Melt Pressure Transmitter (Dynisco)

Melt pressure measurement is a discipline of its own. The sensor sits directly in a polymer melt at up to 400 °C, exposed to abrasive fillers and corrosive additives, and it must survive constant thermal cycling while keeping accurate readings for screen-pack, die and gear-pump control. Dynisco melt pressure transmitters are built for exactly this duty.

A diaphragm at the process tip transmits pressure through a rigid or flexible stem to the electronics, which output 4–20 mA with optional HART. An optional thermocouple or RTD in the same probe delivers melt temperature, saving a second tapping in the barrel.

Ranges span 25 psi to 30,000 psi (approximately 1.75 to 2,000 bar), with static pressure to 2,300 bar and accuracy of ±0.25 %, ±0.5 % or ±1.0 % depending on model. Threads are ½-20 UNF, M18 × 1.5 and ½-14 NPT, the industry standards for extruder barrels, with electrical connection via PT1H-10-6P connector, conduit or armoured cable. Wetted parts are DyMax-coated for wear resistance, or 316 stainless steel, Hastelloy or Inconel.

Accessories include mounting flanges, armoured capillary, connectors and rigid or flexible stems, and hazardous-area versions are available for compounding and reactor installations. Typical users are plastics compounding, film and pipe extrusion, fibre lines, injection moulding and polymer reactors.