Flintec Learn
What is a Beam Load Cell?
A beam load cell operates as a simple cantilever that flexes slightly when subjected to a force or weight. The single-ended beam load cell is the most common type and behaves similarly to a diving board, with one end fixed and the other free. Additionally, there are double-ended beam load cells, which are secured at both ends and bear the load in the center, resembling a hammock's structure.
Beam load cells are commonly categorized into two other subtypes, based on their method of measuring force or weight. Bending beam load cells determine the extent of bending distortion, while shear beam load cells evaluate the shear distortion.
Beam load cells represent the largest and most versatile group of load cells, covering an extensive range of capacities, diverse mounting options and accessories. They are often used in combination with larger weighing equipment and scales when the use of a single-point cell becomes impractical.
How Do Beam Load Cells Work?
A beam load cell, like all other modern load cells, is essentially a transducer that converts force or weight into an electrical signal by way of strain gauges. When a load is applied, the body of the load cell flexes due to the elastic properties of the metal material from which it is made. Attached strain gauges, strategically positioned and secured to the surface of the load cell, will also stretch or compress alongside the main body. This alters their electrical resistance and leads to a change in the voltage across the circuit. This effect is proportional to the initial force or weight, allowing it to be calculated.
Design
Beam load cells, including single-ended and double-ended varieties, come in numerous shapes and sizes to accommodate a broad range of applications. Typically, they all maintain a relatively low vertical profile relative to their length, contrasting with some column-like compression load cells, which often have the reverse ratio, being narrower than they are tall.
Bending beam load cells are designed so that certain parts of the load cell body bend or curve in response to an applied load. They tend to offer high amounts of strain or flex at relatively low forces, which suits them for lower capacity applications.
Strain gauges placed on the convex surface will stretch, while those placed on the concave surface will contract. This means that there are always two surfaces subjected to equal and opposite strain, which is convenient for implementing a full-bridge circuit or for temperature compensation.
A shear beam load cell, although it may look similar at first glance to a bending beam load cell or other types of load cells, works a bit differently. A recess is machined in each side of the load cell, leaving a relatively thin vertical web in the centre. This gives the load cell a cross-sectional appearance similar to structural I-beams seen in construction, and as with them, most of the shear strain is focussed in this thinner vertical web. Strain gauges are mounted on the side surfaces of this web, at 45-degree angles to detect the strain. At the same time, the top and bottom flanges help resist any moment or bending.
Shear beam load cells, including the specialized thin beam load cell variant, have become quite popular for medium and high capacity applications, featuring excellent resistance to side forces. They are typically not made for low capacity owing to the difficulty of needing to make a web thin enough to obtain the necessary strain levels. Bending beam and single-point load cells would be more suitable in such use cases.
Flintec Products
Flintec has a broad range of beam load cells for purchase, accommodating both large and small volume orders. All of our products are entirely manufactured by us, ensuring high-quality materials and excellent build quality. Should you need something unique, we can help you with a custom solution. We can offer several services, including mechanical design, electrical and software development, testing and calibration, regulatory and certification governance, up to fully project managed projects. Contact us to find out more about how we can help.