How Meixin Forming Fabric & Press Felt Cleaning System Boosts Paper Machine Performance

Main Topics：

1. Hidden production losses from forming fabric, press felt and vacuum-roll contamination

2. Warning signs indicating need for fabric cleaning system

3. Working principle of PF·Clean cleaning system

4. Selecting proper cleaning solution matched with paper-machine operating conditions

5. Key points for cleaning equipment supplier evaluation

6. Conclusion

7. FAQ

1. Hidden Production Losses from Forming Fabric, Press Felt and Vacuum-roll Contamination

Many paper mills focus heavily on pulp preparation and dryer-section equipment, yet tend to overlook progressive fouling of wet-end forming fabrics, press felts and vacuum rolls. Fabric clogging builds up gradually. By the time operators notice uneven cross-direction moisture, streaking, frequent sheet breaks or limited machine speed, severe contamination has already occurred. During production, forming fabrics, press felts and vacuum rolls continuously trap fine fibers, fillers, stickies and other deposits. Pores of fabrics, felts and vacuum-roll holes become progressively blocked and trigger a chain of operational issues.

Deteriorated dewatering performance

Pore blockage directly impairs dewatering efficiency. To maintain target sheet moisture, mills are often forced to lower operating speed or increase press load, resulting in direct capacity loss. Fouled vacuum-roll holes weaken vacuum draw-off and further degrade press-section dewatering.

Paper quality defects

Partial nozzle blockage creates cleaning streaks. Local fabric fouling causes cross-machine moisture variation, water marks and spots on paper sheets. For grades with strict surface requirements, finished reels may be downgraded.

Unstable paper-machine operation

Dirty fabrics raise sheet-break frequency and trigger unplanned downtime. Deposit build-up on vacuum rolls disrupts dynamic balance, accelerates mechanical wear and shortens vacuum-roll service life.

Higher consumption of water, power and chemicals

Conventional cleaning consumes large water volume. Severe fouling may prompt higher dosage of chemical cleaning agents, increasing chemical cost and burdening white-water systems. Frequent shutdowns for manual fabric cleaning also cut effective production time.

2. Warning Signs Indicating Need for Fabric Cleaning System

Some fouling can be visually observed, while more problems are reflected in production data.

Evaluation for dedicated cleaning equipment is recommended when multiple symptoms below appear:

1. Deteriorated dewatering performance under stable paper grade and output; machine speed must be reduced to maintain target sheet moisture.

2. Severe cross-direction moisture variation, recurring cleaning streaks or surface spots on paper.

3. Visible deposits on forming fabric, press felt or vacuum-roll holes.

4. Higher sheet-break frequency in wet section.

5. Excessive water consumption during routine cleaning; frequent shutdowns for manual fabric washing.

6. Service life of fabrics and vacuum rolls obviously shorter than design expectation.

Offline cleaning during scheduled shutdowns can temporarily restore fabric performance, yet it occupies production time and cannot stop re-fouling during operation. The PF·Clean cleaning system maintains fabric and vacuum-roll cleanliness during production and reduces shutdown-based cleaning frequency. It suits high-speed paper machines, lines with high recycled-fiber content and production lines with limited maintenance windows. Most mills adopt combined strategies: continuous in-production maintenance by cleaning systems plus deep offline cleaning during major overhauls.

3. Working Principle of PF·Clean Cleaning System

PF·Clean forming fabric and press felt cleaning system consists mainly of high-pressure water cleaning unit, high-pressure pump station, PLC intelligent control unit and high-performance filter unit. Process water firstly passes through high-performance filters for impurity removal, then is pressurized by high-pressure pump station to generate high-pressure cleaning water. The cleaning unit is fitted with high-efficiency cleaning heads that traverse reciprocally across the machine width. Travel motion is controlled by PLC, and operating parameters are set via touch-screen HMI. High-pressure water jets at a defined angle onto forming fabric, press felt or vacuum-roll surface to strip surface and embedded deposits, keeping fabrics and rolls clean for stable production. Nozzles can be inspected or replaced without halting production, eliminating production stops for nozzle maintenance. For vacuum-roll treatment, the system effectively removes deposits inside roll holes, preserves vacuum draw-off capacity and extends roll service life.

4. Selecting Proper Cleaning Solution Matched with Paper-machine Operating Conditions

Wet-end layouts vary greatly among paper machines; one-size-fits-all equipment rarely works.

Confirm these critical parameters in selection phase:

Paper-machine operating speed

Machine speed determines fabric dwell time in cleaning zone. Higher speed imposes stricter requirements on traverse speed of cleaning heads, jet energy and full-width cleaning uniformity to avoid incomplete cleaning or residual moisture causing sheet defects.

Fabric width

Fabric width defines effective traverse stroke of cleaning beam, structural dimension, quantity of cleaning heads and nozzle layout. Equipment is mostly custom-built according to site measurements.

