Patent ID: 7891315

Claim:
A powder supply system for supplying a processing apparatus with a granular substance, including a first main container and a powder conveying system with a storage container for conveying the granular substance into the processing apparatus, wherein a regulation unit is configured to control a first valve between the first main container and the storage container so that, in the operating state of the processing apparatus, a predetermined amount of the granular substance can be conveyed by actuation of the first valve to the storage container out of the first main container as working powder in such a way that at least a minimum amount is available as granular substance in the storage container, wherein the regulation unit is configured to actuate the first valve such that a predetermined amount of the granular substance does not exceed a maximum amount such that a level of the granular substance within the storage container always lies in a predetermined range between an empty level and a full level of the storage container, and wherein the regulation unit is configured to provide a first dose of the predetermined amount of the granular substance to the storage container by opening the first valve in response to a signal provided to the regulation unit from a measuring device of the storage container that the level is at the minimum amount and by closing the first valve in response to a signal provided to the regulation unit that the level is at the maximum amount which is below the full level of the storage container, wherein a metering container is provided between the first main container and the storage container for accepting doses of the pre-determined amount of the granular substance via a second valve between the first main container and the metering container and for delivering the doses of the pre-determined amount of the granular substance to the storage container, wherein the regulation unit is configured to actuate the second valve to provide the metering container with a second dose of the pre-determined amount of the granular substance from the first main container after the regulation unit has closed the first valve in response to the regulation unit detecting that the first dose of the pre-determined amount of the granular substance has been delivered to the storage container from the metering container.