Optical valve position sensor system

Claim 1

A valve condition sensor operable with a valve having a movable member the position of which is indicative of the degree of opening of said valve, comprising: (A) optical fiber means defining first and second separated but optically aligned light conducting sections; (B) light transmitter means operable to project a light beam into said first section; (C) light receiver means positioned to intercept any of said light emanating from said second section; (D) a light modulating means in the form of a rotatable shutter having both transparent and opaque sections rotatable into the light path between said first and second light conducting sections; (E) said rotatable light modulating means being positioned proximate said movable member of said valve; (F) means communicating movement of said movable member to said rotatable light modulating means to thereby rotate it to change its positional orientation; (G) additional optical fiber means defining third and fourth separated but optically aligned light conducting sections; (H) optical transmitter and receiver means for transmission of light into and reception of light from said additional optical fiber means; (I) a second rotatable shutter having both transparent and opaque sections rotatable into the light path between said third and fourth light conducting sections; (J) said second shutter being rotatable in response to movement of said movable member of said valve; and (K) said shutters being oriented such that during normal operation only one of said shutters will allow light transmission at a time.