Rice Lake Z6 Single-Ended Beam, SS Welded-seal, IP67, OIML C3 - Manual (Page 36)

32 Load Cell and Weigh Module Handbook
16.0 Weigh Modules: Compression Canisters
16.1 Introduction
When mounts are needed in capacities over 100,000 lb,
canister load cell mounts are one of the choices available.
These cells are good in severe conditions and have provided
proven performance for decades in truck, railroad, and
heavy-capacity tank applications. Available in capacities to
500,000lb per mount assembly, most canister mounting
assemblies require more components than mounts using
beam load cells, especially if the mounts are designed to
accommodate expansion.
The load is transferred to the cell through a hardened, convex
load button which mates with a hardened flat loading plate.
The rounded load button and flat plate tend to promote point
loading, minimizing extraneous forces.
16.2 General Mounting Principles
• A compression canister should be mounted on a flat
plate of sufficient thickness to prevent deflection.
The foundation must be rigid.
• The load should be introduced through a spherically
radiused load button which is hardened.
• The load must be introduced vertically along the
center line of the cell.
• The top plate which contacts the load button must
be hardened to prevent peening of the contact point.
• Some external method of both horizontal and vertical
checking may be required.
Figure 16-1.
16.3 RLC Weigh Modules
The RLC self-aligning silo mount, together with the RLC load
cell family, is an ideal solution for medium capacity process
cont ro l , batch weig hi n g, s i l o / h o p p e r a n d b e l t s c a l e
applications.
The RLC mount incorporates a removable rocker pin design
that uses hardened stainless steel components on all load
bearing surfaces. The full stainless steel construction
guarantees long term reliability, even in the harshest
environments.
Allowable Movement
The RLC mount shown in 16-2 tolerates controlled movement
in all directions. The silo or hopper is held captive, eliminating
the need for additional check rods, unless major load
movement is anticipated. The unique design allows the load
cell to be easily removed for replacement.
Figure 16-2.
Construction and Features
1. The RLC load cell consists of three concentric rings
machined from a single piece of stainless steel. The
outer ring rests on the base plate. The middle ring
contains four circular strain gauges. The inner ring
accepts the load and deflects vertically, activating
the strain gauges in the middle ring.
2. A separate loading pin fits into the load cell’s inner ring
and into a hardened bearing cup on the top plate of the
mount. The inner ring vertical travel is limited by the
base plate, providing positive overload protection at
150% of capacity.
3. The RLC ring load cell is held captive in the mount by
three pins at the cell’s outer circumference. To install or
replace the load cell, the mount’s top plate need only be
raised with the integral jacking screws a fraction
beyond the height of the pins.
4. The jacking screws provide lift-off protection as well as
lateral self-checking capabilities to eliminate the need
for check rods.
Figure 16-3.