HIGH THROUGHPUT DOUBLE VALVE WITH REDUCED OUTLET PRESSURE DURING A FAULTED STATE

摘要

A double valve having inlet (13), outlet (15), and exhaust ports (17) maintains an outlet pressure below one percent of inlet pressure during a faulted state while maintaining a relatively small exhaust for reduced overall valve size. Crossover passages (2 ',25) receive inlet pressure through main crossover poppets (40,153) when the respective valve units (18,20) are not in a deactuated position. When the valve units are in a deactuated position, then the crossover passages receive inlet pressure through respective bypass passages (44,152) whose flow rate can be controlled independently from the size of the crossover poppets. The use of bypass passages provides particular benefits for double valves for non-press applications which have a ratio of exhaust flow coefficient to inlet flow coefficient that is less than about 2.5.