Flowserve Electro-pneumatic Transducers - Manual

30-1 Orig. 3/89 Valtek No. 81369
GENERAL INFORMATION
The following instructions are designed to assist in
installing, operating, calibrating and performing mainte-
nance as required on the Valtek Electro-pneumatic
Transducer. Product users and maintenance personnel
should thoroughly review this bulletin prior to working
on the transducer in conjunction with the Valtek Instal-
lation, Operation, Maintenance Instructions for the
appropriate control valve and control valve positioner
being used.
To avoid possible injury to personnel or dam-
age to valve parts, WARNING and CAUTION
notes must be strictly adhered to. Modifying
this product, substituting nonfactory parts, or
using maintenance procedures other than out-
lined could drastically affect performance, be
hazardous to personnel and equipment, and
may void existing warranties.
The Valtek Electro-pneumatic (I/P) Transducer may be
mounted directly to the control valve, or mounted
remotely from the valve in any position. A two-inch pipe
mounting bracket is available from the factory.
The (I/P) transducer is Factory Mutual approved and
intrinsically safe for Class I, II, III, Division 1, Groups C,
D, E, F and G, when installed with the appropriate
energy limiting safety barriers. The unit is also explo-
sion-proof for Class I, Division 1, Groups B, C and D;
dust-ignition proof for Class II, Division 1, Groups E, F
and G; and suitable for Class III, Division 1, hazardous
locations, indoors.
I/P TRANSDUCER OPERATION
The input current flows through a fixed coil where a
magnetic force is created. The flux lines of the coil are
exposed at a gap, creating a magnetic force propor-
tional to the input current. This force is applied against
the force of a small magnet mounted on the end of a
balance beam. The magnet is positioned in the electro-
magnetic field, it interacts with the small magnet on the
balance beam, thus repositioning a flapper at the oppo-
site end of balance beam. When energized, this flapper/
balance beam is the only moving part in the system.
The flapper is in close proximity to a nozzle. The nozzle
is supplied with air through a throttle from the output of
a power amplifier that is controlled by the pressure
change in front of the nozzle. The air flowing from the
nozzle forms a restoring force to the force applied to the
magnet. Hence, a linear correspondence of electric
input and pneumatic output signal is achieved.
The zero adjustment is made by twisting the tension bad
to which the balance beam / flapper is mounted.
Range adjustment is performed at the potentiometer
connected with a resistor in parallel to the coil.
INSTALLATION INSTRUCTIONS
The following instructions are designed to assist in the
field installation of Electro-pneumatic Transducers.
The I/P transducer may be mounted directly to the
control valve with a bracket supplied by the customer, or
remotely from the control valve with a two-inch pipe
mounting bracket available from the factory.
Valtek Electro-pneumatic
Transducers