New radar solution for level monitoring in closed melting furnaces
Radar system measures contact-free from the outside through furnace lid / Easy integration into closed melting furnace: small opening of ~50 mm is sufficient / Accuracy of up to 0.3 mm – even with significant fluctuations in fill level
Freiburg, Germany, 23 June 2026 – OndoSense has developed a measurement system for the level monitoring of molten aluminum, steel or copper inside closed furnaces: The new OndoSense FurnaceProtect radar solution measures the fill level in closed melting, casting and holding furnaces from the outside through a small opening in the furnace lid of only ~50 mm. The radar system offers a measurement accuracy of up to 0.3 mm – even in the presence of dust, steam, smoke, vibrations and metal temperatures of up to 1600 degrees Celsius. Significant fluctuations in fill levels during the melting process do not affect the measurement precision or reliability. This is due to the unique combination of a high measurement rate (500 Hz) and smart filter algorithms inherent in OndoSense radar technology. The level monitoring system therefore consistently delivers error-free, highly accurate and rapid measurements, even in the presence of wave motion, bubble formation or other abrupt fill level fluctuations.
Based on the OndoSense apex Level Line, the new OndoSense FurnaceProtect radar system not only enables higher productivity in the operation of melting, casting and holding furnaces: It also reduces energy costs, optimizes raw material usage and prevents furnace overfilling. As a result, OndoSense is setting new standards for the automation and optimization of casting processes in the aluminum, steel and metal industries.
More information: https://ondosense.com/en/radar-sensors-industries-applications-solutions/radar-sensors-steel-and-metal-industry/level-control-metal-melting-furnace-crucible/
Easy integration & highest performance: radar makes it possible
The new radar-based level measurement solution meets the highest requirements for heat, temperature or pressure resistance and can be integrated into melting or holding furnaces very easily. Thus, the OndoSense FurnaceProtect housing is simply mounted on the furnace lid, with the housing’s protective tube inserted through an opening in the lid measuring just ~50 mm.
“The radar waves are guided through the tube, enabling a contact-free measurement of the furnace fill level. The housing is shielded against heat from both the inside and the outside. To ensure maximum heat protection, the radar system is equipped with connections for optional air cooling. With this innovative, highly reliable level measurement solution, we can achieve an accuracy of up to 0.3 mm – even in the presence of smoke, steam, or metal temperatures of 1600 degrees Celsius," says Rainer Waltersbacher, Co-CEO of OndoSense.
The OndoSense FurnaceProtect radar solution is equipped with either an advanced Profinet interface or a proven analog current interface (4–20 mA). It also offers three digital switching outputs (PNP/NPN). The measurement range extends from 0.1 meters to 30 meters. The radar system features a webserver-based configuration software with pre-installed application profiles, ensuring simple and rapid sensor commissioning.
No calibration or radiation protection required: advantages over radiometric measurement
Non-contact level control of molten metal in closed containers is possible with, among other methods, radiometric measurement techniques. However, these have several drawbacks: Measurements involving radioactive isotopes are subject to strict regulatory approvals, extensive safety training, and rigorous radiation protection requirements. Furthermore, radiometric systems require frequent recalibration based on container wall thickness as well as the specific metal or alloy to ensure reliable readings. The new OndoSense FurnaceProtect radar solution eliminates these shortcomings:
"Our radar system requires neither time-consuming recalibration for different metal types or alloys nor, of course, any safety measures for radiation protection. This simplifies commissioning and significantly reduces costs and effort associated with maintenance and servicing," explains Co-CEO Waltersbacher.
Whether aluminum, steel, or copper: The OndoSense radar system is suitable for monitoring the level of any type of metal or alloy in closed furnaces.
Savings costs through determination of energy requirements
The OndoSense FurnaceProtect radar solution enables a more accurate measurement of the energy required for melting metal:
"Precise level measurement within the melting furnace allows for a better estimate of the amount of metal inside. Consequently, the energy required to melt the metal can be determined more accurately. This saves energy costs and enables better planning of the melting process. It also helps avoid furnace overfilling – which leads to unnecessary raw material consumption, unplanned downtime, potential accidents, and high additional costs," explains Co-CEO Waltersbacher.
The level control in melting furnaces is required in particular for the recycling of scrap metal such as aluminum, steel or copper to determine exactly when the metal has fully melted. At the start of the melting process, the still solid metal scrap typically forms a pile in the center of the furnace, resulting in a lower level at the furnace rim. As the melting progresses, the level at the rim rises. Once the metal has completely melted, the level readings are uniform throughout.
OndoSense FurnaceProtect: innovative radar technology for level measurement
The OndoSense FurnaceProtect radar solution is based on the powerful, innovative OndoSense apex Level Line, designed for high-precision level measurement. With a very narrow beam angle of just ±1.5 degrees, the radar level sensor delivers stable, reliable measurements with a very small measurement spot. This makes it ideal for confined spaces or long-distance measurements. Furthermore, the radar sensor features an IP67 rating – making it dust-tight and protected against water jets – and is perfectly suited for harsh environments thanks to its durable PTFE lens.
The range of applications for the OndoSense apex Level Line extends from the level control of molten metal in melting, holding and casting furnaces, casting molds, ladles, ladle cars, launder systems, channels and crucibles to measuring throughput on conveyor belts and determining the level or volume of bulk material stockpiles in the mining industry.
OndoSense FurnaceProtect – at a glance:
- Radar measures contactless from the outside through furnace lid
- Easy integration into melting furnace: small opening of ~50 mm is sufficient
- Accuracy of up to 0.3 mm – even with significant fluctuations in fill level
Industry & application focus:
Melting, holding and casting furnaces in the aluminum, steel and metal industries
More information: https://ondosense.com/en/radar-sensors-industries-applications-solutions/radar-sensors-steel-and-metal-industry/level-control-metal-melting-furnace-crucible/
Product video: https://ondosense.com/en/video-level-control-in-melting-furnaces/
Articles:
- https://www.aluminium-journal.com/level-measurement-melting-furnaces-radar
- https://www.ien.eu/article/ondosense-gmbh-level-monitoring-in-closed-melting-furnaces
About OndoSense
OndoSense realizes breakthrough radar sensor technology for a digitized industrial world. With sensor solutions based on high-precision, robust radar technology and smart sensor software, we ensure customers get relevant data for the intelligent control of production plants and machines. That way, we are helping to drive digital transformation in the industry. Our innovative, high-performance radar sensors can be used reliably in a wide range of applications - even in challenging environments with dust, steam, smoke, fire, or noise. OndoSense was founded in 2018 by two radar experts from the Fraunhofer Institute for Applied Solid State Physics IAF.
Media contact
Michael Teiwes
Head of Marketing & PR
mteiwes@ondosense.com
+49 761 79114762
OndoSense GmbH
Bötzinger Str. 60
D-79111 Freiburg
Image 1:
Caption: OndoSense FurnaceProtect radar solution for enclosed holding, melting and casting furnaces enables non-contact, high-precision level measurement of molten metals at temperatures of up to 1600 degrees Celsius. © OndoSense
Image 2:
Caption: With the OndoSense FurnaceProtect radar solution, the level is measured from the outside through a small opening of only ~50 mm in the lid of the melting or holding furnace. © OndoSense
Image 3:
Caption: The OndoSense FurnaceProtect radar solution for level measurement in melting furnaces is based on the robust, high-precision OndoSense apex Level Line radar sensor. © OndoSense