Flowserve XL User Manual
Valtek XL Series
High-Performance
Positioner
GENERAL INFORMATION
This bulletin is designed to assist in installing, calibrating, troubleshooting and performing maintenance as
required for the Valtek® XL Series high-performance
positioner.
Product users and maintenance personnel should thoroughly read and strictly follow the instructions contained in this bulletin prior to operating the positioner.
Any questions concerning this product should be directed to a Flowserve representative.
To avoid possible injury to personnel or damage to valve parts, WARNING and CAUTION
notes must be strictly followed. Modifying this
product, substituting non-factory parts or using maintenance procedures other than outlined could drastically affect performance and
be hazardous to personnel and equipment.
NOTE: The air supply should conform to ISA
Standard S7.3 (a dew point at least 18° F / -8° C
below ambient temperature, particle size below 5
microns, oil content not to exceed one part per
million).
The XL Series positioner features an adjustable gain of
400-1100:1. The medium gain setting is standard on
size 25 actuators, while the high gain setting is standard
on size 50 and larger actuators (refer to ‘Gain Adjustment Procedure’ section for further details.)
All positioners come with one of two types of cams:
a linear characteristic cam for use on linear actuators or
a combination linear / modified equal percentage
characteristic cam for rotary actuators. Refer to the
‘Rotary Actuator Cam Characteristic’ chart on page 4 for
specific installed characteristics.
The XL high-performance positioner is a two-stage
device and is designed for use in control loops where
fast response is required. The XL positioner is designed
to be modular and use the P/P module for 3-15 psi input
signal or the NT 3000 Series Transducer Module for
4-20 mA input signal.
The XL high-performance positioner is designed as a
four-way device, but can easily be converted to a threeway device by plugging one of the output ports.
NOTE: The XL high-performance positioner must
use the I/P NT 3000 Transducer. The I/P 2000 Transducer is not acceptable for use with the XL Series
Positioner.
The XL positioner can handle supply pressures up to
150 psi; thus, a supply regulator is usually not required.
However,
matic positioners and a coalescing filter is required for
I/P positioners.
Valtek No. 10077320
a five micron air filter is required for pneu-
POSITIONER OPERATION
The positioner schematic (Figure 1) shows an XL Series
positioner connected for double-acting service on a
linear actuator. Tension on the feedback spring provides feedback to the positioner, which varies as the
stem position changes. The spring-loading force is
applied through the feedback linkage and cam to the
positioner’s input capsule.
Instrument signal pressure is applied between the diaphragms in the input capsule. Therefore, the input
capsule serves as a force-balance member, matching
the valve stem position (as measured by tension on the
feedback spring) to the instrument signal.
When the opposing forces balance exactly, the system
will be in equilibrium and the stem will be in the exact
position called for by the instrument signal. If the opposing forces are not in balance, the input capsule will move
up or down and, by means of the pilot-valves, will
45-1
Supply Seat
Upper Pilot
Poppet
Exhaust Seat
Port No. 1
Restriction
Supply
Pilot Valve
Capsule
Exhaust Seat
Port No. 2
Lower Pilot
Poppet
Supply Seat
Balance Adjustment
Input Capsule
Figure 1: XL Positioner Schematic for Air-to-Open
change the output pressures, moving the stem until the
tension on the feedback spring opposes exactly the
instrument signal pressure.
The sequence of operation is as follows: An increase in
instrument signal pressure forces the input capsule
downward. Displacement of the capsule in turn moves
the flapper away from the detecting nozzle. This allows
a larger flow rate through the nozzle, decreasing the
pressure exerted on the top of the pilot valve capsule.
Supply air biases the pilot-valve in an upward direction.
As the capsule moves up, it will close the exhaust seat
of the upper pilot poppet and open the supply seat,
which applies increased air pressure to the bottom
cylinder port. At the same time, the pilot-valve capsule
will open the exhaust seat for the lower pilot poppet;
thus, decreasing pressure to the top cylinder port.
