Abstract: A sampler for insertion in a flow duct carrying a stream of dry particulate material, including a housing with a sample head traversing the stream of flowing material and being movable within the head across the breadth of the stream of flowing material; a rotary disc in the bottom wall of the housing mounting the sample head; the mounting disc having a protective flange or ledge over the seal and thrust bearing at the periphery of the disc as to fully protect the seal and bearing ring against deteriorating effect of the particulate material; a sample spout extending through and rotatably mounted in the rotary mounting disc and being connected with the sample head for delivering samples of the material to the exterior of the housing; a rotary actuator for revolving the disc first in one direction and then the other; and a slide rod attached to the sample spout and moving through a slide block maintaining the sample head in predetermined upstream orientation facing the inlet of the housing.