I. Product Introduction

GRAEFF's G series melt pressure sensors/transmitters are a full range of monitoring equipment developed for high-temperature, high-pressure, high-viscosity and corrosive molten medium environments, covering multiple sub-series to meet the needs of different industrial scenarios. The entire series of products generally adopt a stainless steel main structure, combined with special process materials and advanced technologies (such as titanium compound coating, high-temperature calibration and temperature compensation, etc.), featuring core advantages such as high precision (±0.25% FSO to ±0.5% FSO), strong stability, anti-interference and long service life It can meet the strict requirements ranging from conventional industrial control to special fields such as food and pharmaceuticals, providing reliable solutions for melt pressure monitoring.

GINS series Melt pressure sensors/transmitters

✔Accuracy is better than ±0.5%FSO; Measurement range 0... 17.5 the bar... 2000bar

✔Stainless steel body, titanium compound coated diaphragm, resistant to high-viscosity/friction media, small temperature drift, long service life

GMP series Melt pressure sensors/transmitters

✔Accuracy is better than ±0.5%FSO; Six refined testing processes

✔High-performance core components combined with anti-interference analog circuits and high-temperature calibration at 350°C ensure high-precision measurement

GHP series Melt pressure sensors/transmitters

✔Accuracy is better than ±0.25%FSO; Measurement range 0... 17.5 the bar... 2000bar

✔High-performance components and anti-interference circuit design, with high-temperature calibration at 350°C, achieve high measurement accuracy

GCM series Melt pressure sensors/transmitters

✔Accuracy is better than ±0.5%FSO; Measurement range 0... 17.5 the bar... 2000bar

✔Stainless steel body + titanium-coated diaphragm, resistant to high-viscosity media, suitable for food and pharmaceutical fields, with strong temperature stability and long service life

GM series Melt pressure sensors/transmitters

✔The accuracy is better than ±0.25%FSO and ±0.5%FSO. Six refined testing processes

✔Stainless steel body + titanium-coated diaphragm, suitable for food and pharmaceutical fields, with precise measurement and small temperature drift

GMX series Melt pressure sensors/transmitters

✔Output signal: 4-20mA (+HART); Six refined testing processes

✔Stainless steel body + titanium-coated diaphragm, food-grade transmission medium, suitable for food and pharmaceutical fields, stable performance

GMC series Melt pressure sensors/transmitters

✔The accuracy is better than ±0.25%FSO and ±0.5%FSO. Multiple output signals are available for selection

✔80% internal calibration, excellent stability and repeatability. A variety of optional electrical connections. It adopts a special threaded installation design, featuring simplicity, less and more stable influence by temperature drift, etc. The special exposed design can meet the requirements of special application environments

GMR series Melt pressure sensors/transmitters

✔Special circuit design, super strong anti-interference

✔It adopts TI series high-performance digital chips, with a special circuit design that has strong anti-interference ability and complies with SIL2 and PL'C' safety standards. The range limit is controlled by relays to ensure the safety of extrusion equipment and production lines, and is suitable for fields such as refrigeration, chemical engineering, and environmental protection

GAIM series AI intelligent (zero temperature drift) melt pressure sensor/transmitter

✔Temperature compensation at high temperatures Special diaphragm coating, resisting the adhesion and damage of the diaphragm due to the cooling of the melt

✔The temperature compensation technology is adopted to perform zero drift compensation on the product at 350° C. When the pressure measurement probe is exposed to high temperatures, it achieves nearly zero temperature drift, making the measurement more accurate and stable

GAIMX explosion-proof series AI intelligent (zero temperature drift) melt pressure sensor/transmitter

✔4... 20mA+Hart protocol Used in explosion-proof environments

✔It adopts temperature compensation technology to perform zero drift compensation on the product at 350° C. When the pressure measurement probe is exposed to high temperatures, it achieves nearly zero temperature drift. Additionally, it integrates an intelligent 4... The 20mA+Hart protocol circuit ensures more accurate and stable measurement

GPX series Melt pressure sensors/transmitters

✔Zero point calibration in a 200℃ environment; Six refined testing processes

✔Stainless steel main body + titanium-coated diaphragm, food-grade medium filling, suitable for food and pharmaceutical fields, with strong temperature stability

GMPG series melt mechanical pressure gauge

✔Optional 4... 20mA, 2mV/V, 0... 10V output model IP65 protection rating

✔Special coated film sheet + high wear-resistant coating, stable operation at 400°C high temperature, standard thread installation, suitable for injection molding and chemical fiber fields

GMG series Intelligent digital melt meter

✔4-digit LED display, no indication error; Two control point relay outputs 220V3A

✔High-temperature compatibility with 400°C, standard threaded installation, high stability and long service life, suitable for high-temperature pressure monitoring.

Ii. Application and Significance

High-temperature melt pressure sensors are indispensable key components in industrial process control, especially in fields involving high-temperature, high-pressure, high-viscosity, and corrosive molten materials. They play a crucial role in ensuring process stability, product quality, equipment safety and production efficiency.

（二）(1) Main application fields

1. Plastic industry

Extrusion molding: Monitor the melt pressure inside the extruder barrel, before and after the screen changer, and at the mold inlet. This is one of its most core application fields. It is used to control plasticizing quality, protect equipment (such as preventing overpressure from damaging the filter screen or screw/barrel), stabilize extrusion volume, optimize output and ensure product dimensional accuracy (such as pipes, plates, films, profiles, wire and cable coating).

