Taking a moisture sample when you are drying may seem like an easy process, and in some ways, it is. But it can also give you a false sense of having a very precise result.
Take the case of when you go to the dryer and take a grab sample. You take the sample back to the bench top tester and get a digital readout. Let us say this time the readout is 15.2 percent… So, what does this number mean?
It does not mean that all the grain coming out of the dryer is at 15.2 percent. One way to easily see this is to watch the continuous readout from the Dryer Master, which can move up and down a few tenths of a point over a few minutes.
Another way to see this is to take three samples three or four minutes apart and see if the three samples give you the same reading. In most cases, they will not be exactly the same. The questions begin: Which one is right, and which one should you be using to make any adjustments to your drying?
Small differences are actually a very normal part of sampling. It is all but impossible to get an exact reading that covers all the grain exiting the dryer. There is simply too much inherent variation. This also explains why you may see small differences with your readings and the Dryer Master readings when you are doing calibrations.
That brings us to one of the benefits of Dryer Master. The DM510 continually (6 times a second) samples the grain moisture at the outlet of the dryer, and at the inlet too, so you always have a good idea of the moisture levels going into and coming out of the dryer. The Dryer Master is also aware of these variations and takes them into account when making its control (discharge rate) adjustments.
One of the things that makes grain drying a challenge is the number of uncontrollable variables—such as different moistures, temperatures, wind speeds, and humidities. But there are a few things you may have some control over (at least some of the time) that can make your drying more efficient. In this post we are going to highlight two of them:
Longer dryer runs. The trend to larger dryers has meant that in some cases there is only enough product for short runs, so the dryer may only run for a couple of hours, then be turned off for a few hours. The problem is that the grain that is left in the dryer during the shutdown will tend to come out over dried. And of course, the more often there are shutdowns the more grain will come out over dried. Ideally, the goal should be to try for longer dryer runs when possible because a dryer is most efficient when running continuously at capacity.
Tempering. Many times on the graphs we download from our customers, we can see the clear difference in moisture variation between day time and night time operation.
During the day, incoming product may go straight into the dryer, but as the product is coming from different locations, the moisture may vary significantly from one truck load to the next. This variation in moisture makes drying to a constant target that much more of a challenge.
In contrast, the product being dried at night may have sat for a few hours in storage having some time to temper—or an opportunity to mix with other product. The result is more consistent moisture going into the dryer and an easier process to control.
This entry was posted in Control Technology, Grain Drying and tagged canada grain, canada grain dryer, canada grain drying, corn, grain dryer, grain drying, grain humidity, grain moisture, grain moisture measurement technology, grain tempering, moisture control, wheat.
It may be a bit hard to believe, but we have actually seen cases where a dryer has lost up to 50 percent of its capacity! We don’t want to see this happen to anyone so in this post, and the next one, we will talk a little bit about maintaining dryer efficiency.
Let’s start with the basics. Maintaining maximum air flow is the key to efficient performance. Because drying grain involves hot air passing through the grain, anything that reduces this air flow impacts performance.
With screen dryers, a great deal of moisture is expelled from the top few feet of the dryer. Much of the easy-to-dry product such as fines, broken kernels, chaff (red dog or bees wings) loses the bulk of its moisture here. These particles then tend to get pushed through the screen to the outside where they build up as a wet mess and stick to and plug the screens—thereby reducing air flow.
Over time, this wet section will steadily move further and further down the dryer as the screens in the higher portion above it plug up. This process gradually reduces the effective capacity of the dryer, and when drying capacity is lost, drying efficiency is reduced.
One way to slow this process is to clean the product ahead of drying. This will reduce the broken, fines, and red dog (bees wings) which tend to plug the screens.
This entry was posted in Control Technology, Moisture Sensors and tagged agriculture, bees wings, canada farming, canada grain dryer, coffee, corn, dryer master, drying, farming, grain dryer, grain moisture, midwest grain, north america grain, red dog.