Rice Lake Mild Steel - Manual (Page 7)

Mechanical Installation 3
2.0 Mechanical Installation
2.1 General Installation Guidelines for Tank Mounts
1. The mounting surface for the base and top plate must be level. After installation,
the top and bottom plates must be level within ±0.5°. If the mounting surfaces are
not level, then shims and or grout may be used to level the mount.
If possible, check that the mount is level when the vessel is fully loaded because
excessive deflections in legs and supporting structures may cause additional side
forces which greatly affect accuracy. Deflection of the mount’s top or base plate
due to loading should not exceed ±0.5°. Reinforcement of legs or other support
structures may be necessary to correct this. Vessels with long legs should have
cross bracing applied between adjacent legs to keep them from spreading under
load.
2. Compression mounting systems use three, four, or more mounts. More than
eight-mount systems should be avoided as even weight distribution becomes
extremely difficult to achieve. The load on each mount assembly should vary by
no more than 20%. Add shims where necessary to achieve correct load distribu-
tion.
3. If the actual load cells are used
during installation, take extreme care
to prevent overload damage. A tank
or hopper can exert huge forces
when dropped only a fraction of an
inch. Dummy load cells can be used
during installation.
4. It is crucial that all piping or conduit
be horizontal and flexible. If flexible
piping is not used, make sure dis-
tance from vessel to the first pipe
support is 20-30 times pipe diameter. For details, see the “Technical Information”
section of the RLWS Load Cell Product Selection Guide (PN 22054). In smaller,
lower capacity tanks and hoppers, isolating resultant forces becomes extremely
critical.
5. Load cells should not be installed in mounts until all welding is completed. The
heat generated from welding current passing through a load cell can damage the
adhesive holding the strain gauge to the body. If possible, use a dummy load cell
when welding to maintain finished height. If welding is unavoidable after load
cell installation, connect the ground in such a way that the current does not flow
through the load cell. For example, if welding on the mount top plate, the ground
must be connected to the vessel, not to the mount base or support structure. Also,
protect the load cell and cable from weld splatter.
6. Use only “hermetically sealed” RL72010MH load cells in washdown applica-
tions. “Environmentally protected” load cells are not suitable for such applica-
tions and will be damaged. If tanks and surrounding equipment are frequently
steam cleaned or if the load cell is subjected to direct washdown, a protective
shroud for the weighing assembly is recommended. Proper drainage is necessary
so the weighing assembly is not standing in water.
7. All support points should be equally stiff so that they deflect by the same amount
as the vessel is loaded.
Level - 0.5
Flexible Piping
J-Box