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

Abstract: Pneumatic pressure cells with thin metallic spherical diaphragm of shallow spherical shell configuration linked with vibrating wire pickup or vibrating cantilever pickup were reported in the past. In order to enhance the sensitivity of the pressure cell this work considers dual diaphragm structure fitted with cantilever pickup. The design and development of the pressure cell with this dual diaphragm structure having cantilever pickup is presented here. The geometrical design is optimally made as to sense either mono pressure or differential pressure resources. The cantilevers of the two diaphragms are excited to produce vibrations and the frequencies of vibrations are determined by picking up signals from orthogonally arranged opto-coupler links. With the computed frequency a lookup table is referred to obtain the pressure acting on the concerned diaphragm. In the external circuits, the average pressure and the differential pressure acting on two diaphragms are computed. Furthermore transmitting circuits taking the average pressure and differential pressure in digital form and analogue form to remote area are presented. Performance analysis of the proposed mechatronic pressure cell is made and its improved performance over other pressure cells is presented.