Abstract: A rotor (2) surrounded by a strainer basket (3) is arranged vertically in a housing (1). Conveyor blades (7) arranged one above the other are distributed over the rotor (2) to convey plastic granules from a product inlet (14) arranged at the bottom of the housing to a discharge unit (15). A fan (19) is disposed in a discharge hood (16) and it has ejector blades (21) for assisting the radial discharge of the granules into unit (15). In order to change the residence time of the plastic granules in the dryer, a change in pressure is produced in the centrifugal dryer by replacing the fan with one having ejector blades whose outer diameter and/or length is different, the diameter of rotor (2) and its conveyor blades (7) being kept the same.

Abstract: A method for the separation of granulate and water in an after-treatment section following a granulator in which a vibrating screen receives the water and granulate mixture. In order to obtain low residual moisture without subsequent drying, the granulate-water mixture on the screen is subjected briefly to a vacuum over the entire width of the vibrating screen at longitudinally spaced locations, in alternation, from above and below the screen within the first third of the length of the screen.

Abstract: A cooling device for plastic granulate which is formed by cutting plastic strands emerging from a nozzle plate of an extruder and is fed to a stream of cooling water which adjoins the nozzle plate in the region of a cutting device. A pipe conducts the stream of cooling water containing the granulate to a granulate-water separator. In order to obtain a well-defined, infinitely adjustable dwell time of the granulate in the stream of cooling water, the pipe is essentially developed as a vertically arranged riser having a larger cross section passage area than that of the pipe itself. The upper outlet end of the riser is connected to the suction side of a feed pump, which serves as a section pump, and to a suction pipe which has an end connected to ambient atmosphere. A regulating valve is connected in the suction pipe. The delivery side of the feed pump communicates with the granulate-water separator.

Abstract: A method and apparatus for regulating the drive of dosaging devices for the controlled feeding of plastic particles, color concentrates and additives into a supply hopper of a screw extruder for producing a mixed plastic product of determined coloration, comprising periodically measuring the coloration of the mixed product at an outlet of the extruder by a spectrometer connected to a measurement probe, comparing the measured coloration of the mixed product with the coloration of the desired product, and adjusting the supply of the plastic product, concentrates and additives, as necessary, so that the measured coloration of the product at the outlet of the extruder is the same as the coloration of the desired product.

Abstract: Apparatus for dewatering and drying plastic granulate comprising a multistage dewatering rotor having conveyor and aerating blades and surrounded by a screening member located within a housing between a product inlet and a product outlet. In order to simplify the handling of a wide variety of plastic granulate with only a small amount of space being required, a collection container which is open at its top coaxially surrounds the first stage of the dewatering rotor and accumulates separated water in a reservoir region for discharge by a suction pump. The product inlet discharges into a feed vessel secured in the collection container. The first stage of the dewatering rotor is provided on its circumference with worm segments of increasing pitch in the direction of granulate conveyance.

Abstract: In a process for mixing and proportioning a plurality of mixing components, the latter are supplied in individually weighed manner to a continuous mixing process and the mixture is subsequently continuously removed in a proportioned manner. For this purpose, a mixer, metering feed means positioned upstream of the mixer and a continuously proportioning removal device positioned downstream of the mixer are provided. In order to ensure a troublefree addition and an accurately proportioned removal, the individual mixing components are in each case successively supplied in timed continuous manner to the mixing process, accompanied by the weighing of the total mixing material. During the feed pauses, the mixture is gravimetrically controlled and during addition is removed in volumetrically controlled manner.

Abstract: In a process for mixing and proportioning a plurality of mixing components, the latter are supplied in individually weighed manner to a continuous mixing process and the mixture is subsequently continuously removed in a proportioned manner. For this purpose, a mixer, metering feed means positioned upstream of the mixer and a continuously proportioning removal device positioned downstream of the mixer are provided. In order to ensure a troublefree addition and an accurately proportioned removal, the individual mixing components are in each case successively supplied in timed continuous manner to the mixing process, accompanied by the weighing of the total mixing material. During the feed pauses, the mixture is gravimetrically controlled and during addition is removed in volumetrically controlled manner.