AN APPARATUS FOR MEASURING A FLOW RATE OF A POWDER

摘要

[PROBLEMS] To provide a powder flow measuring device for measuring variation of the flow of pneumatically conveyed powder as a variation of capacitance and measuring the flow of the powder with high precision in consideration of the temperature drift of the capacitance due to the variation of the temperature of the conveying gas. [MEANS FOR SOLVING PROBLEMS] A capacitive powder flow measuring device comprises a protective pipe for conveying powder, an electrode arrangement pipe with a measuring electrode, and a converter circuit (converter) for sending the output of the measuring electrode to a powder flow indicator. The powder flow measuring device further comprises an environment temperature sensor and a conveying gas temperature sensor (31) directly joined to a portion of the protective pipe (20). The portion is not covered with the electrode arrangement pipe (10). The powder flow measuring device still further comprises a temperature correcting circuit which corrects by calculation the output of capacitance from a capacitance converter by using the flow 0 as a reference based on the output analytical curve of the flow/capacitance and by using the difference between the outputs of the temperature sensors for sensing the environment temperature and the conveying gas temperature and thus performs temperature correction.