Flowserve XL90 Series - Manual

GENERAL INFORMATION
This bulletin is designed to assist in installing, calibrating,
troubleshooting and performing maintenance as required for the
XL90 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.
The XL90 high-performance positioner is a two-stage device
and is designed for use in control loops where fast response is
required. The XL90 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 XL90 high-performance positioner is designed as a four-
way device, but can easily be converted to a three-way device by
plugging one of the output ports.
NOTE: The XL90 high-performance positioner must use the
I/P NT 3000 Transducer. The I/P 2000 Transducer is not
acceptable for use with the XL90 Series Positioner.
The XL90 positioner can handle supply pressures up to 150 psi;
thus, a supply regulator is usually not required. However, a five
micron air filter is required for pneumatic positioners and a
coalescing filter is required for I/P positioners.
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 XL90 Series positioner features an adjustable gain of
400-1100:1. The medium gain setting is standard for smaller
actuators, while the high gain setting is used on larger actuators
(refer to ‘Gain Adjustment Procedure’ section for further details.)
POSITIONER OPERATION
The positioner schematic (Figure 1) shows an XL90 Series
positioner connected for double-acting service on a rotary rack-
and-pinion 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 feed-
back 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 change the output pressures, moving the
stem until the tension on the feedback spring exactly opposes
the instrument signal pressure.
The sequence of operation is as follows: An increase in instru-
ment 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.
VLAIM 048-00 (181157.000.000) Flowserve Corporation, Valtek Control Products, Tel. USA 801 489 8611 48-1
Flow Control
Installation, Operation, Maintenance Instructions
XL90 Series
High-Performance
Positioner