Combine harvester explained: Class and types of combines, types of headers and how it works!

 Class and types of combines, types of headers, and how it works!

How a combine harvester works

A combine harvester is a machine that harvests crops by performing multiple operations simultaneously. The typology “combine” is derived from the fact that numerous operations are combined inside one machine. These operations include:

1. Cutting- by the header

The crop is chopped by the cutter bar and conveyed into the feeder house.

2. Feeding- by the feeder house

The crop is conveyed from the header into the processing system. This is the “neck” section of the combine.

3. Threshing- by the processor

The grain is removed from the point of attachment with the crop materials.

4. Separating – by the Processor

Once the seed is removed from the straws, it has to be separated from the non-grain material otherwise called MOG (material other than grain).

5. Cleaning- by the cleaning system

Air is used to remove residues of the non-grain materials from the grain.

6. Residue control – by the discharge system

Material other than grain has to be discharged from the combine. Depending on the type of combine, MOG could be chopped and spread as green fertilizer or dropped whole ready for balling.

7. Grain management – by the unload auger and the grain bin

The grain is conveyed into the grain bin for temporary storage before it is emptied into a trailer.

Classification of combined harvesters

Combine harvesters are classified according to their rated engine power. Engine power is measured in horsepower or Kilowatts. 1 KW=1.36HP.

The table below shows the various classes of combines in the market today. You should note that the various classes of combines are just for discussion purposes only and are not a reference for performance or capacity. This classification is reviewed annually by the association of equipment manufacturers.




Less than 280










More than 680

Types of Combine harvester

There are many types of combine harvesters in the market that are different in many ways. However, there are some key features and operations that help in determining the type of combines. In general, there are 4 types of combines which are:

1.    Axial combines

2.    Transverse combine

3.    Conventional combines (straw walker)

4.    Hybrid combines

1. Axial combines

The characteristic of the axial combine is that its rotor runs from front to back of the combine. You can find combines with a single rotor or dual rotor. Axial combines are known to be simple and capable of handling high volumes within a short time, hence the fastest harvesting combines. Axial combine produces low-quality straws for balling.

2. Transverse combine harvesters

The rotor of a transverse combine runs from side to side of the combine, hence the name transverse

3. Conventional combines with straw walkers

A conventional combine harvester uses a cylinder located immediately behind the feed chain and uses straw walkers to separate the grain. Straw walker combines are best known for the quality of straw that they produce which are very suitable for balling.

4. Hybrid combine harvesters

A hybrid combine is a mixture of the conventional and axial combine. It uses a transverse rotor to thresh the crop. After threshing, the crop proceeds to an axial rotor for separation. This means that straw walkers are replaced by the separation rotors. A hybrid combine works at the speed of an axial combine and produces straw's quality of a conventional combine.

Type of combine headers

A multi-crop combine can harvest a variety of crops by simply changing the header. The choice of the header depends on the application (crop to harvest, spacing, grain size, etc.), combine capacity (what’s the combine’s throughput?), and the ease to transport the header along the roads.

The various types of combine headers include the following:

1.    Rigid auger header

It is also called the original combine header and is used to harvest wheat and other cereal grains. It uses a sickle cutter bar to chop the crop. Crops are then pulled into the auger by a reel that has tines. The auger then pulls the crops into the centre of the header and directs it into the feeder house.

2.    Flex auger header

Used for wheat, cereals, grains, and soya beans. It utilizes the same principles as the rigid auger header apart from that the sickle cutter bar is flexible. It is more suitable for crops that are cut close to the ground like soya beans because the sickle bar is flexible.

3.    Flex draper header

Suitable for harvesting crops such as soybeans, wheat, and other grains. It functions on the same principle as flex auger header apart from, instead of a conveying auger, flex draper header uses a belt system to pull crops to the centre of the header and then into the feeder house. This allows crops to lie in the same position (no rotations) hence a smooth feeding).

4.    Power flow header

A power flow header is a combination of flex auger and flex draper headers. It uses the belt system to deliver the crop from the cutter bar to the auger which directs the crop into the feeder house.

5.    Striper header

Used to harvest wheat and rice. Much of the threshing takes place in the header. The header strips the grain from the crop and deflects it into the feeder house. This type of header allows minimal MOG to be fed into the combine.

6.    Pick up header

Mostly used to harvest canola and other windrowed crops. The pick-up-header is used when the crop is cut and windrowed. This header uses a rubber belt with tines to pull the windrowed crops into the feeder house.

7.    Corn header

It a header that is specifically designed to harvest maize. The type of maize header depends on the crop spacing (planter used) as well as the size of the combine.

8.    Sunflower header

It is specifically designed to harvest sunflower crops. The header is also designed for a specific row spacing.

Read also: Rice combine harvester MF 2168 by Massey Ferguson

Read also: The difference between the natural flow (transverse) and axial flow in combine harvester's design