Silicon Nitride Dewatering Element for Board, Paper and Tissue Machines

Silicon Nitride Dewatering Element Applications

• Board and packaging paper machines – forming and vacuum section

  ✅Key Advantages

  1. Stable drainage under high basis weight – Maintains slot and edge geometry to keep dewatering curves repeatable across heavy board grades.
  2. Lower friction for reduced vacuum energy – Smooth Si₃N₄ surfaces help reduce fabric drag over vacuum boxes, lowering drive and vacuum power.
  3. Longer forming fabric life – Uniform contact surfaces reduce local pressure peaks, cutting fabric wear and unplanned fabric changes.

  ✅ Problem Solved

  A packaging paper mill operating a 6.5 m wide board machine at 900 m/min replaced plastic vacuum box covers on the high-vacuum zone with silicon nitride dewatering elements. After one full year of operation, the line recorded a reduction of approximately 18% in vacuum and drive energy on the forming section, a drop from six to three unplanned fabric-related shutdowns per year, and an average forming fabric life extension from 75 days to around 110 days. The initial investment in Si₃N₄ elements was offset within roughly 12–15 months through lower energy use and reduced fabric and downtime costs.

• Tissue and towel machines – high-speed forming section

  ✅Key Advantages

  1. Low wear at very high fabric speeds – High hardness and toughness remain effective where peripheral speeds exceed 1800 m/min.
  2. Smooth water film for gentle tissue formation – Smooth Si₃N₄ surfaces support a controlled water film that helps protect thin forming fabrics.
  3. Chemically robust with spray and cleaning cycles – Material resists common machine clothing cleaning chemicals and white water chemistry.

  ✅ Problem Solved

  A modern tissue machine running at 1900 m/min experienced frequent hydrofoil wear and localized fabric damage on the forming roll side. After switching to silicon nitride dewatering elements at the critical foil positions, foil life increased from roughly 6–8 months to 18–20 months, while tissue quality complaints related to formation streaks dropped by about 40%. Fabric budget was reduced by approximately 12% per year and the number of emergency slow-downs linked to hydrofoil problems decreased from eight to three per year.

• Speciality and technical paper machines – controlled drainage for high-value grades

  ✅Key Advantages

  1. Precise drainage pattern for critical formation – Slot and hole layouts can be engineered to support narrow operating windows in filter paper or technical grades.
  2. Dimensional stability over long campaigns – Limited wear keeps drainage geometry and cross-direction profiles stable over extended runs.
  3. Resistance to aggressive process water – Good corrosion resistance helps where high conductivity, additives or pigments are present.

  ✅ Problem Solved

  A speciality paper producer making filter base paper on a 3.8 m machine had issues with cross-direction basis weight variation linked to uneven wear on mixed plastic and alumina dewatering covers. By redesigning the forming board and high-vacuum box with custom silicon nitride dewatering elements, the mill reduced 2-sigma CD basis weight deviation by around 25%, scrap related to filter performance failures by 30%, and the frequency of profile grinding from every 6 months to once per year. This directly improved order fulfillment stability and reduced quality claim costs.

Si3N4 Dewatering Element Usage Instructions

• Installation

  1. Check each silicon nitride dewatering element against the machine position drawing before installation.
  2. Clean and inspect the supporting frame or box top for flatness, corrosion and contamination.
  3. Use specified torque and tightening sequence for mounting bolts to avoid inducing stress into the ceramic element.
  4. Verify that joints between elements are flush with minimal height difference along the cross-machine direction.
  5. Confirm fabric run-in clearance and contact conditions with low-speed roll-around checks before ramping up to full speed.

• Operation

  1. Maintain recommended vacuum levels and differential across forming and suction boxes to avoid excessive local loads.
  2. Monitor fabric tension and drive loads; unexpected increases can indicate misalignment or contamination on the dewatering elements.
  3. Record operating hours and grade mix by position to build a realistic life-expectancy profile for each silicon nitride dewatering element.

• Storage

  1. Store spare silicon nitride dewatering elements horizontally on flat, padded supports, never directly on concrete or steel.
  2. Avoid stacking heavy objects on top of stored elements; keep them away from impact zones in the warehouse.
  3. Maintain a dry, clean storage area to reduce corrosion of mounting hardware and support frames shipped with the elements.

