Double Doctor

A multi-doctoring system designed to upgrade single doctors on today's machines - improves productivity and performance.

Features/Benefits

Integrated design
Integrated shower for enhanced cleaning
Custom designed for each installation.
Enhanced roll cleaning
Reduced picking
Eliminates holes
Enhanced product quality
Improved machine efficiency

Double Doctor Development - The Need

Doctors themselves were developed to answer a number of papermaking needs. Some peel the sheet from the roll at startup or after a break; others clean rolls, redirect the sheet, direct the flow of water, regulate coatings, perform creping functions, or condition rolls. In many applications, a vacuum is created between the circumference of the roll and the under-side of the doctor blade. This causes fiber and fillers to be pulled to the underside of the blade, accumulate and break away causing holes in the sheet and sheet breaks. In this situation, it would help to provide more than one doctoring function on a single roll. However, on most of today's paper machines, there is simply not enough space to mount two separate doctor assemblies.

Double Doctor Development - The Engineered Solution

As far back as 1978, Kadant Web Systems developed double doctoring techniques in response to specific needs of papermakers. However, it took today's advancements in computerized design technology to open the door to new levels of space efficiency and utilization. Our systems engineering now allows us to integrate not only two doctors, but a shower assembly as well, into a compact, structurally superior unit — a unit capable of being mounted within the severe space restrictions of contemporary paper machines. There are two reasons why Kadant Web Systems is at the forefront of double doctoring technology:

Over sixty years experience dealing with conventional holders and assemblies assures doctoring systems engineered for:

Ease of blade change
Ease of maintenance
Corrosion-proof cladding
Our advanced, computerized design capabilities allowed us to develop a system that achieved optimum strength and rigidity within unique space restrictions.

Double Doctor Operational Efficiency

Cleaner rolls
Improved roll life
Fewer sheet breaks
Better quality sheet
Longer blade life

An additional benefit is the ability to use a conditioning blade in the second position, which will condition rolls without sacrificing doctoring capabilities.

Double Doctoring Using an Equalizer Doctor

Placing an Equalizer Doctor in the first blade position will provide for angle-changing capabilities when there is a change in the roll diameter or roll material—all done without relocating the second blade. A conventional double doctor will not allow for an angle change without the relocation of the second blade. The Equalizer Doctor changes angles using a pivot point closer to the roll, causing the doctor back to rotate slightly. The second blade stays in contact with the roll during this angle change.