Paper grade and pulp composition

Contaminants differ significantly between virgin pulp and OCC recycled pulp. Recycled-fiber lines generate heavy stickies and fine-fiber deposits, demanding stronger filtration capacity and higher jet energy. For tissue produced from virgin pulp, residual-water control should be prioritized to prevent sheet defects. For cultural paper, full-width cleaning consistency deserves high attention. Containerboard lines using OCC face heavy fouling load, so filtration performance should be emphasized. For paperboard  production, the system must adapt to spatial constraints of the press section.

On-site water supply conditions

Verify feed-water quality, filtration precision, flow rate and pressure stability. Inlet impurities cause frequent nozzle clogging and degrade cleaning performance.

Available installation space

Wet-section space is often compact. Check frames, walkways and maintenance access for proper layout of cleaning beam, pump station, filter tanks and electrical cabinets, without interfering with existing operation and fabric replacement.

Interface compatibility with original machine

Confirm PLC signal interconnection to realize reliable signal exchange between cleaning system and paper-machine control system.

Key design considerations:

Filtration & nozzles: filtration accuracy, filter-element replacement method and easy nozzle access for maintenance. The capability to service nozzles without shutdown is a major advantage.

Traverse mechanism: smooth reciprocating movement of cleaning heads with controllable speed and reversing position to prevent missed zones or over-cleaning.

Waste-water handling: arrange collection and discharge of cleaning effluent to avoid splashing inside wet-end area.

Note: Working pressure cannot be simply copied from reference cases. Parameters such as water pressure and traverse speed shall be fine-tuned on-site based on fabric material, machine speed and fouling severity.

5. Key Points for Cleaning-equipment Supplier Evaluation

Custom engineering capability

Wet-section layouts differ widely. Standard off-the-shelf hardware seldom fits perfectly. Suppliers shall provide site survey, CAD layout design, interference checking and customized mechanical design adapted to existing paper-machine structures.

Process know-how for papermaking

Suppliers need solid understanding of fabric / vacuum-roll fouling characteristics and wet-end operating conditions. Avoid situations where hardware is mechanically sound yet cleaning performance fails production requirements.

On-site installation & commissioning competence

Final cleaning results heavily rely on field tuning including water pressure, traverse parameters, jet angle and cleaning cycle. Rich commissioning experience is essential for stable long-term operation.

Convenient long-term maintenance

Evaluate replacement complexity for wearing parts: filter elements, nozzles, seals and pump components. Maintenance work shall not disrupt paper-machine production. Suppliers should supply spare parts and timely technical support.

6. Conclusion

Fouling of forming fabrics, press felts and vacuum rolls is easily overlooked, yet gradually impairs dewatering efficiency, paper quality, sheet-break rate and service life of fabrics & rolls. Equipped with filtration, high-pressure jet and PLC-driven reciprocating mechanism, PF·Clean cleaning system continuously removes deposits during production. It preserves performance of fabrics and vacuum rolls, cuts water consumption and reduces chemical-agent dosage to improve overall paper-machine efficiency. This is not universal standard equipment. Before project execution, comprehensively evaluate machine speed, fabric width, paper grade & pulp, water-supply condition and installation space. Satisfactory performance comes from well-tailored design plus professional on-site commissioning. When planning retrofits, provide paper-machine drawings, operating speed, paper grades and photos of current fabric / vacuum-roll conditions to help suppliers deliver targeted proposals.

A: Installation normally takes place within scheduled shutdown windows. After commissioning, cleaning can run during production. No production halt is needed for nozzle inspection and replacement.

Q: Can this system reduce chemical cleaning agent consumption?

A: Yes. Physical high-pressure cleaning can lower or eliminate chemical-agent usage. For stubborn deposits, chemicals may be applied as auxiliary treatment after compatibility verification with fabrics and white-water systems.

Q: Can one system handle multiple paper grades?

A: Within the designed operating envelope, parameters including pressure, traverse speed and cleaning cycle can be adjusted for different grades. If machine speed or fouling load exceeds design limits, hardware modification instead of parameter tuning will be necessary.

Q: Will high-pressure jet damage forming fabrics or press felts?

A: Fabrics will not be damaged if jet pressure, nozzle distance and spray angle are properly matched to fabric material. Pressure settings must be validated on-site against real-world operating conditions.

Q: How to evaluate actual cleaning effectiveness?

A: Assess dewatering performance, sheet-break frequency, cross-direction moisture, paper defect rate, service life of fabrics and vacuum rolls, plus visual observation of discharged contaminants. Combine multiple indicators for comprehensive judgment.

Q: What are the key routine-maintenance items?

A: Monitor filter differential pressure and replace filter elements periodically; inspect nozzle wear and clogging; maintain high-pressure pump seals; check traverse-mechanism performance. Include these items in regular paper-machine maintenance schedules.