Metso Paper Inc.

Valmet Automation

Haarla Oy

Jouko Niinimäki

Tero Jussila

Pekka Jakkula

Rauli Virkkala

Mika Körkkö

Urpo Kasurinen

Markku Rislakki

Johannes Haarla

Terhi Suopajärvi

Sakari Paunila

Ari Ämmälä

A method and an arrangement for treating stock formed of recycled fiber. The method comprises treating the stock in screen means and a flotation cell means, and screening the stock into accept and reject. Reject from the screening is directed to a mechanical dispergator and a dispersed reject is formed of it.

Method and arrangement

The invention relates to a method of controlling quality of pulp. Pulp formed in mechanical defibering of wood is screened into at least two fractions, the accept that has passed the screening phase being forwarded for further use and the reject that did not pass the screening being removed from the screening phase. The invention comprises determining flow amount and consistency of the pulp supplied to the screening phase and, correspondingly, of the reject removed therefrom, and calculating a passage ratio of the reject and the supplied pulp by means of the flow amounts and consistency values verified through the measurement, and adjusting the screening phase according to said passage ratio.

Method for controlling screening by measuring flow amount consistency of the pulp

A method for controlling the quality of pulp. Pulp produced by mechanical defibering of wood is screened to provide at least two fractions, of which the accept that has passed the screening phase is carried forward for use and the reject that has not passed the screening is removed from the screening phase. The consistency of the reject that is to be removed from the screening is measured and the consistency value thus obtained is used for controlling the defibrator to adjust the quality of the accept.

Method for controlling quality of pulp

The invention relates to a method for measuring gas content in a fluid, such as papermaking pulp or coating paste, and to a gas content measuring device. Pressure variations generated by a pump, for instance, are to occur in the fluid. Travel time, phase and/or attenuation of the microwave signal (20) are measured with the gas content measuring device while the signal (20) penetrates through the fluid (13), and the gas content is determined on the basis of changes in travel time, phase and/or attenuation of the microwave signal (20) caused by pressure variations of the fluid (13).

Method for measuring gas content and a gas content measuring device

Growing community of inventors

Oulu, Finland

Jouko Niinimäki