Cylinder driers

Cylinder driers are drum driers used for material in continuous sheet form, such as paper and cloth. The wet solid is fed continuously over the revolving drum, or a series of such drums, each internally heated by steam or other heating fluid. 

Before processing, wool has to be scoured to remove contaminating particles such as dirt, sweat, and wool fat. The wool is dried in perforated cylinder driers and then opened in the breaker card. After these stages the fibers are oiled to alter the frictional properties of the fibers and to prevent electrostatic charging. The fibers are then pneumatically transported to the mixing chamber. Because raw wool scouring systems are very expensive and subject to strict environmental protection laws, most worsted spinning mills purchase scoured wool, card slivers, or combed slivers. 

The second Hquefaction process is carried out at temperatures from 261 to 296 K, with Hquefaction pressures of about 1600—2400 kPa (16—24 atm). The compressed gas is precooled to 277 to 300 K, water and entrained oil are separated, and the gas is then dehydrated ia an activated alumina, bauxite, or siHca gel drier, and flows to a refrigerant-cooled condenser (see Drying agents). The Hquid is then distilled ia a stripper column to remove noncombustible impurities. Liquid carbon dioxide is stored and transported at ambient temperature ia cylinders containing up to 22.7 kg. Larger quantities are stored ia refrigerated iasulated tanks maintained at 255 K and 2070 kPa (20 atm), and transported ia iasulated tank tmcks and tank rail cars. 

Trommel-ofcn, m. rotary furnace or oven cylinder roaster, -probe, /. (Coke, Ceram.) rattler test, -sieb, n. drum sieve, cylindrical screen, trommel, -trockner, m. drum drier, rotary drier. -versuch, m. = Trommel-probe. 

Hanni et al. (1976) described a continuous fluidized bed drier using the centrifugal principle. It consisted of a perforated horizontal cylinder rotating inside a plenum with hot air blown across the outside of the cylinder and perpendicular to the axis of rotation (Figure 1.20). Vanes placed in the air inlet allowed the incident angle of the air flow to be varied from 0° to 45° to the perpendicular. Particles were fluidized inside the Teflon-coated stainless steel cylinder which could be tilted by up to 6° in order to control particle residence time. The cylinder, of... 

The driers described below consist of long, open drums (cylinders), which heat and dry the wet materials fed inside of them... 

Figure 3 presents the time evolution of tangential stresses at the surface and the core of the cylinder according to the viscoelastic and elastic models. The stress reverse can be explained as follows when the body dries, the drier surface attempts to shrink but is restrained by the wet core. The surface is stressed in tension and the core in compression and inelastic strain occurs. Later, under a surface with reduced shrinkage, the core dries and attempts to shrink causing the stress state to reverse [4],... 

The web passes the screen vertically into the drier above the drying or pre-gelling of the print is by means of hot air blown on both sides of the web, the air being heated by thermal oil or, more usually, by direct gas firing. The volume of air circulated and its temperature are controlled and can be varied. After drying or pre-gelling the web must be cooled so that it will not carry heat to the next screen, and this is done by passing it round two water-cooled cylinders. 

The selection of the extruder design is based on the principal requirements of the extrudate and the nature of further processing. For the production of uniform granules to be dried in a fluid-bed drier, a low-compaction system, such as that provided by the various types of screen extruders may be suitable. Cylinder or gear-type extruders may be more appropriate when aiming for a densified extrudate, such as that required for spheronization. Ram-extrusion systems, which allow precision control of extrudate density, size, and shape, are ideal for the extrusion and forming of pharmaceutical polymers of the type used for sub-dermal implants. 

Drying capacity is influenced by the speed of the drum and the temperature of the feed, which may be preheated. With the double-drum drier, the gap between the cylinders determines the thickness of the film. 

RECEIVER-DRIER - Cylinder (container) in a refrigerating system for storing liquid refrigerant and which also holds a quantity of desiccant. 

Rotating cylinders, similar in some respects to those used as rotary driers or kilns, have been used for the crystallization of solutions. The cylinder slopes slightly from the feed liquor inlet down to the crystal magma outlet. Cooling may be provided either by cold air blown through the cylinder or by water sprayed over the outside. In the former case internal baffles disturb the liquor on the inside wall and cause it to rain through the air stream. In the latter case internal scraper devices prevent excessive build-up of crystal on the walls. 

The rotary calciner is similar to a rotary drier, except that it is specially constructed in stainless steel or special metals lined with refractory materials which can withstand the higher temperatures required. The direct-heating type consists of an inclined metal cylinder lined with a refractory material, down which the crushed material... 

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