This difference in pressure will drive the piston upward,
which stretches the feedback spring until the spring
tension exactly opposes the force resulting from the
instrument signal pressure. At this point, the flapper will
be moved toward the detecting nozzle to restore the
pressure above the pilot-valve capsule to its equilibrium
value. As a force-balanced condition is approached, the
pilot-valve capsule will be forced back to a neutral
position where the pilots are neither supplying air to, nor
exhausting air from, their respective sides of the piston.
A decrease in instrument signal pressure reverses the
described actions and causes a proportional downward
movement of actuator piston and stem.
Installation of XL Series Positioner on
Double-Acting, Linear-Cylinder Actuators
When installing or retrofitting the XL Series positioner
on all sizes of linear actuators, proceed as follows:
NOTE: For retrofitting to an actuator equipped with
a Beta or 80R positioner, the same bracket, follower
arm and take-off arm can be used (begin with step 4).
Cylinder
Zero Adjustment
Feedback
Spring
Detecting
Nozzle
Flapper
Range
Adjust Screw
Piston
Cam
Follower
Arm
Upper Diaphragm
Instrument Signal
Lower Diaphragm
Take-off Arm
Size 25, 100, 200 Size 50
Figure 2: Positioner Mounting Bracket
Hole
A
Air-to-Open Air-to-Close
(Air-to-Retract) (Air-to-Extend)
Return Spring
Cam
Positioner
Base
Figure 3: Return Spring / Cam Mounting
(viewed from positioner’s right side)
O
S
Hole B
45-2
Flowserve Corporation, Valtek Control Products, Tel. USA 801 489 8611
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Start
Position
Roller
Bearing
Cam
Follower Arm
Figure 4: Cam Alignment
cam roller-bearing when the valve is seated. (See
Figure 4.) Tighten the stem clamp.
10. For air-to-open action, tube ‘output 2’ to the top of
cylinder and ‘output 1’ to the bottom of cylinder. For
air-to-close action, tube ‘output 1’ to top of cylinder
and ‘output 2’ to the bottom of the cylinder.
NOTE: For three-way diaphragm actuators plug
output 2, tube output 1 to desired side of
diaphragm.
11. Attach supply air and instrument tubing or wiring.
CAUTION: Signal air pressure higher than 30
psi may damage the module gauge and instrument signal capsule; a 3-15 psi instrument signal is recommended on the pneumatic module.
NOTE: When retrofitting the XL positioner to an
actuator equipped with other positioners, remove
the existing positioner, tubing and associated bolting.
See tubing instructions in Step 10.
1. Place the stem clamp onto the actuator stem with
the boss on the right side as illustrated in Figure 1.
2. Mount positioner bracket to the yoke leg which has
the stroke indicator plate attached. (See Figure 2.)
3. Mount the take-off arm on the stem clamp so the
slots in the end of the arm step upward toward the
cylinder. The holes in the follower arm should line
up with the slots in the take-off arm.
4. For air-to-retract action, install the cam in the positioner, with L-R facing outward. For air-to-extend
action, L-D side of the cam should face outward.
When installing the cam, position it so the center
mark on the cam lines up through the center of the
cam roller-bearing on the cam follower arm with the
follower arm perpendicular to the base of the positioner. (See Figures 3 and 4.) Apply a small amount
of grease to the bent end of the return spring and
feed it through the hole in the cam. Loop the other
end of the return spring over the screw and screw it
into the positioner base.
NOTE: Screw head will not bottom out.
5. Feed the appropriate follower arm onto the cam
shaft boss with the hole markings facing outward.
Secure with the lockwasher and nut. (See Figure 7.)
6. Fasten the follower pin into the correct hole in the
follower arm for the desired stroke length of the trim.
(Stroke lengths are stamped on the follower arm.)
7. Feed the follower pin into the appropriate slot in the
take-off arm. (See Figure 4.) Tighten the nut on the
pin and grease the slot where the pin rides.
NOTE: A light industrial grease is recommended. Failure to lubricate the pin can cause
premature wear.
8. Using three screws, mount the positioner to the
brackets as shown in Figure 2.
