Patent ID: 7358451

Claim:
Apparatus for dispensing particles, comprising: a particle retainer for retaining a supply of the particles to be dispensed; a particle release actuator for causing, in response to an actuation signal, some of said supply of particles to be dispensed from said particle retainer; a weight measuring device for measuring the apparent weight of particles dispensed from said particle retainer and for outputting a signal representing the measured apparent weight; wherein said particle release actuator is arranged to transmit a discrete impulse of force to said particle retainer; and wherein the energy of said discrete impulse of force corresponds to a characteristic of said actuation signal provided to said particle release actuator, whereby the number of particles dispensed from said particle retainer is related to the energy of said discrete impulse of force; further comprising a processor operatively connected to said particle release actuator and arranged to provide said actuation signal thereto, said processor also being operatively connected to said weight measuring device and being arranged to receive said measured apparent weight signal therefrom; wherein said processor provides an actuation signal having a characteristic that causes a less energetic discrete impulse of force to be transmitted to said particle retainer as the weight of particles dispensed approaches a target weight.