Fisher 3700 Pneumatic Valve Positioner

Technical Specifications

Model：3700 Brand：Fisher Product Type: Pneumatic valve positioner

Module Feature

Fisher 3700 is force-balance pneumatic valve positioner for Fisher linear diaphragm actuators. It receives 3-15psi pneumatic signal and adjusts supply air pressure to drive actuator for accurate valve stem positioning. It supports zero/span calibration and direct/reverse action switch. It has stable performance and low air consumption. Widely used in chemical,oil & gas and power plant control valves. Working principle: Pneumatic force balance feedback Onboard components: Bellow assembly, nozzle-flapper, pneumatic relay, cam feedback mechanism, pressure gauge ports

LED indicators

Not equipped

Hardware self-diagnosis

Supply air pressure inspection, zero & span calibration, valve stroke test, air tightness leakage test

Programming software

No dedicated software required

Pneumatic Parameters

Input signal:3~15psi pneumatic signal Supply air:20~150psi Application:Linear diaphragm control valve

Mechanical & Structure

Mounting: Direct mount on linear actuator Protection class:IP54

Environmental

Operating temperature:-40℃ ~ +85℃ Ambient humidity:5~95% non-condensing Certification:CE Status:Fisher classic pneumatic positioner

System compatibility

Compatible with Fisher sliding stem diaphragm actuators and linear globe control valves for industrial process control system.

Function

3700 is pneumatic valve positioner manufactured by Fisher. It compares pneumatic control signal with actual valve stem position and adjusts actuator air pressure to eliminate position error. It can realize split range control and switch direct/reverse action. It has built-in purge function to protect internal components from dust and moisture. It is widely used for modulating linear control valve in process industry.

Installation

Follow lockout/tagout safety procedure before installation. Cut off instrument air supply. Mount positioner on valve actuator, connect instrument air tubing and signal tubing. Perform zero and span calibration, test full stroke. Restore air supply and run valve function inspection.

Interface

1/4"NPT pneumatic signal ports, pressure gauge ports, fixed mounting holes on 3700.

Diagnostic

Valve no movement: Supply air lost or signal pipeline blocked. Stroke inaccuracy: Zero/span drift or cam wear. Air leakage: Gasket damage or loose pipe fitting.

Product Brief

3700 Fisher pneumatic valve positioner,used for industrial linear diaphragm control valve stroke positioning in oil,gas and chemical plant,pneumatic positioner spare part.