Metso saves energy and improves safety

As a result of problems with fires caused by dust on the head of the yankee on tissue machine TM1, Metsä's tissue plant in Tento Zilina turned to Metso for help. The fires were difficult to handle due to the confined space and made it a major safety issue. An installation of a tailor made yankee head metal covering from Metso solved the problem as well as reduced the steam consumption significantly.

The main reason for the installation, according to deputy head Peter Simo, was to reduce problems with fires. "We had problems with potential of fires on yankee shell caused by dust accumulation on the surface of the heads. Burning pieces of dust collection threatened to release during rotation of yankee which could start fires close to the machine environment. We quenched the fires with hot water, but this still made stress for yankee and was also raising danger against the employees. So, we had to prevent this issue," Simo tells.

Rising costs and saving of energy are big issues in Metsä Tissue. "I suppose it's like that in every mill, so we found out a "two in one" solution. We decided to install yankee head covering from Metso". Metso's installation of a compact metal covering prevents steam from leaking out as well as dust from coming in to the hot yankee head. The technique solves both the energy problem and eliminates the risk for fires. "The installation was done during the annual shutdown, in September 2008, as the work takes three days with 12 working hours per day. The work was performed by three persons from Metso and went on without any problems, thanks to good advanced preparations and communication before the installation".

"Two months after the installation of the yankee head covering we have not had any fire accident on yankee heads." And concerning energy...?

"If we compare steam consumption, with the most similar condition on machine, before and after installation of covering plates; in our case the reduction in steam consumption exceeded 6% or 70 kWh/ton produced tissue paper". Peter Simo reveals

Metso's yankee head covering design consists of plates attached to the head which can easily be removed for inspection and with one covered opening for easy access to the manhole cover. The material used is of high quality for maximum performance and minimum deterioration due to ageing and facilitates long-term use with minimum maintenance. Thanks to a Metso-designed mobile tool the shutdown time for the installation of the yankee head covering has been reduced to three days.