Problem: Strong growth in healthcare spending, especially in emerging economies, is driving increased demand for medical testing, drug discovery, genomics, and proteomics, as well as the instruments used to carry out these processes. To address this market growth, equipment manufacturers are introducing devices that are easier and more cost effective to deploy in small laboratories, clinics, and physician’s offices. This new generation of equipment must also be suitable for the remote locations that are often found in emerging markets, with a lack of infrastructure and limited technical resources that make service and maintenance more difficult and costly than in traditional markets.

To meet these requirements, designers and manufacturers must find a way to reduce the complexity and size of their instruments while increasing reliability and serviceability. Integral to the function and performance of diagnostic and analytical devices are the microfluidic valves that control the dispensing of blood, reagents, and other fluids within the instrument.

Solution: In diagnostic instruments, the most important performance parameters for microfluidic valves are flow, pressure resistance, and accuracy. Until the introduction of dual-solenoid valves, these performance characteristics were directly related to the physical size of the valve. The new Twin Power valve technology from Burkert Fluid Control Systems breaks this correlation, offering the same performance in a smaller footprint.

Rocker type solenoid valves are commonly used in life science applications due to their separating diaphragm, which allows the use of aggressive media and provides excellent cleanability of the fluid path. In the normally closed configuration, rocker valves are designed with a spring that closes the valve and an electrical solenoid that acts against the spring to open the valve when a current is applied. It is this action that allows fluid to flow through the valve. In this single-solenoid and spring configuration, the amount of back pressure that the valve can withstand while remaining closed is limited by the strength of the spring to resist the pressure.

The Twin Power design from Burkert employs two solenoids— one for closing the valve and one for opening it. This higher power density—a solenoid, rather than a relatively weak spring, is now keeping the valve closed— allows the valve to withstand higher pressure and higher flow rates. This means that a 10mm valve using the Twin Power principle has the same performance as a traditional 16mm valve, while reducing space by 54 percent.

Reliability is addressed by choosing a valve with wetted parts such as PEEK, FFKM, FKM, and EPDM, that can withstand harsh media. Integrated power-reducing “hit and hold” electronics reduce heat transfer from the solenoid coils to the media, further ensuring reliability and performance of the valve and the system as a whole.

For more information, visit www.burkert-usa.com

A valve with two solenoids, which provides the same flow and pressure resistance in a smaller valve.

The areas that are easily flushed and cleaned (all except the small orange/red areas) in the valve’s fluid path.

Burkert’s 10mm Twin Power valve has the performance of a traditional 16mm valve, but takes up 54 percent less space and has a 75 percent lower power consumption.