Abstract: A pipe switch includes a plug with a spherically arched circumferential surface and having ports for at least one channel. The plug is rotatably supported in a housing about a pivot axis which is formed with an inlet port and two outlet ports. In order to simplify the shape of the housing and reduce the complexity of manufacture, the plug is a spherical segment within a spherical volume bounded by the great circle, with the ports of the channel being bounded at least approximately by substantially coincidental ellipses in the spherical segment of the plug in a projection along an imaginary line connecting the centers of the ports, whereby this imaginary line extends offset with respect to the pivot axis of the plug.

Abstract: A rotary valve for feeding bulk material comprises a housing having a cavity, a supply opening leading to said cavity, and a discharge opening. Within the cavity, there is a cellular wheel rotatably supported. The distance between the outer circumference of the cellular wheel and the inner wall of the cavity can be altered. At least one sensor determines the distance and provides an output signal representative for it. Either the cellular wheel or the inner wall of the cavity or both are at least locally deformable in dependence on the output signal. In addition, the invention relates to a method or operating a cellular wheel where the above-mentioned distance or gap is determined or measured and at least one of said inner and outer radial dimensions of the cellular wheel and the cavity are controlled accordingly.

Abstract: In a method of screening bulk material, a gas is conducted in counterflow to a direction of movement of bulk material for separating the bulk material into a fraction of coarse particles and a fraction of fine particles. In order to limit the amount of coarse particles in the outgoing fraction of fine particles, the amount of coarse particles contained in the fraction of fine particles is measured and compared with a desired value. When encountering a deviation of the measured the amount of coarse particles contained in the fraction of fine particles form the desired value, the energy of gas is so controlled as to match the amount of coarse particles contained in the fraction of fine particles with the desired value.

Abstract: A rotary valve includes a housing having a housing bore which can be laterally closed by bearing covers. Inside the housing, a cellular wheel is rotatably supported. A guiding device extends in an axial direction of the cellular wheel and serves for drawing the cellular wheel in the direction of its axis of rotation out of the housing bore. This guiding device includes an additional bearing which can be displaceable in the axial direction relative to that bearing cover which is on the guiding side. The additional bearing serves to support the cellular wheel temporarily during removal from the housing bore. This additional bearing can be connected to that end of a cellular wheel shaft which is situated at the side of the guiding device.

Abstract: A rotary feeder for dosing bulk material, includes a casing having an inner chamber and formed with a top inlet, a bottom outlet and spaced-apart bearing covers flanking the inlet and the outlet. A rotor is accommodated in the chamber and is mounted on a shaft for rotation about a pivot axis. The shaft supports a plurality of vanes extending radially outward from the shaft between lateral end disks, with the shaft being supported on opposite sides of the rotor by bearings. In order to minimize the length of the shaft and a flexure of the shaft when encountering a substantial pressure differential between the inlet and the outlet, the chamber of the housing is sealed from the ambient environment by at least one shaft seal situated axially outwardly from the one bearing of the first and second bearings which is located on a same side of the rotor as the shaft seal.

Abstract: In a process for making plastic granulate, a polymeric material is plastifyed into a plastic mass which is divided into single plastic strands. After pressing the plastic strands in a stream of cooling liquid, the plastic strands are shredded in the cooling liquid into granules, thereby forming a dispersion which is conveyed through a first conduit to a separator. The dispersion is concentrated in the separator by withdrawing a portion of cooling liquid, and subsequently transported to a dryer along a second conduit which is longer than the length of the first conduit. In the dryer, the cooling liquid is separated from the granulate.

Abstract: The present invention relates to a rotary valve for conveying and metering bulk material into a pneumatic conveying conduit. Exemplary embodiments include a housing with a supply opening, a discharge opening and a cellular wheel supported rotatably about a substantially horizontal axis within a cavity of the housing. The cellular wheel rotates in a predetermined direction of rotation so that as some of its cells move upward, other cells move downward. The housing has at least one venting opening for venting the upward moving cells, the venting opening being arranged before the supply opening when seen in the direction of rotation. A perimeter of the at least one venting opening lies on a peripheral wall of the housing and has a plurality of recesses which extend in a direction towards the cellular wheel when the latter rotates in the direction of rotation.

Abstract: In a process for hydraulic transport of bulk material from a receiving site to a remote location via a conveying pipeline, a dispersion is prepared from bulk material and a liquid, and conducted into a feed pump which has a pressure side in communication with the entry into conveying pipeline, whereby a fraction of the liquid is withdrawn at a location between the pump and the entry into the conveying pipeline. Suitably, either the volume flow of the withdrawn fraction of the liquid represents a manipulated variable which is changed in dependence on a controlled variable constituted by the volume flow through or pressure in the conveying pipeline, or/and the dispersion is produced upstream of the feed pump from a controllable bulk material stream and controllable liquid amount, whereby the amount of liquid may also include at least a fraction of the liquid withdrawn from the pressure side of the feed pump.