Grain Systems Blog

The indent cylinder machine is designed primarily to separate grain by kernel length. It separates long kernels from shorter ones. The cylinder itself is a thin-walled tube with indents formed on the inside to the shape of a hemisphere. These indents are known as pockets.

By using indent pocket size, the kernels that fit into the pocket are lifted up and dropped into a trough that runs the entire length of the cylinder, while the longer kernels slide off and tail out the end. Indent pocket sizes are measured in 64ths of an inch similar to screen sizes used on screen machines. These cylinders are case hardened to give them a longer life span. Cylinders not hardened would wear out very quickly.

The cylinder always lifts up the shorter product that fits into the pocket and always tails off longer kernel; shorter from longer! A smaller pocket like a #13 will lift small weeds like buckwheat while tailing out wheat, while a larger pocket like a # 20 will lift wheat and tail out wild oats. Using combinations of different indent pocket sizes can do very fine separations of these products.

Indents use a combination of pocket size, centrifugal force, friction and gravity to make separations possible. By using different pocket sizes, particles of a certain size are able to be lifted off. The speed that the cylinder turns creates friction and centrifugal force that hold the particle in place. As the cylinder turns, that particle is lifted to a point where gravity takes over and allows the kernel to fall into a collection trough.

Speed of the cylinder is critical: too fast and the kernel is carried too far; too slow and gravity drops the product before reaching the collection trough.  Usually indent speeds are between 42 and 58 RPM. One or two RPMs can make a huge difference in separation and capacity.

The receiving trough catches and carries the lifted kernel to the end of the machine and discharges them into a spout. This trough is adjustable in order to make the cut or separation at the exact point of the particle size variation desired. The separation of the products usually happens between 60 and 45 degrees ahead of top dead centre.

Due to the fact that various seeds have different moisture, surface conditions, and specific gravity it is important to be able to hold the cylinder at a constant speed. Any fluctuations in speed will affect the actual trough adjustment and therefore the separations.

While feed flow and constant cylinder speed are critical, the unit is no better than the person running it. If you take time to understand the operation of the unit and allow a reasonable time after making adjustments you will find that the indent cylinder, regardless of make will do a good job for you. It will do this with minimal attention and service for a long period of time.

We at Flaman have several models and makes of indents available for sale. We are here to help.

This is one man’s opinion...