Do You Know How to Clean The Press Felt ?

Mechanical Cleaning of Paper Making Felt

The process of using paper-making felts on machines involves a continuous buildup of dirt.

Through experience, it has been found that felts removed from the machine due to heavy dirt can only be cleaned to remove about half of their dirt, even with thorough washing. Therefore, washing the felt as soon as it becomes dirty is the most effective way to clean it. Continuous mechanical washing is a highly effective method for this purpose.

The main mechanical cleaning equipment includes: standard low-pressure water spray pipes, felt washing tanks, felt beaters, squeeze rollers, high-pressure movable water spray pipes, low-pressure fan-type water spray pipes, and vacuum suction boxes.

High Pressure Spray Pipe

The high-pressure movable water spray pipe has several nozzles along its main pipe, allowing it to move horizontally across the felt.

These high-pressure spray pipes are generally installed before the low-pressure fan-type spray pipes. Their main functions are:

1. Using the high-pressure force of water to break up fine fibers, fillers, and attached dirt on the surface of the felt, loosening the dirt within the felt structure for easier removal in later steps.

2. As the pressurized water passes through the felt, the fiber layer regains its loose structure and elasticity, maintaining the felt's ability to hold water and restoring its permeability to some extent.

Low Pressure Fan Type Spray Pipe

The low-pressure fan-type spray pipe, high-pressure movable water nozzle, and vacuum suction box are the three major tools used in washing paper felts.

None of these can be omitted in the actual washing process.

The functions of low-pressure fan-type spray pipes are:

1.To further wash away the dirt that has been loosened by the high-pressure water, allowing it to be carried away in the dilution water, which helps it be absorbed by the vacuum suction box.

2.To form a uniform water film on the surface of the felt, providing lubrication between the felt and the vacuum suction box panel, thus reducing wear.

3.To create a sealing effect on the surface of the vacuum suction box, resulting in a stable and strong vacuum, which effectively removes moisture from the felt.

Vacuum Suction Box

Depending on the role played by the vacuum suction box on paper machines, they are typically divided into two types.

One type is used to remove moisture from wet paper sheets, and is usually located before the felt enters the pressing zone of the mesh and press sections. This is commonly called a dehydration vacuum box. The other type is specifically used for washing paper felts and is located in the return section of the pressure zone felt. It is commonly known as a washing vacuum box, or vacuum washing box.