Product Overview | Diaphragm Air Motors
Valve positioners employ the full force of their air supply to drive the piston or diaphragm in a pneumatic actuator to the position called for by a control instrument-and to hold that position, regardless of the forces which tend to change valve position. Each positioner receives a signal from a control instrument; and using an air supply as high as 100 psig, the built-in valve positioner strokes the valve actuator to the required position. (For more-detailed information on operation, see the appropriate side of this page.) Like all valve positioners, the R620-2101 has a feedback circuit which measures the position of the actuator's piston or diaphragm. The built-in valve positioner supplies or exhausts air to make the actuator obey the control-instrument signal.
MATERIALS OF CONSTRUCTION
Aluminum, brass, stainless steel, neoprene and/or Buna-N.
The positioner is a pneumatic booster. It requires 26-30 psi clean supply air, which it applies directly to the motor.
The motor is set to go from fully closed to fully open with a range of 7-19 psi. Control instrument signals are the same 3-15 psi as when operating without a positioner, but the positioner boosts them to as much as 30 psi to the motor, thereby increasing motor torque and assuring appropriate control motor response. The positioner also allows customizing of the span to match various controllers. The standard full travel span of 12 psi (3-15 psi control signal) can be altered by changing the spring in the positioner. Springs are available to yield 3, 4, 5, 6, 8, 10, or 24 psi spans. See Parts List 1600-1 for spring part numbers.
SPECIFICATIONS
Input Range: 3-15, 3-9, 9-15, 3-27, 6-30 psig
Valve Travel:
Minimum ¼" Maximum 4"
Supply Pressure:
Minimum 3 psi above required actuator pressure Maximum 50 psig
Air Consumption:
73N-F 73N-B
0.25 scfm 0.6 scfm
(in balance condition with
INTERCHANGEABLE RANGE SPRINGS
20 psig supply and 9 psig dead-ended output). Overrange Limit: 150 psig to any connection Response Level: 0.1% of input span
The position of the piston or diaphragm in the valve actuator is sensed by the amount of compressive force exerted by a range spring on the valve positioner's diaphragm assembly. By selecting the appropriate range spring, from a wide selection which is available, almost any combination span (from 2 to 24 psi) may be obtained.
(Output sensitivity to input pressure changes)
Bulletin 1600-P Page 2
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