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How To Maintain Fans And Optimize Their Performance For Improved Cooling And Reduced Costs

How To Maintain Fans And Optimize Their Performance For Improved Cooling And Reduced Costs

Monday, July 04, 2016

Poultry house fans; we all have them - and depend on them, to maintain optimum growing conditions year round, so whether our primary concern at the time is maximizing fresh air intake, ammonia reduction, or heat removal, regularly ensuring our fans are performing at peak levels has to be an extremely high priority in every grow-out cycle.

Although it's surprisingly often overlooked in a regular maintenance schedule, attentive fan care can significantly improve house conditions and reduce your costs too. Some of the key elements here are to make sure your fans are properly cleaned, the belts are tight, bearings are greased, and louvers are working properly.

By performing these few simple tasks you'll see an increase in revolutions per minute and reduce how hard your fans have to work to move air, which essentially leads to the same fans using the same amount of power - but moving a lot more air. From my own experience, this then reduces the number of fans required to do the same job, while also minimizing your power consumption and reducing fan / drive belt wear for a lower ongoing maintenance cost.

As many of us know all too well, in the hot summer months the temperature can spike fast, resulting in elevated mortality due to heat stress as well as a reduction in feed consumption and corresponding weight gain. In this scenario, the compounding problem is that when the house is warmer than optimal temperature, the birds tend to sit down and pant, trying to cool down. Unfortunately, this only traps heat between their bodies and the floor, which raises their body temperature even more.

In many instances though, attentive fan maintenance could literally prevent the outside temperature spike from negatively affecting the birds in the first place, or at the very least greatly reduce any potential repercussions to your flock.

"Attentive fan maintenance could literally prevent the outside temperature spike from negatively affecting the birds." - @poultryservices - Click to Tweet

Different Fans - Their Advantages and Disadvantages

Most of the poultry farmers where I live use "belt drive fans", including myself. They seem to last longer, they're easier to work on, and the belt drive ensures a more consistent load on the motor, so it doesn't overheat and shut down.

Recently it seems that many of the newer houses are being fitted with "variable speed fans" to allow for minimum ventilation, however this trend has produced mixed results.

These days, the least common fans are "direct drive fans" - these are usually the cheapest fans to purchase, but when the motor, fan blade, or bearings go bad, the entire fan usually needs to be replaced.

The direct drive fan motors also tend to overheat and shut down when any significant load is placed on them: meaning if you're using a direct drive sidewall fan and your tunnel fans come on there's competition for the available air, so as the pressure in the house increases the load on the motors also increases, often causing the direct drive fans to overheat. 

For example, farmers using direct drive fans for minimum wall ventilation often find it necessary to switch over to using a tunnel fan for minimum ventilation as soon as they open and activate their tunnel fans; otherwise the competition for air puts too great a load on the direct drive motor and it overheats.

Importance of Keeping the Belts Tight on Belt Drive Fans

When using belt drive fans, it's essential to keep in mind that loose belts can cause several ventilation issues, including a reduction in revolutions per minute (your fan blades), reduced air flow, increased wear on belts, and even accelerate bearing failure.

When the belt isn't fitted tightly it's not fully engaging the pulley, so when the motor makes a revolution the belt doesn't turn the pulley spinning the blade proportionally every time it rotates. This slippage can wear a belt out very quickly, especially when the slipping friction on the sides of the belt is well beyond acceptable levels.

The motor however, is still working just as hard as it would be if it were turning the fan proportionally with every revolution, so you're paying for the power but not getting maximum efficiency.

Along with the reduction in air flow in this instance, more money is then wasted when the house's controller has to turn on an additional fan (or more) to cool the house to the proper temperature. Compounding the issue further, the vibration sent down the fan shaft from the slack belt on the rerun side jumping adds additional stress on the bearings by stressing them inconsistently, and this can greatly accelerate bearing failure too.

