Experimental study on the parameters effect on the sampling method based on negative pneumatic conveying

Abstract

The factors of pipe diameter, drilling velocity and the degree of hole collapse effects on vacuum pneumatic conveying were studied by the self-developed vacuum pneumatic conveying experimental system. The results revealed the following three facts. 1) for a certain external diameter 73mm∼ the best choice for the inner diameter was 36∼ 46mm; 2) when the drilling velocity was below 0.44m/min, the total pressure drop in the system is low and the sampling time cost is moderate; 3) for reducing the particle breakage ratio during the process of vacuum pneumatic conveying for sampling with a 50m distance, the roots vacuum pump with a pressure range above 40kPa and air flow rate of about1000πD2m3/min was required. The above results provide a suggestion for coal sampling based on the vacuum pneumatic conveying parts selection.