Key points
Compact solutions for different processes within bulk material handling for the grain industry
Wheat, barley, rye, maize, semolina, bran, groats or oats – to name just a few of the many officially approved cereal varieties you can find during processes in a mill. To guarantee a smooth process flow each stage needs reliable level control of the material with sophisticated sensor techniques.
Today’s animal feed mill is a high-tech, complex manufacturing plant with fully automated processes. The demand for measurement sensors is to work with innovative techniques to meet the variable and complex challenges of this industry. Level controls need to handle granular material, light powders, sticky atmospheres and abrasive process conditions.
The right choice of level measurement detection
The Mononivo vibrating rod level switch has recently been used by a leading UK pet food manufacturer to accurately measure the powdered components during the production of a number of their most popular dog food products.
The manufacturer had tried various types of level measuring devices, including capacitance and vibrating forks, within the product transfer system however had experienced problems due to the small diameter of the ducting.
Level control devices using the capacitance principle had proven to be problematic as the level switch experienced interference from the close proximity of the duct wall which resulted in the creation of false level alarms and thus halting the manufacturing process.
UWT UK Ltd. proposed the use of the Mononivo MN4020 level switch, which uses the vibration principle, as a successful solution to reliably measure the feed additive which was a light powdery consistency with a relatively low density when in transfer.
The availability of a 1” BSP connector ensured that the Mononivo could replace the capacitance switch in the transfer duct without the need for any modifications.
Other advantages for the customer included the ability to adjust the sensitivity of the Mononivo easily via an internal switch meaning that the device was versatile enough to use to measure different materials, whatever the product size or density.
Also the IP67 enclosure allowed them to use the Mononivo not only inside the plant but also in applications on the external storage silos. The 316 stainless steel shaft also met the high hygiene standard requirements.
Since installing the UWT Mononivo level sensor, the false alarms that the customer had been previously experiencing have ceased which in turn has reduced the plant down-time and so production has increased.
Individual product concepts – flexible, modular and economical
UWT configured the appropriate measurement technology with the vibrating rod probe Mononivo® 4000 so that with its modular design, it could be flexibly configured for several of the mill’s applications – even under constantly changing conditions. It can be used in silos and tanks as a full, demand or empty detector.
Sensor, process fitting, electronics and housing were matched to the specific requirements so that the installation was provided with an effective and reliable measurement technology.
To detect any type of bulk solids the technology with adjustable sensitivity, compact design and robust construction is universally applicable for the varying bulk materials. To ensure the smooth, safe and efficient operation of every single process, a comprehensive range of innovative measurement technology is needed.
After the quality control of the incoming raw material the whole process flow is fully automatically regulated by the miller so that nobody comes into contact with the grain materials during the manufacturing steps.
Due to the compact construction of the vibrating rod Mononivo® MN 4020 including available threads from 1″,s the unit is also appropriate as an overfill detector within pipes and shafts where space is limited. Vertical, horizontal and/or oblique installation is possible. With the adjustable sensitivity the device is suitable to measure light bulk solids from 20g/l.
Electronically stimulated piezos cause the probe to vibrate. As soon as the sensor is covered with material, the vibration is dampened and the resulting electrical current change causes the output signal to switch. For the conveying system the point level detector can generate a blockage alarm for elevators and for the chain and screw conveyors.
Assessing explosive environments
Within mills the grinding processes are areas with potentially explosive environments caused by dust from grain. These areas have to be assessed and classified into corresponding zones. Plant technology also has to be adjusted and approved according to these individual zones.
For level control within the milling industry, MN sensors fulfil the requirements of the ATEX, IEC-Ex and FM directives. Thus the Mononivo® can be installed for safe and reliable use in potentially explosive environments. The dustproof product design of the MN device and the abrasion resistant device materials offer a reliable long-life solution for the miller.
The Mononivo® offers a measurement solution that can be quickly and easily achieved. Focus is on the device’s particularly high compatibility for different container vessels and conditions, which means more flexibility for users and plant operators.
