Abstract:
A method and apparatus for underwater pelletizing and subsequent drying of polyethylene terephthalate (PET) polymers and other high temperature crystallizing polymeric materials to crystallize the polymer pellets without subsequent heating. High velocity air or other inert gas is injected into the water and pellet slurry line to the dryer near the pelletizer exit. The slurry line has a substantially straight component, and air is preferably injected at the end of the straight component nearest the pelletizer exit and in a direction substantially coincident with the axis of the straight component. The air injection significantly increases the speed of the pellets into and out of the dryer such that the PET polymer pellets leave the dryer above at least 135° C., and preferably above 145° C., to self-initiate crystallization.
Abstract:
Certain polyamide beads or granules are useful as a sustaining material for underground natural or artificial cracks of the earth's crust essentially employed for the extraction of hydrocarbons such as crude oil or natural gas; such polyamide beads have a spherical or ellipsoidal shape and have a surface free of concave portions, advantageously having a uniform shape, and having a mean diameter lower than or equal to 1.7 mm and a porosity lower than 0.1 ml/g, and are produced using a particular cutting device/extruder.
Abstract:
The present invention relates to a pelletizer, preferably in the form of an underwater pelletizer. In particular, this invention relates to a cutter and/or grinding head for such pelletizer, comprising a tool carrier which can rotatorily be driven about a tool carrier axis of rotation, and at least one cutting and/or grinding tool, which is attached to the tool carrier and is spaced from the tool carrier axis of rotation, for knocking off plastic melt emerging from a pelletizer die plate and/or for grinding said pelletizer die plate. In accordance with the invention, the cutting and/or grinding tool is rotatably mounted on the tool carrier about an axis of rotation spaced from the tool carrier axis of rotation. This provides a second component of movement for the cutting and/or grinding tool. On the one hand, the cutting and/or grinding tool rotates together with the tool carrier about its tool carrier axis of rotation, and on the other hand, the cutting and/or grinding tool can rotate about its own axis of rotation relative to the tool carrier. The tool carrier has a pivot bearing for the cutting and/or grinding tool, by means of which the cutting and/or grinding tool can rotate about itself.
Abstract:
A method and apparatus for underwater pelletizing and subsequent drying of polyethylene terephthalate (PET) polymers and other high temperature crystallizing polymeric materials to crystallize the polymer pellets without subsequent heating. High velocity air or other inert gas is injected into the water and pellet slurry line to the dryer near the pelletizer exit. Air is injected into the slurry line at a velocity of from about 100 to about 175 m3/hour, or more. Such high-speed air movement forms a vapor mist with the water and significantly increases the speed of the pellets into and out of the dryer such that the PET polymer pellets leave the dryer at a temperature sufficient to self-initiate crystallization within the pellets. A valve mechanism in the slurry line after the gas injection further regulates the pellet residence time and a vibrating conveyor after the dryer helps the pellets to achieve the desired level of crystallinity and to avoid agglomeration.
Abstract:
A method and apparatus for underwater pelletizing and subsequent drying of polyethylene terephthalate (PET) polymers and other high temperature crystallizing polymeric materials to crystallize the polymer pellets without subsequent heating. High velocity air or other inert gas is injected into the water and pellet slurry line to the dryer near the pelletizer exit. The slurry line has a substantially straight component, and air is preferably injected at the end of the straight component nearest the pelletizer exit and in a direction substantially coincident with the axis of the straight component. The air injection significantly increases the speed of the pellets into and out of the dryer such that the PET polymer pellets leave the dryer above at least 135° C., and preferably above 145° C., to self-initiate crystallization.
Abstract:
A centrifugal pellet dryer screen especially adapted for drying micropellets includes an exterior or outer support screen in the form of a cylindrical perforated plate, an inner screen of small wire mesh material, and an optional middle screen of wire mesh material sandwiched between the outer support screen and the inner screen. The screen layers are preferably diffusion bonded to each other. These multi-layer screens produce drier micropellets exiting the dryer and reduce banding of the micropellets and plugging of the dryer screen outlet holes.
Abstract:
A method and apparatus for underwater pelletizing and subsequent drying of polyethylene terephthalate (PET) polymers and other high temperature crystallizing polymeric materials to crystallize the polymer pellets without subsequent heating. High velocity air or other inert gas is injected into the water and pellet slurry line to the dryer near the pelletizer exit. Air is injected into the slurry line at a velocity of from about 100 to about 175 m3/hour, or more. Such high-speed air movement forms a vapor mist with the water and significantly increases the speed of the pellets into and out of the dryer such that the PET polymer pellets leave the dryer at a temperature sufficient to self-initiate crystallization within the pellets. A valve mechanism in the slurry line after the gas injection further regulates the pellet residence time and a vibrating conveyor after the dryer helps the pellets to achieve the desired level of crystallinity and to avoid agglomeration.
Abstract:
A melt processing plant including a melt charger for charging a processing head, in particular a pelletizing head, with melt, is provided. Upstream of the processing head a diverter valve for discharging the melt during a starting and/or retooling phase is associated with the melt charger, and a portioning device for portioning the discharged melt into melt portions is associated to the diverter valve. A cooling device for cooling the melt portions to at least partly solidified chunks of material is also provided, the cooling device including a cooling bath having an associated belt conveyor with a first collecting belt portion inclined at an acute angle to the horizontal and extending through the level of the cooling bath for collecting chunks of solidified material.
Abstract:
The present invention relates to a melt processing plant, comprising a melt charger for charging a processing head, in particular palletizing head, with melt, wherein upstream of the processing head a diverter valve for discharging the melt during a starting and/or retooling phase is associated to the melt charger, and to a method for melt processing in such melt processing plant. In accordance with the invention, a portioning device for portioning the discharged melt into melt portions is associated to the diverter valve, wherein a cooling device for cooling the melt portions to at least partly solidified chunks of material is provided.
Abstract:
The present invention relates to a filtration apparatus for filtering and separating solids from liquids comprising at least one liquid-permeable, continuously or intermittently drivable filter belt, an intake for charging the liquid/solid mixture to be filtered onto the filter belt in a charging zone and a belt cleaner for removing the solids deposited at the filter belt from a belt section conveyed out of the charging zone in an expulsion zone. In accordance with the invention, the belt cleaner has at least one rotatingly drivable brush with which a brush cleaner having a scraper is associated which is arranged in the path of the bristles of the rotating brush. The rotating brush efficiently removes the deposited solids from the filter belt, while the scraper of the brush cleaner simultaneously ensures that the dissolved solids do not settle at the brush and clog it. The continuous self-cleaning of the brush is in particular very helpful with sticky contaminants of the liquid to be filtered in order to be able to ensure a permanently efficient, continuous separation of the solids.