Volume 7, Issue 6 (November 1979)
High-Speed Sampling Cutters and Their Effect on Bias
Currently, in the United States, systems used to obtain a gross sample of flowable bulk material on a conveyor belt generally use a cross-chute sampler. With higher tonnage material handling systems, it would be advantageous to employ higher cutter speeds to keep the size of the gross sample collected within practical limits. Current cross-chute sample cutters are somewhat limited to cutter speeds in the range of 30 to 61 cm/s (12 to 24 in./s), primarily because of mechanical and structural limitations. Swing-arm-type samplers have features that permit higher cutter speeds, which reduce the quantity of primary increment taken. This paper presents the results of a test program for swing-arm samplers operating at cutter speeds up to 122 cm/s (48 in./s) and determines the parameters of control that must be considered to stay within acceptable statistical limits for bias.