Capacitive pressure sensor with linear response - contains piston comprising mass of mercury forming capacitor with metallic deposit on tube

摘要

The device has sealed metallic envelope (1) with an inlet to which the pressure being measured is applied. A ceramic tube (6) passes through the wall which forms two separate compartments. The tube contains a mass of mercury contained by two washers to form a capacitor with a metallic deposit on the tube. The pressure in the outer compartment moves the mass of mercury against the action of a spring attached to a rod which is fixed to the base of the tube. The change in capacitance is detected by connections to the rod and the deposit. The device can be used as an altimeter and has a linear response which is independent of axial acceleration.