Valtek XL Series Positioners - Flowserve

1 XL Series Positioners2 Valtek XL Series PositionersFlowserve Corporation, Valtek Control Products, Tel. USA 801 489 8611 FeaturesFigure 1: Features of XL Series Positioners with Pneumatic or Electro-pneumatic ModulesSimple signalconversion withinterchangeablemodulesCorrosion-resi stantcover and baseIndependent zero andspan adjustmentsTwo-sided cam foreasy field reversibilitycommon with Betaseries positionerSplit rangescan be easilyadjustedEasy calibrationOutput 1 Output 2 Adjustable gainfor preciseprocess tuningSupplyPortGround ScrewSupplyPort3 Valtek XL Series PositionersFlowserve Corporation, Valtek Control Products, Tel. USA 801 489 8611 Figure 2: XL positioner Mounted onValtek Linear ActuatorFigure 3: XL PositionerMounted on Competitor s ActuatorIntroductionThe Valtek XL Series (XL and XL90), two-stagepositioners offer fast and sensitive dynamic responsecharacteristics to meet extremely demanding controlobjectives.

2 The Positioners are available with either anelectro-pneumatic (I/P) transducer module for milliampcurrent control signals or a pneumatic module for aircontrol for high performance, these Positioners arefield reversible and ruggedly built for reliability in se-vere industrial environments. The XL positioner usescommon mounting brackets and follower arms with theValtek Beta and 80R Positioners . The XL90 uses com-mon rotary mounting brackets identical to the Logix 1000 Series Positioners : therefore, the Positioners can bemounted on existing Valtek linear or rotary actuatorswithout additional hardware.

3 Two and three-way splitranges are available without special feedback kits are available to install the XL Seriespositioners on other manufacturers actuators forimproved XL Series PositionersFlowserve Corporation, Valtek Control Products, Tel. USA 801 489 8611 For Single or double -actingUsable with either single or double - acting actuators (both linear andActuatorsrotary) makes the XL Series Positioners Field ReversedAction can be reversed in the field on linear valves by simply turning thecam over, reversing anti-backlash spring and changing output Flow CharacteristicsEasily changed cam provides flow Calibration ProceduresCalibration is easy due to minimal interaction between zero and positioner adjustments are enclosed for protection to ServiceStandard signal ranges are 4-20 mA for the electro-pneumatic (I/P) modeland 3-15 psi ( bar) for the pneumatic (P/P) model.

4 Optional rangeis 10-50 mA (I/P) or 6-30 psi ( bar) (P/P). All models can becalibrated for a 2- or 3-way split range without additional and Vibration ResistantXL Series Positioners are designed with a high natural frequencycoupled with pneumatic damping unaffected by vibrations withacceleration up to 2 g s and frequencies to 500 to Mounting PositionPositioners can be mounted in any orientation without or P/P Signal ConvertibleField conversion from one control signal to another is easilyaccomplished by replacing one module with the other, greatly reducingspare parts Resistant PartsCover and base assembly are epoxy powder-painted and continuouslyfor Long Lifepurged from the inside with instrument air.

5 Internal working parts areconstructed from 300 Series stainless steel, anodized aluminum or MaintenanceThe XL Series Positioners simplicity, modular design and few parts,make maintenance quick and Regulator* RequiredThe XL Series Positioners with the NT 3000 I/P or the pneumaticmodule are designed to withstand 150 psi ( bar) at all ports andare relatively insensitive to supply pressure fluctuation.*With any sensitive pneumatic instrument, a clean air supply is required. This instrument must have an air supply meeting or exceeding the XL Series Positioners is easy due tominimal interaction between zero and span. Also, thepositioners simplicity, modular design and few parts,make maintenance quick and addition to providing premium performance to meetdemanding control needs, the XL Series Positioners arealso adaptable for various applications and can be usedon both single- and double - acting valve actuators.

6 (SeeFigures 2 and 3.) The XL Series Positioners withNT 3000 I/P transducer module are universally certifiedfor intrinsically safe and explosion-proof applications.(See Table II for a complete listing.)When an application demands fast strokes and finecontrol, the XL Series Positioners are clearly the best,dependable XL Series PositionersFlowserve Corporation, Valtek Control Products, Tel. USA 801 489 8611 AdvantagesLow Air ConsumptionSteady state air consumption is SCFM ( m3/hr) @ 60 psi( bar); supply maximum SCFM ( m3/hr) with I/P moduleExtended Temperature ModelI/P: -40 F to 185 F (-40 C to 85 C)P/P: -50 F to 250 F (-46 C to 121 C)Oxygen Service ModelPneumatic models are available with fluorosilicone diaphragms 90 positioner Additional AdvantagesDirect Rotary MountingEliminates linkage backlash or deadband, thus increasing Position IndicatorHigh visibility neon green provides quick visual indication of valve /actuator position.

7 With optional UltraDome, visibility is increased to morethan 180 Internal Switches4-20 mA position transmitter provides analog feedback of positionindependent of control or magnetic switches provide discrete open and closed (or anyposition in between).Optional UltraSwitchProvides explosion-proof / intrinsically safe 4-20 mA position feedbackand discrete limit the NT 3000 I/P TransducerReplaceable Coalescing Filter*Removes particles that may clog transducer. Large orifice / airpassages provide additional protection against clogging. Positionerincludes orifice screen to prevent Pressure CutoffWhen enabled, allows the NT 3000 transducer output to decrease tonear zero when input signal falls below a user-settable Gauge Helps Monitor UnitIndicates transducer output to positioner , permitting Internal RegulatorReduces pressure to 22 psi ( bar), eliminating need for externalregulator.

8 *With any sensitive pneumatic instrument, a clean air supply is required. This instrument must have an air supply meeting or exceeding XL Series PositionersFlowserve Corporation, Valtek Control Products, Tel. USA 801 489 8611 OperationFigure 4: XL Series Positioners Schematic for Air-to-Open (linear valve shown)The positioner operates as follows: An increase in theinstrument signal forces the instrument signal capsuleand flapper downward. The nozzle now releases airand the pressure decreases on top of the pilot valvecapsule. The pressure differential moves the pilot valvecapsule upward, opening the upper supply seat andallowing supply pressure to output 1.

9 This opens theexhaust seat on output 2, causing the actuator pistonto move upward motion of the piston is transmitted back tothe positioner through the feedback linkage and camresulting in the spring being stretched proportionally tothe valve position. The piston continues to strokeupward until the force in the feedback spring increasessufficiently to counter the force generated by theinstrument signal capsule. At this point, the balancebeam and spool begin to return to their equilibriumposition. As the valve spool ports start to close, the airflow rate to the actuator is the piston has reached the required position, thefeedback spring tension force will equal the forcegenerated in the instrument signal capsule.

10 The flap-per and instrument signal capsule will remain in theirequilibrium positions with no air flowing to the actuatoruntil a change in the instrument signal is decrease in signal reverses the action, causing down-ward movement of the actuator piston and XL Series Positioners are two-stage, force-balanced instruments. Figure 4 shows an XL Seriespositioner used in conjunction with either an electro-pneumatic or pneumatic module, installed on a double - acting actuator for air-to-open action. Positioning isbased on a balance of two forces: one proportional tothe instrument signal and the other proportional to thestem current signal for the NT 3000 I/P module is firstconverted to a 3-15 psi ( bar) air signal, whilethe 3-15 psi air signal for the pneumatic model is passeddirectly into the positioner .