Oy Tampella Ab

Matti I Aario

Pekka O Haikkala

Raimo Pessa

Ari A Maijala

Eero Hanhilahti

A blocking slab for a pulp grinder, which blocking slab comprises a striplike frame to be mounted between a wall of a grinding chamber in the grinder and a grindstone, said frame being parallel to the axle of the grindstone. In order to prevent splinters and chips from getting out of the grinding chamber, the frame is provided with a longitudinal retaining edge facing to the peripherical surface of the grindstone. The retaining edge has at least one longitudinal recess, which is limited by two longitudinal retaining ribs, to prevent splinters and chips from getting out of the gap between the grindstone and the blocking slab.

Blocking slab for pulp grinder

A method of improving the utilization of the heat energy produced in a wood grinding process when wood is ground in a grinding space (3) under a pressure exceeding atmospheric pressure, and warm shower water (G) is sprayed into the grinding space. Steam (H) is separated from the groundwood pulp (A) discharged from the grinding space in a steam separator wherein the groundwood pulp is allowed to expand from its inlet pressure to atmospheric pressure in at least two steam separators (11,14) by releasing steam from the groundwood pump in each steam separator by decreasing the pulp pressure. The amount of steam (H1,H2) released in the separate steam separators is adjusted according to the proportions in which steam is needed for utilizations purposes. Thus the heat energy of the pressure grinding process can be recovered in separate steam fractions the amount and pressure of which correspond to the requirements of the utilization purposes. It is preferable to heat the shower water by steam of such a volume and pressure that the temperature of the shower water increases to a desired degree, preferably above 100.degree. C.

Method of improving the utilization of the heat energy produced in a

A sealing arrangement for a shutter for a feeding chamber of a continuously operating pressure grinder. The feeding chamber is provided with an inlet opening for feeding wood batches at atmospheric pressure into said feeding chamber and with an outlet opening for feeding said wood batches into the grinding chamber at overpressure. Each opening of said feeding chamber is provided with a shutter movable between an opened position and a closed position for preventing of escape of said overpressure through said feeding chamber. The feeding chamber is provided with a fixed guide supporting the shutter during its movement between opened and closed positions. Said guide comprises two parallel support surfaces between which the shutter is slidably mounted. The distance between said support surfaces is greater than the thickness of the shutter adjacent said support surfaces so that the shutter is displaceable towards and away from said support surfaces in a direction perpendicular to said support surfaces. A sealing element is provided in one of said support surfaces in such a way that, when the shutter is displaced away from said one support surface towards the other support surface, the shutter is released from contact with said sealing element. In this way the shutter is due to the pressure difference between opposite sides of the shutter pressed against said one support surface and against said sealing element but is released from contact with said support surface and said sealing element when the pressures are equilized on opposite sides of the shutter and can be moved to open and closed positions without said contact.

Sealing arrangement for a shutter of a pressure grinder

A classifying apparatus for a suspension, especially for a pulp suspension, having a screen drum, means for feeding the suspension to one side of the screen drum, for removing thickened suspension from the same side of the screen drum and liquid from the opposite side of the screen drum, blades inclined in relation to their direction of rotation so that any one of the ends of the inclined blades is substantially on the same screen drum line parallel to the screen drum axis as the opposite end of some other blade and fitted to sweep at least one surface of the screen drum, and driving means for moving the blades in relation to the screen drum.

Growing community of inventors

Pirkkala, Finland

Matti I Aario