A biomedical pressure sensor having a pressure sensing diaphragm is provided with a distensible membrane overlying the diaphragm, and the diaphragm is provided with one or more holes. During normal operation, externally applied pressure forces the membrane against the diaphragm so that the membrane and...http://www.google.ca/patents/US5257630?utm_source=gb-gplus-sharePatent US5257630 - Pressure sensing probe with calibration capability
