CAPACITIVE PRESSURE PICKUP AND PROCESS OF ITS ASSEMBLY Russian patent published in 2004 - IPC

FIELD: aviation instrumentation. SUBSTANCE: invention refers to capacitive pressure pickups installed aboard aircraft. Given capacitive pressure pickup incorporates case with membrane, connector, capacitive converter comprising instrument capacitor sensitive to pressure and reference capacitor insensitive to pressure formed by proper electrodes. Four electrodes insulated one from another are anchored inside case of pickup. One of them is put on rod of membrane. Reference capacitor is placed uniaxially to center of pickup and configuration of elements forming it replicates configuration of instrument capacitor. Electrodes are electrically insulated with the help of metal bushings and glass rings. Longitudinal slots ensuring screening of current leads put in them are made along outer diameter of case elements carrying electrodes. In process of assembly of pickup metal is vitrified with glass with subsequent chemical milling of metal-and-glass joint, sensitive and insensitive capacitors are attached by welding. Electrodes are assembled separately prior to their installation at point of final assembly with test of their geometrical and electrical parameters. First stage of secondary converter includes first amplifier with capacitive feedback and is mounted directly on contacts of connector of pickup to avoid use of screened cable. EFFECT: increased accuracy of pressure measurement with simultaneous reduction of effect of external interference on first stage of secondary converter. 2 cl, 4 dwg