Apparatus and method for dispensing small quantities of particles

1. An apparatus comprising a hopper provided with a sieve at a bottom portion thereof, the hopper in use containing powder to be dispensed therefrom through the sieve, a support for the hopper, the support holding a portion of the hopper so that the hopper can in use be held above a container into which the dispensed powder is to be received, and at least one actuator for delivering taps to the hopper for causing a discrete amount of the powder to be dispensed through the sieve when the hopper receives each tap, wherein the at least one actuator is arranged to deliver the taps to the hopper from different directions and/or at different locations on the hopper;

wherein one said actuator is provided which is mounted on the support and is adapted to deliver the taps to the hopper alternately in two opposing directions; and wherein the actuator is a solenoid having an armature which is adapted to impact two opposed parts of the support.

2. An apparatus according to claim 1 wherein the actuator is adapted to cause rotation of the hopper by successive delivery of the taps to the hopper.

3. An apparatus according to claim 1 wherein a plurality of actuators are provided and are mounted at different positions around the hopper so that the hopper receives the taps at a plurality of different locations.

4. An apparatus according to claim 3 wherein each actuator is provided on a respective arm of the support and the actuators are angularly spaced in a radial orientation around the hopper.

5. An apparatus comprising a hopper provided with a sieve at a bottom portion thereof, the hopper in use containing powder to be dispensed therefrom through the sieve, a support for the hopper, the support holding a portion of the hopper so that the hopper can in use be held above a container into which the dispensed powder is to be received, and at least one actuator for delivering impact energy to the hopper for causing a discrete amount of the powder to be dispensed through the sieve when the hopper receives the impact energy, wherein the at least one actuator is arranged to deliver the impact energy to the hopper from different directions and/or at different locations on the hopper;

wherein one said actuator is provided which is mounted on the support and is adapted to cause rotation of the hopper by successive delivery of the impact energy to the hopper.

6. An apparatus according to claim 2 wherein a plurality of actuators are provided and are mounted at different positions around the hopper so that the hopper receives the impact energy at a plurality of different locations.

7. An apparatus according to claim 6 wherein each actuator is provided on a respective arm of the support and the actuators are angularly spaced in a radial orientation around the hopper.

8. An apparatus according to claim 5 wherein the hopper is rotatably mounted in the support via a ratchet mechanism and an impact of the actuator on the hopper causes partial rotation of the hopper by operation of the ratchet mechanism.

9. An apparatus according to claim 8 wherein the ratchet mechanism comprises a plurality of angularly spaced radial projections adapted to engage with the armature.

10. An apparatus according to claim 9 wherein partial rotation of the hopper by operation of the ratchet mechanism occurs incrementally through an angle defined by the angular separation of the projections of the ratchet mechanism.

11. A method comprising the steps of: disposing in a hopper provided with a sieve at a bottom portion thereof a powder to be dispensed therefrom through the sieve; supporting the hopper by holding a portion of the hopper with a support so that the hopper is held above a container into which the dispensed powder is to be received; and delivering taps to the hopper by at least one actuator thereby to cause a discrete amount of the powder to be dispensed through the sieve when the hopper receives each tap, the at least one actuator being arranged to deliver the taps to the hopper from different directions and/or at different locations on the hopper;

wherein one said actuator is provided which is mounted on the support and is adapted to deliver the taps to the hopper alternately in two opposing directions; and wherein the actuator is a solenoid having an armature which is adapted to impact two opposed parts of the support.

12. A method according to claim 11 wherein the actuator is adapted to cause rotation of the hopper by successive delivery of the taps to the hopper.

13. A method according to claim 11 wherein a plurality of actuators are provided and are mounted at different positions around the hopper so that the hopper receives the taps at a plurality of different locations.

14. A method according to claim 13 wherein each actuator is provided on a respective arm of the support and the actuators are angularly spaced in a radial orientation around the hopper.

15. A method comprising the steps of: disposing in a hopper provided with a sieve at a bottom portion thereof a powder to be dispensed therefrom through the sieve; supporting the hopper by holding a portion of the hopper with a support so that the hopper is held above a container into which the dispensed powder is to be received; and delivering impact energy to the hopper by at least one actuator thereby to cause a discrete amount of the powder to be dispensed through the sieve when the hopper receives the impact energy, the at least one actuator being arranged to deliver the impact energy to the hopper from different directions and/or at different locations on the hopper;

wherein one said actuator is provided which is mounted on the support and is adapted to cause rotation of the hopper by successive delivery of the impact energy to the hopper.

16. A method according to claim 15 wherein a plurality of actuators are provided and are mounted at different positions around the hopper so that the hopper receives the impact energy at a plurality of different locations.

17. A method according to claim 16 wherein each actuator is provided on a respective arm of the support and the actuators are angularly spaced in a radial orientation around the hopper.

18. A method according to claim 15 wherein the hopper is rotatably mounted in the support via a ratchet mechanism and an impact of the actuator on the hopper causes partial rotation of the hopper by operation of the ratchet mechanism.

19. A method according to claim 18 wherein the ratchet mechanism comprises a plurality of angularly spaced radial projections adapted to engage with the armature.

20. A method according to claim 19 wherein partial rotation of the hopper by operation of the ratchet mechanism occurs incrementally through an angle defined by the angular separation of the projections of the ratchet mechanism.