Delta Application Technics specializes in the design and manufacture of application machinery and dosing systems for silicone and other pasty, sludgy liquids. The Ophasselt, Belgium, company recently determined that by incorporating highly accurate Coriolis flow measurement technology into their silicone mixing and dosing machines, the overall efficiency of the silicone production process could be significantly improved.

Silicone, a versatile polymer with a wide variety of industrial and household uses, is expensive and challenging to produce. The manufacture of silicone involves extremely high-precision dosing and mixing of very viscous liquids. Operators often dedicate as much as two hours per day just to measuring, recording and adjusting these processes.

After much observation and testing, Delta Application Technics determined that the accuracy of their existing machines for silicone mixing and small-quantity dosing no longer suited the requirements of the customers purchasing these machines.

Jacques Coppens, the company's managing director, said, "Silicones are thixotropic, meaning that they are thick and viscous at rest, and can change state when kinetic energy is applied. The manual adaptation and weighting system used previously to control product quality resulted in shifts of up to 15%. Given the high cost of silicone, any offset turned out to be very expensive."

To improve the efficiency of the silicone production process and keep its customers satisfied, Delta Application Technics set out to build new machines that would guarantee constant supervision with less than 5% shift. The design called for incorporating high-accuracy Coriolis mass flow meters to automatically obtain measurements and record production values.

"The success of our projects depends on the availability and quality of the components used, so we compared the technical specifications of various mass flow meters from different suppliers to ensure that our flow measurement would be optimized," Coppens said.

An Optimal Solution

Siemens was one of the instrumentation suppliers who volunteered to participate in this optimization project, and a representative suggested the Sitrans F C Mass 2100 Coriolis flow meter. The Research and Development department at Delta Application Technics carefully considered this meter along with several other options and concluded that the Siemens solution would be the ideal choice for this particular application.

The Mass 2100 offers the advantage of being equipped with a graduated tube - a single-piece curved tube free of any reducer, flow distributor or internal seams. Despite the high viscosity of the liquid being measured (approximately 40,000 mPa•s) and slow flow within the pipe, the device demonstrates only limited pressure loss because of its full-bore design and has a very high measurement accuracy of ≤0.1% of flow rate.

"The results are impressive," Coppens said. "Thanks to the Mass 2100 flow meter, with installation and fine-tuning by Delta Application Technics, measurement tolerance is now better than 1%."

At the same time, the new silicone machines are capable of determining the quantity of silicone for each ingredient injected, along with the pump velocity and the pressure, density and temperature of the silicones employed. This leads to optimum traceability in the production process.