Cooling drum

Rotating drum — single and duble drum models are made. In either case (he internally cooled drums turn thru the molten material picking up a layer that is flaked as it is scraped off by a doctor knife (or knives) into... 

A gas black apparatus consists of a burner pipe approximately 5 m long, which carries 30-50 diffusion burners. The flames burn in contact with a water-cooled drum, where about half of the carbon black formed is deposited. This black is scraped off and transported by a screw to a pneumatic conveying system. The gas black apparatus is surrounded by a steel box open at the bottom. At the top of it, fans suck the off-gas into filters, which collect the carbon black suspended in the gas. 

Figure 55. Degussa gas black process a) Oil evaporator b) Burner c) Cooling drum d) Bag filter e) Blower f) Rotary valve g) Conveying srew...

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. 

In some machines the film is not passed over a cooling drum, but is directly transported over the slot and metallized ( free-span metallization). This increases the efficiency of the evaporation sources and prevents the formation of creases initiated by the cooling drum [6]. The thermal load of the film also changes. On the one hand it increases, because there is no cooling by the drum on the other hand it decreases, because there is also no heat reflection from the drum and the distance between evaporator and substrate can be increased. Whether the heat load increases or decreases depends very much on the configuration of the machine. For equal evaporator-substrate distances the thermal load, and thus the density of the metal structure, increases with free-span metallization (Fig. 8.6). 

Taking, for instance, Al, with a melting point of 660 °C and a web substrate temperature of 50 °C, zone I formations will be created (porous structure, pointed crystallites, large voids) and up to 250 °C, formations in the transitional area (densely packed fibers) will appear. Up to 450 °C zone II (pillar-shaped crystallites), and above this temperature zone III (conglomerate-type crystallites) formations will be seen. Because of the relatively low maximum thermal stress that may be applied to polymer webs, the growth in metallized layers on polymer webs mainly occurs in Zone I or in the transitional zone. The different growth is also evident from comparison of cooling drum and free-span coater methods. 

Before the coated base is wound up cooling is necessary. Some ovens include a cooling zone but more usually cooling is in ambient air as the material is passed round a number of water-cooled drums. 

The line may include several printing stations in sequence, each one of which comprises essentially a print head, a vertical drier, and two cooling drums. Holders in the print head support the screen, hold it in tension, and drive it the screen can be adjusted for lateral registration with others in the sequence. 

In drum flakers, a thin film of molten feed is applied to the polished external surface of a revolving, internally-cooled drum (Fig. 6.5). Virtually... 

The centres of these products are normally made as a continuous rope, either with the components previously mixed together or deposited as layers in the case where there is a layer of caramel, the caramel passes from the cooker to a cooling drum which cools the caramel to an appropriate temperature, satisfying the requirements mentioned above if the caramel is to be mixed with other ingredients, e.g. nuts, they are mixed prior to depositing. The rope of product is then cut into pieces and cooled as necessary prior to being coated with chocolate. 

A typical "flaker , such as used in manuf of TNT and some other HE s consists of a horizontal, hollow, metallic (usually cast-iron), water-cooled, drum, with hollow trunions mounted in bearings. It is given in Perry, pll64-L as Fig 68 and reproduced here as Fig 6. The lower part of drum dips into molten material located in a hollow, steam... 

See Sheet also material solidified from a melt on a rotating, cooled drum (flaker) and removed by scrapers. 

A polymer solution containing dissolved or dispersed Cl particles is fed from the slot head onto a continuous band 2 whose surface adheres poorly to the polymer and which moves at a constant speed. Film formed on the band is dried by IR heaters 3. It is set and dried completely on contact with the cooling drums 4. The film sheet is then centered, its edges are trimmed by device 5 and it is wound onto roll 6. 

Thermascrew is a hollow screw, jacketed trough dryer that provides three to four times more heat transfer surface than simple jacketed screw conveyors and six times more than water-cooled drums. In either continuous or batch operation, it provides efficient and uniform heating, cooling, evaporating, or other processing. It can operate in either a pressure or a vacuum environment. Polyester and polyolefins are among the materials dried with good thermal efficiency in such devices. 

The Sandvik continuous cooled belt crystallizer (Figure 8.25) may be considered as an alternative to the rotary cooled drum. The underside of the steel belt is sprayed with cooling water to provide a controlled temperature gradient along... 

Figure 14.34. Melt coating machine. 1 melt rollers, 2 take-off roller, 3 embossing roller, 4 supply tank, 5 textile preheating drum, 6 cooling drums. [Adapted from Wypych Q Polymer Modified Textile Materials, John Wiley, New York, 1988.]...

This continuous votator process was first used for margarine production by Girdler USA in 1938, introduced in the UK during the 2nd World War and in the rest of Europe in the 1950s. In some factories, the semi-continuous cooling drum/hopper/vacuum kneader process is still used, but almost exclusively for special-purpose margarines. 

A great variety of driers and drying techniques have been used for soap (McCutcheon, 1958). Specific methods such as frame cooling, drum cooling and atmospheric flash drying are still widely used for laundry-grade soaps in particular. By far the most important class of driers for toilet-grade soaps are the vacuum spray driers of which the Mazzoni type are widely used (Mazzoni, 1959). 

---