Manufacturer: Johnson Controls |
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Description: 4R POSITIONER, LESS SPRING
Category: Valve Actuators
V-9502 Series
Pneumatic Valve Actuator Positioners
V-9502 Series Pneumatic Valve Actuator Positioners
are precision relay devices designed to operate
pneumatic valve actuators in applications requiring
stable, accurate control. These positioners provide
maximum positioning power to resist external forces
that might otherwise overcome the positioning power
of the actuator. Adjustable operating span (on all
pneumatic valve actuators except the V-3000 Series)
and starting point also make the V-9502 ideal for valve sequencing applications.
The V-9502 Series can be mounted directly to
V-3000 Series, 3R, 4R, 5R, 8R, or MP8000 Series
pneumatic valve actuators.
Features and Benefits
�� Maximum Positioning
Power -
Compensates for flow surges in the piping
system, and holds the valve at the position
dictated by the controller
�� Field-Selectable Operating
Span (All Pneumatic
Valve Actuators Except
V-3000 Series)
Allows for easy valve sequencing from a
single control signal
�� Field-Adjustable Starting
Point -
Tailors the starting point in order to provide
accurate control
�� Expanded Usability Provides application flexibility since models
can be mounted directly to V-3000 Series, 3R,
4R, 5R, 8R, and MP8000 Series Pneumatic
Valve Actuators
Operation
Feedback from the actuator stem (through the
positioner spring and lever arm assembly) activates
the V-9502 Pneumatic Valve Actuator Positioner to
compensate for flow surges in the piping system and
holds the valve at the position dictated by the
controller. The V-9502 modulates the stroke of the
actuator in relation to a pressure change from the
controller.
Supply air enters the control chamber of the relay and
is admitted to the actuator when the control pressure
in the pilot chamber exceeds the preestablished
starting point. This pressure causes the actuator stem
to move. Movement of the stem is fed back to the relay
through the positioner spring and lever arm assembly,
to impose a balancing force against the control
pressure. When all forces are in balance, the V-9502
does not allow supply air to pass through to the
actuator. The actuator establishes a position that is
proportional to the value of the pressure from the
controller. Any change in stem position unbalances the
relay. As a result, air pressure in the actuator
increases or is exhausted in order to reestablish a
balance at the desired stem position.
Operating Range
The span and starting point adjustments of the
V-9502 Pneumatic Valve Actuator Positioner
determine the operating range. The lower value of the
operating range is the control signal pressure at which
the actuator just begins to stroke. The upper value of
the operating range is the control signal pressure at
which the actuator reaches its maximum stroke. The
difference between the upper and lower values of the
control signal pressure is the operating span.
Operating Span
The operating span of the V-9502 Pneumatic Valve
Actuator Positioner is field selectable from 3 to 13 psi
(21 to 90 kPa) on 3R, 4R, 5R, 8R, and MP8000 Series
pneumatic valve actuators. The operating span is
determined by the location of the spring in the
positioner operating span lever arm. When the spring is installed in the hole
closest to the V-9502 Positioner cover, the spring
allows a span of 3 psi (21 kPa). When the spring is
installed in the hole farthest from the positioner cover,
the spring allows a span of 13 psi (90 kPa).
The operating span for V-3000 Series Pneumatic
Valve Actuators is determined by the positioner spring
used with the actuator. To change the operating span,
simply select a different positioner spring. In all instances, the spring should be
installed in the hole on the operating span lever arm
that is farthest from the positioner body.
Starting Point
The starting point is the input pressure (Pilot P
pressure) at which the actuator just begins to stroke.
The starting point is field adjustable from 2 to 12 psig
(14 to 83 kPa) using the starting point adjusting screw
located under the V-9502 Positioner cover. Turning the screw clockwise
decreases the starting point and turning the screw
counterclockwise increases the starting point.
Note: The sum of the starting point pressure and the
operating span must not exceed the supply air
pressure to the V-9502 Pneumatic Valve Actuator. A
nominal supply pressure is typically between 20 and
25 psig (138 and 172 kPa). Be certain to maintain a
starting point pressure and corresponding operating
span accordingly.
Mounting Methods
Most V-9502 Pneumatic Valve Actuator Positioners
are furnished with a mounting bracket for attachment
directly onto the actuator yoke. For V-3000 Series
Pneumatic Valve Actuators, the V-9502 Positioner is
installed directly onto the side of the actuator.
Regardless of the actuator chosen, be certain to allow
enough clearance for removal of the V-9502 Positioner
cover and adjustment of the relay.
Replaces Part Numbers: V-9502-2, CARV-9502-2