Silicon Nitride Dewatering Elements for Board, Paper and Tissue Machines

Silicon Nitride Dewatering Element Applications

Silicon nitride dewatering elements are used in paper machine wet-end sections to support stable drainage, low fabric friction and wear resistance. ADCERAX supplies custom Si₃N₄ covers, foils and suction box components made to drawings or existing parts.

• Board and Packaging Paper

  Silicon nitride forming blades, foils and suction-box covers in the forming section handle the demanding combination of high-speed wire contact, abrasive fillers and the need for consistent sheet formation across wide machine widths. The low-porosity, hard-wearing surface of AD-SIN-ST maintains the dewatering profile and working-face condition under continuous running, reducing the profile wear that disrupts drainage uniformity and leads to unscheduled cover changes. Submit the machine position, forming-wire details and basis weight range for a drawing review.

• Tissue and Towel

  Tissue machines run at high wire speeds with tight requirements on drainage uniformity and wire life. A silicon nitride vacuum-cover or forming element with a precisely ground contact surface supports consistent vacuum distribution across the full width without aggressive wire wear. The element geometry — slot layout, vacuum zones and contact-surface finish — is defined to the machine position and fabric specification. Share the machine layout, fabric data and working-face width to start the review.

• Speciality and Technical Paper

  Speciality and technical paper grades often involve demanding stock chemistry, unusual fibre blends or strict formation requirements. Silicon nitride elements can be specified for these positions because the material holds its profile and surface condition in chemically aggressive or abrasive stock conditions where other cover materials may require more frequent replacement. The element is always machined to the drawing, so drainage geometry, opening pattern and surface finish are set for the actual process position rather than a standard catalogue shape. Provide the process position, stock conditions and paper-quality acceptance criteria.

• Press-Section Felt Dewatering (Uhle / Felt Suction Box)

  Uhle bars and felt suction-box covers contact the press felt rather than the forming wire, with different load, speed and surface-finish requirements than forming-section elements. Silicon nitride covers for this position are ground to the felt specification and suction-opening layout defined in the drawing. The low-porosity contact surface resists fouling and maintains suction-opening geometry across the service life. Identify the felt specification, vacuum zone arrangement and backing interface when submitting an inquiry.

Si3N4 Dewatering Element Usage Instructions

• Before Installation

  1. Check the drawing revision, segment identity, dimensions, profile, edges and working surface.
  2. Verify support-frame or box-top flatness, condition and cleanliness.
  3. Record critical geometry and surface acceptance against the drawing.

• Mounting & Alignment

  1. Check support datums, locating features, segment-joint gaps and working-face level.
  2. Follow the specified fastening torque, tightening sequence or bonding procedure.
  3. Verify joint-height differences against the agreed alignment requirements.

• Startup & Operation

  1. Check the wire or felt path, speed, tension, vacuum zones, pressure difference, lubrication, water supply and drainage.
  2. Confirm fabric tracking and contact at the specified low-speed stage before increasing speed.
  3. Record settings, fabric tension, drive loads, operating hours, paper grades and baseline observations.

• Handling & Storage

  1. Protect edges and faces. Separate parts and provide horizontal, padded support suited to their length.
  2. Store clean and dry, keeping segment labels linked to the drawing and installation position.

• Cleaning

  1. Use equipment-approved cleaning media, concentration, temperature and contact time, with specified showers and non-metallic tools.
  2. Inspect working faces, openings and edges after cleaning.

• Maintenance & Replacement

  Inspect wear, profile changes, cracks, chips, joints, fasteners and backing condition.
  Compare findings with the agreed acceptance limits. Record replacement locations and causes.

FAQ – Silicon Nitride Dewatering Element

1. Q1: What are the common failure modes for Si₃N₄ dewatering elements?
   Common issues include contact-face wear, height loss, profile changes and leading-edge chipping. Impact, fabric-edge flutter or insufficient section thickness can cause edge damage. Thermal shock and weakened bonds may cause cracking or loosening. Periodic profile measurements help detect uneven wear that visual inspection alone may miss.
2. Q2: Where are silicon nitride dewatering elements used?
   They are used on forming boards, hydrofoils, low- and high-vacuum boxes, Uhle felt suction boxes and transfer positions. They support forming fabrics or press felts while controlling water removal in paper, board and tissue machines.
3. Q3: Why choose Si₃N₄ over alumina or plastic covers?
   Si₃N₄ is considered where edge toughness, impact resistance and wear resistance are important, particularly at demanding positions or with abrasive furnish. Alumina and plastic covers remain options within their operating limits. Selection depends on machine position, fabric type and stock conditions.
4. Q4: What surface finish should be specified?
   Finish depends on fabric type, machine speed, vacuum level and contact position. ADCERAX supplies ground contact surfaces, with optional fine polishing for demanding positions. Define roughness and texture direction on the drawing.
5. Q5: What information is needed for a quotation?
   For an initial inquiry, provide the machine position, drawing or photographs with dimensions, and quantity. Detailed review covers element dimensions, profile, openings, mounting, fabric specification, speed, vacuum, stock type and cleaning conditions.
6. Q6: How should a worn element be described without a complete drawing?
   Mark worn areas and intact reference faces on photographs or a sketch. Separate measured wear from the intended geometry. For individual replacement segments, show their position, orientation, neighbouring joints, working-face level and locating features.