Drum extruder

Method of feeding Feedstock preforming J grooved drum extruder extruder extruder extruder... 

In some equipment, such as filter drums, extruded profiles such as division strips are affixed on to the lined sheet rubber and then cured. These profiles can be strips of different cross sections for enabling other components to be fixed in the rubber lined equipment such as drum filters (see Figure 7.3). 

There are several extruders that do not use an Archimedean screw for transportation of materials, but still belong to the category of continuous extruders. These machines are sometimes referred to as screw-less extruders. Usually they employ a disk or a drum. Most disk extruders are based on viscous drag transport principle. To this category belong stepped disk extruders [Westover, 1962 Raleigh, 1879], drum extruders, spiral extruders [Ingen Housz, 1975], diskpack extruder [Tadmor, 1979, 1980 Tadmor et al, 1979, 1983 Hold et al., 1979 Valsamis, 1983], and many others. 

Drum extruder n. A plasticating machine having a rotating cylindrical element inside a concentric or eccentric housing. Pellets or powder are fed into the gap between drum and housing at the top. Shear action melts the solids and the melt exists through a slot about 270° around from the feed point. 

Viscous drag extruders Drum extruder Diskpack extruder Stepped disk extruder... 

Another rather old concept is the drum extruder. A schematic picture of a machine manufactured by Schmid Kocher in Switzerland is shown in Fig. 2.15. 

One special feature of this design is the capability to adjust the local gap by means of a choker bar, similar to the gap adjustment in a flat sheet die, see Section 9.2. The choker bar in this drum extruder is activated by adjustable hydraulic oil pressure. Drum extruders have not been able to be a serious competition to the single screw extruder over the last 50 years. 

Disk extruders. There are several types of screwless extruders. These machines employ a disk or a drum to plasticate, mix, and extrude. Most designs are based on viscous drag flow. They include Maxwell s elastic melt extruder, Westover s stepped disk and drum extruders, and Diskpack [39]. The Diskpack extruder has the capability of performing all the elementary steps of plastics processing by combination of differently shaped rotating... 

Wet pastes that cannot be granulated or extruded may be predried and preformed on a steam-neated finned drum. Preforming on a finned drum may be desirable also in that some prediying is accomplished. 

The turbo-tray dryer can handle materials from thick slurries [1 million (N s)/m (100,000 cP) and over] to fine powders. It is not suitable for fibrous materials which mat or for doughy or tacky materials. Thin slurries can often be handled by recycle of dry product. Filter-press cakes are granulated before feeding. Thixotropic materials are red directly from a rotary filter by scoring the cake as it leaves the drum. Pastes can be extruded onto the top shelf and subjected to a hot blast of air to make them firm and free-ffowing after one revolution. 

The third process for cross-linking is the Sioplas process developed by Dow. The first stage of this involves the grafting of an easily hydrolysable trialkoxyvinylsilane onto the polyethylene chain, the site activation having been achieved with the aid of a small amount of peroxide. The compound is then extruded onto the wire, which is collected on a drum. The drum is then exposed to hot water, or, more commonly, low-pressure steam. The water hydrolyses the alkoxy groups, which then condense to form a siloxane cross-link. ... 

The storage facilities at the end of the profile production line depend on the type of product (see Fig. 4.19). If it is rigid then the cooled extrudate may be cut to size on a guillotine for stacking. If the extrudate is flexible then it can be stored on drums. 

Initially a molten tube of plastic called the Parison is extruded through an annular die. A mould then closes round the parison and a jet of gas inflates it to take up the shape of the mould. This is illustrated in Fig. 4.21(a). Although this process is principally used for the production of bottles (for washing-up liquid, disinfectant, soft drinks, etc.) it is not restricted to small hollow articles. Domestic cold water storage tanks, large storage drums and 2(X)... 

Nitrogen is pumped in and molten polymer is extruded and cooled on a drum to form ribbons. Nylon 6, 10 is formed in similar way at a lower temperature. Nylon 6, 6 can also be prepared in a continuous process in three separate tubes wherein reaction is started, steam removed and polymerisation completed. The product is directly melt spun into fibres. 

Molding of flat film canvas is usually performed by pouring a melt coming out of a flat-slit extruder head (spinneret) on the receiving drum (a roll with sufficiently... 

Once a hollow segment is extruded, it can t be bent nor its shape changed,so I have to coax the clay out of the extruder with exactly the curve I want it to have in its final form. The didjibodhran is extruded in four separate segments, which are attached once they have dried to a leather-hard state. The goatskin drum head is then attached using water-soluble glue. 

The polymer is extruded from the bottom of the polymerizer through a slot or holes on to the surface of a water-cooled drum. The ribbon is cut to chips and dried before melt spinning in a manner similar to that described for nylon. The filaments are stretched, with the application of heat, to about 3 to 6 times their original length. 

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