Sometimes the smallest things make the biggest difference – to what could this wisdom be more accurate than on the capabilities of measuring instruments? Often little more than palm-sized and almost inconspicuously placed in massive silos, they still ensure smooth processes in the large dimensions of industrial production. Their continuous use is most noticeable by the fact that nothing happens. That everything goes well in hundreds of cubic meters of compressed, dry bulk material. Measuring instruments ensure that nothing explodes – since explosions are a known threat when large amounts of energy can be released. Dry materials such as mill products can form an explosive atmosphere or mixture with air.
These issues are the incentive for the measurement technology experts at MBA Instruments GmbH in Quickborn near Hamburg. Their applications range from bucket elevators and storage silos to hoppers, ship loaders, and transfer stations. The MBA technologies in the field of level measurement are characterized by coordinated measuring principles and the greatest possible scope for different applications.
Focus on measurement technology
“Non-electrical” products do mainly not generate temperature themselves but transmit the process temperature. The areas inside of product containers are particularly at risk for so-called dust explosions. Explosion-proof devices in mills are cost-intensive and even if these investments are made, the correct pressure relief must be ensured and the filling level must not become too high. This is where level measuring instruments come into play. MBA Instruments has developed a complete series on this subject and has specialized in perfecting them for decades. Companies that have been using devices such as the MBA700 for more than ten years now had previously measured levels with electrical probes – but in some cases could not rely on their perfect functioning. However, this must be ensured so that no incidents can occur which would result in an emergency shutdown of the machines and loss of entire production days. The MBA700 is particularly suitable for light and powdery bulk materials due to its highly sensitive sensor. Deposits are effectively prevented due to the sword-like shape of the vibrating vane, and jamming of bulk material is simply not possible.
The electronic, digital, and MBA patented rotating paddle series MBA800 is mainly based on the stepping motor technology used especially for this purpose. The torque and thus the sensitivity of the unit is variably adjustable in order to be applicable for as many fields of application as possible. Other parameters that influence each other – for example, rotational speed, change of direction of rotation or switching time – are combined in freely selectable parameter combinations. It was particularly important to the manufacturers that the stepper motor series is maintenance-free, wear-free, and insensitive to vibrations in order to be able to guarantee long-term use. And the plug-and-play version, the MBA888, is suitable for quick commissioning. Since 2003, only those devices, components, and protective systems that comply with the ATEX product directive may be used in potentially explosive atmospheres. That directive covers equipment and protective systems that are intended for use in potentially explosive atmospheres. In this respect, the ATEX approval is crucial for measuring equipment that is ultimately intended to prevent an explosion.
Various types in one product line
Within the product series for level measurement, there is also the MBA801 series of pivoting paddles with half-pipe. The wing in the half-pipe is directed 90° downwards and is ideally suited for horizontal, i.e. lateral installation in silos. Thus, the new level switches can be used in positions where the level measurement was previously not possible. As shaft and vane under the roof are completely protected against falling bulk material, the MBA801 halfpipe can also be used in the bulk flow, while the falling bulk material has no influence on the measurement. With the MBA369 plumb bob system, the level can be measured in all kinds of bulk solids. Only a plumb bob system like this can determine the height of sediments below the surface of water or liquids by means of a sieve weight. Furthermore, it is suitable for the continuous level measurement of a liquid level. The mechanical switch MBA100 reliably measures the limit level in free-flowing bulk materials such as granulates, powders, or animal feed. Switching operation is triggered by light pressure of the bulk material on the stainless steel membrane – 950 grams are already sufficient for this. A microswitch is actuated, which switches an electrical signal, while the device itself does not require any power for its function”. Finally, the devices MBA2.2 and MBA3.2 are ATEX-certified rotary blade level indicators which are used in dust Ex-zone 20 and gas Ex-zone 1. The MBA2.2 (vertical version), as well as the MBA3.2 (horizontal version), are therefore particularly suitable for measuring the limit levels of granulate, dust or sludge, if a gas Ex-zone is present at the same time, for example, due to solvent vapors. A measuring blade is driven by a synchronous geared motor, which stops as soon as it is covered by the product. A sinking fill level releases the rotating vane.
Therefore, mill operators and other bulk material processors can feel safe as long as the small devices monitor their huge production processes.Click here for related articles and news
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The SMB Group unites under the SMB and MBA brands the areas filling and conveyor technology, ship loading, storage technology, level measurement and conductivity measurement. With its business focus on planning, development and manufacturing, and the worldwide sale and service of highly complex systems as well as warehousing logistics, SMB Group ...