RL9000 TWM
Load Cell Mount
Installation
Guide
To be the best by every measure
89284
Contents
1. Introduction............................................................................. 1
2. Mechanical Installation .......................................................... 2
2.1 General Installation Guidelines for Tank Mounts ....................... 2
2.2 Installing the RL9000TWM ........................................................... 3
3. Load Cell Wiring ..................................................................... 5
4. Junction Box Connections, Adjustments & Calibration ....... 6
5. Troubleshooting ...................................................................... 6
6. Dimensional Drawings ............................................................ 7
7. RL9000 TWM Limited Warranty ............................................. 9
© 2011 Rice Lake Weighing Systems. All rights reserved.
Printed in the United States of America.
Specifi cations subject to change without notice.
1. Introduction
The RL9000 TWM Load Cell Mount provides an extremely accurate method for weighing
medium and large capacity tanks and hoppers that are subject to large thermal expansion/contraction or vibration forces. The design uses a low profi le shear web load cell
(350Ω bridge) and transmits the load via a spherical washer on the load-bearing hub
of the cell. This design is very effective in providing for thermal expansion/contraction
with little friction.
In most applications, the assemblies are selfchecking and held captive with no need for check or
stay rods, making this mount a good choice for most
vessel weighing applications. The shear web design
eases load cell installation and replacement without
the need to raise the weighed vessel a large amount,
which could disturb piping and other connections.
The RL9000 TWM is available in stainless steel, in capacity sizes from 1,000-450,000
lb. The RL9000 TWM utilizes a welded-seal stainless steel load cell.
The installation should be planned by a qualifi ed structural engineer. Each installation
is unique, and this manual is meant to serve only as a general guideline for installation.
The RL9000 TWM is capable of weighing accurately with as much as a 3˚ non-parallel
loading. The RL9000 TWM module offers 100% sideload, 100% uplift and 300%
overload protection.
Thermal
Expansion
Authorized distributors and their employees can
view or download this manual from the Rice Lake
Weighing Systems distributor site at www.rlws.com.
2. Mechanical Installation
2.1 General Installation Guidelines for Tank Mounts
1. The mounting surface for 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 defl ections in legs and supporting structures may cause additional side
forces which greatly affect accuracy. Defl ection 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 eightmount systems should be avoided as even weight distribution becomes extremely
diffi cult to achieve. The load on each mount assembly should vary by no more
than 20%. Add shims where necessary to achieve correct load distribution.
3. Take extreme care to prevent overload damage. A tank or hopper can exert huge
forces when dropped only a fraction of an inch.
4. It is crucial that all piping or conduit be
horizontal and fl exible. If fl exible piping
is not used, make sure distance from
vessel to the fi rst pipe support is 20-30
times pipe diameter. In smaller, lower
capacity tanks and hoppers, isolating
resultant forces becomes extremely
critical. For details, see our Weigh
Modules & Vessel Weighing Systems
manual, P/N 43918.
LEVEL ±0.5
FLEXIBLE PIPING
J-BOX
5. The weighing assemblies should not be
installed 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 mount
when welding to maintain fi nished height. If welding is unavoidable after load
cell installation, connect the ground in such a way that the current does not fl ow
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” load cells in washdown applications. “Environmentally protected” load cells are not suitable for such applications 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 defl ect by the same amount
as the vessel is loaded.
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