How to clean an open headbox?

How to clean an open headbox?
The cleaning of an open headbox is crucial as it directly affects the operational efficiency of the paper machine and the quality of the paper. Here are some detailed cleaning steps and precautions:
1、 Preparation work before cleaning
Shutdown preparation:
Before shutting down, it is necessary to ensure that the slurry pump and pressure screen are locked to prevent accidental start-up during the cleaning process.
After shutdown, allow the white water to circulate for a few minutes to flush the dilution circulation system, short circulation system, and headbox, reducing residue.
Protective measures:
Operators should wear protective clothing and equipment, especially when handling chemical cleaning agents.
When removing the float or floating plate from the headbox, protective gloves should be worn to avoid being cut by thin edges.
Tool preparation:
Prepare tools such as scrapers, soft brushes, clean cloths, and appropriate cleaning agents made of wood or plastic. Ensure that these tools do not scratch the inner surface of the headbox.
2、 Cleaning steps
Cleaning surface:
Clean the inner walls, baffles, and lip edges of the headbox with clean water and a soft cloth. Pay special attention not to scratch the surface, especially the leading edge of the baffle and lip.
If there is adhesive or other difficult to remove stains on the inner surface, organic solvents such as kerosene and turpentine can be used, or weak acids (such as dilute acetic acid) can be used for cleaning. But before use, it is necessary to ensure that these solvents do not damage the materials of the headbox.
Clean the pressure balance chamber, tube bundle, and turbulence generator:
Use a cleaning device to clean the pressure balance chamber, tube bundle, and turbulence generator. The pressure of cleaning water should be controlled within an appropriate range (such as 1.2Mpa), and the flow rate should be moderate (such as 5L/s).
During the cleaning process, the spray pipe of the headbox can be closed, but it should be kept running during the shutdown period to ensure the cleaning effect.
Inspection and maintenance:
After cleaning, carefully inspect the components inside the headbox for any damage or wear, and replace or repair them in a timely manner.
Nitric acid passivation treatment is applied to the convection slurry box to improve its corrosion resistance.
3、 Precautions
Avoid scratches:
During the cleaning process, it is essential to use tools and equipment that do not cause scratches to avoid damaging the inner surface of the flow box.
Cleaning agent selection:
Choose a suitable cleaning agent and avoid using chemicals that may damage the headbox material. If using organic solvents or weak acids, it is necessary to first understand their applicability and precautions.
Security protection:
Operators should wear protective equipment to avoid direct contact with chemical cleaning agents or high-temperature components.
Regular inspections:
Regularly inspect and maintain the flow box to ensure it is in good working condition. This helps to extend the service life of the headbox and improve the operational efficiency of the paper machine.
Cleaning records:
Record the time, method, and results of each cleaning for subsequent tracking and analysis of changes in the performance of the headbox.
In summary, the cleaning work of an open headbox requires meticulous attention and adherence to certain steps and precautions. Regular cleaning and maintenance work can ensure the normal operation of the headbox and extend its service life.