Laboratory Internal Mixers
General design principles
The laboratory internal mixer, together with the main drive system and all other auxiliary devices, required for the correct functioning of the machine, are mounted onto a common base plate:
- Mixer unit with ram
- Gear reducer for friction (N-type) or even speed (E-type) operation, with hand wheel for the manual rotation of the rotors to assist in cleaning the mixing chamber and rotors
- Main drive motor designed as a thyristor controlled DC motor or frequency controlled AC motor, for infinitely variable rotor speeds
- User-friendly multi-function control panel for machine operation
Special design features
- Easy cleaning of the mixing chamber and rotors. The mixing chamber is split along its' horizontal centre line to give direct access into the chamber and rotors
- Temperature control units, with direct or indirect cooling, for the mixing chamber, rotors and drop door
- Process oil injection nozzle. For the injection of oils into the closed mixing chamber during the mixing process
- Dosing and injection unit for process oils
- Compound Temperature Sensors.
Compound temperature measurement by thermocouples in the mixer sidewall or drop door - Supervision of dust ring lubrication
- Ram position indicator
Supervision of dust ring lubrication (Typical example)
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Hydraulic tilt mechanism for the top half of the mixing chamber (Typical example) |
Dosing and injection unit for process oils (Typical example) |
Special split mixing chamber
In contrast to a production machine, the chamber of the laboratory internal mixer can be split along its' horizontal centre line. For cleaning the chamber can be opened by a hand crank and spindle mechanism, or by a hydraulic tilt mechanism if required. This ensures easy access to the mixing chamber and rotors and so ensures optimum cleaning.
Optimum wear protectionAll machine parts that come into contact with the compound are hard-chrome plated to protect them from wear and corrosion.
Dust rings
The rotor shafts are fitted with spring-loaded, externally adjustable, dust ring seals. When worn the split sealing rings can be replaced easily and quickly.
Compound temperature measurement
A thermocouple located in the sidewall of the mixing chamber provides accurate measurement of the compound temperature. If required a thermocouple can also be located in the drop door.
Mixer drive
Laboratory internal mixers from Harburg-Freudenberger are equipped with a thyristor controlled DC motor, or with a frequency controlled AC motor to provide infinitely variable rotor speeds. The rotors are driven through a special spur gear unidrive gearbox.
Electrical control
The manual push-button control system of the laboratory internal mixer is designed as a programmable logic control (PLC) system and is housed in a separate cabinet. It contains all the circuit, display and control elements required for the operation of the machine. A multi-function operators' panel, equipped with the most important operating and display elements, is attached directly to the mixer for convenient manual operation.
As with other types of mixer, the laboratory internal mixer can be connected to a process control system. Process control systems and other monitoring devices, e.g. for torque or pressure measurement can also be supplied by Harburg-Freudenberger.
GK15, E Laboratory internal mixer with pneumatic ram
GK-E Intermeshing Rotor System
The intermeshing rotor system facilitates high energy input within the shortest possible time, thereby considerably improving compound quality. The exceptionally low volume to cooling surface area ratio means that even heat sensitive compounds, where high quality is required, can be processed without problems.
| GK-E Series (Intermeshing rotor geometry) | ||
|---|---|---|
| GK 1,5 E | GK 5 E | |
| Chamber volume approx. l | 1.55 | 5 |
| Useful volume (fill factor 0.70) approx. l | 1 | 3.3 |
| Batch weight at specific gravity 1.2 approx. kg | 1.2 | 4 |
| Rotor speeds 1/min | 20 - 100 | 20 - 100 |
| Rated motor power kW | 24 | 60 |
| Specific ram pressure at 8 bar*) N/cm² | 10 - 45 | 10 - 45 |
| Air consumption at 60 double strokes/h approx. Nm³/h | 2.5 | 10.6 |
| Ram cylinder - diameter mm | 110 | 160 |
| Useful volume of feeding hopper
Up to feeding door shaft (including mixing chamber) approx. l | 2.5 | 7 |
| Size of feeding hopper | ||
| length mm | 156 | 240 |
| width mm | 100 | 140 |
| Drop door opening | ||
| length mm | 156 | 240 |
| width mm | 100 | 140 |
| Space requirements for mixer | ||
| length approx. mm | 2450 | 3000 |
| with gearbox and motor width approx. mm | 1300 | 1700 |
| height approx. mm | 1900 | 2500 |
| Weight approx. kg | 2200 | 4100 |
(*) For hydraulic ram the specific ram pressure is variable within the same range.
PES rotor geometry for GK-E Intermeshing system
GK-N Tangential Rotor System
The tangential rotor system allows a high fill factor in the mixer, with short filling and discharge times. It is particularly suitable for high output applications producing less thermally sensitive compounds and is used extensively in the tire industry.
| GK-N Series (Tangential rotor geometry) | ||
|---|---|---|
| GK 1,5 N | GK 5 N | |
| Chamber volume approx. l | 1.45 | 5 |
| Useful volume (fill factor 0.75) approx. l | 1 | 3.8 |
| Batch weight at specific gravity 1.2 approx. kg | 1.2 | 4.5 |
| Rotor speeds 1/min | 22.2/20 - 111.2/100 | 22.2/20 - 111.2/100 |
| Rated motor power kW | 24 | 60 |
| Specific ram pressure at 8 bar*) N/cm² | 10 - 60 | 10 - 54 |
| Air consumption at 60 double strokes/h approx. Nm³/h | 2.5 | 10.6 |
| Ram cylinder - diameter mm | 100 | 160 |
| Useful volume of feeding hopper
Up to feeding door shaft (including mixing chamber) approx. l | 2.5 | 6.4 |
| Size of feeding hopper | ||
| length mm | 140 | 240 |
| width mm | 75 | 125 |
| Drop door opening | ||
| length mm | 140 | 240 |
| width mm | 80 | 125 |
| Space requirements for mixer | ||
| length approx. mm | 2450 | 3000 |
| with gearbox and motor width approx. mm | 1300 | 1700 |
| height approx. mm | 1900 | 2500 |
| Weight approx. kg | 2150 | 4100 |
ZZ2 rotor geometry for GK-N Tangential system
