15
08 2025
Melt Gear Pump Pressure PID Control Set
Why Pressure PID Control?
The melt flow rate produced by the extruder is affected by screw speed, feed stability, material viscosity, and temperature fluctuations. These fluctuations impair thickness tolerances, surface finish, and product repeatability.
Gear pump + pressure PID control maintains constant melt pressure at the pump inlet, thus:
Providing constant flow and low fluctuations (±0.5–1 bar),
Reducing film/sheet weight and thickness deviations,
Maintaining performance stability when using recycled raw materials,
Reducing energy consumption and scrap rates.
What is a "Melt-Gear Pump Pressure PID Control Set"?
The integrated set recommended by Meltsensor.com typically consists of the following components:
Melt Pressure Sensor / Transducer
0–200 bar, 0–500 bar, or other ranges to suit your process
mV/V output (strain gauge) or 4–20 mA / 0–10 V industrial output
Option: integrated type J/K thermocouple (for also monitoring melt temperature)
Standard process connections such as 1/2-20 UNF, M18x1.5; Protective diaphragm
Industrial PID Controller / Display
INPUT: Pressure sensor (mV/V, 4–20 mA) + optional temperature
OUTPUT: Analog 0–10 V / 4–20 mA (inverter/pump driver) or SSR/Relay
Alarm relays (HI, HI-HI, LO), autotuning, soft-start, setpoint ramp
Pump Driver Integration
The gear pump servo/AC drive is speed controlled with an analog reference.
The controller's PID output → Drive speed reference
Wiring and Accessories
High-temperature cable, connection connectors
Mounting adapters, protective heat shield, test port
Short logic: Sensor measures pump inlet pressure → PID controller calculates the difference based on the desired pressure setpoint → Maintains constant pressure by increasing/decreasing pump speed.