Load cells are devices used to measure weight or force. They play a critical role in many industries and applications where precise weight measurement is needed, such as in industry weighing scales, medical devices, and scientific instruments. As with many technologies, load cells have seen continuous innovation and improvement over the years. Here is an overview of some of the key advances in load cell technology.
One major innovation has been the development of digital load cells. Early load cells were analog devices, providing an electrical output that varied proportionally to the weight applied. While analog load cells are still widely used today, digital load cells offer higher accuracy and more options for interfacing with modern digital systems. Digital load cells contain electronics for analog-to-digital conversion and data processing. This allows for computerized analysis, storage, and transmission of weight data.
Another important advancement is the strain gauge load cell. This type of load cell uses foil strain gauges bonded to a structural element. As weight is applied, the structural element deforms slightly, causing the foil gauges to change resistance. This resistance change, which corresponds to the weight, is converted to an electrical output. Strain gauge load cells provide high accuracy and sensitivity in a compact device. Advanced strain gauge technologies continue to push the performance boundaries.
Early load cell designs were limited to single-point shear beam or bending beam elements. Today, more complex multi-beam load cell geometries are common. This provides performance benefits such as better linearity, less sensitivity to off-center loading, and cancellation of extraneous forces. Load cells combining both shear and bending elements are able to achieve remarkable accuracy.
One challenging application for load cells is weighing large tank and silo loads in excess of 100 tons. For this, single-point load cells are impractical. New technologies such as types of digital load cells with multiple load introduction points allow even very large vessels to be accurately weighed.
For hygiene-critical applications, sealed load cells prevent bacterial ingress. Stainless steel construction resists corrosion from cleaning chemicals. Explosion-proof load cells are designed to contain internal sparks, preventing ignition of flammable environments. High-temperature load cells withstand use in hot ovens or autoclaves.
Wireless data transmission has freed many load cells from the tether of a cable. Battery powered load cells can be placed in remote locations or on moving equipment. Wireless communication keeps the weight data flowing. This greatly expands the flexibility of load cell placement and application.
On the smallest scale, microscopic load cells measure minute forces such as those encountered in biochemical testing or single-cell manipulation. Fiber-optic load cells harness light transmission within miniature etched glass fibers, providing exceptional sensitivity and resolution.
At the largest scales, gigantic load cells are embedded in roadways to weigh trucks as they drive across. Train weighing systems use long weighbridges outfitted with hundreds of load cells. Oceangoing vessels can be weighed using specially designed underwater load cells.
For critical processes, redundant load cell configurations provide failsafe operation. If a load cell fails, the redundant backup units maintain weighing accuracy. Redundancy ensures uninterrupted operation during load cell servicing as well.
In summary, load cell technology has progressed enormously, providing unprecedented performance capabilities. With innovative new designs and materials, load cells continue to reduce in size and cost while improving in accuracy, reliability, and connectivity. The weight measurement needs of today and tomorrow will be served by these remarkable devices.
