Do You Know The Application of Paper Machine Doctor Blade ?

The doctor blade is normal device for paper machine, can be divided into two type. The one is cleaning blade for cleaning the rolls and cylinders (such as forming section rolls, press section rolls, dryer cylinder, calender roll, reel), another one is functional blade such as coating blade and creping blade.

Working Principle of Doctor Blade on Paper Machine

The doctor blade remove contaminants and water from the roll and dryer surface by maintaining the blade in a fixed position and swinging back and forth under the same pressure, such as swinging on a smooth press roll to remove debris caused by paper breakage. When used for roll cleaning and in conjunction with a spray system, doctor blade is an effective tool for maintaining fabric cleanliness, as most of the machine surface contaminants transfer from the fabric to the smooth rollers. Scrapers are commonly used to remove these pollutants in order to prevent their accumulation and re contamination or damage to fabrics.

Doctor Blade Holder

The doctor blade holder is a part that keeps the blade in its operating position. The blade holder must have a suitable design to allow the blade to be easily and quickly inserted and moved, and to fix the blade in place. There are many types of blade holder, two of which are commonly used. One type is a rigid blade holder, which cannot automatically adjust when the contact surface changes after being fixed. The second type is a flexible or self-adjusting blade holder. When the position of the scraper seat changes or the pressure changes, this structure can be automatically adjusted. The trachea is filled with hydraulic or compressed air. The trachea provides sufficient flexibility to accommodate connections; The surface changes upon contact.

Material Requirement of Doctor Blade

The material of the doctor blade must match the surface material of the roll, and the friction coefficient between the blade material and the roller surface material is usually between 0.15 and 0.30. The actual line pressure of FRDC scraper is usually 90-220N/m, and its friction coefficient depends on the blade material; The installation angle of the blade relative to the roller must be correct, generally between 15-30 degrees. The installation angle of the blade in different parts of the paper machine should be adjusted appropriately according to the different paper types and design needs produced by the user.

The doctor blade must be in close contact with the surface of the roll. To ensure good and tight contact between the scraper blade and the surface of the roller banner, the straightness requirement of the scraper blade is generally between 0.1~0.3mm to ensure relative consistency with the straightness requirement of the roller.