Controlling level of toxic liquids for the foam industry case study


Solid provides a durable solution for level controlling of toxic liquids, using the SmartScan 50L ultrasonic measurement gauge.

Polymers Ashkelon Industries located in the city of Ashkelon, is a major supplier of foam for the furniture and mattresses industry in Israel. The company has a long-standing reputation in manufacturing of foam in various shapes and sizes for mattresses, furniture and padding for upholstery.

The problems

The factory is using many kinds of chemicals when producing the foam for different types of applications. One of the basic materials used in the production process is Toluene-2,-Diisocyanate, or in its common name – TDI. TDI is a liquid with a sharp, pungent odor, which reacts with water to produce carbon dioxide. It is widely used in the production of urethane foams and elastomers, but due to its toxicity must be handled carefully.

The TDI is stored in 4 meters (12.8 ft) high metal tanks. During the production process it is streamed through pips to the production tunnel where it is mixed with water. This procedure produces an immediate chemical reaction that causing the mixture to swell, and eventually creating the foam. Controlling the level of TDI in the tank is most important for the production process. The complete process is managed from the main control panel. If the level of fluid inside the tank is below the minimum it can affect the quality of foam and the process time. Because of the TDI's toxicity when exposed to the open air, it must be cautiously supervised when filling the tank and streaming the fluid to the production tunnel. Therefore, it was essential for the factory's engineers to receive constant readings of the TDI level in the tanks and know when to pour in more material.

The solution

The engineers' final decision was to install the SmartScan 50L as the ultimate solution for this application. The SmartScan 50L is based on Solid's patented ultrasonic technology providing a noncontact level measurement solution for problematic materials like the TDI. Being comprised of two units: electronics and a sensitive transducer, SmartScan 50L simplified the installation procedure. With a measuring range of up to 12 meters (39 ft) and accuracy of 0.2%, it was easy to position its transducer on top of the tank and the electronics remotely on the main control panel. SmartScan 50L was connected to the main control panel via 4-20mA output, displaying continues readings of the TDI level in the tank on its large LCD screen. In this way engineers can receive a clear picture of the fluid status during the production process. By utilizing this information, maintenance personal could decide when to stream more TDI into the tank and out to the production tunnel.


By installing SmartScan 50L in their factory, Polymers Ashkelon now has a reliable level measurement solution for monitoring the TDI level in the tank. This solution replaces mechanical devices, used before in the factory and which tend to wear and tear in time. The SmartScan 50L has a Scan Distance function which scans the tank for disturbances and noises and eliminates them in future scans. Additionally, SmartScan 50L offers control over pumps, alarm systems and other process elements via five independent SPDT relays. It can also communicate digitally through RS485.

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