Liq. volume measuring appts. for e.g. motor vehicle IC engine - uses microprocessor controlled electromagnetic transducer to apply vibrations to elastic medium inside tube immersed in liq.

摘要

The device contains an electromagnetic transducer which generates vibrations which are transmitted to an elastic medium inside a tube immersed in the tank. The acoustic resonance frequency of the elastic medium is an inverse function of the distance between the source of vibrations and the surface of the liquid. In this system, the frequency applied to the transducer is controlled by a microprocessor. The AC voltage from the transducer is digitised, so that it can be input to the microprocessor. The microprocessor finds the resonance frequency by using this digital word and the transducer frequency which it output. The resonance frequency is output by the microprocessor to a display.