Doctor Blades For Paper Machines

Doctor blades for paper machines divide into press doctor and dryer doctor, although this component is small relative to the entire paper machine, it has an important effect on the quality of the paper. So do you know the function of doctor in every section? And how to maintain the doctor blades to extend his life?

The doctor blades is mainly composed of six parts, including frame, doctor fixture, doctor, pressure relief device, bearing and swing device.

1.  Frame

The deflection of the frame should be less than 0.01mm, the maximum length of the maximum allowable deflection of 2.5mm. The total deviation of the combined frame should not be greater than 0.13mm.

2. Doctor fixture

The fixture should be adjustable, sufficient rigidity and self-sealing. The fixture should be able to meet the requirements for quick and easy loading and removal of the blade

3. Doctor

a: The material of the blade must match the material of the roller surface.

b: The mounting angle of the blade relative to the drum must be correct.

c: The blade must be in close contact with the drum surface.

Doctor blades wear and cause analysis

phenomenon	Reason	Approach	Remarks
Uneven wear	Roll uneven The fixture is damaged Fouling	Use a softer doctor Clean the fixture Use a wear doctor
Middle or end wear serious	Doctor do not match the roll Long-term use cause doctor over-contact or virtual contact	Reload and use the gasket to adjust the relationship between the fixture and the doctor holder Replace the new doctor
Was zigzag	Fouling on the roll Doctor pressure is too large Material excellent	Use a wear doctor relieve pressure Use a softer doctor