Applications
In polymer production plants, controlling pressure and temperature during the various stages of the process is essential to ensure operational continuity, safety, and consistent quality of the final product. Starting with the monomer, the cracking and reaction stages are followed by melt processing, extrusion, and granulation. Throughout this process, it is necessary to control the process by measuring the pressure and temperature of the fluid.
Depending on the consistency and temperature of the fluid, pressure is measured using flush diaphragm sensors specifically designed for high temperatures.
Requirements:
Thermoregulation
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Pressure control in ATEX zone
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Pressure control in palletizing
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Requirement:
Thermoregulation
Stable rheological behavior and the resulting dimensional consistency of the extrudate are achieved through proper temperature control.
It is essential to ensure thermal stability in these areas so that the system can respond quickly to changes in thermal load or process, avoiding potential defects (surface instability, thickness variations, or alterations in the optical quality of the product).
Solution:
Gefran technology for the thermal control of extruders is based on static relays, PID controllers and thermocouples:
- Each resistance is managed in a closed loop via PID regulation, integrated in the PLC or entrusted to dedicated controllers such as the 1850, which allows the melt temperature to be maintained within ±0.5°C of the setpoint, ensuring constant viscosity and the absence of surface or dimensional defects
- The compact GRP-H solid state relay with integrated heat sink ensures precise current control up to 120 A. IO-Link communication also reduces the number of I/O cards required, thanks to the integrated management of commands, alarms, and current consumption
The solution is scalable and compatible with PIDs integrated in PLCs or remote modules. Recipe storage and historical trend functions support rapid production changes and continuous quality improvement.
Requirement:
Pressure control in ATEX zone
During the polymerization phase, pressure is a key parameter for controlling the progress of the reaction and maintaining stable operating conditions. In the early stages, pressures can vary from very low values to tens of bars, while in secondary reactors they become critical for managing polymer transfer pumps.
Reliable measurement prevents process instability and risky situations.
Solution:
The HMJ high-temperature melt sensor is the ideal solution for monitoring the pressure of molten polymer in polymer production plants, where reliability, operational continuity, and process safety are critical factors. It is particularly suitable for applications where melt pressure measurement is directly linked to reaction stability, transfer pump control, and output material quality.
It is designed to support complex industrial processes, ensuring constant measurement even under harsh operating conditions:
- Protection in classified areas: built to Ex d standards (explosion-proof housing) with ATEX, IECEx, and Nepsi Ex certifications, suitable for installation in potentially explosive atmospheres
- HART protocol: configuration and diagnostics directly from the control system
- High-temperature operation: designed to measure melt pressures up to high temperatures (up to ~400 °C), maintaining stability and accuracy even at the hottest points of the process
Requirement:
Pressure control in palletizing
During the grânuloizing phase, the molten polymer is extruded and cut into granules for subsequent processing. In this phase, melt pressure stability is essential to ensure a smooth flow to the cutting head and avoid variations in grânulo size and quality.
Pressure fluctuations can cause extrusion instability, cutting defects, or plant downtime. Continuous pressure monitoring allows you to maintain constant operating conditions and not lose the rheological properties of the polymer obtained in the previous stages of the process, improving process efficiency and the repeatability of the final product.
Solution:
Gefran Melt sensors are designed to control the pressure of molten polymer during extrusion and grânuloizing, where high reliability and continuous operation are required. Their integration allows real-time monitoring of melt behavior, supporting pump control and extrusion stability.
Main features:
- High measurement stability: precise pressure control for constant melt flow rate
- Easy integration: compatibility with grânuloizing line control systems
- Configuration flexibility: versions available with oil, NaK, mercury-free, or fluid-free filling (Impact series), depending on process requirements
Operating principle:
In polymer production plants, pressure and temperature control during the various stages of the process is essential to ensure operational continuity, process safety, and consistent quality of the final product. Starting with the monomer, the process involves cracking and chemical reaction, followed by melt processing, extrusion, and granulation. Throughout this process, it is necessary to control the process by measuring the pressure and temperature of the fluid.
Depending on the consistency and temperature of the fluid, pressure measurement is entrusted to flush diaphragm sensors designed for high process temperatures.
Requirements and technology:
In polymer production plants, the quality of the final product and the stability of the process depend on the coordinated control of temperature, pressure, and flow rate of themolten polymer throughout all critical stages, from reaction to grânuloizing.
Accurate temperature control of the heating zones is essential to maintain constant melt viscosity, ensure dimensional stability, and prevent surface defects or alterations in the rheological properties of the material. At the same time, pressure control during the reaction and polymer transfer phases allows the process to be controlled, ensuring operational continuity and safe operation even in classified areas.
In the final stages of extrusion and grânuloizing, stable measurement of melt pressure is directly related to flow rate control , regularity of flow to the cutting head, and repeatability of grânulo quality. Uncontrolled fluctuations can compromise plant efficiency and negate the benefits achieved in previous stages.
Gefran meets these needs by offering integrated solutions for temperature control and melt control, designed to ensure reliability, precision, and safety in the most complex polymer production processes.