ABSTRACT
Sampling positions are determined so as to divide the powder bed into equal areas. Sampling spears can be used to take samples from deep inside the powder bed. A sampling device of the air-suction type is also useful to get vertical samples of the powder bed in which particles are mixed with air at the sampler nose and the resulting gas–solid mixture is sucked into a gas–solid separator such as a cyclone or bag filter. A special constant-volume sampler or slide-valve type of sampler may be adopted in the sampling of powder sliding on an inclined chute. When powder is poured into a heap, size segregation will occur: fine particles tend to remain at the center of the heap and coarse ones congregate at the periphery. Even when the powder is slowly transported by a belt conveyor, coarse particles tend to float on the surface of the powder bed.
