The rotary dryer is a type of industrial dryer employed to lessen or minimize the liquid moisture content of the material it is handling by bringing it into direct contact with a heated gas. A rotary dryer is reported to be of the direct type if by virtue of its design, heat is added to or removed from the solids by direct exchange between the gas and solids. The direct heat dryer would be the simplest and the most economical class.
They are used each time a direct connection with the gas or air is not detrimental for the fed. When high temperature is needed for rotary evaporator in a direct-heated rotary dryer, a combustion chamber can be used so when low temperature is required on the contrary, for thermolabile materials, steam coil is used. Rotary dryer can also be said to be indirect once the heating medium is separated from contact with the solid with a metal wall or tube.
Single Shell Rotary Drum Dryer – The dryer consists of a big, rotating cylindrical tube, usually maintained by concrete columns or steel beams. The dryer is inclined to slopes slightly in order that the discharge end is less than the material feed end to be able to convey the content through the dryer under gravity. Material to become dried enters the dryer, and because the dryer rotates, the material is lifted up by several internal fins lining the interior wall from the dryer. If the material gets high enough to roll back off the fins, it falls back to the bottom of the dryer, passing through the hot gas stream since it falls.
This gas stream may either be moving toward the discharge end from the feed end (referred to as co-current flow), or toward the feed end through the discharge end (referred to as counter-current flow). The gas stream can be produced up of a combination of air and combustion gases coming from a burner, in which case the dryer is called a direct heated dryer. Alternatively, the gas stream may consist of air or another (sometimes inert) gas that is preheated. If the gas stream is preheated by some means where burner combustion gases do not go into the dryer, the dryer called an indirect-heated type. Often, indirect heated dryers are used when product contamination is an issue. In some instances, a mix of direct-indirect heated rotary dryers can also be found to improve the overall efficiency.
A rotary dryer is acceptable to dry metallic and nonmetallic mineral, clay in cement industrial and coal slime in coal mine, etc. Rotary dryers could be widely used to dry various materials, and therefore are easy to operate.
Rotary Dryers have many applications but are most commonly seen in the mineral industry for drying sands, limestone, stones and soil, ores, fertilizers, wood chips, coal, iron sulphate, filter cakes, sewage sludge, etc. May also be put on food industry mainly for liquids as well as for granular material such as food grains, cereals, pulses,coffee beans, fermented tea leaves, etc.
Drum or shell variations: Double Shell Rotary Drum Dryer. Triple Shell Rotary Drum Dryer – A rotary dryer can consist of just one shell or many, though any further than three drums is not usually necessary. Multiple drums is able to reduce the volume of space the equipment consumes. Multi-shell dryers include several concentric tubes. Multiple shells permit the dryer to become utilized in a more compact space. The drums are frequently heated directly by oil or gas burners. Adding a combustion chamber on the entry end helps ensure efficient fuel usage, and this homogenous drying air temperatures. Since the material moves from the rotating drum is heated and moisture released. Some dryers also provide the choice to cool, clean, shred, and/or separate the dried material.
For evaporating moisture from concentrates or any other products from plant operations, Rotary Dryers are created and constructed for high efficiency and economy in fuel consumption. Anytime you can to apply heat direct to the material to be dried, Rotary Dryers from the Direct Heating Design are used. Should it be not possible to use heat direct for the material to be dried, Rotary Dryers in the Indirect Heating Design may be furnished so the heated gases is not going to can be found in direct exposure to the material.
Rotary Dryer is an easy, inexpensive unit for lowering the moisture content of flotation concentrates, as well as chemical and industrial products. Frequently the saving of shipping weight so effected will pay tjihbx the dryer in a couple of months. Difficulties from freezing when in transit will also be eliminated. Many industrial projects are using Dryers for control and production purposes on many materials.
Three main types of rotary evaporator can be supplied. The direct heat unit is utilized after it is permissible for your drying gases in the future in direct contact with the fabric being dried. Partition plates raise the heating surface. Drying might be by heat or exhaust gases off their operations. If the drying gas has a deleterious effect on the product, then an indirect kind of dryer may be supplied. A further derivation is the Tedrow Steam Dryer.
The movement of the material is a result of combined effect of inclination in the shell to the horizontal as well as the internal tumbling action or mechanical turn over thus the name tumbling dryer. The type in the feed determines the directions of gas flow with the cylinder which is relative to the solid. This drying equipment may also perform batch or continuous processing from the wet feed.