The most obvious indication of an extremely loose fan belt is when the louvers or butterfly doors fail to fully open. As this can often be seen from a good distance away, make sure to address the issue immediately should you spot it.

When the belt is only slightly to moderately loose though, you'll see the return side of the belt (not the side doing the pulling of the pulley) jumping from the excess slack. In either of the two above instances, always attend to your fans straightaway.

Drive belts often first become slack due to stretching of the belt itself; a new belt that has never had a load placed on it hasn't been pressure tested, so as it's used and worked it will naturally stretch to some degree. So if you're using an interlock style belt, a few links will need to be removed to tighten the belt up, however when using a solid belt a tension arm should remove any excess slack, if it's working properly of course.

If the solid belt is operating with slack you probably need to loosen up the tension arm to remove the slack. If you're unable to get the tension arm operating properly an interlock belt can be used in its place. I install the interlock belt by bypassing the tension arm and installing the new belt from the drive directly to the blade’s pulley.

If a slack belt isn't corrected the sides of the belt wear down very quickly, causing the belt to sit deeper in the pulley’s channel. Sitting deeper in the channel reduces required belt length even further - so the belt becomes even looser, which can quickly escalate to belt failure. 

It's important to note that fan bearings which are greased regularly and have tight belts can last for many years.

Dirty or Malfunctioning Louvers or Fan Fences

Fan fences are used to prevent birds, equipment, and of course the caretaker’s body parts from inadvertently getting into an operating fan and causing injury or equipment damage. The fan louvers can be positioned on the inside or outside of the fans, closing when a fan isn't in use, thereby preventing a backdraft of air and loss of heat.

Both of these pieces of equipment are critical to the efficient and safe operation of the poultry house, however if they aren't properly maintained both can also cause a reduction in air flow, resulting in wasted power, reduced weight gain, and increased mortality.

It may not seem like it (it sure didn't to me), but a buildup of dust and feathers on the fences or louvers can significantly reduce air flow, specifically due to restricted access to free flowing air and increased friction on the air that's actually getting through. 

The fan fences that keep us and our equipment safe through the cores of operation collect feathers. As these feathers build up, they collect dust - even to the extent of creating a solid wall in places, areas of the fence that literally don't allow air to pass. Even worse, such walls expand quickly because the solid section has more surface area to trap even more material, so once it goes beyond a certain threshold the developing problem only escalates. 

The louvers or shutters are designed in a smooth aerodynamic shape that causes them to open flat when the fan is operating for maximum air access. After extended use (especially if cool pads or internal foggers are being used) dust will accumulate on the edges of the louvers.

Very much like the fan fences, as the dust builds up it creates more surface area and a non-smooth surface that increases the amount of dust that sticks to the louvers. This accumulated dust also adds weight to the louvers, so they don't fully open when the fan is operating. The combination of friction on the air from the tacky nature of the dust and the reduction of open space from the louvers not opening fully can have a major impact on a fan's operation as well as performance.

Luckily both of these problems can easily be resolved with a long soft bristled brush like the one in the picture below. I've purchased one of these brushes for each of my houses; I added a piece of drinker line cord to the handle of each one, and they hang near the tunnel fan end of each of my houses. I found that if I had to walk all the way back to the shop to get a brush, more often than not I'd get side-tracked and wouldn't brush them clean of debris at that time. 

There's no way to measure the savings for sure, but I believe the small upfront cost of my ten brushes has been paid back a hundred times over with the power I’ve saved, the reduction in mortality, and higher weight gain from better feed conversion - all through maintaining the proper temperature more consistently. 

To Sum It Up

Our power bill is one of the largest operational expenses associated with operating a commercial poultry farm and the numerous fans used to keep the birds cool are by far the biggest consumers of power. Doing everything you can to keep this expense to an absolute minimum while reducing mortality, improving feed conversion and maximizing weight gain is just common sense. I hope these tips help you increase your farm's profit potential!

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