Replacing Dynisco and Gefran Melt Pressure Sensors Without Rewiring Your Extrusion Line
- Bob
- 5 days ago
- 2 min read
Many plastics extrusion plants operate equipment that was originally designed around sensors from Dynisco or Gefran.
When these sensors eventually fail, engineers often worry that replacing them will require rewiring the extrusion line or modifying the control system.
Fortunately, most modern melt pressure sensors follow standardized mechanical and electrical configurations.
Mechanical Compatibility
Most extrusion pressure sensors use a standard 1/2-20 UNF mounting thread.
This allows replacement sensors to install directly into existing barrel ports without machining or modification.
Typical compatibility factors include:
Thread size
Probe length
Diaphragm style
Seal type
Matching these parameters ensures the new sensor fits properly.
Electrical Connector Compatibility
Another concern when replacing sensors is the connector type.
Common connectors include:
6-pin Bendix
6-pin standard industrial connectors
Integrated cable leads
Many replacement sensors are designed to maintain connector compatibility so plants can simply reconnect the existing cable.
Output Signal Matching
The most important electrical consideration is the sensor output signal.
Extrusion control systems typically expect one of the following signals:
3.33 mV/V
2.5 mV/V
4–20 mA
When replacing a sensor, the output must match what the indicator or PLC input expects.
If the signal type differs, recalibration or signal conditioning may be required.
Calibration Considerations
After installing a replacement sensor, it is important to confirm:
Zero pressure reading
Span calibration
Indicator scaling
Many modern pressure indicators allow simple calibration adjustments to accommodate compatible sensors.
Replacing melt pressure sensors does not usually require major system modifications.
By matching the key specifications—mechanical fit, connector type, and output signal—plants can replace failed sensors quickly and keep extrusion lines running.
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