US Patent 7509865 Pressure differential sensor comprising an excess-load membrane

A pressure difference transducer includes a hydraulic body, in which is formed an overload chamber containing an overload membrane. The overload chamber divides the overload chamber into a high-pressure chamber portion and a low-pressure chamber portion. The high-pressure chamber portion communicates with a first hydraulic path, which extends between a first diaphragm seal and a high-pressure side of a pressure measuring cell, and the low-pressure chamber portion communicates with a second hydraulic path, which extends between a second diaphragm seal and a low-pressure side of the pressure measuring cell. The low-pressure chamber portion has an essentially convex membrane bed, against which the overload membrane lies in a rest position.