Krauss-Maffei Aktiengesellschaft

Gunther Hultsch

Peter Ostermeyer

Franz Alstetter

Helmut Wilkesmann

Peter Niedner

Kurt Zeppenfeld

Harald Bock

Herbert Schiele

Siegfried Baumgartner

Reinhold Schilp

Johannes Feller

Uwe Breuer

Peter Sedlmayer

Erhard Aufderhaar

Paul Franzen

Walter Kisslinger

A nonreturn valve connected to a passage venting a gas-containing part of the filtrate collection chamber is located in a centrifuge drum base is operated as a siphon to increase the pressure differential, thus filtration rate, across the centrifuge filter or alternatively a system of rotatable siphon cups connected to the chamber are provided so that gas collecting in the collection chamber during filtration may be evacuated of the centrifuge. This device can also be used in the discontinuously operating filter centrifuge with a rotating siphon whose housing interior is at the pressure of the surroundings or is acted on with a gas pressure for additional acceleration of the filtration.

Filter centrifuge for separating suspensions with system to release

A centrifuge apparatus and a method of filtration are described. The centrifuge has radial and lateral filtration surfaces and separate discharge chambers for each. The lateral filter is located at an imperforate radial distance from the radial filter. This distance forces the filtration to occur through the radial filter and develop the filter cake rather than pass through the lateral filter which has no developed cake. The use of separate, laterally-disposed withdrawal chambers at different radial heights allows accurate control over the hydraulic filtration forces acting across the filter surfaces.

Centrifuge with two withdrawal chambers

Agitator elements are provided in an apparatus and a process for the transport of heat and material between finely grained solid particles and a flow of carrier gas in a rotating fluid bed in order to prevent settling of coarse particles or agglomerates. The agitator elements are immersed into the fluid bed and move at a velocity different from that of the revolving fluid bed.

Apparatus and process for drying finely grained solid particles

A pocket centrifuge has a plurality of sieve pockets having sieve surfaces and orbitable about an axis with the sieve surfaces forming sieve angles with perpendiculars to planes including this axis. A filtrant is fed radially to these pockets so that solids collect on the surfaces thereof and a filtrate passes through the surfaces. These solids have a friction angle measured to a perpendicular to the centrifugal force acting on them which is dependent on the magnitude of this force and their coefficient of friction. The angular orbiting speed of the pocket is periodically varied between one speed at which the respective friction angle of the solids is smaller than the sieve angle and the solids slide on the sieve surface and another angle at which the respective friction angle of the solids is greater than the sieve angle and the solids sit on the sieve surface. This variation in angular orbiting speed can be obtained by periodically braking or accelerating the rotor carrying the pocket, or by mounting this rotor for rotation about two axes for continuous acceleration and deceleration of the pockets. Alternately the sieve angles can be changed by pivoting the pockets on the rotor to achieve the same effect.

Pocket centrifuge and method of operating same

A method of operating a particle-treating apparatus having a hollow foraminous drum centered on and rotatable about an upright axis comprises the steps of feeding particles into the upper portion of the interior of the drum, rotating the drum about the axis at a speed sufficient to form the particles into an annular body lying on the inner surface of the drum, passing a drying gas radially inward through the drum into the interior thereof and withdrawing the gas axially from the interior to at least partially fluidize the body and dry the particles, and collecting the particles beneath the drum as the body moves off the lower edge thereof. The rate of gas flow through the drum and the rotation rate of the drum are such that the body moves axially down in the interior toward the lower edge of the drum. For a batch of particles the drum rotation speed is low at the start of treatment of the batch but is thereafter increased as the batch forms a continuous such body covering substantially all of the interior of the drum to be relatively high.

Apparatus for drying particles and method of operating the apparatus

A centrifugal filter has a centrifuge drum rotatable about an axis and provided with a plurality of sieve support plates lining the drum. Each of the plates is generally flat and rectangular and has a radially inwardly directed inner face. They are each formed with an array of flow grooves extending on and opening radially inwardly at the inner face and each having an outer end and an inner end spaced along the plate therefrom. The flow grooves are of increasing flow cross section from their outer ends to their inner ends. An outlet serves for draining liquid from the inner ends. A filter medium overlies the inner face over the flow grooves. Thus flow is maintained substantially uniform even at the outer groove ends, where relatively little filtrate moves. As a result clogging of these flow grooves is impossible; they will stay clear along their entire lengths.

Filter-medium support plate for centrifugal filter

A process for the dewatering and particle classification of solids from suspensions, e.g. coal from a slurry in which the coal is transported, makes use of a dewatering centrifuge having two frustoconical centrifuge drum sections of different inclinations such that in a first filtering zone the particles are preliminarily dewatered and then pass by automigration to the next centrifuge drum at which further dewatering takes place. The suspension on the first sieve surface forms a thin layer classification zone having a thickness up to 5 mm and in which the coarse fraction is retained while the fine fraction is passed. The coarse fraction automigrates to the next sieve surface where it is dewatered and the fine fraction separated out in the thin layer classifying zone is then filtered under pressure in a subsequent stage.