• Cleaning

  1. Use low-pressure water or approved showers to remove deposits from the fabric-side surface during operation.
  2. When offline, use non-metallic tools and pads to clean any residual scale or filling, avoiding sharp impact or concentrated point loads.
  3. Avoid aggressive mechanical grinding on the Si₃N₄ surface unless carried out with suitable equipment and procedures.

• Typical misuse points and corrective actions

  1. Misuse: Over-tightening bolts under the element ends, causing local stress and later chipping.
  Action: Apply torque according to installation instructions, use calibrated tools, and check for even contact with feeler gauges.

  2. Misuse: Using metal scrapers directly on the fabric-side surface to remove build-up.
  Action: Replace with plastic or composite scrapers and adapt shower configuration to keep the silicon nitride dewatering element surface clean.

  3. Misuse: Running the machine at full speed after a major rebuild without verifying fabric tracking over the new elements.
  Action: Run at reduced speed with visual checks on fabric contact, adjust guide and tension settings, then gradually increase speed when contact is stable.

FAQ – Silicon Nitride Dewatering Element

1. Q: Where are silicon nitride dewatering elements typically installed?
   A: They are commonly installed on forming boards, hydrofoils, low-vacuum and high-vacuum suction boxes, felt suction boxes and transfer boxes in board, paper and tissue machines.
2. Q: How does a silicon nitride dewatering element differ from plastic covers?
   A: Compared with plastic covers, a silicon nitride dewatering element offers much higher hardness and better wear resistance, so drainage geometry and surface quality remain stable for a longer time and are better suited to high-speed machines.
3. Q: Can silicon nitride dewatering elements be used on older, lower-speed machines?
   A: Yes, silicon nitride dewatering elements can be used on lower-speed or rebuilt machines where mills want to extend replacement intervals, reduce energy consumption or stabilize formation, even if the original design used plastic or alumina covers.
4. Q: What information is needed to design a custom silicon nitride dewatering element?
   A: For a custom silicon nitride dewatering element, the supplier typically needs machine position, length and width, slot or drilled pattern, mounting bolt layout, fabric type, operating speed and target vacuum levels.
5. Q: How long does a silicon nitride dewatering element usually last in operation?
   A: Service life depends on machine speed, furnish, cleaning practices and position, but in many cases silicon nitride dewatering elements run several times longer than equivalent plastic covers and significantly longer than softer ceramic grades in high-wear positions.
6. Q: Do silicon nitride dewatering elements reduce energy consumption?
   A: A well-finished silicon nitride dewatering element surface can reduce fabric drag over vacuum boxes and forming boards, which helps lower drive and vacuum energy demand in the wet end, where vacuum boxes alone can account for a significant share of paper machine electricity use.

Silicon Nitride Dewatering Element Reviews

• ⭐️⭐️⭐️⭐️⭐️
  We installed silicon nitride dewatering elements on the high-vacuum boxes of our main board machine. After two rebuild cycles we see much less wear on the covers and a noticeable reduction in fabric-related stoppages. Working with ADCERAX as a ceramic supplier gave us the flexibility to match our existing frames without major structural changes.
  --Michael Braun – Maintenance Manager, NordPack Board Mill
• ⭐️⭐️⭐️⭐️⭐️
  The silicon nitride dewatering elements on our new tissue line helped stabilize wet-end drainage when we pushed speed above 1800 m/min. Energy data also showed a reduction in forming section drive load compared with the old plastic covers. The price level was reasonable for a high-performance ceramic solution.
  -- Laura Chen – Process Engineer, EuroTissue Converting Group
• ⭐️⭐️⭐️⭐️⭐️
  For a recent forming section rebuild we selected silicon nitride dewatering elements for the forming board and felt suction boxes. The Si₃N₄ covers from ADCERAX arrived to drawing, with accurate slot patterns and very good surface quality. Installation was straightforward and early operating results from the mill are positive.
  -- Jussi Lehtinen – Project Director, Nordic Paper Machine Services Oy
• ⭐️⭐️⭐️⭐️⭐️
  Our technical paper grades are very sensitive to drainage and formation changes. After switching to custom silicon nitride dewatering elements on two key suction boxes, basis weight variation decreased and we reduced geometry-related complaints. The ability to fine-tune slot and hole patterns in the Si₃N₄ elements has been important for our product development.
  -- Patricia Gómez – Technical Director, IberFilter Speciality Papers