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How to Clean Forming Fabrics

Released on Oct. 10, 2022

In recent decades, the paper industry has made great progress, and the speed and width of paper machines have been continuously improved, thus greatly enhancing the production capacity. However, high speed puts forward higher requirements on the design of paper machines, especially the requirements for composite forming fabrics become more stringent.

In the paper machine clothing, the forming fabric plays the role of dewatering the pulp and forming the paper sheet. The cleanliness of the forming fabric is critical to the running state of the paper machine and the quality of the paper produced, and it is also important to maximize the life of the forming fabric.

How to Clean Forming Fabrics

Contaminated forming fabric

Cleaning concept for forming fabrics

Over time, contamination build-up on your forming fabrics can have drastic effects on runnability.

Removing all impurities before the pulp enters the headbox is the best option, but it is difficult to achieve this, so the efficient cleaning of forming fabrics by various cleaning methods is very important in the papermaking process system.

Currently, the two most effective cleaning methods for forming fabrics are:

  1. Oscillating high pressure water jet cleaning

  2. Chemical cleaning: acid cleaning agent, alkaline cleaning agent

Oscillating high pressure water jet cleaning

The oscillating high pressure water jet cleaning is the best and most widely used method of cleaning forming fabrics.

Recommended installation location

  • Best for guide rollers

  • Do not install on the tension roller

  • Single or composite layer forming wire installed on the opposite side (wear side) of the forming wire

  • Double or triple mesh installed on the front side of the forming wire (paper side)

Recommended technical parameters

  • Nozzle size [Ø]: 0.7-1.2mm, 1mm is best. Conversely, with larger diameter nozzles, water consumption will increase without a noticeable improvement in cleaning.

  • Nozzle Spacing: 200mm stroke for 66, 100 and 200mm spacing; 300mm stroke for 75, 150 and 300mm spacing.

  • Spacing between nozzle and forming fabric: 100-300mm for best cleaning effect.

  • Washing water pressure: suitable water pressure is 20 to 30 bar, more than 30bar may damage the forming fabric.

  • Angled at 0 – 20° with the run of the forming fabric. Angling the shower against the fabric run direction generates the highest impact energy for cleaning, but also increases misting.

How to Clean Forming Fabrics

Angled at 0 – 20° with the run of the forming fabric

How to Clean Forming Fabrics

Damaged by High Pressure Showers

Oscillation speed calculation

R = (MS / L) x D 


R = oscillation rate (mm/min) 

S = fabric speed (m/min) 

L = fabric length (m) 

D = diameter of jet contacting the fabric (mm), about twice the diameter of the nozzle.

Chemical cleaning

Forming fabrics are primarily made of polyester monofilaments, which are susceptible to contaminants such as asphalt and tar. Recycled paper can also contain latex, making the situation worse. In this case, chemical and mechanical cleaning can be used simultaneously.

Requirements for cleaning agents:

  • Fast response time

  • No corrosive effect on polyester and polyamide materials

  • Easy and safe to use

  • Environmentally friendly

Common types of cleaning agents and their efficacy

  • Alkaline cleaner for removing organic contaminants such as resins, rosin, organic esters, etc.

  • Alkaline solvent mixture that reacts faster than pure caustic products

  • Acid cleaner for removing inorganic contaminants such as calcium carbonate, chalk, etc.

  • Acidic solvent mixture with dual action to remove organic and inorganic deposits

  • Neutral cleaning agent, the cleaning effect is relatively limited

Chemical Cleaning Operations

  • Shower with 1.5mm holes at a distance of 5 mm

  • The jet has to be orianted against an inside return roll which will distrubute the jet all over the fabric

  • Machine speed at its minimum

  • All showers closed

The Risk of the Chemical Cleaning

  • Fabrics containing PA Yarns are damaged by strong acid cleaning

  • PES Yarns are damaged by strong alkaline cleaning

How to Clean Forming Fabrics

Polyamide yarns are damaged acid improper cleaning

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