Process and apparatus for the dewatering of solids in suspension

A centrifuge filter has a sieve drum normally rotated about its axis and normally fed internally with a filtrand that is separated when the drum rotates into solids lying on the inner surface of the drum and a filtrate that passes radially outwardly through the drum. A pusher plate is axially displaceable in the drum and has an outer edge closely juxtaposed with the drum's inner surface so that it can scrape solids from the surface. A cylinder is rotationally fixed to the drum and has a cylinder chamber that is axially subdivided by a piston into a front compartment and a rear compartment. This piston is jointly axially displaceable with the pusher plate and is axially biased backward. A liquid is introduced into one compartment to fill it as it rotates so that the liquid will be forced radially outward by centrifugal force and will urge the piston axially forward. This liquid is periodically drained off so that the force it exerts is less than that of the biasing means. In this manner the piston will move back and forth each time the rear compartment is filled and drained.

Pusher-type centrifuge filters

A pocket-type centrifuge for processing sugar-beet or cane-sugar mash has a rotor which carries an annular array of pockets whose inner portions are formed as sieves and whose outer portions are constructed to mix a wash liquid with the mash that is fed axially into the rotor and that passes radially out over the pockets. A primary filtrate can be extracted from behind the sieves of the inner portions of the pockets, and the remainder of the mash mixture is then mixed with a wash liquid fed into an annular inwardly open chamber above the rotor that feeds its liquid into the outer portions of the pockets. From the pockets the mixed wash liquid and mash is projected onto a downwardly flared skirt of the rotor, and from this skirt onto an upwardly flared outer drum that is rotated slower than the rotor. The lower portion of this drum is solid and imperforate to insure good mixing of the wash liquid and the remaining solid phase, and its upper portion is foraminous so that as the material migrates axially upwardly all of the remaining liquid is extracted from it, along with any soluble substances in the mixture. In this manner most of the liquid phase in the original mixture is extracted, undiluted, at the inner regions of the pockets, and the remaining soluble substances are leached out by the wash liquid. The solids recovered at the upper end of the outer drum are almost completely dry and free of soluble substances.

Pocket-type sieve centrifuge

A wobble centrifuge has a housing in which a tube shaft is rotatable about a first axis, this tube shaft having a lower tube part centered on the first axis and an upper tube part centered on a second axis that crosses the first axis at an intersection. An at least partially flexible core shaft has a lower core part rotatable in the lower tube part about the first axis and an upper core part rotatable in the upper tube part about the second axis. A downwardly flared sieve drum is carried on the upper core part and is centered generally on the second axis, this sieve drum having a wall tapered upwardly from a lower edge spaced below the intersection in a direction parallel to the second axis by a predetermined distance. A suspension to be centrifuged is introduced into the drum generally radially of the axes at a location spaced above the intersection in a direction parallel to the second axis by a spacing equal to substantially more than the spacing between the lower end of the drum and the intersection. The tube shaft is rotated about the first axis and the core shaft parts about the respective axes for advancing the solid phase of the suspension being centrifuged down inside the drum from the introduction location toward the lower edge. The center of gravity of the drum lies offset from this intersection, but imbalance is corrected by providing at least one counterweight on the tube shaft.

Centrifuge

A centrifuge has a drum to which a wobble or nutating motion is applied to discharge the centrifuged material over the edge of a wall of the perforated basket. The wobble or nutation is caused by tilting the axis of this wall relative to the axis rotation of the assembly. According to the invention, the basket is rotatably driven by an inner shaft and ride upon an inclined member driven by an outer shaft. The ratio n.sub.2 /n.sub.1 of the rotating speed n.sub.1 of the inner shaft and the rotating speed n.sub.2 of the outer shaft can be varied between values of -5 and +7 preferably -5 to +6 excluding values of about 0, 0.9, 1 and 2. The ratio determines the effective nutating angle.

Wobble centrifuge and method of operation

Particles to be dried are loaded into the bottom of an upwardly open vessel which is then spun about a central axis at a speed sufficient to form the particles into an annular body and to urge the particles radially outwardly with a centrifugal force greater than the force of gravity. The outer wall of the vessel is gas-pervious and drying gas is passed radially inwardly through this wall to contact the particles and at least partially fluidize the body of particles. The dried particles are drawn off out of the upper end of the rotating vessel as fresh wet particles are loaded into the lower end.

Centrifugal fluidized-bed drying method and apparatus

A centrifuge for the separation of solids from liquids has a centrifuge drum rotatable about a substantially horizontal axis and formed, in addition to the filtering periphery, with a perforated ring annular disk transverse to this periphery for increased separation of liquid. The filtering ring, which lies inwardly of the perforated shell of the centrifuge advantageously opens toward an annular trough having the same radius as the ring or a greater radius. The trough is provided with a scoop or other emptying device to permit the radial position of the liquid level therein to be adjusted and/or to permit discharge of the trough.

Centrifuge drum with lateral filtration

A method of operating a filter centrifuge or centrifugal filter in which a hydrostatic head is provided at the filtering surface so as to control liquid passage therethrough. The head may promote movement of the liquid through the filter layer or may induce reverse flow of liquid for backwashing or rinsing. In addition, a hydrostatic balance may be provided at this surface through control of the head to limit passage of the liquid through the filter layer. Preferably the head provides a suction augmenting centrifugal filtration.

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Oberschleissheim, Germany

Gunther Hultsch