Used to strip the bark from logs, the debarker is among the most robust pieces of machinery operating within the Pulp and Paper industry, facilitating high volume processing at an early stage within the paper making process. The debarking process handles several logs at any one time, combining:

• A wet drum phase – where the logs enter a cycle with water, designed to loosen and soften the surrounding bark.
• A dry drum cycle – exfoliates the bark, separating the materials for further treatment.

Altogether, this method creates an incredibly abrasive environment, progressively wearing the machine’s components.

Severe wear and abrasion

A Polish paper mill, operated by Stora Enso, was suffering from this exact problem, as the hardened steel protection plates were wearing away at a rate of 2-3mm per year. Each log averaged 170kg in weight, impressing significant static and dynamic stresses and severely abrading the equipment. Stora Enso required a solution to prolong the life of the equipment. However, if the problem was not resolved during the planned maintenance period, then the customer was risking a stoppage to the plant and costly downtime.

Dealing with the debarker dilemma

As an existing customer, the mill contacted Belzona’s Polish Distributor, Belse Sp, for further advice on the situation. Having completed a range of applications for the mill previously, they specified an abrasion resistant solution which, crucially, could be cold-applied within the designated maintenance period.

Belse had carried out an identical application for a debarker the previous year. This had been a big success, particularly in terms of the longevity within a severely abrasive environment. Therefore, the mill chose the Belzona solution to complete the repairs and lining of the debarker.

Applying the Protection

Upon selection, eight technicians performed the application over the course of six days. This included full surface preparation of both the wet and dry drum by grit blasting. Initially, the steel drums were coated using Belzona 1321 (Ceramic S-Metal), a ceramic filled epoxy coating, designed to combat highly erosive environments. As a final measure, they installed a protective barrier of Belzona 1811 (Ceramic Carbide). Incorporating abrasion resistant ceramic aggregates, this system was chosen to provide the debarker with long-term wear and abrasion resistant characteristics, alleviating the issues currently faced by the debarker.

The sheer size of the application required large product quantities, including 5000kg of Belzona 1811 and 360kg of Belzona 1321. Due to the scale of the debarker, which measured 10m in length and 3.9m in diameter, the paper mill was impressed that the application was completed within the designated timeframe so quickly and effectively. Moreover, the customer was pleased to hear how other debarker applications, carried out by Belse, had fared since their installation. This further reinforced the long-term, cost-effective nature of the project versus traditional repairs or replacement.

Solid outcome

Pleased with the result, Stora Enso commented

“The application on the dry and wet sections of the debarker was good quality and completed on time. We recommend the company Belse as a solid company, and Belzona technology as a high quality and durable solution”

Such a big application serves to indicate the potential in other paper mills, as well as throughout the pulp and paper industry. This solution is suitable for many kinds of wood processing, paper or pulp plants, that have a debarker drum suffering from a similar amount of abrasion and wear.