Build material container, and collection tube structure

A collection tube structure for mounting in an additive-manufacturing build-material container comprising a reservoir to hold build material and an outlet opening through which build material can be removed from the reservoir, the collection tube structure comprising:

• a pair of nested tubes, a first of the nested tubes being a collection tube to collect build material at one end thereof from the reservoir upon application of a suction force at the other end thereof, and to guide the collected build material to said other end, and a second of the nested tubes being a vent tube to admit gas from outside the reservoir into a bottom portion of the reservoir;
• and
• a skirt arranged around a collection opening of the collection tube, the skirt comprising a surface that extends perpendicular to a longitudinal axis of the collection tube, the surface disposed opposite of a gas delivery opening of the vent tube to receive and deflect gas that has exited the gas delivery opening of the vent tube away from collection tube and the collection opening of the collection tube, the skirt further comprising an annular member that extends from an outer circumference of the surface toward the collection opening of the collection tube, the annular member tapering to a narrower diameter from the circumference of the surface toward the collection opening of the collection tube.