Gravimetric level measurement in vessels

In the pharmaceutical, building materials and food industries, on vessels and silos, on platforms and dosing systems, right around kitchen and bathroom scales ? weight is measured everywhere. In industry, it becomes particularly interesting when it comes to the particular level in vessels. There are many possibilities for weight measurement or weighing. The filling level can be determined optically, hydrostatically, by ultrasound, microwaves and radar, mechanically, capacitively, by heat dissipation, by displacement and resistance or, what this short article is about, gravimetrically.
The term gravimetric comprises the Latin ?gravitas? for ?gravity? and the Greek ??? ??????? for ?measure?. In gravimetric measurement, therefore, the heaviness of the mass is combined with weight force to create a meaningful value and therefore the level depends upon weighing vessels (the filling level results from the density of the medium and the geometry of the vessel). This makes gravimetric level measurement part of weighing technology.
Gravimetric level measurement is specially suitable when uneven distribution may appear within the vessels.
Gravimetric level measurement: Advantages
This type of weighing has several advantages. Perhaps the greatest advantage is that the force transducers useful for gravimetric level measurement can be found beyond your vessel. Thus, they don’t come into contact with the product. Nor is it necessary to open or modify the vessels. Contamination can thus be eliminated. Cleaning is also easier. Furthermore, very precise measurement is possible ? 0.02 % of the rated load isn’t uncommon when it comes to relative linearity error. This makes dosing possible when, for instance, food is filled into bags ? and of course the packaging must support the amount specified.
Another advantage is that the merchandise will not influence the measurement. The level can be determined gravimetrically for several contents ? solids, liquids, viscous substances, foaming substances ? even toxic or aggressive contents can be considered. Furthermore, the measurement isn’t falsified even though voids or uneven contents distribution occur in the silo or tank, as the entire contents are weighed.
Suitable mounting modules not only ensure that the weight force is properly led into the force transducers, in addition they make installation super easy. The module and force transducer have a minimal height and a small installation volume. However, it really is problematic if the vessels are already permanently installed and will only be placed on modules with significant amounts of effort. Then it is probably advisable to bolt strain transducers to the supports. The strain transducers determine the compression of the supports due to the weight of the contents. They thus be able to weigh immovable vessels gravimetrically.
Gravimetric level measurement: Disadvantages
The disadvantages of gravimetric level measurement vary in significance depending on application. Email address details are mainly distorted when force shunts can’t be prevented. Ideally, the vessel ought to be mechanically decoupled. In practice, however, it can always happen that, for instance, struts are essential. Then it depends on how great their supporting effect is. pressure gauge octa can occur if the measurement is influenced by a high bearing weight. pressure gauge octa of the vessel when compared to product, the more accurate the gravimetric measurement. Finally, free-standing outdoor vessels can be suffering from natural factors. For instance, if wind pushes or snow leads to a significant upsurge in weight.
Typical force transducers for the weighing of vessels
Single point load cells are classically useful for scales. These not merely have a minimal price and high accuracy, however the weight is also determined reliably, no matter where it is placed on the platform. For optimal force introduction, bending or shear beams with the corresponding weighing modules are often installed under tanks, silos or vessels that stand on supports. To determine the rated load of the force transducers, divide the full total weight of the vessel by the number of supports. If the rated load exceeds 10 t, you’ll be able to switch to compression force transducers, the utmost capacity which reaches around 300 t. With four supports, vessels as high as 1,200 t could be weighed with the best accuracy. Alternatively, vessels can be suspended from S-type force transducers or fitted with strain transducers.
Note
Level could be measured in many various ways. Whether gravimetric as described, or with a submersible pressure sensor, float switch or pressure sensor ? WIKA gets the right sensor for every application. Would you like to buy the products? In our WIKA online-shop you will find some of our standard designs. When you have any questions, your contact will gladly help you.
Also read our posts
Bending beam and shear beam in weighing technology
Practical application of strain transducers

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