What is a bending beam load cell?
Bending beam load cells are the most commonly used load cell types and are one of the main types of load cells in industrial weighing and laboratory technology as well as in the process industry. Typically, bending beams are fixed at one end and are free at the other end. However, there are also symmetrical variants that are attached at both ends and loaded in the middle. Bending beam load cells bend slightly when a force or weight is applied and are thus responsible for determining forces in a wide range of applications. To determine how high the force is in the application, strain gauges or thin-film sensors, which are attached to the measuring body, are used. With the help of the strain gauges and thin-film sensors, the force or weight is converted into an electrical signal.
What is a shear beam load cell?
Compression forces are required for the operation of shear beam load cells. The main element of a shear beam is an elastic body that deforms when force is applied and returns to its original state when the force ceases. Just as with bending beam load cells, the deformation is detected by strain gauges or thin-film sensors and converted into an electrical signal. Shear beam load cells are often used for a medium and high loads and are known for their very good resistance against lateral forces. The difference to bending beams lies in the thin vertical I-beam cross-section in the centre of the load cell, which is created by the machined recesses. In this vertical I-beam cross-section, the greatest portion of the shear strain is focused. The strain gauges are attached to the side surfaces of the beam to detect the strain.
How do shear beam and bending beam load cells work?
Both shear beams and bending beams use strain gauges or thin-film sensors attached to, or in, the measuring bodies to measure force. When using bonded strain gauges, the strain gauges deform when the measuring body deforms. Through the application of force and the associated deformation, the strain gauge stretches or compresses, causing the resistance to change. When compressed, the resistance decreases, whereas it increases when stretched. Using an electrical signal, the difference between input and output signal is measured. This value is then converted into a readable weight value.
WIKA is the only supplier in the field of force measurement that also has force transducers with welded-in thin-film sensors in its product portfolio. The standardised thin-film sensor is welded into the measuring element using a laser, enabling automated series production. The thin-film technology guarantees high quality, high long-term stability, precise measurement directly in the force flow, and very good temperature characteristics.
Where are bending beams used?
Bending beams are used in process and laboratory technology, in dosing units and in hopper and industrial scales. They are used in dynamic and static measurement projects.
Where are shear beams used?
Shear beams are used in various types of scales, such as floor scales, weigh feeders and platform scales as well as in laboratory technology and stage construction. Shear beams with thin-film technology are used in industrial weighing technology, in machine building and plant construction, in factory automation and also in theatre and stage construction, in the chemical and petrochemical industries and for weighing in safety applications. Shear beam load cells are not normally used for low loads as the I-beam cross-section cannot be constructed thinly enough to achieve the required strain values. For these very low loads, load cells are suitable. With very high loads, the limit is 100 kN and 10 t, respectively.
