Sulzer Mixpac AG

Trial and Error Is a Thing of the Past – Sulzer Mixpac Uses CFD Simulation to Deliver more Precise Mixtures

Sulzer Mixpac, the Swiss specialist for two-component mixing systems, will once again be in attendance at this year's COMPAMED international trade fair. From November 14-16, visitors can gain an insight into the company's existing product range and new developments on stand C01 in hall 8b. One development is guaranteed to be the center of attention this year: the more precise definition of multi-component mixtures in medical engineering, leading to optimized design of the corresponding mixing and dispensing systems. Sulzer's ground-breaking achievement is based on the use of CFD simulations – a completely new computation method in the medical engineering context.

The manufacturer of mixing systems for the viscous substances used in dental technology, for example, is quietly revolutionizing the scope of application for computational fluid dynamics (CFD) techniques. Starting now, optimal mixes of two or more components can be achieved by computing what are known as numerical flow simulations. Sulzer Mixpac's customers – mostly manufacturers of multi-component substances for end users such as dentists and dental technicians – can now reap the benefits of CFD simulations that optimize existing and new products. Sulzer Mixpac, a subsidiary of leading pump manufacturer Sulzer, is currently the only company in the world that uses CFD technology for multi-component mixing in the medical engineering industry.

Strong demand for homogeneous mixtures

Product development at Sulzer Mixpac benefits from the vast expertise of its parent company, which boasts a wealth of experience in fluid dynamics. "The breadth and depth of the Sulzer Group's offerings enables us to expand our own portfolio too," explains Dietmar Salzgeber, the man in charge of medical products at Sulzer Mixpac. Sulzer has identified particularly strong demand for homogeneous mixtures in medical engineering and is doing its bit to improve mixing outcomes.

Guaranteed reproducibility in return for minimal test outlay

Trial and error used to be standard practice in medical contexts, meaning that dentists, medical technicians and substance providers would mix the various components by hand. It would often take a large number of tests before providers knew whether and how two components react to each other. But even then, they would still not know why they react and what chemical reactions are involved. "Producing a homogeneous mass by hand can be an awful lot of work," Salzgeber notes. "For one thing, this kind of approach can never deliver the same result twice. And especially where components share similar colors, it is very difficult to identify the quality of a mix. Another issue is that this 'strategy' makes the time to market for new products much longer, while development becomes much more expensive. But now, thanks to CFD, we can identify the optimal mixing ratios and thus guarantee efficient and reproducible mixing outcomes. And not only that: We can also significantly shorten the whole development process."

Simulating the optimal dispensing system

The purpose of simulation is to optimize the mixing ratio for multiple components. Factors such as viscosity, pressure, density and surface tension all affect how a substance flows. Based on the mixing geometry and the properties of the components, the experts at Sulzer Mixpac simulate the best possible dispensing system to generate high-quality – i.e. very homogeneous – mixes. Using CFD simulations, it is possible to calculate the optimal retention time for a substance in the mixer. If this time is too long, the components would already begin to react before leaving the dispenser. It would be similarly counterproductive if, for example, so much pressure was needed to eject the substance from the mixer that users could not do this by hand. Numerical flow simulations thus make sure that the two substances both spend the same amount of time in the mixer – and that they meet at the right time.

At the COMPAMED 2012 trade fair, Sulzer Mixpac will for the first time take the wraps off its new developments – especially the use of CFD simulation for multi-component mixtures – on stand C01 in hall 8b.
For more information about the company's products and services, visit www.sulzerchemtech.com.