Abstract: Apparatus for removing a sample of particulate catalyst material from a reactor while the reactor is at operating conditions. The sampling apparatus includes an elongated tube terminating in a chamber located inside the reactor, the chamber having a valve at one end which opens to receive a catalyst sample and a valve at the other end which opens to deliver the catalyst sample to a sample receiver. A rotatable actuating shaft extending from outside the reactor to the sampling chamber enables an operator to selectively obtain a catalyst sample or deliver a previously obtained catalyst sample to a receiver. A stuffing box is attached to the end of the elongated tube outside the reactor and is removable therefrom. A turning member extending through the stuffing box engages the actuating shaft. The stuffing box may be detached and repacked without removing the rest of the sampling apparatus from the reactor.