Aspiration Problem 1

[ingmap]

I have to reduce the dust wich is generated by the load of grain to be processed. I don't know wich is the real calculation about this. How the air flow relations with the dust?.<br>
If anyone know aboutit, please tell me.

 

[MikeVV]

Grain contains a LOT of dust - as a young man I worked in a grain elevator during harvest - one of my duties was that of sweeping up dust at the top of the elevator. I swept dust every hour and each time I was moving a layer at least 6 inches thick that gathered from the previous hour!<br>
<br>
Reducing dust in the facility could be done by pulling it out of the grain before processing OR by keeping the dust sealed up with the grain during processing. Does your process require that the dust be removed or simply controlled?<br>
<br>
Dust can be pulled out of the grain using forced air - it usually comes out in areas where air flow can move "lighter" particles but not heavy ones - like at the junctions in pipes. I beleive that the momentum of the moving grains is too great for them to leak out of the pipe joints but the momentum of the dust particles is not so they escape (to be swept up by young men).<br>
<br>
Air may carry dust because of its shape (feather vs. rock) or because it is light (small particle vs. big particle). Also, the "dust" in grain is really many different things - dirt, rocks, grain matter, bugs, weeds, etc. Mechanical combines use seives AND airflow to separate seeds from chaff. Much of the material separated is also "dust". Relating air flow to its capacity to carry dust can be done statistically and mechanically. I believe the best (and most accurate) method is experimental however. The range of "dust" properties (size, shape, mass) is such that a statistical approach is required. These properties are needed to predict air flow required for moving or separating the dust from the grain. This action is also influenced by humidity, temperature and physical arrangement - Taking dust from wet grin in a humid environment would be harder than from dry grain in a dry environment for example.<br>
<br>
Mike Van Voorhis<br>
MJVanVoorhis@Compuserve.com<br>