REMOVAL OF ENTRAINED AIR FROM WHITE WATER BY APPLICATION OF CENTRIFUGAL FORCE

Air must be removed from the fibre suspension in the paper machine to avoid problems such as pinholes, foam spots, drainage impairment and p ressure pulses. A new type of centrifugal pump, called a pomp, has bee n designed for this purpose. The pomp functions by centrifuging air ou t of the fibre suspension. It is quite possible that the wire pit coul d be replaced with pomps. One of the main functions of the wire pit is to remove entrained air from the white water. The pomp fulfils this r equirement. At the same time the amount of white water in the short ci rculation is reduced, resulting in faster process dynamics. The wet en d response to the changes in stock composition and process parameters is improved, allowing greater control of production and product qualit y. This study explains the working principle of the pomp. Mill trials show that the pomp removes practically all entrained air from the fibr e suspension.