A bending beam or sheer beam load cell determines weight indirectly by measuring the deformation of its strain gauge or thin-film sensor. These force transducers are a smart – and often the only – way to measure load in industrial applications.
Direct weight measurement using a balance beam scale.
Direct vs. Indirect Weight Measurement
There are two main types of weight measurement: direct and indirect. Direct weight measurement is what occurs in a balance beam scale, like the type that can still be found in some doctor’s office. Indirect weight measurement, on the other hand, determines weight by measuring the deformation of a measurement body as force (mass) is applied. In a mechanical bathroom scale or a hanging scale, that measurement body is a spring. As the spring is compressed or tensed (stretched), it moves mechanisms that move the scale’s pointer across a dial face.
Electronic weighing devices like digital scales also use indirect measurement, and the measurement body is typically a beam type load cell.
Strain Gauges vs. Thin-Film Sensor in Beam Load Cells
In a beam type load cell, the beam deforms slightly in the presence of weight force. Glued to the beam is a strain gauge that deforms alongside the beam, measures the tiny physical displacement, and then converts that data into an output signal. Such changes in electrical resistance can be very accurately measured, between 0.01% and 0.05% Fnom.
For greater stability and resistance against shock and vibration, some beam load cells have a welded-in thin-film sensor rather than a strain gauge. This is a technology that WIKA excels in and for which, in the field of force measurement, is the only supplier on the market. The sensor is welded into the measuring element using a laser, which enables automated series production. Thin-film technology offers consistently high quality, an exact measurement directly in the force flow, very good temperature characteristics, and high long-term stability.
Bending Beam and Shear Beam Load Cells: Similarities and Differences
Bending beam load cells and shear beam load cells have the same measuring principle, and both types are suitable for static or dynamic loads. But there are a few differences that affect their use case.
Load Cell Type | Load Capacity | Force | Products |
Bending beam | Small: 0…44 lb. (0…20 kg) | Perpendicular | |
Shear Beam | Medium: 0…1,100 lb. ( 0…500 kg) | Perpendicular Parallel (lateral) |
Shear beam load cells (top) are usually rectangular blocks with two machined recesses, while bending beam load cells (bottom two) are cylindrical with a hole bored through the center.
The two types also look different. Bending beams have a hole bored through the center of the cylinder. Shear beams have two partially bored holes, and between them is a thin I-beam cross section.
Bending beams are capable of measuring light loads, whereas the I-beam cross section of shear beams cannot be constructed thinly enough to achieve the required strain values to detect small mass. On the other hand, because shear beams can handle both perpendicular and lateral forces, this load cell type offers high precision and excellent measurement stability regardless of the point of load within a set range.
Applications Where Beam Type Load Cells Are Used
Bending beam and shear beam load cells are found in a variety of weighing technologies in laboratories and industrial processes. Here are a few examples.
- Agriculture: baling presses, on-board weighing systems (seeds, fertilizer, grain, etc.), weigh feeders, livestock weighing, gravimetric level monitoring in silos
- Transportation: material handling, truck scales, floor scale, platform scale, pallet weighing, railroad scales
- Food & beverage: filling machines, weigh/label systems, hopper scales, checkweighers
- Building: stage construction, plant construction, manufacturing automation, forklift scales
- Chemical/Petrochemical: tank and hopper scales
Level monitoring with bending beam or sheer beam load cells
Beam load cells, installed at the foot of a vessel, can be used to calculate the content’s level.
With indirect weight measurement of the content within a tank or silo, beam type load cells – installed at the foot of the vessel – can be used to calculate the content’s height. This is gravimetric level monitoring, and it offers numerous advantages:
- Monitor the content’s level and exact mass with one measuring instrument
- No need to access the inside of a vessel
- Reliable level measurement regardless of the vessel’s geometry
- Level measurement independent of the content’s properties: liquid or solid, aggressive or mild, conductive or nonconductive, foaming or dusty, steaming or icy, hot or cold, small or large grain sizes, even or uneven distribution
- Easy replacement of the bending beam or shear beam load cell as necessary
Robust Load Cells by WIKA
WIKA is a leading manufacturer of bending beam and shear beam load cells. These high-precision force transducers are fabricated from steel or stainless steel for long-term stability. High ingress protection (IP67, IP68, or IP69K, depending on the electrical connection) makes these load cells suitable for the dusty, wet, and extreme conditions found in agriculture, mining, basic materials processing, machine building and automation, and the chemical/petrochemical industries.
The standard output signal is mV/V, which can be amplified to 4…20 mA using a cable amplifier. A junction box, with up to four inputs, can sum the input from several shear beams and output an analog signal. Some models come standard with voltage, current, and digital output signals.
Bending and shear beams are among the most common load cells. Depending on the application, other force transducers may be more appropriate. WIKA offers a complete portfolio of load cells for ranges between 0.3 kg (0.66 lb.) and 300 tons.
- Single point load cells –for small to medium platform scales. Single points are also suited for off-center loads.
- Compression force transducers – for weighing medium and large vessels and silos. These robust load cells are easy to install and retrofit.
- Tension/compression force transducers – mainly for weighing suspended loads, with measurements made directly in the force path. The force sensors in this category include the S-type.
Also available are mounting kits, amplifiers, junction boxes, weighing indicators/displays, and other accessories for load cells.
These and other force measurement solutions are designed and produced by WIKA Sensor Technology in Greater Columbus, Ohio. The 20,000 square foot facility was re-certified to AS9100 quality standard in 2024, and our central U.S. location means that our customers receive local engineering and sales support, quality assurance, quick turnaround times, and a lower total cost of ownership.
With so many types of force sensors, it can be difficult to choose the right load cell for your weighing technology or level monitoring needs. Contact the product specialists at WIKA Sensor Technology for personalized recommendations on the correct bending beam, shear beam, or other load cell for your specific applications.
Products mentioned in this article
• F3203 bending beam load cell (up to 1,100 lbs. / 500 kg), OIML certified
• F3833 bending beam load cell (up to 1,100 lbs. / 500 kg)
• F3201shear beam load cell (up to 4,400 lbs. / 2,000 kg)
• F3301/F33C1/F33S1 shear beam load cell with thin-film technology (up to 22,480 lbf / 100 kN)
• F3831 shear beam load cell (up to 10 tons / 10,000 kg)
• F2802 tension/compression force transducer, S- type (up to 11,240 lbf / 50 kN)