Stock mixing and dosing
Higher paper quality thanks to outstanding stock homogeneity at the headbox
The basis for a stable basis weight profile is the constant consistency of the stock fed into the headbox. If this is not ensured, greater basis weight fluctuations can result, thereby affecting the optical and mechanical quality of the paper.
Voith systems in the approach flow section provide efficient thick stock blending and homogeneous dilution of thick stock with the white water. Our solutions can be used in machines from Voith as well as from other manufacturers and meet the highest quality requirements – even for a wide range of grades or production of specialty papers.
Mixing and dosing systems for all applications
HydroMix – The new generation in stock dilution
Voith’s proven HydroMix solution has been used for decades in the paper industry for the homogeneous dilution of the fiber stock with white water and is crucial for uniform sheet formation. With the new HydroMix generation, Voith gives its customers added flexibility through a significantly expanded operating window for production of a wide range of basis weights and consistencies. The patented new nozzle design is adjustable and guarantees excellent mixing quality under all operating conditions. With the digital connection to the process control system and features such as automatic nozzle adjustment, built-in sensors, or the automated tank cleaning system, the new generation of HydroMix is Papermaking 4.0-ready.
Computer simulation supported mixing zone and nozzle design. Homogeneity is a achieved in short distance after injection.
Improved paper quality and maximum flexibility
The design of the HydroMix, optimized by means of CFD analysis, ensures an optimal velocity profile from the white water channel to the mixing area. The execution as an acceleration elbow prevents vortex formation and dead zones. The design also allows for a compact construction. In combination with the patented nozzle with optimized design, the new HydroMix generation guarantees the best possible mixing of the stock for a stable basis weight profile. The automatic adjustment function of the nozzle thereby ensures a uniformly high sheet quality.
Maximum flexibility thanks to greatly expanded operating window
The revised nozzle design for the fiber stock feed-in permits a very wide operating window. This is especially beneficial for customers in the packaging paper segment, where the same machine is used to produce a large range of basis weights. With its automatically adjusting nozzle, HydroMix always mixes the required amount of fiber into the white water under optimal flow conditions to achieve a uniform sheet appearance.
Papermaking 4.0-ready thanks to innovative features
The mixing nozzle is adjusted fully automatically from the control room. Based on the production output and the paper grade, an optimal nozzle opening is selected to ensure optimal distribution with minimal energy input. Precise pressure sensors measure the liquid level and can estimate the concentration of free gas. As a result, the defoamer additive can be accurately dosed and optimized, in turn resulting in lowered operating costs. The cleaning of the white water channels is another automated process. Cleaning nozzles are switched on at intervals and cover the entire white water channel with rotating jets. This provides for maximum cleanliness and consequently leads to fewer web breaks.
Your benefits with HydroMix
- Outstanding stock mixing for improved paper quality
- Maximum flexibility thanks to greatly expanded operating window
- Lower pressure drop for energy savings at high-consistency stock pump
- Compact design with acceleration elbow saves space and building investment costs
- Operator-friendly concept thanks to high degree of automation
ComMix – Furnish mixing system with optimal mixing efficiency
Stable supply with a homogeneous stock quality is the core task of the approach flow section of the paper machine. A uniform raw material supply is decisive for the overall efficiency of the paper machine. Top quality paper requires stability in the furnish mixing system. The ComMix system from Voith ensures this by reliably and efficiently mixing the furnish components.
The heart of the ComMix system is a static mixer. Static mixers are established in the chemical industry and are characterized by a very high mixing efficiency and low space requirements. Voith developed the concept further for the needs of the paper industry and uses mixing elements that have been optimized for fiber-containing suspensions and simultaneously prevent blocking by fiber bundles.
The heart of the ComMix system is its static mixer that ensures very high mixing efficieny.
The mixing quality downstream of the static mixer of the ComMix is above average. Consequently, a small machine chest can be used in the Voith system, whereas other systems need two large tanks. This results in significant energy savings for agitators and pumps. In addition, the small installation space simplifies installation. This is especially relevant when it comes to machine rebuilds.
The Voith ComMix system creates the conditions required for homogeneous stock quality at the headbox by reliably mixing the furnish components and, thanks to a low volume, responding well to regulating adjustments.
Your benefits with ComMix
- Outstanding mixing quality for optimal process stability
- Blockage-resistant mixing elements for guaranteed higher machine availability
- Lower maintenance requirements because no wear parts in static mixer
- Compact size for flexible installation and energy savings
FlowJec – Resource-saving dosing of chemicals
With FlowJec, Voith has developed today’s most efficient dosing system for sustainable and resource-conserving dosing of all chemicals and additives in the paper manufacturing process.
Efficient dosing in the approach flow system or the wire section results in significant reduction in chemical, fresh water and energy consumption. In addition, dosing with FlowJec leads to improved paper quality and runnability of the paper machine.
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