Oy Tampella Ab

Juhani Ahonen

Pekka O Haikkala

Jouko Hautala

Veli-Matti Rajala

Raimo Pessa

Toivo Lajunen

The invention relates to a method for controlling pressurized screening devices in which fiber pulp is fed to the pressurized screening device and is divided into the accepted portion of the fiber pulp passing through perforations of a cylindrical screenplate and the rejected portion which is removed from the screenplate, the perforated screenplate being treated by a device movable relative thereto and rotatable around the center axis of the screenplate, the fiber pulp being fed parallel with the center axis of the screenplate to baffle blade assembly comprising at least two baffle blades and also being rotatable around the center axis, wherein the speed of rotation of the baffle blade assembly and/or the radial dimension of the baffle blades are adjustable to control the screening. The invention additionally relates to pressurized screening devices for implementing the method.

Method for controlling pressurized screening devices and pressurized

Frame construction for a pressure grinding machine of press type, which frame construction comprises a gastight, pressure-proof grinding chamber, bearing housings for a grinder member revolving in the grinding chamber, as well as at least one press chamber for the pulpwood and a press device limiting the press chamber on one side. The frame construction consists of two separate parts, namely a pressure frame, which constitutes the said grinding chamber and press chamber and which substantially receives the pressure forces resulting from the positive pressure prevailing in the grinding chamber, and a power frame, which connects the press device and the bearing housings of the grindstone to each other and which substantially receives the tensile and circumferential forces resulting from the grinding and from the pressing of the wood against the grindstone.

Frame construction for a pressure grinding machine of press type

A method for feeding a wood batch into a pressure grinder, according to which method the wood batch is first fed into a pressurizable feeding device (9) and thereafter from the feeding device into a continuously pressurized grinding chamber (5) to make contact with a grinding means (3) rotating in the grinding chamber. The wood batch is fed from the feeding device into the grinding chamber essentially in a horizontal plane in the direction of the axis (4) of rotation of the grinding means for maintaining proper order of the wood batch during the feeding operation. In a feeding device for carrying out the method the feeding device (9) is positioned on the side of the grinding chamber (5) so that the bottom (10a) of the feeding pocket (10) formed by the feeding device is essentially in level with the bottom (5a) of the grinding chamber. The feeding device is provided with a pushing means (17) displaceable in the feeding pocket towards the grinding chamber in parallel with the level of the bottom.

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Tampere, Finland

Juhani Ahonen