Specifications

METTLER TOLEDO Weigh Module Systems Handbook
(12/99)4-4
F = 4,936 lb
30,000 lb gross
5,000 lb tare
c.
g
.
20’
4’
8’
Figure 4-3: Wind Force Exerted on Sample Tank Scale
By using statics (see Appendix 4), we can calculate the maximum downward force and
maximum uplift force:
• Maximum Shear Force: 4,936 pounds (equals wind force
F )
• Maximum Downward Force: 16,138 pounds
• Maximum Uplift Force: 7,388 pounds
Compare these forces with the load ratings chart in Appendix 5. Note that they exceed
the allowable loads for 10,000-pound weigh modules. To accommodate wind forces for
this tank, you will need to use four 20,000-pound weigh modules or add external check
rods that are strong enough to handle the additional force (see Chapter 5).
Alternative Method
The following equation provides a generic method for determining resultant wind force:
F
W
= 0.00256 × V
2
× h
T
× d × S
where:
F
W
= Resulting Wind Force (pounds)
V
2
= Wind Velocity Squared (mph)
h
T
= Height of the Tank (feet)
d = Diameter of the Tank (feet)
S = Shape Factor:
Circular Tanks = 0.6
Hexagonal or Octagonal Tanks = 0.8
Square or Rectangular Tanks = 1.0
F
W
will be the horizontal force applied at the tank’s center of gravity. Use statics to
determine the resulting reaction forces at the supports, and compare the results with the
allowable load ratings to size the weigh modules.
F
W