BASIC OPERATION AND FUNCTION OF CONTROL VALVES

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BASICBASICOPERATIONOPERATIONANDANDFUNCTI ONFUNCTIONOFOFCONTROLCONTROLVALVESVALVES 02-99- 2 -That valvedrives me crazy!??What ishappening insidethat valve??Gaskets Won't Seal!Unusually HighTrim Maintenance!!Packing Always Leaks!NOISY!!VIBRATING!!Positioner AlwaysNeeds Calibration!Too much seat leakage!LOUSY CONTROL !RATTLING!Table of ContentsTOPIC - SUBJECTSECTIONTerminology--------------- ---------------------------------------- ------- 1Control Valve BASIC Designs --------------------------------------- 2Characterization and Trim Design -------------------------------- 3Control Valve Technical Considerations ----------------------- 4Force-Balance Principle ---------------------------------------- ----- 5Actuator BASIC Designs ---------------------------------------- ------ 6Control Valve Unit Action ---------------------------------------- --- 7Actuator Benchset Range ---------------------------------------- --- 8Valve Positioner basics ---------------------------------------- ------ 9Control Loop Action

characteristic, flow: An indefinite term, see “characteristic, inherent flow” and “characteristic, installed flow.” - characteristic, equal percentage: An inherent flow characteristic which, for equal increments of rated travel, will ideally give equal percentage changes of the existing flow coefficient (Cv).

  Basics, Characteristics