Grain Systems Blog

Operation of an Air and Screen

As the name implies, air screen machines use a combination of suction air that is drawn through the curtain of grain as it falls from the hopper onto a series of screens. The screens then size the product by width of the kernel, and a final air suction process is used.

With an air screen, the grain is fed onto the screens by either a vibrating feed system or by using a metered feed roll. In either case a feed gate controls the flow and an even flow is given to the machine. Making sure there is an even flow is critical to the quality of the job to be done.

As the grain falls from the feed system onto the screens, there is a process by which air is drawn through the curtain of grain. By doing so, light grain, chaff and dirt are drawn off the product before the grain touches the screens. The air mixed with dirt etc. is drawn into an expansion chamber where the chaff etc. separate and the heavy material is augured out. This process is the first thing that happens and it is also the last process as the grain leaves the machine. Increasing or decreasing the air volume allows the operator to decide how much product he wishes to remove.

Screens size the kernels by width. A system of screens removes any product that is wider than the kernel chosen [scalping], or narrower than the product chosen [sifting]. Screens are generally measured in 64ths of an inch, For example a 5.5 round would be a sifting screen for flax and would be 5 and ½ 64ths of an inch in diameter.

There are several types of screens available in perforated steel. Round hole, slotted hole, and triangular hole are the ones generally used for grain cleaning. There are also a variety of wire mesh screens available for special use. The type of grain dictates the type of screen.

We at Flaman have over 100 years of combined experience in screens, over 55 sizes of screen material in stock, and are dedicated to offering our customers top notch service.

This is one man’s point of view…