Pulp and Paper Industry
In the pulp and paper industry, abrasive raw materials such as wood chips and waste paper are processed into a fibrous pulp mixture. This mixture easily clogs and blocks pipes and valves. In addition, aggressive chemicals, alkalis, acids, and bleaching agents are used, which require valves with high corrosion resistance. Robust materials and a design without cavities are essential for valves in paper processing.
Our
competence
The original Wey knife gate valve was developed more than 70 years ago specifically for the paper industry. Since then, we have continued to perfect our design. Today's Wey knife gate valves are successfully used in paper production for media with a solids content of up to 24%. A self-cleaning mechanism reliably prevents blockages.
Typical
Media
- Pulp
- Lime slurry
- Lye
- Bleaching agents
- Chemical solutions
- Wastewater
Typical
Processes
Stock preparation
Wood is defibrated mechanically or chemically. Undesirable components are removed by adding chemicals in a cooking process. Valves must be able to withstand temperatures that can reach well over 100°C.
Waste paper recycling
Waste paper is dissolved and de-inked in the pulper. Foreign objects such as staples have an abrasive effect on valves and must not damage them.
Sorting
The fiber material rotates in a cleaner. Foreign objects are separated by centrifugal force. Valves used here must be robust and abrasion-resistant.
Bleaching
Peroxides, ozone, and sometimes chlorine are used to bleach the pulp and remove the remaining lignin. The corrosive bleaching agents attack the surfaces of valves and require corrosion-resistant materials.
Paper formation
The pulp is pumped through the plant as a fiber-water mixture and enriched with fillers and chemicals. Solids accumulate in cavities and cause blockages. Conventional valves with gland designs and dead space in the body are not a suitable option here.
Wastewater treatment
Many paper mills have their own wastewater treatment plants where process water is filtered and returned to the process. Valves must be able to withstand corrosion from chemical residues.
Our Wey valves
for the pulp and paper industry
VN Series
MG Series
Options
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Stainless steel as the body material makes the valve particularly resistant to corrosion.
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A gate made of hardened stainless steel provides extra protection against wear.
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A wear ring protects the body and seal from severe abrasion.
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The add-on Weyotine cutter-pack can be used to cut long-fiber media, preventing jamming and blockages.
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Further options depending on project requirements
References
The Munksjö paper mill in Spain
Replacement of 160 error-prone valves from other manufacturers with Wey knife gate valves in a Spanish factory for decor paper.
Show CASE STUDY
Magazine and newsprint production in Switzerland
In one of Switzerland's largest paper mills, Wey knife gate valves have been used for years in a wide variety of process steps, such as stock preparation, paper formation, and internal wastewater treatment.
