The paper machine doctor blade system is generally composed of a doctor blade seat, a doctor blade holder, a pressurizing/lifting device, a swing device, and a doctor blade. It also includes accessories such as bearings and journals.
The core component is the pneumatic thumb, which is connected with the scraper body through a rotating shaft. The doctor blade is inserted in the middle of the pneumatic thumb knife magazine. The pressure of the doctor blade is completed by pressurizing and depressurizing two pneumatic tires. The doctor blade body is used to fix the pneumatic thumb. Must have sufficient rigidity and straightness. In order to better protect the roller surface, the doctor blade needs to swing back and forth at a constant speed. Depending on the use environment, the swing device has two options: pneumatic and electric.
The hardness of the doctor blade holder must be calculated, designed and produced very strictly. This structure requires that the doctor blade holder and the doctor blade be supported in the proper position. The doctor blade holder used in the wet part must be plated with high-quality stainless steel or directly made of stainless steel to prevent corrosion For the doctor blade seat used in the dryer section, the painted carbon steel structure is sufficient.
At the same time, it is also necessary to design the cross section of the doctor blade seat according to different paper machine widths. For a complicated triangle or four-corner section welding, any angle must ensure that the overall deviation is not greater than 12mm. The doctor blade holder also includes different structures depending on the use position. For example, the doctor blade used in the steering roll and part of the press roll, the shovel, the white water collection tray and the pipe are also the main components.
The doctor blade holder is the part that keeps the doctor blade in its operating position. The doctoe blade holder must have an appropriate design so that the blade can be inserted and moved quickly and easily, and the doctor blade can be fixed in place. There are many series of doctor blade holders, two of which are commonly used.
One is the metal holder. After being fixed, it cannot be adjusted automatically when the contact surface changes.
The second type is a flexible or self-adjusting holder. This structure can be automatically adjusted when the position of the doctor balde seat changes or the pressure changes. The air pipe is filled with hydraulic pressure or compressed air. The trachea provides sufficient flexibility to change according to the contact surface.