| 摘要 |
The present invention relates to an electro-pneumatic positioner for use with a pneumatically controlled two-chamber actuator comprising a first valve unit (10) comprising a first air supply valve (14) and a first air outlet valve (37) connected to a conduit (30, 38, 50), which in turn is connectable to a chamber of the actuator, a second valve unit (12) comprising a second air supply valve (14') and a second air outlet valve (37') connected to a conduit (30', 38', 50'), which in turn is connected to a second chamber of the actuator; a first control device (60, 74) acting on the first air supply valve, which first control device comprises a first control valve (60); a second control device (60', 76) acting on the said second air supply valve, which second control device comprises a second control valve (60'). The invention is characterized in that said first control device further comprises a first air supply means (74) able of supplying pressurized air to said first air supply valve (14) and that said first control valve (60) acts on and controls said first air supply means (74); that said second control device further comprises a second air supply means (76) able of supplying pressurized air to said second air supply valve (14') and that said second control valve (60') acts on and controls said second air supply means (76); that said first air supply means (74) is able of supplying air to said second air outlet valve (37'), and that said second air supply means (76) is able of supplying air to said first air outlet valve (37).
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