Differential pressure measuring apparatus

摘要

A differential pressure transducer of the diaphragm displacement type uses optical techniques to measure disphragm displacement. White light from a source is conducted by optical fibres to the transducer and interference is produced between light reflected at a thickened region of the diaphragm and a partially reflecting end face of the light conductor which is lapped flat and parallel to the diaphragm surface. The interfering reflected light is conducted back to a prism where it is dispersed onto photo-arrays. The wavelengths of dark fringes in the spectrum are measured to determine the displacement of the diaphragm. Measurements can be made on both sides of the diaphragm and used to eliminate dependence on reflective index.