Feeding Technology
Solid Material Dosing Unit
For efficient charging of your biogas plant
With its innovative operating principle, the Grundmann solid material dosing unit has stood for reliable and efficient substrate feeding in biogas plants for over 10 years. With a large number of successful installations in Germany, Europe and China, our system has established itself as a robust and economical solution.

Operating Principle
The substrate is stored in the dosing container on a sturdy rubber conveyor belt running on heavy-duty support rollers. The dosing unit works with a special tine design that continuously removes small amounts of material from the pouring cone. This principle enables energy-saving operation without friction losses.
The vertical container walls and lateral seals prevent bridging and the escape of seepage juices. For even dosing, layered loading with a wheel loader is sufficient. Pre-mixing is not required.
Suitable Substrates
• Grass and maize silage
• Whole crop silage (GPS)
• Solid manure
• Dried chicken manure (HTK)
• Feed residues
• Green and vegetable waste
• Millet and sugar beet
Standard Equipment
The basis of our proven dosing system consists of three perfectly matched components: the robust container made of high-quality steel with plastic-coated multi-layer composite panels, the precise dosing unit with matching transfer housing, and an energy-efficient drive system.
System Integration
Combined with the appropriate intake conveyor, our solid material dosing unit can be seamlessly integrated into your existing plant technology. Depending on your requirements, we supply and install the optimally matched conveying technology or design the complete feeding system for you, including all necessary peripheral components.
Further Applications
Beyond biogas plants, the solid material dosing unit is also suitable for feeding waste disposal, composting and fermentation plants, for processing fruit and vegetables, for feeding systems in agriculture, and for sewage sludge drying plants.
Technical Data
Abmessungen Behälter:
| Container volume: | 40 to 320 m³ |
| Container width: | 2.4 or 3 m |
| Container height: | 2.5 or 3 m |
| Container length: | 9 to 45 m |
Overall machine dimensions:
| Overall width: | approx. 3.5 to 4 m |
| Overall height: | approx. 3.5 to 4.1 m |
Output and energy requirements::
| Installed electrical power: | 6.8 to 13.2 kW |
| Throughput capacity: | 6 to 18 t/h |
| Specific energy consumption: | 0.28 kWh/t* |
*at 200 kg/min maize/grass silage
Example Sizes*
| Volume (m³) | Outer length (m) |
| 40 | 9.15 |
| 52 | 11.15 |
| 82 | 15.15 |
| 105 | 19.15 |
| 123 | 22.15 |
| 140 | 25.15 |
| 200 | 35.15 |
| 320 | 45.15 |
*Intermediate sizes readily available thanks to modular design

Custom configurations
Additional Equipment
Transfer housing
The stainless steel housing protects the transfer point between the dosing unit and the intake conveyor from weather influences and prevents material loss. Inspection openings allow easy access for maintenance work.
Hopper attachments
Specially designed stainless steel hopper attachments enable safe material transfer between different plant components. Tailored to the respective plant, they ensure an even substrate flow.
Control technology
The control system with touchscreen operation and remote maintenance module enables precise process control. The system automatically monitors and regulates the dosing process based on the measured drive power.
Weighing technology
The system of load cells and digital display enables exact recording of the dosed quantities. The large display makes the values easy to read even from the wheel loader’s cab.
Hydraulic dosing cover
The hydraulically operated cover protects the material from weather influences and prevents odour emissions. It can be conveniently opened for filling.
Wheel loader impact protection
A raised wall made of powder-coated sheet steel prevents substrate from spilling over the edge of the container, keeping the area around the dosing unit clean.
Overload protection
A raised wall made of powder-coated sheet steel prevents substrate from spilling over the edge of the container, keeping the area around the dosing unit clean.
System Integration
Peripherals
For complete system integration, we offer coordinated peripheral components. Conveyor belts and screw conveyors in various designs, powerful size reduction technology, and precisely matched pump systems for liquid feeding enable a consistently optimised material flow from loading through to introduction into the fermenter.
Conveyor belts
Low-wear rubber conveyor belts transport the material energy-efficiently and gently. The belts are oil- and acid-resistant, ensuring reliable material transport.
Screw conveyors
Robust stainless steel screw conveyors with PTFE lining ensure reliable material transport for more liquid substrate mixtures, even on steep inclines.
Size reduction technology
Smaller substrate particles are converted to gas faster and more efficiently by bacteria, while also placing less strain on pumps and agitators. Our robust hammer mill reliably shreds all common substrates, increasing your gas yield with shorter retention times.
Pump technology
Efficient transport of the substrate into the fermenter requires robust and reliable pumps. Our Bio-Mix and progressive cavity pumps are specially developed for biomass and easily handle high throughput volumes.
Mixing system
With our special mixing system with integrated stone trap, you optimally prepare your substrates for the fermenter. The well thought-out arrangement of the agitator arms ensures thorough mixing of solids and liquids, while contaminants are removed before entering the fermenter.
Switchgear
From planning through construction to installation, we offer complete switchgear for automating your entire plant system. The custom-tailored PLC control system not only regulates the dosing process as needed, but can also integrate and monitor the complete peripherals, so you always retain full control over all plant components.
PHOTOS
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