Grain dryer maintenance
Feb. 1, 2011
When the harvesting and drying season is over, probably the last thing on your to do list is dryer maintenance. However, year-end dryer maintenance is extremely important to make sure that your dryer operates at its best the next fall or whenever it is called upon.
Dryer manufacturers will tell you that there are really three times that dryer maintenance should be performed: preseason, operating season and postseason. POSTSEASON MAINTENANCE
The most important part of postseason maintenance is a complete cleaning of the entire unit. Whole grain and fine accumulations in the dryer that are left after the dryer has been shut down can cause signifi cant problems later on. Since the dryers are exposed to the outside elements, rain and snow will get into the dryer and the fines and grain left over will become wet. This will cause possible chemical reactions that can attack the steel of the dryer. Any accumulation of fines and grain can also be an excellent place for insects to hibernate and infect your grain storage at a later time.
Any grain that is attached to the sides or floors should be scraped loose and removed. Likewise, fines should also be removed from the unit. Both vacuums and air can be used to accomplish this. Using a high-pressure washer on the unit is a good way to make sure it is completely washed down. If there is any evidence of rust, the area should be wire brushed or sandblasted to remove any loose scale and then painted to prevent further metal degradation.
It would also be advisable to check all of the wiring at this time. While doing this, check all places where the wire goes into control modules, motors etc., to make sure they are protected against vermin entry. Few things cause more damage to wiring in dryers than mice. Insects can also build nests or accumulate in large numbers in such locations, causing electrical problems at some time in the operation. It is also important to make sure all locations are properly sealed to prevent moisture from getting into the area.
You should also check the burner. With certain types of burners, it is possible that chaff and other small items can accumulate inside the unit. If this is the case, you may have to remove the burner to give it a good cleaning. Even if it is a closed unit, you should examine the small opening that the gas is forced through. Check with the dryer manufacturer to determine the size of the holes. Use a drill bit of the same size to make sure each hole is open and free of any obstruction.
Dennis Haynes of GSI Group, Inc., Assumption, Illinois, U.S., also suggests putting a tarp over the burner. The burner in some dryers is located in such a way that rain can get into the burner and gas supply line. Opening the gas pipe drain plug and covering the burner will prevent water from accumulating in the line and freezing, which can cause damage to the gas line.
You should also check with the dryer manufacturer to see what its recommendations are for blocking the fans. There appears to be two schools of thought on this. One is that it is good to allow the fan to windmill in the wind to keep everything lubricated. The other is that it is better to keep the fan from doing this to prevent wear and tear on the motor bearings. At this time you should also make sure that the gas and electricity are shut off to the unit. PRESEASON MAINTENANCE
Several months prior to harvest, you need to start thinking about the upcoming drying season. The dryer has been shut down for a few months and you did a good job of postseason maintenance, so why do you need to do anything before the harvest season arrives? No matter how good a job you do in the postseason, it is amazing what can happen during downtime.
Some dryer manufacturers have a program where they will, for a fee, check the dryers to make sure they are in operating order. You may decide to contract with the manufacturer for this service or you may decide to do the maintenance yourself. Regardless of what you decide, it is very important to make sure the unit is ready to run days before you need it. If you find anything major during the preseason checks, you will have time to order needed parts and make the necessary fixes.
During preseason maintenance, you need to confirm that all bearings are properly lubricated. If there are relief plugs, be sure to remove them before adding grease. If there are no relief plugs, do not over lubricate. Brent Bloemendaal of Brock Grain Systems, Milford, Indiana, U.S., says that more bearings are damaged by overgreasing than undergreasing. Overgreasing can damage the seals, which creates premature failure.
It is also important to make sure all belts are properly adjusted. A good rule of thumb is that you should be able to push the belt down halfway between the pulleys by one belt width. If the belts show excessive wear, it is a good idea to install new ones before the start of the season. You also need to check the oil in gear cases. Be sure you are using the proper grade and type of oil when you are adding it. If in doubt, check with the manufacturer.
Hopefully you did a good job of cleaning the dryer after fall shutdown. If not, it is imperative that this be done in the preseason period. You need to make sure that all foreign material is removed from both the inside and outside. Clean under the roof, the grain exchangers, hopper divider floor, unloading auger or belts and any other place where grain and fines can accumulate.
Part of the preseason maintenance routine is to carefully inspect the physical structure of the dryer. Are there any tears or rips in either the inner or outer skin? Are there any missing bolts? Does there appear to be excessive wear or rust on the dryer? If any of these problems are found, repairs should be made now so that they don’t negatively manifest themselves during the operating season.
The ignition system and flame-sensing system as well as the wiring should also be carefully checked. Are there any cracks in the porcelain? All wiring connections should be tight. The control boxes need to be checked to make sure that they are clean of all trash and insects and made rodent-proof if necessary. Mice love to hide in control boxes and chew on the wiring. All electronic systems must be properly grounded to function correctly. Make sure the connection to the ground rod has not become ineffective because of rust.
You also must check all gas line connections to make sure they are tight. One of the best ways to do this is to open the gas valve and then spray a solution of dishwasher soap and water at each connection. If there is any leakage, small bubbles will appear. If the line has drain plugs in it, you should have drained the lines in your postseason maintenance. Make sure the plugs are back in place and properly sealed. Also, check the solenoids to see if they are functioning properly. Examine overheat controls make sure they are also working properly.
During postseason maintenance, you should have made sure all openings in the burner were open. Even if you performed this function at shutdown, it is a good idea to check them again prior to the startup. If you are not getting an even fl ame out of the burner, your drying efficiency can be affected as well as having uneven heat in the dryer chamber. SEASON MAINTENANCE
The most important maintenance task during the operating season is to keep the fines accumulation in the dryer heating chamber to a minimum. Fine accumulation is the number one cause of grain dryer fires. You obviously need to do the necessary bearing lubrication based on the operating hours as recommended by the dryer manufacturer. Belts should also be checked for wear and proper adjustment. You also need to monitor the flame to make sure the burner is operating at maximum efficiency.
This article certainly does not include everything that needs to be accomplished in the maintenance of your dryers. Check with your dryer manufacturer to see what type of checklist it has developed. In many cases, you may find that information on the manufacturer’s website. Some of the newer electronic controllers even have checklists and suggestions in them.
Remember, this is a mechanical piece of equipment that is essential to your operation. If properly maintained, it will give you many years of efficient service and the chance of a breakdown during the critical time of use will be reduced.