Injection molding: Measure the melt pressure in the mold cavity (cavity pressure sensor) or the pressure at the nozzle during the injection process. It is crucial for controlling the pressure-holding switching point, optimizing the pressure-holding curve, monitoring the filling status, reducing flash and shrinkage, improving product consistency and lowering the scrap rate.

Blow molding: Monitor the melt pressure of the extruder head or storage cylinder to ensure uniform wall thickness of the parison and stable molding.

Casting/calendering: Control the melt pressure at the lip gap of the die to obtain a film or sheet of uniform thickness.

2. Chemical fiber industry

Melt spinning: The pressure of high-temperature polymer melts (such as polyester, nylon, and polypropylene) is measured before and after the spinning box and the metering pump to precisely control the conveying volume of the spinning pump, ensuring the uniformity of fiber fineness and product quality. This is another extremely important application field.

3. Chemical Industry

High-temperature/high-pressure reactor: Monitoring the pressure inside the reactor during the synthesis reaction process to ensure that the reaction takes place within the set safe pressure range is crucial for process control and safe production.

Molten material transportation: Measure pressure on pipelines transporting high-temperature molten chemicals (such as sulfur, alkali, molten salt, heat medium), monitor pipeline conditions and pumping performance.

4. Rubber Industry

Extrusion and calendering: Similar to plastic extrusion, it is used to monitor the melt pressure of rubber compound at the extruder and calendering roller, control the dimensional stability of extrusion and the thickness of calendering.

5. Food Industry

High-temperature processing: In food production lines such as chocolate, candies, and oils that require molten processing, monitor the pressure of the molten material to ensure process continuity and product consistency (which must meet food-grade hygiene requirements).

6. Metallurgical Industry

Metal smelting and casting: Measuring the pressure of molten metals (such as aluminum, zinc, and copper alloys) in the injection system of furnaces, holding furnaces, or die-casting machines. Although facing higher temperatures and harsher environments, specially designed sensors also have applications in this field.

7. Pharmaceutical Industry

Hot melt extrusion: In the process of preparing sustained-release drug preparations, etc., the pressure of the drug-polymer blend melt in the extruder is monitored to control the uniformity of mixing and process stability.

(II) Importance

1. Core parameters of process control

Melt pressure is one of the most direct signals reflecting the flow state of materials, the uniformity of plasticization, and the load of equipment. Real-time and accurate pressure data is the foundation for achieving closed-loop automatic control (such as adjusting the screw speed and the opening degree of the back pressure valve), ensuring that the process operates stably in the optimal state.

2. The key to product quality assurance

The fluctuation of melt pressure directly affects the dimensional accuracy, mechanical properties, appearance quality (such as surface defects, weld line strength) and batch-to-batch consistency of the product. Precise control of pressure is a prerequisite for producing high-quality products. For instance, the holding pressure in injection molding determines the density and internal stress of the product.

3. Guardian of Equipment Safe Operation

Excessively high melt pressure can damage expensive core equipment components, such as the extruder screw and barrel, the filter screen of the screen changer, the mold runner, and even cause safety accidents (such as pipe burst). The pressure sensor is a key input in the overpressure alarm and shutdown protection system.

4. Enhance production efficiency and reduce costs

Reduce scrap and downtime: By stabilizing the process and preventing overvoltage damage, significantly lower the scrap rate and unplanned downtime.

Optimize production capacity: Under the premise of ensuring quality and safety, allow the equipment to operate at process parameters closer to the limit to increase the output speed.

Reducing energy consumption: Optimizing the process (such as reducing unnecessary back pressure) can lower the energy consumption of the drive motor.

Extend equipment lifespan: Avoid operating the equipment under overload or abnormal pressure to reduce wear and tear.

5. Basis for fault Diagnosis and process optimization:

The changes in pressure curves (such as pressure peaks, fluctuations, and failure to reach the set value) are important clues for diagnosing equipment faults (such as filter screen blockage, screw wear, poor plasticization of materials, and leakage) and optimizing process parameters (such as temperature curves and screw speed).

6. The Foundation for achieving Automation and intelligent Manufacturing

As a key online process parameter, melt pressure data is an indispensable input for achieving production automation, digital monitoring (SCADA/MES), and intelligent manufacturing (such as predictive maintenance and self-optimization of process parameters).

7. Addressing the challenges of extreme working conditions:

Conducting precise measurements in high-temperature (often above 350-400°C, and even higher for special applications such as metallurgy), high-pressure (tens to hundreds of megapascals), high-viscosity, and potentially chemically corrosive or abrasive melt environments is itself a technical challenge. High-performance high-temperature melt pressure sensors are engineering solutions that overcome these challenges and achieve the above-mentioned application values.

Summary

High-temperature melt pressure sensors are the "eye of process" and "shield of safety" in modern industry, especially in the processing of polymer materials (plastics, chemical fibers, rubber) and high-temperature chemical fields. They provide crucial melt pressure information and are directly related to the safety, stability, efficiency, product quality and cost control of the production process. They are indispensable core sensors for achieving efficient, high-quality and safe production. Its technological development and performance improvement have a profound impact on the progress of these industries.