Gravimetric dosing & mixing units
GRAVIPLUS ® is a synchronous loss-in-weight gravimetric dosing and mixing station for granulate, regrinds, powders, flakes, fibers and liquids. Thanks to its modular design, GRAVIPLUS® is a complete dosing system which adapts optimally to every requirement.
Each system can be equipped with up to eight precision screw dosing modules and is designed for throughputs from 0.25 kg/h to 7,500 kg/h. All components are dosed continuously. The material flow for each component is constantly monitored and regulated. Consistently high dosing accuracy of GRAVIPLUS® enables the production reliability which is essential to continuous manufacturing processes.
Our unique gravity-mixing principle offers you a high level of mix consistency without the need to mechanically mix. This plays a key role in achieving perfect plasticization and homogenization of the materials in the extruder.
Synchronous dosing offers you excellent recipe accuracy and reproducibility, which can be followed at any time. So, for example, you can check the actual dosed throughput of any dosing module at any given time and these values can be documented by the reporting function of the GRAVInet GP control.
Extremely compact construction due to the unique design of the supply hoppers and the location of the load cells.
This allows you to install the unit where many other similar units would not fit. Because all the dosing modules feed into a single collecting bin you have the big advantage of only having one interface between the dosing station and the machine.
The GRAVIPLUS® is self-calibrating, eliminating the need to take manual weight samples or calibrations.
Single screw dosing modules are ideally suited for dosing granules, free-flowing regrinds, and flakes.
The compact, modular design gives you the flexibility to meet your changing process requirements. The specially shaped supply hopper has a large intake zone above the dosing screw and guarantees no dead zones in material flow.
Quick material changes are possible because of the quick discharge slide plate and the fact that you don’t need any tools to swap the dosing screws. A material change can typically be carried out by one person in 2-3 minutes - saving you valuable time.
Dosing modules equipped with twin screws allow you to dose non-free-flowing materials such as powders, fibers, and flakes.
The compact, modular design gives you the flexibility to meet your changing process requirements. The horizontal agitator above the dosing screws constantly keeps material in motion, thus eliminating bridging and maintaining consistent screw fill.
A vertical mixer can be installed in the supply hopper for materials that bridge easily.
For the dosing of liquids you have the option of dosing gravimetrically with either gear pumps for self-lubricating liquids or for other fluids such as water using piston or piston diaphragm pumps.
Single and twin screw hoppers are interchangeable and there are many different types of dosing screws available, e.g. single, twin, spiral and auger. This allows you to configure the dosing unit for nearly any type of material in a matter of minutes.
The mechanically decoupled platform for material refilling prevents any negative impact on the weighing process during refilling.
If refilling with metro loaders is not an option, then our fast refill double slide valve with up to 40 refills per hour can significantly reduce your system size and cost.
Fast refill systems, in contrast to conventional systems, do not require large hoppers, thus reducing costs and installation volume.
In addition, the volumetric dosing time is reduced and your recipe runs gravimetrically for longer, giving you greater accuracy.
The high accuracy of GRAVIPLUS® is based on the use of state-of-the-art weigh scale and control technology. This technology, as well as the control software, is tried and proven in the global marketplace.
The material flow is constantly measured by load cells in real time and is regulated by the control system.
Variations in material flow per component are immediately sensed and compensated for by the controller. The built-in digital load cells have an extremely high resolution of 1:1,000,000 of their weight range. They are microprocessor-based and utilize vibrating wire technology, which is temperature and voltage protected, delivering unparalleled accuracy, with +/- 0.1% values being achievable.
All exterior and interior surfaces of the GRAVIPLUS® are constructed from materials designed to not cause contamination, such as electro-polished stainless steel.
All seams are fully welded, making the unit absolutely dust proof.
The sophisticated design of the dosing module guarantees easy cleaning and quick material changes.
Because the GRAVIPLUS® is controlled by the GRAVInet GP control system, it allows the unit to work as part of a more complex dosing and mixing system.
For example, on a compounding line a GRAVIPLUS ® station may be mounted over the main inlet of an extruder and a C-FLEX unit will be used to dose fillers or reinforcement through a side inlet downstream of the melt.
In combination with the gravimetric collecting bin, the GRAVIPLUS® can be configured for flood-fed operation (single and counter-rotating twin screw extruders).
This configuration is ideal for fibre and textile applications because the material level above the extruder must be as low as possible to avoid material separation in the collecting bin.
The GRAVInet GP control system is designed for controlling multiple dosing modules and stations. It boasts an innovative, Ethernet-based open network architecture.
In addition, it offers you excellent control characteristics when handling set point jumps and ramp mode thanks to its optimised control settings and filter functions.
The high-tech touch screen colour display with LCD-TFT resolution enables simple, intuitive, fast, and reliable operation. It has comprehensive features for process and recipe management, offering you reporting functionality for quality assurance and it delivers advanced service functions and graphical display of process data.