Views: 0 Author: Site Editor Publish Time: 2026-09-23 Origin: Site
Karvil Machinery has completed the production and factory testing of a 2L electric-heated vacuum sigma mixer with screw discharge and PLC control for an Australian customer.
The compact mixer is now ready for shipment to Australia, where it will be used to process lyocell solvent and wood pulp for lyocell spinning dope preparation.
This project combines a small working volume with advanced process-control functions, including vacuum mixing, electric heating, variable-speed Sigma blades, screw discharge and Siemens PLC control.
The Australian customer required a compact mixer for small-batch process development.
Instead of using a standard laboratory mixer, the customer needed several process functions integrated into one machine.
Karvil customized the system with:
2L total mixing volume
0.6–1.4L working volume
Electric heating with thermal oil jacket
Vacuum operation up to -0.09 MPa
Sigma blade mixing
Variable-speed control
Screw extrusion discharge
Siemens S7-1200 PLC
7-inch Siemens color touchscreen
SS316L mirror-polished material-contact parts
The machine was manufactured and tested at the Karvil factory before shipment.
The machine will be used to process lyocell solvent and wood pulp for the preparation of lyocell spinning dope.
Because the application requires controlled processing conditions, the mixer was equipped with a jacketed heating system and vacuum system.
All major material-contact parts, including the mixing chamber, Sigma blades and upper cover, are manufactured from SS316L stainless steel with a mirror-polished finish.
This configuration provides a clean and controlled material-contact environment for the customer's process.
The mixer uses electric heating with thermal oil as the heat-transfer medium.
The heating system includes three 0.8 kW heating elements, providing a total heating power of 2.4 kW.
The temperature range is 90–120°C, with PID temperature control.
Two independent temperature sensors monitor the mixing chamber and jacket. The temperature control accuracy can reach ±1°C.
The 2L sigma mixer is designed for vacuum operation up to -0.09 MPa.
A jacketed vacuum buffer tank is included in the system, together with the required valves, flexible hose and vacuum connections.
The upper cover also includes an ISO-KF25 / NW25 vacuum flange and a reserved connection for a Pirani vacuum gauge.
The vacuum pump is supplied by the customer.
The mixer uses a dedicated screw extrusion system for controlled material discharge.
The screw is independently driven by a 0.75 kW Siemens Beide motor and controlled through a Siemens VFD.
The screw speed can be adjusted from 0–65 rpm, and the screw can rotate in both forward and reverse directions.
This gives the Australian customer greater control over material discharge during testing.
Another important feature of this shipment is the Siemens PLC control system.
The machine uses a Siemens S7-1200 PLC with a 7-inch Siemens color touchscreen.
The operator can monitor and control:
Sigma blade speed
Mixing time
Heating temperature
Vacuum
Screw discharge
Screw speed
Motor current
Forward / reverse operation
Process data can also be exported through USB in CSV format.
Safety functions include a cover interlock and process alarms for conditions such as high temperature and vacuum loss.
Before leaving the Karvil factory, the mixer was assembled and tested to verify the main mechanical, electrical and control functions.
The factory testing covered:
Sigma blade rotation
Forward and reverse operation
Variable-speed control
Screw discharge operation
Heating system
Temperature control
Vacuum system
PLC functions
Touchscreen operation
Safety interlock
Alarm functions
Factory testing helps ensure that the machine is ready for installation and commissioning at the customer's site in Australia.
After testing and inspection, the 2L vacuum sigma mixer was prepared for shipment.
The compact machine combines several functions in one system while maintaining a small footprint, making it suitable for laboratory and pilot-scale process development.
From material selection and machining to assembly, electrical wiring, PLC programming and factory testing, the complete system was prepared according to the Australian customer's requirements.
This Australian project is another example of Karvil's approach to customized mixing equipment.
Different materials and processes can require different combinations of heating, vacuum, mixing speed, discharge and control systems.
Karvil can customize sigma mixers from small laboratory units to larger industrial machines according to the customer's material, batch size and process requirements.
Looking for a custom sigma mixer for your process? Contact Karvil Machinery to discuss your requirements.
