Aneroid barometer for radio-meteorology - uses internal isolated plate and flat membrane surface separation giving pressure proportional capacitance

摘要

The barometer consists of an aneroid diaphragm(10) and forms part of a radiometeorograph. The diaphragm consists of two membranes fastened together at their flanges(13). It is evacuated and contains a disc-shaped capacitor plate(17) which is held in the centre by a butt-weld(19) to a stub(16) which passes through a hole in the centre of the spring membrane(11). The stub is inserted in a cylinder of insulating material and fixed to the membrane by a collar(14). A circular flat section(18) of the lower membrane(12) forms the second capacitor plate. Under pressure the electrodes separation changes thus altering the capacitance to give an electrical signal. The separation is almost linearly related to the pressure. The sensitivity can be chosen by varying the inner plate radius(r). The device is stable and mechanically robust.