专利名称：Methods and apparatus for operating and
performing diagnostics in a control loop of acontrol valve
发明人：Kenneth W. Junk,Annette L. Latwesen申请号：US10828706申请日：20040421公开号：US06999853B2公开日：20060214
专利附图：
摘要：A control loop of a control valve is operated using outlet pressure from apneumatic amplifier as the control parameter. The control loop may be operated
continuously in pressure control mode, or may be switched from another mode, such astravel control mode, to pressure control mode in response to certain operatingconditions such as operation in the cutoff range, operation with the throttling elementengaging a travel stop, or as a backup in the event of primary control parameter sensorfailure. Operating the control loop in pressure control mode further allows diagnosticsto be performed on the control loop components, even when the system is operating incutoff range or has engaged a travel stop. The diagnostics may be performed usingpressure and displacement sensors normally provided with a positioner. A processor maybe programmed to receive data from the sensors and generate fault signals according toa logic sub-routine. The logic sub-routine may include calculating mass flow of controlfluid through pneumatic amplifier outlet ports and comparing other operating
parameters to detect leaks and blockages in the control loop components. Once a faultis detected, the location of the root cause of the fault may be identified by characterizingoperating parameters of the control loop at the time of the fault.
申请人：Kenneth W. Junk,Annette L. Latwesen
地址：Marshalltown IA US,Marshalltown IA US
国籍：US,US
代理机构：Marshall, Gerstein & Borun LLP
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