Danger lurks in, around, and on top of storage silos. In a proactive approach to employee safety, a leading North American cement producer undertook a company-wide initiative to reduce risk. Their solution to keep people firmly grounded in a culture of safety? Automating silo level measurement using a variety of level sensors.
The goal of the silo safety initiative was to eliminate the inherent risks associated with personnel climbing ladders or walking on top of silos to check cement, sand, limestone, and aggregate inventory.
Additional hazards associated with inventory monitoring include opening and closing lids on silos, which can lead to injuries when entering silos. The threat of entrapment in shifting material is also a major concern. To address the dangers of manual inventory monitoring, the cement producer turned to sensors to measure silo levels.
Numerous Sites with Sensors Connect Through the Cloud
When evaluating the company’s worksites, worn-out equipment—such as high-level sensors and dust collection systems—needed to be replaced. In many cases, upgrading to the latest technology was the easiest and most affordable solution, as existing mounting flanges and power connections could be used.
BinMaster first connected with corporate safety personnel. Nathan Grube, BinMaster's VP of Sales – Central U.S., spearheaded the effort and assembled standardized quotes, made available company-wide so each location could place their orders. Local plants worked with BinMaster directly to discuss specific concerns for their location.
The sites had diverse equipment of varying ages and conditions. Locations had anywhere from two to 20 silos, with the average plant housing three or four. More than one material type was being stored. Dust was a significant challenge in sensor selection, as many silos contained powdered cement or fly ash.
Plant preferences and regional weather variations were addressed by offering a variety of sensors, including rotaries, non-contact and guided-wave radar, and SmartBobs®.
So Many Silos & Sensors—All in One Company
Custom Rotaries with a Fail-Safe Bonus
One of the most popular selections across many batch plant locations were extended rotaries used for high-level detection in silos. This sensor prevents the overfilling of silos, reduces wasted product, and eliminates costly downtime due to cleanup. In many locations, outdated high-level controls were replaced with roof-mounted rotaries.
The company overwhelmingly selected the BMRX-300 fail-safe rotary, as continuous sensor operation was critical for continuous production at the plant. The custom configuration was inserted through an existing opening with a collapsible paddle. Custom extensions were outfitted with a seal shaft guard to prevent material from building up on the shaft, preventing interference with the rotary's performance.
The BinMaster BMRX-300 alerts to the status of the rotary if power loss, electronic error, or motor failure occur, allowing it to be used confidently for process control. Visual statuses are displayed via a light on the lid of the unit or can be sent via relay to an audible horn or light mounted at a convenient location.
The cement producer installed about 400 of these fail-safe rotaries as high-level indicators across numerous locations in the USA.
Radars Measure Inventory Levels
The company was also presented with options for continuous level measurement. BinMaster's 80 GHz non-contact radar emerged as the most popular choice, with close to 100 units being installed across the organization.
Radar's powerful frequency excels in high-dust environments, including those typical in the cement industry. The rugged NCR-80 radar was ideal for the environmental conditions at batch plants. With a wide variety of models and options available, each plant could configure the radar for its particular control system and wiring needs. Most plants selected a two-wire version. Some used Modbus communications. When it came to mounting options, most used the metal-jacketed flanged model.
BinMaster offers a 10° swiveling mount option to aim the measurement point within the the silo. While some plants chose this mounting, others opted for the 1-1/2” NPT connection, as this was easier to install through an existing opening.
Non-contact radars are easy to set up using BinMaster's BinDisc module, easily installed under the cap of the device. Following a series of simple push-button steps, each device can be configured in a matter of minutes. Only one BinDisc is needed per location, as it can be transferred quickly from one sensor to another.
Solid & Liquid Measurements with Guided Wave Radar
The guided wave radar level detector was preferred by some plants for measuring the level of solids. An 8 mm cable, suspended from the sensor head, detects the level of material along the cable in silos up to 100 ft. (30 m) high.
Guided wave radars excel in environments with high dust levels, considerable air movement, or excessive noise. Models are resistant to buildup and perform well in conditions with high condensation. The GWR-2000 guided wave radar is compatible with radar sensors, ideal when a location prefers measurements from both sensors to appear in the same software system.
Staying with Proven SmartBobs
Not all plants chose to switch out their level technologies. With weight-and-cable-based SmartBob sensors' long service life, there was no reason to switch to another type of sensor. Some locations even opted to add more bobs to their existing system!
SmartBobs continue to be a popular, affordable sensor for inventory management. The sensors are highly reliable, offer consistent performance, and include wireless options to save on installation costs. When teamed up with Binventory® software or the BinView® web app, inventory data can be accessed from a centralized office location or from a phone or tablet.
Individualized Output Options
With plants of various sizes constructed over several decades, a diverse range of equipment was in use throughout the company.
In many cases, their existing control systems and PLCs were perfectly suited for use with the new level sensors. Some plants chose to upgrade to new inventory management software, while others wanted simpler solutions like bar graph displays. The key was to customize the solution to every plant, which saved costs while meeting the final end goal of improved safety.
Benefits of Level Sensors
By using sensors to measure silo levels and report inventory, the cement producer was able to address dangerous manual practices in inventory monitoring, achieve greater efficiency, and improve overall inventory control. Moreover, complying with safety regulations became easier once level sensors were installed.
The long-term perks of level sensors include labor and cost savings, plus the potential to reduce insurance claims and premiums. Furthermore, the project improved traceability and the quality of the product. The result is fewer errors, less rework, and less downtime due to waiting for adequate materials to be delivered and refilled.
A Proactive Approach to Health and Safety Practices
As one of the largest building materials producers in North America, this company made worker safety an inherent part of its culture. The proactive approach to health and safety practices at all locations helped to ensure all workers could arrive home to their friends and family each day.
It's safe to say they accomplished their aim of integrating automation, initiating safety improvements, and protecting employees while also supporting innovation and fostering productivity in its business operations.