9. If necessary, adjust the height of the stem clamp so
the first line of the cam aligns with the center of the
Flowserve Corporation, Valtek Control Products, Tel. USA 801 489 8611
Reversing Air Action of XL Series
Positioners on Linear Actuators
Reversing the air-action of the positioner is simple. No
additional parts are required, although the tubing will
need to be rerouted on the linear actuator.
To reverse the air-action of XL series positioners on all
sizes of linear actuators, proceed as follows:
1. Using the ‘Spring Cylinder Linear Actuators’ Installation, Operation, Maintenance Instructions, reverse
the air-action of the actuator.
2. Disengage the return spring from the cam and
remove the cam from the cam shaft.
3. Reverse the cam, return spring and tubing for the
desired air-action by referring to Steps 4-8 in the
‘Installation of XL Series Positioner on Linear Actuators’ section of these instructions.
Installing XL Series Positioner on Rotary
Actuators
Proceed as follows when installing the XL Series positioner on all sizes of rotary actuators if the cam and
follower arm are not already installed, otherwise refer
directly to step 7.
1. With the desired cam and its identification letter
facing toward the cam shaft, slide the cam onto the
end of the cam shaft with the shorter shoulder. (Ref er
to Table I to determine desired cam characteristic.)
Fasten with the star lock washer and nut.
2. Insert the follower arm into the back recess of the
Table I:
Rotary Actuator Cam Characteristic Chart
45-3
Follower
Pin
Follower
Arm
positioner. Figures 11 through 16 show the shaft
rotation versus instrument signal of a valve (Valdisk,
ShearStream or MaxFlo). These graphs should be
used when visually checking the valve shaft rotation
versus positioner signal relationship.
Cam
Read Cam
Characteristics
from this side only
Actuator Lever Arm
Figure 5: XL Series Positioner
Installation on Valtek Rotary Actuator
positioner with part identification number facing out to
the right side. Slide the cam shaft through the inner
bearing and then slip flatted hole of the follower arm
over the longer stepped shoulder of the cam shaft.
3. Place a small amount of thread-locking compound
(Loctite No. 222 or equivalent) to the threaded portion
of cam shaft nut. Slide the cam shaft nut through outer
bearing and screw it onto the cam shaft. Tighten the
cam shaft together firmly so that the follower arm is
securely clamped. Also, make sure the cam is tightly
secured to cam shaft. Check to be sure there is no
slippage. Apply a small amount of grease to the bent
end of the return spring and feed it through the hole in
the cam. Loop the other end of the return spring over
the screw and screw it into the positioner base.
NOTE: Screw head will not bottom out.
4. Rotate the zero adjustment arm back into place and
reinstall the feedback spring.
5. If the follower pin is present, insert it into the hole in the
actuator lever arm and drive it firmly into place with a
hammer. (See Figure 5.)
6. Apply grease to the sliding surfaces of the follower
arm before mounting the positioner to the transfer
case. When mounting the positioner to the transfer
case, make sure to guide the follower arm so the pin
slides in the slot on the follower arm. (See Figure 5.)
Fasten the positioner to the transfer case with the
three mounting screws. Push up on the cam to verify
the pin is riding in the follower arm slot or remove
transfer case cover plate to inspect.
CAUTION: Failure to replace the cover plate before pressurizing or operating the actuator will
cause damage to the shaft since the cover plate
houses a shaft-support bearing.
Depending on the positioner cam side selected, the
valve flow characteristic may be linear or equal percent when compared to the instrument signal to the
Reversing Air-Action of XL Series
Positioners on Rotary Actuators
Reversing the action on rotary actuators is achieved by
mounting the yoke to the opposite side of the transfer
case. Refer to maintenance instructions ‘Spring Cylinder
Rotary Actuators’ for details.
Note: When reversing action on rotary actuators, also
change cam. (See Table I.)
