?Phew, I?ve not gained anything!?: Aren?t you relieved when your bathroom scales show that? Probably ? but actually Naked don?t measure your weight directly. Instead, the load cell built into it converts the weight force into a path. In lots of industrial applications, bending beams and shear beams tend to be useful for such measurements.
Background: How is weight measured?
Whether your bathrooms scales, a finely calibrated laboratory balance or the gravimetric level monitor of a silo: In every cases, these are measuring instruments that determine a mass. As a rule, they gauge the weight force occurring. But unlike, for example, a beam balance or a spring balance, the load cells used for this determine the weight force indirectly. For this purpose, these force transducers convert the weight force right into a path.
The principle: In the strain cell, the weight force deforms a built-in spring or a bending beam. The intensity of the deformation then gives information regarding your weight, for example (more precisely about your bodyweight force). Sufficient reason for that, it also answers the question of whether you can still order a dessert or simply start thinking about an eating plan.
The ?core? of bending beams and shear beams
The different design stages of force transducers in weighing technology: shear beam, bending beam, single-point and S force transducer.
How can you determine 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 come 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, this is transferred to any risk of strain gauges. These convert the elastic deformations proportionally into electrical signals. Such changes in resistance can be easily and very accurately measured: with a measurement accuracy of between 0.01 % and 0.05 % Fnom. The calibration is manufactured in grams, kilograms or tons.
Instead of these glued foil strain gauges, you can find force transducers with welded-in thin-film sensors: a technology that the WIKA Group excels in and with which, in the field of force measurement, it’s the only supplier out there. The thin-film technology offers a consistently high quality, an exact measurement directly in the force flow, excellent temperature characteristics and a higher long-term stability. With bending beams and shear beams, the standardised sensor is welded into the measuring element using a laser, which enables automated series production.
Application fields for bending beams and shear beams
Bending beams and shear beams are employed in weighing technology to look for the weight of small and medium-sized vessels and are also frequently used in effect measurement. In agricultural engineering, for instance, such load cells are generally encountered: for example, when weighing livestock, dosing animal feedstuff, in gravimetric level monitoring of 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 can be used in a wide variety 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. In particular, in applications in the building materials industry, the chemical industry, the food industry and medical technology, bending beams and shear beams tend to be 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 this gravimetric level monitoring. This measurement method offers a number of advantages:
Level and the exact mass could be measured simultaneously.
Usage of the tank or vessel is not needed (this eliminates connection with the medium).
The measurement is independent of 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 must not affect the measuring result and the permanent function. This also 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 sparkles too: In the agricultural industry bending beams for weighing are very much in demand. When sowing or fertilising, for instance, lots of money can be saved through the exact distribution of the goods. The basis for this, as is always the case with automation, are exact measured values, which explains why high-precision shear beams (which are also insensitive to side loads) are perfectly suited.
Bending beams, shear beams and other load cells: versatile problem solvers
Bending and shear beams are being among the most popular load cells. According to the field of application, there are other force transducers which you can use. Our program includes load cells designed for ranges between 0.3 kg and 300 t.
Single point load cells. These are found in weighing technology for platform scales with smaller and medium sizes. Also, they are known as ? Violated ? 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 as the installation; furthermore, the design is robust.
Tension/compression force load cells. They 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 merchandise range for force measurement, e.g. our bending beams and shear beams, can be found on the WIKA website.
See also our article
Load pins: Definition and application areas