Sukup Fastir, Owner’S Instruction And Parts Manual

Page: 39 / 70

Principles of Grain Drying
39
II.
Drying Guidelines to Prevent Bin Wall Spoilage
A large amount of moisture is removed from grain during drying. About 1 gallon of water (3.785 liters) can be
removed from one bushel (.029 metric tons) of corn at 25% moisture.
With so much moisture
present, drying hot grain in
bins can cause sidewall
condensation. Some of this
water condenses on bin wall
and causes spoiled grain,
especially when high drying
temperatures - 100°F (38°C)
to 120°F (49°C) - are used
while outside temperatures
are low. For example, when
outside temperatures drop
below freezing, ice up to 1/2”
thick can form on bin
sidewalls. When sun shines
on south side of bin, ice located there melts, but remains on shaded portions of wall. If bin is filled at this time, ice
on shaded sides is covered up and remains in bin if grain is believed to be dry and operation of fan and heater is
discontinued. When temperature rises, ice will melt and soak into grain, resulting in caking and spoilage of grain.
Hard spots in the bin, sour-smelling grain when bin’s top hatch is opened, and leakage around middle bin sheets
all may indicate this type of problem.
Steps must be taken to ensure moisture is properly removed and to prevent spoilage along bin walls:

Install Sukup Airway tubes , which pipe air from bin plenum to areas along bin wall where it is needed
most, working like a defrosting system on a vehicle’s windshield. Sukup Airways consist of a system of
10’ or 12’ triangular, perforated tubes attached every 9” along inside of bin sidewall. Required number of
tubes is four times diameter of bin. The main purpose of Airway tubes is to remove moisture
condensation and reduce spoilage costs. Tubes work by directing a metered amount of warm air along
bin sidewalls. Ensure tubes are not plugged with fines or bees wings and that flashing is punched so
tubes extend through flashing to allow maximum airflow. Figure 47 shows Airway tubes in bin.

Completely empty bin before filling with final batch of grain.

Dry grain at no more than 100  F (38°C) on final batch. In cooling process (after grain is dried) run fan
with heater for one (1) day at 50  F (10°C) to cool grain (air should not steam eyeglasses when checked),
then run fans with no heat for two (2) days before shutting down system.

Run fans and stirring machines with no heat for 24 hours each month while grain is in storage and only
on days in which humidity is 50% or less.
Sukup Manufacturing Co. also suggests the following to prevent grain spoilage caused by moisture condensation:
Bin floors with perforated flashing to ensure maximum airflow along bin wall.
Fans providing a minimum of 1.75 CFM/bu (117 m³/hr/MT) when bin is full. See Table 14 for recommendations.
Table 14 - Minimum Fan Recommendations Based on 16' (5 m) Grain Depth and 1.75 CFM/bu (117 m³/hr/MT)
Bin Dia. Type of Cent. Fan Fan Qty Type of Axial Fan Fan Qty
24' 10 hp 1 28" 10-15 hp 1
27' 15 hp 1 “ 1
30' 20 hp 1 “ 2
33' 10 hp 2 “ 2
36' 10 hp 2 “ 2
42' 15 hp 2 “ 2
48' 20 hp 2 “ 3
Figure 47 - Sukup Airway System in Bin