Abstract: The strainer arrangement is adapted for straining a liquid from a mixing arrangement, such as a mixing tank, containing black liquor including solid particles of ash. The strainer arrangement comprises a strainer pipe with axial gaps defined therein for permitting a radial inflow of liquid into the strainer pipe. An axially movable shaft is disposed inside the strainer pipe and has cleaning pins attached thereto that extend into the gaps.

Abstract: The invention relates to a device for dissolving smelt chemicals from recovery boilers, a so-called soda smelt dissolver, and to a process for such dissolution using the device. The device is characterized in that it consists of at least two separate dissolving tanks (I, II), which are connected to each other near the bottom, via a connecting pipe (3), to allow free flow of liquid between them, and of devices for the separate supply to each tank of dissolving liquid and smelt chemicals in dependence on the measured and established chemical concentration in the solution in each of the tanks (I, II), wherein the outlets from the tanks (I, II) can be separately shut off and regulated. The process according to the invention involves using the device and switching over the functions of the different tanks.

Abstract: A recovery boiler for combusting spent liquor from cellulose cooking while at the same time recovering chemicals. The recovery boiler is constructed for so-called "rotafire" combustion and the speed of rotation of the secondary air has been increased by a constriction of the boiler being arranged at the tertiary air level. The invention also includes a process for using the boiler which is based on certain ports through which the secondary air is blown in being provided with air which is at a higher pressure than that at the other ports on the same level, thereby achieving a higher inflow velocity than from the other ports.