ACOUSTIC TYPE CAPACITY MEASURING APPARATUS

摘要

PURPOSE:To enable accurate measurement of capacity by a method wherein diaphragms of two electroacoustic converters are arranged as opposed to each other in a closed container and driven synchronously to add electrical outputs with an addition circuit and a resonance frequency determined by the capacity of the closed container is detected. CONSTITUTION:Electroacoustic converters 13 and 33 the same in the characteristic are arranged sideways on the upper part in a closed container 11 to be measured while diaphragms 13a and 33a are arranged as opposed each other. Both peripheries of the diaphragms 13a and 33a are connected with a cylindrical body 34 and a space 35 formed between the diaphragms 13a and 33a is isolated from the inside of the closed container 11. Output pulses of a pulse generator 15 are supplied to driving circuits 16 and 36 simultaneously to drive electroacoustic converters 13 and 33 synchronously. Electrical outputs of the electroacoustic converters 13 and 33 are fed to an addition circuit 37 to add and the results are inputted into a resonance frequency detecting section 38.