Patent ID: 6895130
Filing Date: 2005-05-17
Classification: F16K

Abstract:
1. An arrangement for measuring the true position of a diaphragm membrane within a diaphragm valve, said diaphragm valve including a valve body having at least a pair of reservoirs controlled by said diaphragm membrane and an actuator for moving said membrane between an open position and it closed position, the arrangement comprising a reflective element disposed on the backside of the diaphragm membrane; an optical probe including an optical transmitting device, an optical receiving device and an optical waveguide, said waveguide for launching an optical test signal from said optical transmitting device onto the reflective element and receiving therefrom a reflected optical test signal, said reflected optical test signal thereafter coupled into the optical receiving device, wherein the optical power of the reflected signal coupled into the waveguide is proportional to the position of the diaphragm membrane; and a sensing circuit coupled to the optical receiving device for converting the received, reflected optical signal into an electrical equivalent and, in conjunction with a measurement of the actuator input pressure, determining the pressure on the process side of said diaphragm as a function of the electrical representation equivalent.