Self-centering pendulum load cell
These load cells automatically guide the superstructure back to its original position when the load is introduced with lateral displacement (inclination). The process makes use of a well known principle of physics, the state of stable equilibrium. The load cell, acting as the body of a pendulum, has load application surfaces with a total of bending radii greater than the height of the load cell. A deflection thus causes the load to be raised, which in turn causes it to return to its original position.
The maximum permissible deflection specified in the data (for example a maximum of 13 mm / 5° for type C16/40t) must never be exceeded. Doing so could damage the load cells or load application points. The problem can easily be solved with suitable adjustable stops on the superstructure. In many cases, however, it will also be necessary to use stay rods in this installation situation.
Two HBM thrust pieces, one on the top and one on the bottom, are inexpensive and easy to install and adequate for this purpose. A rotation stop prevents impermissible rotational movements around an object's own axis.
The self-centering HBM C16 load cell is currently available as a pendulum load cell with maximum capacities from 20 t to 200 t. They are suitable for moderate to high accuracy requirements.
Pendulum bearing and pendulum support
A pendulum bearing and pendulum supports make it possible for standard load cells with beam profile and C-type profile to achieve properties similar to those of self-centering load cells. In this manner the tank weigher setup can meet high accuracy requirements. The design of the pendulum bearing mounting parts allow for a deflection of about 3° without any significant measurement errors. Horizontal displacement of support points is therefore possible within limits. While ZPL pendulum bearings usually consist of two thrust pieces and one cylinder piece, only one cylinder piece and one EPO3 thrust piece perform the relevant function in the ZPS pendulum support.
When the pendulum bearing is deflected, the load is raised slightly compared to its original position. This produces a restoring force which returns the system to its original position. Pendulum bearings and pendulum supports can thus be considered as self-centering. They are easy to handle when used as mounting aids during installation. Lateral stay rods are not required to restrain a platform in place. Limiting lateral deflection with end stops is recommended, however. Stay rod restraints must always be provided for tanks with stirrers. As noted previously regarding the use of elastomer bearings, for safety reasons the tank must also be protected against being raised or tipped ove
|C2A with ZPS||Z7 with ZPL|