How High-Pressure Water Systems Solve BOM Press Felt Clogging

During the operation of paper machine, the performance of the press felt directly affects dewatering efficiency and paper quality.

Based on long-term observations of paper mill operations by Sun Hong engineers, approximately 95% of the reasons for removing press felts from the machine are related to pore blockage. Mechanical factors, such as wear, account for only 5%. This phenomenon is particularly pronounced with BOM press felts.

As the press felt running time increases, fine fibers, fillers, and colloidal substances gradually accumulate within the wire structure, causing a decrease in water permeability and a reduction in dewatering efficiency, which ultimately affects the stable operation of the paper machine.

Why BOM Press Felt Clogging Requires Special Attention

In the structural composition of the base layer of BOM press felts, the warp yarns (MD direction) consist of stranded or twisted monofilaments, while the weft yarns (CD direction) are typically monofilaments.

This design results in a smooth surface and high porosity for the base layer, thereby reducing the risk of fine fibers and contaminants adhering to the base BOM press felt layer.

However, this causes the dirt to accumulate primarily within the batt layer in contact with the paper sheet, particularly when that surface layer incorporates a higher proportion of fine, short fibers.

This not only increases the risk of BOM press felt clogging but also raises the likelihood of paper disease, as fine fibers and contaminants tend to accumulate on the felt surface.

Therefore, learning how to clean BOM felts is crucial for improving your production line’s efficiency and reducing downtime costs.

Sun Hoong has previously introduced how to clean the press felt. This time, let’s focus specifically on the cleaning methods for BOM press felt.

How Water Quality Affects BOM Press Felt Cleaning Performance

Water plays an important role in BOM press felt cleaning, its quality is one of the crucial factors affecting the cleaning results.

Effective BOM felt cleaning begins with proper water quality. Water for cleaning should be purified and filtered before use. Even after municipal or plant water treatment, it is recommended that the water pass through a 100-mesh equivalent filter before being supplied to the BOM press felt cleaning system.

This can help prevent fine particles remaining in the water from entering the BOM felt structure, avoid exacerbating pore clogging caused by water, and help reduce cleaning efficiency.

Water Temperature: An Often Overlooked Factor in BOM Felt Cleaning

It is worth noting that hot water is more effective for washing BOM press felt.

When the water temperature is raised from 10°C to 30°C, the viscosity of the dirt on the felt can be reduced by 64%.

Therefore, we recommend using high-pressure water at a temperature above 40°C when washing the BOM press felt.

The Role of High-Pressure Water Systems in BOM Press Felt Cleaning

Installation Location For HPS

Usually, the high-pressure water device(HPS) is installed in front of the low-pressure fan water, and its main functions are as follows

• Be used to dislodge fine fibers, fillers, and adhered dirt from the surface of the BOM press felt, loosening the dirt embedded within the felt’s structure to facilitate its removal in subsequent processing steps.
• When high-pressure water penetrates the BOM press felt, the fiber layers within its structure regain their loft and elasticity, maintaining the blanket’s effective water-holding capacity and restoring its permeability to a certain extent.

Ideal High-Pressure Water Jetting Condition

An ideal high-pressure water jet should exhibit well-defined lateral boundaries, be free of air bubbles, maintain a constant diameter, and make contact with the BOM press felt surface at sufficient pressure.

Recommended Specifications

• Spray nozzle diameter: 0.7–0.9 mm
• Use ruby or sapphire nozzles to improve wear resistance
• Operating pressure: ≤30 bar
• Distance between nozzle and BOM press felt: approx. 10 cm

Oscillation Stroke and Speed Control

The oscillation stroke should be at least equal to the nozzle spacing, with twice the spacing typically being optimal.

Oscillation speed (mm/s) = (Fabric speed [m/min] × Nozzle diameter [mm]) / (Fabric length [m] × 60)

This effectively ensures uniform coverage of the high-pressure water jets across the BOM press felt, preventing localized under-cleaning or excessive impact.