SUPPLY BIAS PNEUMATIC PRESSURE RELAY

PROBLEM TO BE SOLVED: To provide a supply bias pneumatic pressure relay installed in an electro-pneumatic converter easily convertible into a pressure converter from a valve positioning device and its vice versa. SOLUTION: This supply bias pneumatic pressure relay has a housing 12 having a supply pressure inlet, a fluctuation pressure control inlet, an actuator pressure outlet and an exhaust outlet, an input diaphragm 130 connected to a supply port 132, an exhaust port 134 and the fluctuation pressure control inlet, respective valve plugs 138 connected to the input diaphragm for applying fluctuation pressure to the actuator pressure outlet in response to the fluctuation pressure, and a pair of diaphragms 158 and 160 installed in the middle between the respective valve plugs and the input diaphragm. The pair of diaphragms have a supply bias diaphragm means for limiting a supply bias cavity 162 and a flow means for connecting the supply pressure inlet to the supply bias cavity so as to bias a relay to be formed in the actuator pressure outlet. COPYRIGHT: (C)2006,JPO&NCIPI