Industrial equipment that is used to dry or cool free flowing material is called rotary dryer and cooler. This equipment introduces drying/cooling media directly onto processing material to carry out this process. The material to be dried or cooled us fed into dryer and rotated by a sequence of inner fins lining integrated on the interior wall of the dryer. Customers can get Rotary Dryers and Coolers in desired configuration and specification choices.
The equipment is made available under two categories:
- Direct Heaters/Coolers
- Indirect Heaters/Coolers
Working Principle of Direct heaters/coolers:
Material to be dried/cooled comes in direct contact with drying/cooling media. Drying/Cooling media is fed through stationary inlet hood present at one end and is discharged from stationary discharge hood present at the other end. Feeding mechanism like screw feeder/simple chute is used to admit the feed. Rotating shell comes with specially designed material showering mechanism such as lifters and others. Material is moved forward towards discharge end through shell inclination & at rotating speed, which offers required residence time. Drying or cooling is carried out through heat transfer to/from showering material with drying/cooling media within shell. Product is discharged from stationary hood making use of equipment such as rotary valve/ flap valve/screw conveyor/chute among others.
Working Principle of Indirect heaters/coolers:
Material to be dried does not come in direct contact with drying media, unlike in direct heater/cooler. Dryer comprises assembly that features two concentric rotating shells supported on rollers & tyre stations and driven through drive arrangement. Feed is admitted through feeding mechanism such as screw feeder/flap valve into dryer through stationary inlet feed hood. The return gas passages on inside of outer shell allows drying media to admit through inner shell to travel to discharge end and again return towards feed end. Inner shell comes with suitable radial lifters. Drying is carried out through heat transfer to shower material by direct contact with inner shell and return passages.
- Steel made dryers/coolers are supported by solid steel columns and beams/rollers and tyre arrangement.
- Rotating shell is driven by a suitable drive arrangement comprising girth gear and pinion driven through gear reducer and coupled to motor of ideal rating.
- It comes with separate pollution control equipment that is installed alongside dryers.
- Firing arrangement makes use of varied fuel forms such as gaseous, liquid, and solid fuels.
The equipment finds use in drying/cooling of free flowing materials by directly introducing drying/cooling media onto processing material.