10 Key Considerations for Choosing a NEW Melt Pressure Transducer for Your Equipment
- Bob
- Sep 5
- 2 min read
1. Pressure Range
Must match the expected operating and maximum pressure in the extruder/die head.
Too low → risk of sensor overloading and failure.
Too high → poor resolution and less sensitive data.
Typical extrusion: 0–5,000 psi (345 bar) to 0–30,000 psi (2,000 bar).
2. Temperature Rating
The melt environment can exceed 300°C (570°F) depending on polymer type.
Sensor must withstand tip temperature and have adequate thermal isolation for electronics.
3. Mounting Configuration
Thread size and type (e.g., 1/2”-20 UNF standard, or M18 x 1.5 metric).
Tip style (standard melt bolt, extended stem, or special coatings for sticky polymers).
Proper fit avoids dead spots, cold spots, or material hang-up.
4. Electrical Output & Compatibility
Analog: mV/V, 4–20 mA, or 0–10 V.
Digital: CANbus, HART, or smart sensor interfaces.
Must match the plant’s PLC, control system, or monitoring software.
5. Accuracy & Repeatability
Look at combined error (non-linearity, hysteresis, repeatability), typically ±0.25%–0.5% full scale.
Important for process engineers who use melt pressure for material rheology calculations, not just machine alarms.
6. Diaphragm / Tip Material
Stainless steel is common, but exotic alloys (Inconel, Hastelloy) or ceramic-coated tips are used for:
Abrasive fillers (glass fiber, talc, carbon).
Corrosive polymers (fluoropolymers, flame-retardant grades).
7. Sensor Length & Stem Design
Must fit extruder barrel thickness or die head wall.
Rigid stem, flexible stem, or armor cable for environments with vibration or limited space.
8. Temperature Sensor Integration
Many melt pressure transducers include a melt thermocouple (J/K/E type) or an RTD, in the same body.
Saves port space and provides simultaneous pressure + temperature data at the same location.
9. Response Time
Faster response transducers help capture pressure fluctuations during start-up, purge, or unstable runs.
Critical for high-speed extrusion or thin-wall products where stability matters.
10. Compliance & Safety
CE, ATEX, or other certification if used in hazardous environments.
Burst protection and overload limits for operator and equipment safety.
✅ Summary for process engineers: The key factors are pressure range, temperature rating, mounting/thread configuration, electrical output compatibility, and diaphragm material durability. Secondary but still critical are accuracy, response time, and whether a built-in thermocouple is needed.
Explore our NNS Custom Build Feature for basic sensors:
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