?Phew, I?ve not gained anything!?: Aren?t you relieved whenever your bathroom scales show that? Probably ? but actually your bathroom scales don?t measure your weight directly. Instead, the strain cell included in it converts the weight force right into a path. In many industrial applications, bending beams and shear beams tend to be useful for such measurements.
Background: How is weight measured?
Whether your bathroom scales, a finely calibrated laboratory balance or the gravimetric level monitor of a silo: In all cases, they are measuring instruments that determine a mass. As a rule, they measure the weight force occurring. But unlike, for instance, a beam balance or perhaps a spring balance, the strain cells useful for this determine the weight force indirectly. For this purpose, these force transducers convert the weight force into a path.
The principle: In the strain cell, the weight force deforms a built-in spring or a bending beam. The intensity of this deformation then gives information regarding your weight, for example (more precisely about your weight force). Sufficient reason for that, it also answers the question of whether it is possible to still order a dessert or simply start thinking about a diet.
The ?core? of bending beams and shear beams
The various design stages of force transducers in weighing technology: shear beam, bending beam, single-point and S force transducer.
How can you regulate how far the measuring bodies of a bending beam or shear beam load cell deform? At this point special strain gauges or thin-film sensors enter into play. These are mounted on or mounted in the measuring bodies. In the measurement process, they act as a mechanical intermediate stage.
Example of strain gauges: These are glued to the measuring body. If the measuring body deforms, that is transferred to the strain gauges. These convert the elastic deformations proportionally into electrical signals. Such changes in resistance could be easily and incredibly accurately measured: with a measurement accuracy of between 0.01 % and 0.05 % Fnom. The calibration is manufactured in grams, kilograms or tons.
As an alternative to these glued foil strain gauges, there are force transducers with welded-in thin-film sensors: a technology that the WIKA Group excels in sufficient reason for which, in neuro-scientific force measurement, it’s the only supplier in the marketplace. The thin-film technology supplies a consistently high quality, an exact measurement directly in the force flow, excellent temperature characteristics and a high long-term stability. With bending beams and shear beams, the standardised sensor is welded into the measuring element utilizing a laser, which enables automated series production.
Application fields for bending beams and shear beams
Bending beams and shear beams are used in weighing technology to look for the weight of small and medium-sized vessels and so are also frequently used in force measurement. In agricultural engineering, for instance, such load cells are frequently encountered: for instance, when weighing livestock, dosing animal feedstuff, in gravimetric level tabs on vessels and silos or for weighing straw or hay bales directly in the baling press.
But additionally beyond these fields of application, bending beams and shear beams may be used in a wide selection of other ways: for example, in traditional weighing machine construction, platform weighing (platform scales), weighing in process and dosing systems, vessel scales, crane scales and truck scales. Specifically, in Awesome in the building materials industry, the chemical industry, the meals industry and medical technology, bending beams and shear beams are often installed.
Practical example: Level monitoring with bending beam or shear beam load cells
Checking fill levels by measuring the weight of the vessel and contents: The filling height of a vessel or tank could be calculated from the measured data of the gravimetric level monitoring. This measurement method supplies a number of advantages:
Level and the exact mass can be measured concurrently.
Access to the tank or vessel is not needed (this eliminates contact with the medium).
The measurement is in addition to the material, its properties and the geometry of the container.
The bending beam or shear beam can be easily replaced if necessary.
In level measurement, the load cells must function whatever the nature and condition of the media. Liquid or solid, aggressive, conductive or non-conductive, forming foam or dust, steaming, hot or cold, with small or large grain size, regardless of the geometry of the vessel and if the medium in the vessel is evenly or unevenly distributed: Such factors should never affect the measuring result and the permanent function. This applies in temperature-critical applications and where robustness and high durability are required ? for example in the steel industry.
Shear beams and bending beams in the agricultural industry
In another practical example, stainless steel sparkles too: In the agricultural industry bending beams for weighing have become much in demand. When sowing or fertilising, for instance, lots of money can be saved through the precise distribution of the products. The basis because of this, as is always the case with automation, are exact measured values, which explains why high-precision shear beams (which may also be insensitive to side loads) are perfectly suited.
Bending beams, shear beams along with other load cells: versatile problem solvers
Bending and shear beams are among the most commonly used load cells. Depending on the field of application, there are other force transducers that can be used. Our program includes load cells created for ranges between 0.3 kg and 300 t.
Single point load cells. They are used in weighing technology for platform scales with smaller and medium sizes. They are also known as ?single points? and so are also ideal for eccentric load introductions.
Compression force load cells. Just like heavy-duty load cells, they’re tailored to the weighing of medium and large vessels and silos. The force introduction is simply as easy because the installation; furthermore, the design is robust.
Tension/compression force load cells. These are mainly utilized for weighing suspended loads. Measurement is made directly in the force path; in addition, the installation is uncomplicated.
Note
Further information on the product range for force measurement, e.g. our bending beams and shear beams, are available on the WIKA website.
See also our article
Load pins: Definition and application areas