What is a single-point load cell, and how does it work?

A single-point load cell is one of the major categories or types of load cell commonly found within the weighing industry. Other types include, for example; compression, tension and beam. The defining characteristic of a single-point is its ability to accommodate off-centre loading. Typically, the load needs to be aligned with the cell to maintain accurate readings. If the weight moves off-axis, it introduces error. Single-points, due to their geometric design, allow for some flexibility, and can thus maintain accurate readings even if the weight is unevenly distributed.

This ability makes them perfect for use in platform scales where there can be some variability in load placement. Objects can be placed anywhere on the platform, and its weight will still be measured accurately. Practically this is of enormous value, as it removes the effects of human error in placement. Businesses can avoid the need for specialist equipment or training simply to get accurate readings. Furthermore, a scale can be build using a single cell, as opposed to needing a combination of cells placed at each corner.

Working principle

Single-points, like all other modern load cells, are essentially transducers that convert force or weight into an electrical signal. They do this by using strain gauges, which are attached to the body of the load cell. When under load, the shape of the load cell deforms slightly. This change is detected by the strain gauges which distort in unison with the body, resulting in a change of voltage. This voltage signal is proportional to the initial force or weight and can thus be used to calculate it.

Design

Single-point load cells come in numerous shapes and sizes to accommodate different types of applications. All of them feature an inner aperture, which is a geometrically precise cut-out of the body. This is often what visually distinguishes them from beam load cells. This aperture controls the thickness of the metal at various points across the load cell body and is the key to the cell’s ability to accommodate off-centre loading.

Single-points are usually constructed of either stainless steel or high-grade aluminium, the latter being most suited to lower capacity use. They come in both potted or hermetically-sealed versions depending on the degree of environmental protection needed, with some models offering ATEX approval for use in hazardous areas.

Flintec Products

Flintec has a comprehensive catalogue of single-point 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.