The melt pressure systems engineered and supplied by Pyrosales are designed
to measure, control and supervise the temperatures and pressures associated
with plastics extrusion. Pyrosales can assist you in implementing a complete
temperature and melt pressure control system, or supply individual components
to improve your extrusion process.
Melt pressure control improves the quality and uniformity of extruded products,
reducing the instance of defects and imperfections. This both maximises quality
control and improves efficiency, since fewer defective products means less wastage
of time and resources. Melt pressure control can also make the extrusion process
safer. Pressure control provides a means of monitoring and stabilising pressure,
reducing the risk of overpressure and consequent damage. Additionally, melt
pressure control can also extend the life of extruder components by reducing
wear caused by inconsistent pressures.
Melt pressure control is therefore crucial to:
- Maximising quality control.
- Increasing efficiency.
- Reducing waste.
- Ensuring safety.
- Minimising wear on extruder components.
The key components needed to establish a melt pressure control system are transducers,
controllers and indicators.
Melt pressure transducers are specialised sensors which are used to measure
pressure during the extrusion process. Transducer models available from Pyrosales
include the MP1/MF1transducer (rigid stem), the MP2/MF2 transducer (rigid stem
with flex) and the MPX/MFX transducer (pressure and temperature). All models
are interchangeable with competitors’ models. Additionally, Pyrosales
can provide a range of mercury-free transducers, for use in processes where
toxic contamination may be an issue. There is also variation in materials and
surface finishes that can extend the life of the sensor with respect to the
process.
Melt pressure controllers are used to control screw rpm to stabilise and regulate
pressure during extrusion. The RKC HA930/430 Resin Pressure Controller is ideal
for melt pressure control, featuring both single channel strain gauge input
control as well as dual channel strain gauge/temperature input control. Both
single and dual channel controllers have common features, including:
- 5 digit displays
- Adjustable gain to suit any strain gauge (0.05 – 4.00mV/V)
- Selectable temperature input (thermocouple RTD Analogue)
- Adjustable range and engineering units (MPa PSI)
- High sampling rates and control at 0.025 second (40Hz)
- PID parameters set in 1/100 unit
- Auto/manual control over output at the push of a button, with bumpless
transfer between Manual/Auto and Auto/Manual transfer
- 5 configurable outputs control/event (alarms)
- 5 digital event inputs
- RKC Brilliant PID control with enhanced autotuning
- Measuring accuracy of 0.1% of span (strain gauge input)
- Coms rs-485 ANSI/modbus, Protocols DeviceNet, Profibus
- Available in ¼ DIN (96x96) and 1/8 DIN (48x96 vertical) case sizes.
Melt Pressure Indicators are used as under and over pressure indicator/safety
interlocks. The RKC PG500 Resin Pressure indicator features:
- 5 digit display
- Adjustable gain to suit any strain gauge (0.05 – 4.00mV/V)
- Adjustable range and engineering units (MPa PSI)
- High sampling rate 0.1 second
- 4 digital event outputs (alarms)
- Peak value hold
- Bottom value hold
- Analogue retransmit of measured value
- Measuring accuracy of 0.1% of span (strain gauge input)
- Coms rs-485 ANSI/modbus
- Case size 1/8 DIN (96x48 horizontal)
