70 years on, and still going strong

Originally invented in the 1950s, ABB’s Pressductor load cell has become the technology of choice for measuring force in a range of industries. We look at the story behind its development and explain why it is still going strong 70 years after its launch.

Technology | November, 2024

To the casual observer, great ideas can sometimes seem to arrive like a bolt from the blue in a moment of inspiration. In contrast, the people who actually invent things understand that’s almost never the case.

As a pioneering scientist and serial innovator, Dr. Orvar Dahle was all too aware that the process of invention is rarely a spontaneous event. He understood that each new idea builds on the body of work that came before and is typically driven by need – especially in an industrial environment. He even coined the phrase ‘invention on demand’ to describe this process.

While his career was peppered with good ideas, Dahle’s crowning achievement – invented in collaboration with his wife, Birgit - is 70 years old in 2024. Known today as Pressductor, the Dahle’s groundbreaking sensor technology is still going strong and continues to enable manufacturing improvements all these years later.

The intervening decades have seen ABB systems based on Pressductor become the go-to solution for measuring force, tension, pressure and torque in harsh industrial environments such as metals, paper and plastics production. Their strong track record in these sectors also means they are increasingly finding their way into more recent high-growth industries such as battery production.

In 1954, both Orvar and Birgit worked at Asea – later to become part of Asea Brown Boveri (ABB). When their patent was published, it marked the arrival of a truly novel measurement technique based on the magnetoelastic effect. Rather than relying on the approach used in conventional strain gauges, which bend or stretch the measuring element to produce a signal, magnetoelastic technology relies on the ability of certain steels to alter their magnetic properties in response to an applied force.

Pressductor technology

Today’s Pressductor® transducers contain two perpendicular windings of copper wire running through four holes of a steel block. An alternating current is applied to generate a magnetic field in one of the windings. When the transducer experiences a mechanical force, the magnetoelastic property of the steel alters the magnetic field pattern, inducing an AC voltage in the second coil that is proportional to the force.

The arrival of Pressductor® in the 1950s clearly followed the ‘invention on demand’ template, being built on previous work and answering a pressing need at the time.

When the initial patent was published, global steel production was about 200 million tonnes a year. By 1970 – just 15 years later - it had tripled. It would be crazy to attribute that growth to the arrival of the new measurement technology, but the invention clearly happened at the perfect time, with a new generation of rolling mills demanding increased productivity, as well as better control and higher quality.

Today, ABB incorporates Pressductor® technology into a family of related instruments and measurement systems aimed at different applications. It’s still best known as the go-to solution for tension measurement in the metals and paper industries, but you can find it anywhere where products are manufactured as a strip or web.

And it doesn’t stop there. Magnetoelastic sensors also crop up in some wide-ranging applications, such as monitoring the torque on large ships’ propellers, weighing molten steel, ensuring that the supports for North Sea oil rigs are welded together properly, printing newspapers in Oslo, manufacturing the soft fibers for baby’s diapers, optimizing flatness for production of aluminum cans and batteries, and even helping to extend the life of London’s iconic Tower Bridge.

The future looks bright for systems based on Pressductor® technology. Standards of living are improving in many parts of the world, resulting in increased demand for consumer products such as vehicles and white goods, which all depend on a steady supply of high-quality rolled materials.

These solutions can also support manufacturers in the face of some of their biggest challenges and opportunities. For example, they help optimize environmental performance by improving accuracy and reducing off-specification product, waste and reworking. And, as the pace of automation increases, all forms of manufacturing will demand precise measurement data and analysis. Pressductor® technology is ideally placed to meet that demand.

All this means that, as we celebrate the first 70 years of Pressductor®, the coming decades look to be just as successful.