| 摘要 |
PURPOSE:To detect the absence or presence of the flow of coal, by providing a grounding wire, whose one end is connected to the wall of a flow path, and a means, which detects a current flowing through said grounding wire. CONSTITUTION:When coal flows in a pipe 1, the coal is contacted with the inner wall of the pipe 1, and static electricity is generated owing to the friction and stored in the pipe 1. The quantity of the charge at this time is expressed by an experimental expression (where v=flow speed, d=diameter of pipe, z=length of pipe, and k=proportional constant). The value of the current flowing through a grounding wire 3 is about 10<-3>-10<-4> A utmost. The current is outputted through an amplifier 5 and a judging device 6. Then, an waveform (a) is graphed. Meanwhile, when the coal is not flowed, an approximately linear wave form (b) is obtained. Namely, by preliminarily examining the current value obtained by the judging device 6, the case where the coal flows and the case where the coal does not flow can be definitely discriminated. |
