Vibrating Cantilever Transducer Incorporated in Dual Diaphragms Structure for Sensing Differential Pneumatic Pressure

Pneumatic pressure cells with thin metallic spherical diaphragm of shallow spherical shell configurationlinked with vibrating wire pickup or vibrating cantilever pickup were reported in the past. In order toenhance the sensitivity of the pressure cell this work considers dual diaphragm structure fitted withcantilever pickup. The design and development of the pressure cell with this dual diaphragm structurehaving cantilever pickup is presented here. The geometrical design is optimally made as to sense eithermono pressure or differential pressure resources. The cantilevers of the two diaphragms are excited toproduce vibrations and the frequencies of vibrations are determined by picking up signals fromorthogonally arranged opto-coupler links. With the computed frequency a lookup table is referred toobtain the pressure acting on the concerned diaphragm. In the external circuits, the average pressure andthe differential pressure acting on two diaphragms are computed. Furthermore transmitting circuits takingthe average pressure and differential pressure in digital form and analogue form to remote area arepresented. Performance analysis of the proposed mechatronic pressure cell is made and its improvedperformance over other pressure cells is presented.