Return Spring
Read Cam
Characteristics
Screw
Lock
from this side only
Cam
Washer
Grease Here
Nut
Cam Shaft
Figure 6: Cam Return Spring Installation
POSITIONER CALIBRATION
Introduction
Valtek positioners are calibrated at the factory; however, due to shipping and handling, it may be necessary
to check the calibration before operating the valve. The
XL positioner, for strokes 3/4-inch and above, can be
calibrated to a range of 3-15; two-way split range, 3-9,
or 9-15; and three-way split ranging, 3-7, 7-11, 11-15
psi using the standard feedback spring. An alternate
red colored feedback spring on linear actuators is used
for strokes less than 3/4-inch.
WARNING: When stroking the actuator during calibration, keep hands, hair and clothing away from
moving parts. Failure to do so may cause serious
personal injury.
Note: Positioners and I/Ps are calibrated at the
factory. Use mechanical adjustments in positioner
for calibration. Zero and span on the I/P should not
be used to calibrate valve.
For calibration, proceed as follows:
1. For 3-15 or 3-9 psi range, loosen by hand the zero
adjustment locking knob and adjust the zero adjustment knob until the valve begins to stroke with more
than 3 psi signal (for 9-15 psi range adjust to 9 psi).
2. Loosen the range adjustment locking screw no
more than 1/8 turn.
45-4
Flowserve Corporation, Valtek Control Products, Tel. USA 801 489 8611
Output 1
Zero Adjustment
Lock Knob
Zero Adjustment
Knob
Span Adjustment
Cam Follower
Arm (Range Arm)
Output 2
Balance
Adjusting
Screw
Feedback
Spring
Figure 7: Positioner Adjustments
3. With a Phillips screwdriver adjust span adjustment
so valve is at full stroke with more than 15 psi for 3-15
or 9-15 psi range (adjust to 9 psi for 3-9 psi range).
4. Return to 3 psi (or 9 psi for 9-15 psi range) and
check the zero. Repeat steps 1-4 if necessary.
5. Tighten the zero adjustment lock knob and span
adjustment lock knob.
6. Use the same procedure for three-way split range.
Positioner Balance Adjustment
CAUTION: Balance is preset at the factory. If balance adjustment becomes necessary, make changes
carefully and slowly, allowing the positioner to respond before continuing adjustments. Check balance pressure frequently to ensure correct values.
Balance adjustment is set at the factory and normally
should not need adjustment. Balance adjustment (output pressure level) permits the equilibrium pressure in
both sides of the actuator piston to be raised or lowered.
The actuator pressure level of output 1 and 2 should be
approximately 75 to 80 percent of the supply pressure.
When actuator springs are used there will be a pressure
difference between output 1 and 2; the average pressure of both ports should be 75 to 80 percent of the
supply pressure. The minimum recommended supply
pressure is 60 psig.
pressure was used on a fail closed actuator, the balance pressure should be adjusted so that output 1
reads approximately 85 psig and output pressure 2
For example, if 100 psig supply
Feedback Spring
Arm
Span
Adjustment
Locking Screw
Cam
Orifice Screw
Pilot Relay
Assembly
Supply Port
reads approximately 70 psig. The average of these two
pressures is 77.5 percent of the supply pressure.
If necessary, adjust the output pressure level using the
following the procedure:
1. If output pressure level is low, before adjusting, check
for leaks in tubing connections between the positioner and actuator and check supply pressure.
2. Make certain there is no process force or pressure
in the valve (The valve should be removed or
isolated from the process.)
3. On positioners without gauges, connect gauges to
‘output 1’ and ‘output 2’ lines.
4. Remove rubber cap over balance adjustment. (See
Figure 7.)
5. Apply full actuator operating pressure to the positioner supply port.
6. Set input signal to midscale (9 psi for 3-15 psi
span). Output pressure level cannot be adjusted
with actuator against valve seat or travel stops.
Allow actuator pressure to stabilize.
7. Observe the pressure gauges. If reading is not
correct, turn balance adjustment screw about 1/8
turn at a time and wait about 20-30 seconds for
pressure to stabilize (counterclockwise to increase
pressure). Continue until output pressure level of
the higher pressure gauge is approximately 80
percent of supply.
8. Replace rubber cap over balance adjustment screw.
Flowserve Corporation, Valtek Control Products, Tel. USA 801 489 8611
45-5
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