aperture and in a second position does not apply any constraint to said at least one wire thereby permitting said at least one wire to move radially outwards towards its unstrained position.

9. Apparatus according to claim 8 wherein said constraint means comprises a pair of parallel plates each having a number of apertures corresponding to a number of stirrer mechanisms, the plates being positioned relative to the stirrer mechanisms such that their planes are normal to the axes of the stirrer mechanisms and, when the apertures of the plates are in registration with one another, a center of each of the apertures is located substantially coaxially with the respective axes of the stirrer mechanisms, the plates being movable relative to one another between a first position, in which the plates are in register with one another and in which the wires of the stirrer mechanisms are in their unstrained position, and a second position, in which the apertures therein are only in partial registration with one another, and in which the wires of the stirrer mechanisms are constrained in their strained position.

10. Apparatus according to claim 9 wherein both plates are movable symmetrically with respect to the axes of the stirrer mechanisms.

11. Apparatus according to claim 7 wherein the stirrer mechanisms have a speed of rotation and/or a vertical reciprocating movement, the speed of rotation of said stirrer mechanisms and/or vertical reciprocating movement of said stirrer mechanisms relative to the sample holder location being controllable to enable the rate of dispensation of the powder samples from the sample holders to be controlled.

12. Apparatus according to claim 1 comprising nozzle means through which a gas flow may be directed into each sample holder through the first apertures thereof.

13. Apparatus according to claim 1 comprising gas inlet means for directing a gas flow at an external lower wall of each sample holder.

14. Apparatus according to claim 1 comprising gas outlet means for venting gas from the vicinity of an external lower wall of each sample holder.