Glossary – Everything You Need to Know About Rotary Dryers

Glossary – Everything You Need to Know About Rotary Dryers

The construction of rotary dryers includes a vessel (drum) that rotates and tumbles materials inside while the air flows through causing evaporation of the moisture. Additionally, vessels are equipped with lifters attached to the shell of the vessel. These lifters constantly shuffle and tumble the material allowing for better drying.

Depending on the properties of drum chippers your product, you can set the length of drying (retention of time) and optimal temperature. This will allow you to get the material to required condition.

The vast majority of standard models can handle multiple types of drying processes. However, we also manufacture custom rotary dryers that will fit your purposes even better than standard equipment. There is a plethora of factors that we consider when designing a custom rotary dryer.

Construction of Rotary Dryers


The efficiency and longevity of the rotary dryer greatly depends on the material of the shell. It can be made of a rich variety of alloys with the most common choices being stainless steel, Inconel, and carbon steel. Depending on the requirements of your production process, the shape and size of the shell can be altered. Shell thickness also can be adjusted according to desired levels of heat retention. Additionally, shell can have an option of sealing which allows to contain heat better. Note that the shell is one of the most important parts of the construction and deficient quality of the shell will negatively affect both efficiency and longevity of your equipment.

Combustion chamber

This part of the construction is responsible for generating hot gases through combustion of fuel. Chamber also sets the direction of air flow which can be co-current or counter current. Depending on the requirements of your production cycle, co-current or counter current dryers may be better. Chambers prevent materials from contacting with flame. There is plenty of options and modifications that can be applied to the combustion chamber. Another important feature is that combustion chambers can be used in combination with a wide variety of burners. A combustion chamber defines the efficiency of both energy consumption and heat transferring. This means that a subnormal part will decrease the efficiency of your equipment.


Burner generates heat by, as the name suggests, burning fuel. The quality of the burner will affect the efficiency of fuel usage. You can modify a burner to work with a variety of fuels such as propane, natural gas, solid fuels, etc. Burner should be chosen depending on the requirements of your production process.

Material Feed

The part of the construction where the material enters the vessel. It is usually called feed chute. This part of the construction should be made of robust materials in order to prevent wearing. At the same time, accretion risks should also be considered.

Air Seal

The air seal prevents material from falling out from the vessel through the breech between the drum and combustion chamber. You should pick the right type of the seal based on the type of the material that you work with.

Drive Assembly

In order to work, rotary dryers need engines. Drive assembly is a mechanism that combines various parts of the power block. The setup may be different depending on your specific requirements. Amongst available options: pin and gear, chain drives, friction, and direct drive. Different setups serve different purposes. For example, chain/sprocket system is perfect for small application where 75 horsepower is more than enough. On the contrary, gear/pinion system is more suitable for heavy-duty purposes where you need more power. In order to control power output, your drive assembly can be equipped with a reducer. Small drums can be also powered by a friction drive system that works on a shaft mounter engine and reducer. The direct option is usually selected for bigger applications, but rarely for those that require more than 70 horsepower. Direct option, as the name suggests, is one of the most efficient setups with both an engine and reducer connected directly to the shaft.

Riding Ring

This is a very important part for the shell. A small pressure-consuming add-on drastically reduces mechanical wear of the equipment.

Thrust Rollers

Supportive mechanisms for the riding ring that allow you to move it or fixate its position.

Trunnion Wheels

This part of the construction takes off the shell a lot of pressure. Trunnion wheels ensure that the rotating motion is smooth and that the drum never skews its rotation axis. This part is usually build cheap as it is hard to prevent mechanical wear. Trunnion wheels are easy to replace.

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