In the past few weeks I’ve looked at a lot of fans that suffered damage from winter snows. A common problem is a broken discharge cone on a fan due to snow and/or ice sliding off of a steel room. It has also been common to see discharge cones broken or even missing on tunnel fans.
While the ventilation system won’t fail due to the damaged fan housings, operating costs will be higher as more fans must run to move the same amount of air. The same is true when pit fans haven’t been cleaned since last fall.
While fan maintenance may not be a high priority for many as they struggle to plant corn between rain storms, getting fans operating up to snuff needs to be done. This time of year we see temperatures ranging from the low 30’s at night and even remaining in the upper 30’s some days, to +80F. These abrupt changes in outside conditions tax the ventilation system and inefficiencies in air flow due to damaged fan housings only add operating costs to the system. If the damage is severe enough, the system may not be able to keep pigs comfortable on the first hot days that are coming our way.
In general, the addition of a discharge cone to a fan adds 15% to the capacity of the fan. Discharge cones improve fan operating efficiency by controlling how air leaves the fan blade, allowing more air per turn of the blade to be pushed from the facility. Depending on how the discharge cone is damaged, fan output may not just drop back to the equivalent of a fan without a cone. I’ve seen broken cones result in fans operating and not being able to even fully open the shutters on the fan on a day with no wind.
While pit fans don’t move much air relative to the amount moved by 52” tunnel fans, their correct operation is still important, especially on chilly mornings or when we’re starting small pigs. Now that the snow drifts are gone is a good time to do a quick walk around to be sure all fan louvers are functioning, pit lids remain tight, etc.