Electricity + Control April 2018

COVER ARTICLE

VEGA provides fast, reliable stocktaking in a grain mill using Vendor Managed Inventory

FEATURES: • Control systems+ automation+ systems engineering • Flowmeasurement+ instrumentation • Electrical protection+ safety • Lighting • Transformers+ substations

ECAPR2018 cover.indd 1

3/29/2018 8:48:02AM

T he manufacturing processes in the biggest grain mill in Switzerland – Swissmill – are com- plex. Every processing step, intermediate storage and delivered product quantity is recorded and cal- culated meticulously. The measured values from VEGA's installed level sensors, which form the basis for reliable tracking of the product streams, make this possi- ble. In conjunction with VEGA'sWeb-based Vendor Inventory System (VIS), a software system for data recording and visualisation of level data, optimum logistics of raw materials from the supplier up to the production plant are enabled. From a level measurement point of view, flour is not easy to measure. A lot of dust is generated during the filling process and the dust cloud settles very slowly in the silo. The estimated 120 various types of flour all differ slightly in their dielectric constant (Dk). In summer, when the grain is dryer, it is even more difficult because the dielectric con- stant drops further. One of the more challenging measurements is bran, which only has an epsilon value of 1.4 in the summer. Adding to the meas- urement difficulty is the fact that the bran is stored in a very slim, 10 m high steel-reinforced concrete silo. “Thanks to VEGA's products, we are manag- ing very well,” says Mario Keller, Head of Electri- cal Maintenance at Swissmill. I will never forget how, 25 years ago, a VEGA technician visited us, analysed the measuring situation with the bran and explained that we must approach the problem from a different angle. A few months later, a new device, at that time still a VEGAFLEX guided wave radar sensor with adapted software, was installed and it really did provide reliable measured values.” Over the years, new sensors from VEGA have been tested again and again. On rare occasions, the cable of the guided wave radar would twist and get trapped in the grain. This sent a false meas-

uring signal. This measuring instrument type was replaced by the VEGAPULS 69 radar level meas- uring instrument which operates with a frequency of 80 GHz. Since this measure is contact free and can also measure reliably through heavy dust, the measurements now work trouble-free. “However, we must say that, since we have been working with VEGA, measuring uncertainties have never re- ally been a problem because VEGA always feels re- sponsible and takes us seriously,” Keller explains. Level measurements are made all over the fac- tory for which many different instrument types are used. For example, 137 VEGACAP 63 capacitive probes operate in wheat reception. Level sensors are also used for process control, for instance in the production of fodder. When these are pel- letised, the primary hoppers must always be full so that the pellets have the right density later. A reliable measuring signal is therefore crucial in the overflow cell in the pelletiser because other cells can be opened or closed, depending on the level. When the cell overflows, the feeder closes. If the instruments do not function optimally, the mills may even be shut down. Here, the process planners need a 100% signal because otherwise the whole production plan could get out of control. This is an operation in which up to 200 tons are processed daily. Saves time and money The Swissmill team is convinced that working without level measuring technology would be quite different. “When a holiday is coming up and the bakeries need more flour, we can start produc- tion a week earlier thanks to our reliable stocktak- ing. Previously, we had to work special shifts to compensate for bottlenecks,” says Keller. Swissmill recognises VEGA as a problem solv- er and VEGA sensors are a set standard for level measurement at the factory.

Enquiries: Chantal Groom. VEGA Controls SA Tel: +27 (0) 11 795 3249 or email: chantal.groom@vega.com

Electricity + Control

APRIL 2018

17