Load cells are at the heart of every weighing system. These highly accurate transducers have been specifically designed to detect force or weight fluctuations under a wide range of adverse conditions. This information is then converted into an electrical signal which is sent to a remote computer or recorder so that load, pressure and strain, among others, can be monitored.
Picking the Right Load Cell for Your Application
Choosing the right type and capacity of load cell is very important. A compression load cell, for example, is ideally suited for use in heavy duty industrial scales, tank and silo weighing and other, high accuracy applications. These types of load cells can be based on one of four measurements – bending, ring torsion, shear or column.
Compression load cells don't experience the momentum that is often associated with shear beams, meaning they have excellent overload capabilities. However, they are more sensitive to shock loading due to their relatively small deflection.
Tension load cells are primarily used for weights that are suspended, such as hoppers, vessels, or intermediate bulk containers.
Whether you select compression or tension, many installations require 3 or 4 point systems to give an accurate weight reading while balancing the dead weight of the container. The selection of three or four point systems has many factors, and is the subject of a free Hardy whitepaper.
The correct load cell selection, as well as proper maintenance and care, is vital to ensure problem-free weighing throughout the life of any load cell. Hardy helps load cell manufacturers and processors by providing process measurement and weighing solutions that increase productivity, reduce waste and improve quality, often by as much as 50%.
What to Look For
Some of the criteria which needs to be taken into consideration when selecting load cells include:
- The dead weight of the vessel or container
- The operational range from low weight to high
- The collective overall weight capacity of the system
- Legislative requirements, including required accuracy
- The environment in which the weighing system will be used. For example, will it be exposed to extreme temperature fluctuations or harsh chemicals?
- What are the overload requirements – vibration, wind forces, etc.
- How stringent are your accuracy requirements?
Factors such as the dead weight of the vessel and the overload requirements in particular can reduce the live working range of the load cells. This affects the electrical output, which in turn affects the weighing system’s overall performance. That’s why it is so important that you choose the highest quality load cells available for your particular application.
Value-Added: Electronic Calibration
Each Hardy individual load sensor has NIST (National Institute of Standards & Technology) traceable performance characteristics stored on an internal memory device. A Hardy C2 equipped instrument reads these parameters and electronically calibrates the scale for you. A single reference point is entered to calibrate the scale system mechanics. The result is electronic calibration that is easier, quicker, safer, and more accurate than traditional calibration methods
As soon as your weighing system is installed, C2 lets you calibrate it and verify proper scale operation with a small test weight. Traditional calibration with test weights can mask actual scale performance problems, such as container binding. C2 unmasks these hidden performance barriers before you get into production.