Background: Not Too Much and Not Too Little. Just Right

Fill level monitoring is crucial to a variety of industries and simply means checking the fill levels of tanks or storage bins to ensure that they don’t overflow and that they don’t run out. Much like Goldilocks, you don’t want too much or too little, you want the fill level just right.

So what are the tanks and storage bins filled with? It depends on the industry, and could include:

• Fuel: For agricultural applications, fuel stations, or power generation (e.g. petroleum, diesel, propane, gasoline)
• Lubricants and Oils: For manufacturing plants, car dealerships, or automotive repair shops (e.g. automotive lubricant/oil, industrial lubricant, used cooking oil) 
• Chemicals: For wastewater treatment plants (e.g. sulfuric acid, sodium hydroxide)
• Raw Materials: For industrial plants (e.g. coal, wood, minerals)
• Dry Feed: For agricultural farms (e.g. wheat grain)

Whether it’s liquid, solid, or gas, maintaining the proper fill level is critical in all instances. This is true for the companies using the materials as well as for the companies supplying the materials. Too little material can mean halting production, too little coolant/lubricant can mean damage to machinery, too little fuel can mean stopping construction or farming, and in some cases too little can even mean danger to human safety. On the other end, too much of a given resource can mean wasted money or can even overflowing tanks that lead to expensive clean up.

Problem: Manual Checks Are Expensive and Inaccurate, But Remain the Current Standard

To avoid having too much or too little in a tank or storage bin, you need to know the current fill level. However, for many industries the current standard is to check manually. Manually checking the fill level of tanks and storage bins comes with a number of problems:

• Delayed: Manually checking and recording the fill levels of tanks and storage bins means that the collected data is out-of-date as soon as the person is done checking
• Inaccurate: Humans are prone to error, and may inaccurately record the data
• Unsafe: Checking fill levels can mean climbing on top of large tanks, navigating machinery, and/or potential exposure to dangerous chemicals
• Expensive: Not only is it expensive to pay people to check manually, but all of the above problems also contribute to the expense. Delayed and inaccurate information can mean inefficient purchasing of materials, missed production, repairs needed for machinery, and more. Accidents and injuries are terrible in and of themselves, but also represent large expenses

These problems with manually checking aren’t new, and there have been attempts to instrument tanks and storage bins with fill level detectors to automatically collect this information. However, many of these attempts have relied on wired connections for data transfer and power, which have limited their effective range, or else used wireless approaches that are too expensive to support.

Solution: Remotely Monitor Fill Level in Real-time with IoT

The Internet of Things (IoT) is the next stage of digital transformation and means that, for the first time, businesses can remotely monitor thousands of tanks in real-time and completely transform their organizations. The technologies that make this possible are covered below, but the benefits include:

• Resource Optimization: With the real-time fill level of all tanks / storage bins, captured automatically, you can optimize fleet routes and fill schedules to maximize the revenue per fill. Instead of filling up a tank / storage bin that’s already full, and therefore paying the fixed cost to fill it up (labor, fuel, etc.) but getting very little financial return, you do a maximum fill every time
• Configurable Alerts: With configurable alerts, you can get notified when a tank or storage bill is too full and at risk of overflow and you can get notified when too low and at risk of outage. Configurable alerts means you can set the thresholds that matter for your business so you’re given the notice that you need (e.g. “Low”, “Very Low”, and “Critically Low”)
• Theft and Leak Detection: Using the data collected from the fill levels, you can automatically flag when the fill level drops too quickly. This enables you to identify theft or leaks and to be able to respond immediately, rather than finding out too late
• Reduced Costs: All of the above benefits contribute to reduced costs, and you can reduce costs further because now you don’t need to devote valuable labor to manually checking the tanks
• Improved Customer Service: Alerts when tanks or storage bins are low enable you to mitigate situations where your customer runs out of what they need. If you’re in the business of filling up propane to keep houses warm in the Midwest, missing a fill in Winter is no good. In addition, you can even expose the fill levels of the customer’s tanks to them as a value-added service
• Increased Safety: Without the need to manually check tanks, workers don’t need to risk accident and injury climbing large tanks or operating in close proximity to dangerous chemicals
  

The above benefits only cover the real-time data. As you begin collecting millions of data points on fill levels, you can begin applying machine learning to uncover extremely powerful insights and begin predicting into the future.

Technology: Ultrasonic, Lasers, NB-IoT, LoRa, and More

As with any IoT solution, the particular technology approach depends on specific needs. Every IoT solution requires sensors to capture data (in this case, fill level), a network to communicate the data from the sensors to the cloud, and then software to ingest, analyze, and present the data to end users in an interface and/or to trigger and send alerts (text, email, push, etc.).

For sensors, you want to consider the cost of the sensor, ease of install and maintenance, and battery life, regardless of what you’re measuring. However, the best sensor type will depend on what you’re measuring in the tank or storage bin. Some viable sensor options include:

• Ultrasonic sensors
• Radar sensors
• Laser sensors
• Magnetostrictive sensors
• Hall Effect sensors

For network, you want a Low Power Wide Area Network (LPWAN) as these are optimized to be low cost and low battery drain. However, the best LPWAN type will depend on the number, location, and geographic spread of the tanks or storage bins. Some potential LPWAN options include:

• NB-IoT
• LTE-M
• LoRA
• Nanosatellites