J. M. Voith Gmbh

Voith Paper Patent Gmbh

Voith Sulzer Papiertechnik Patent Gmbh

Voith Sulzer Stoffaufbereitung Gmbh

Peter Schweiss

Hans-Dieter Dorflinger

Reimund Rienecker

Theodor Bahr

Samuel Schabel

Rolf Hartmann

Hans-Otto Henrich

Edgar Muschelknautz

Gerhard Veh

Michael Danger

Joachim Nittke

Rudolf Kleinert

Stefan Rippl

Klaus Dolle

Michael Nolte

Pressurized screen to remove contaminants from a contaminant-containing fibrous paper suspension. Pressurized screen includes a housing, a first screen element, essentially axially symmetric and rotatably mounted within housing, and a second screen element, which is essentially axially symmetric. First and second screen elements are successively arranged in suspension flow direction. At least one intake, coupled to housing, supplies suspension to housing, and at least one accepts outlet, coupled to housing, conveys a part of suspension that passes through the second screen element out of housing. At least one coarse reject outlet is located within housing to remove a part of suspension not passing through first screen element, and at least one fine reject outlet is located within housing to remove a part of suspension not passing through second screen element. First screen element includes conical shape with opening angle (&agr;) between about 10&deg; and 170&deg;.

Pressurized screen and process for removing contaminants from a fibrous paper suspension containing contaminants

Hydrocyclone device including at least one hydrocyclone having at least one feeding connector, at least one accepted stock connector, and at least one rejected stock connector. The device also includes at least one distribution and collection device arranged for feeding fluids into and removing fluids from the at least one hydrocyclone, and at least one flange coupled to at least one of the at least one feeding connnector, the at least one accepted stock connector, and the at least one rejected stock connector, which is removably couplable to the at least one distribution and collection device.

Hydrocyclone device for cleaning a fluid

A screen device including a multitude of parallel rods between which are located the sorting slots. The rods are held in position by supporting elements, which are connected with carriers. The respective cover elements are located at the faces of the rods. Due to their special design, the cover elements may be detachable. The screen devices may be used, for example, in the paper-making industry as cylindrical screen baskets or plane screens.

Screen device with slot-shaped openings

Process for manufacturing a sifting device (or strainer baskets) for use in, e.g., in the paper industry for sorting and/or filtering fiber pulp suspensions. Sorter slits may be created between a plurality of substantially parallel rods inserted into respective insets formed in a support element. The rods may be securely held in place by first inserting the rods into the insets and then by permanently bonding the placement of the rods in the support elements with a bonding agent, e.g., as hard-soldering or brazing.

Process for the manufacture of a sifting device with slit-shaped

The invention is directed to a method of regulating a flotation system having an inflow quantity of suspension flow dependent on production demands, including a primary flotation stage and a secondary flotation stage where the secondary flotation stage treats the froth of the primary stage, transporting de-aereated froth from the primary flotation stage to a collection vessel which is in fluid communication the secondary flotation stage; recycling suspension flow from the secondary flotation cells of the secondary flotation stage in part to an inlet of the primary flotation stage, and in part to an inlet of the secondary flotation stage, and regulating the level of de-aereated froth in the collection vessel by controlling the amount of suspension flow recycled from said secondary flotation stage to the inlet of the secondary flotation stage.

Method of regulating a flotation system with a primary and secondary

A pressure sorter for a suspension flow includes a cylindrical housing having at least one inlet opening and at least one outlet opening with a defined pressure drop therebetween. A rotationally symmetric screen basket defining an axis is disposed within the housing. The screen basket has a plurality of openings defining a total screen perforation passage area. The axis of the screen basket is positioned offset a distance of 6 to 12% of the diameter of the screen basket. The axis of the screen basket is disposed in a plane which extends through the housing axis and is perpendicular to the housing outlet opening. A rotor and suspension sorting space are disposed centrically within the screen basket. An accepts space is disposed radially outward of the screen basket between the screen basket and the housing. The accepts space has a cross section causing a pressure drop between the suspension sorting space and the accepts space resulting in a suspension flow through the screen openings having a maximum velocity of 2.5 m/s, and a deviation to higher suspension flow velocity values from an arithmetic mean value based on the total screen perforation passage area across the entire screen basket circumference amounting to a maximum of 25% of the mean value.

