Lafarge-Holcim’s SiloWeigh IIoT installation in Maple Ridge, BC

Background

The SiloWeigh IIoT system is based on the previous SiliWeigh.Net system but is new from the ground up. The original SiloWeigh.Net system was installed at Lafarge-Holcim’s Ready-Mix plant in Coquitlam, BC Canada in July 2016.  A trial by Lafarge-Holcim’s Greater Vancouver Area division determined  the effectiveness of the system at highlighting stock discrepancies in both regular and split silos.  Some of Lafarge-Holcim’s plants have relatively small silos and running out of material impacts the company and its customers. After an extended trial period, Lafarge Holcim’s Greater Vancouver Area manager said that “this was the only plant in their area that never ran out of material and never overfilled its silos”. The consequence of overfilling is bursting of the filters. As a result of the overfill, clouds of cement dust spread over the landscape.  As a consequence of the good results, Lafarge-Holcim ordered SiloWeigh IIoT systems for all nine of their Greater Vancouver Area plants.

Installation was carried out by their own staff between November and December of 2020. As part of this program, Scale-Tron updated its web-based remote user interface. The result allows Lafarge’s bulk material ordering team to view all silos, at all sites, through a single web browser. This makes material control and ordering more efficient.

The installation of Lafarge-Holcim’s SiloWeigh IIoT systems

Scale-Tron’s L-Strain sensors are fully temperature compensated, like load cells and bolt onto the silo legs or skirt. These are usually steel but can equally be stainless steel or aluminum.  SiloWeigh IIoT can be installed on divided silos of any ratio, stacked silos and silos on a shared frame.

Lafarge-Holcim’s maintenance team bolted the sensors in place and tightened them using a torque wrench. After that, they wired them to a “Digital Junction Box” mounted on each silo.  Next, they wired the silo DJBs in daisy-chain fashion, using a single cable, to the display cabinet.  For SiloWeigh IIoT, this cabinet houses the Data Acquisition (DAQ) board, embedded computer and optional touch screen.  Lafarge-Holcim has chosen to use a conventional computer display, keyboard and mouse, on lower volume plants. In comparison, high volume plants added the panel mount touchscreens for ease of use. The embedded computer connects to the plant network and through this to the Internet.  Remote users with the appropriate username and password can access locations via a web browser.

The results from SiloWeigh IIoT Maple Ridge

• Weather filter eliminates sun effects but allows fast fills & discharges.
• SiloWeigh IIoT shows all silos at the plant as bar-graphs on one screen.  Clicking on any silo shows a trend graph of the last 24 hours of use.  This can be zoomed to a week or a month display or a selectable date range.
• Bar-graph display changes color at each alarm level.
• SiloWeigh II and SiloWeigh IIoT both have an advanced weather filter which improves the accuracy greatly during periods of bright sunlight.  SiloWeigh is the only system on the market with this filter. 

Other systems available on the market  display the raw weight readings and consequently can show large errors when the sun hits the sensors.  In comparison, the use of level sensing systems does not offer the accuracy required. This is due to errors caused by material rat-holing, bridging and material compaction, which gives up to 20% difference in level in cement silos.

The operator at the Maple Ridge plant monitors the inventory and uses it to reorder his materials.  To help with this, the bar-graph display changes color at the four programmable alarm points:  Reorder, Low, High and Overfill.  Optional hard-wired alarms are also available to illuminate lights, sound horns or activate a pinch-off valve during filling. The reading file can also be downloaded as an Excel file to measure delivery amounts. Although not legal for trade, they give a good indication for further action.

This article courtesy of Scale-Tron Inc.

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