Pressure sorter

The invention concerns a sorter with at least two screen baskets in a housing unit. The invention is characterized in that with screen basket diameters of at least 600 mm the at least two screen baskets are contained side by side, spaced, in an arrangement such that their longitudinal center axes extend parallel to each other and their end sides or end surfaces are contained each in identical planes extending perpendicularly to the longitudinal center axes of the screen baskets.

Fiber suspensions sorter having a plurality of screen baskets

A device for separation of air from fiber suspensions of flotation devices which are heavily air- and foam-laden or represent a mixture of fluid and foam features a hydrocyclone whose inlet opening is arranged least 2.5 m below the outlet opening of the flotation device for the air-laden fluid or mixture. The separation section of the hydrocyclone is a slender, truncated cone-shaped body on whose pointed (thin) end the deaerated fluid is withdrawn. In this outlet opening there is a back pressure maintained, so that the inlet opening is not completely covered by the vortex of the fluid, leaving still a sufficiently free entrance cross section for the foam. Above the entrance section of the hydrocyclone a mechanical foam eliminator with a rotor is arranged, the rotor comprising an impeller wheel which is provided with radial blades. A funnel-shaped suction socket feeds the foam-air mixture to the impeller wheel.

Device for separation of air from flotation slush

A hydrocyclone has a separating part A with a diameter which toward its outlet end for the heavier fraction decreases gradually from a diameter 2 R.sub.a, with the radius being subject to the formula:

Hydrocyclone

The rotor of a sorter has a circumference which, in cross section perpendicular to the rotor axis of rotation, is essentially composed of circular arcs. Depending on sorter size, the number of circular arcs amounts to between two and eight. The eccentricity of the circular arcs relative to their center, based on the rotor axis of rotation, amounts to preferably between 4 and 10 mm. This makes it possible to obtain slight rotor stresses at a good sorting efficacy, preferably also with a mean substance density of more than 3% of fiber suspensions. The difference between the smallest and greatest rotor spacing e=f.sub.max -f.sub.min amounts to maximally 60 mm, preferably 20 mm.

Device for screening fiber suspensions

A defrothing apparatus whose inlet opening of the foamed liquid contained in a foam duct of a primary flotation apparatus is provided in the bottom of the foam duct. Starting from the lower area of the defrothing apparatus, a rotary flow (potential vortex) is generated in the apparatus by a recirculated lqiuid quantity from a secondary flotation apparatus. In the core of the rotary flow the gas quantity (air) is collected and removed through a removal pipe. Consequently, the foamed liquid from the foam duct of the primary flotation stage which is pumped to the secondary flotation stage contains small shares of gas relative to the total quantity of liquid, thereby allowing the pump to be optimally sized of efficiency and better control of the system.

Defrothing method and apparatus

A flotation cell featuring a mixing pipe which enters the suspension essentially vertically, follows the point of air intake, and generally receives the entire suspension quantity per flotation cell, the injector of the flotation cell is offset sideways relative to the vertical center axis of the round container cross-section and away from the side on which the foam removal opening and the liquid drain opening are located. The mixing pipe (1) enters the suspension only for a distance such that its discharge opening, mouth (2), is located at least at one-half the height of the level of the overflow edge (7) of the foam removal channel (8), figured from the container bottom. The liquid drain opening (9) is preferably provided in the immediate vicinity of the container bottom, with a cover plate (11) extending across the length of the flotation cell and forming a drain channel (12) into which proceeds the clean liquid through an upper (14) and a lower (13) slot.

Flotation container or cell

The injector apparatus is of the kind having a constriction which lies, in the flow direction, immediately before a following adjoining mixing section, in which fibrous stock suspension is mixed with air for the purpose of subjecting the suspension to flotation in a flotation tank. The mixing pipe in which the mixing section is disposed has a radial diffusor at its outlet end, and, for a greater flow rate of air, additional air intake bores are disposed therein a short distance in the flow direction after the constriction. A favorable arrangement is achieved if the injector apparatus with the mixing pipe is arranged perpendicularly in a flotation tank, which may have the form of a reclining cylinder. In this case, the froth, like the cleaned suspension, is drawn off on one long side, i.e., a side which extends parallel to the cylinder axis; the extraction opening for the cleaned suspension being provided preferably immediately below the level of the suspension and/or the froth extraction arrangement.

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Langenau, Germany

Peter Schweiss