Ants plot the best paths for fluid flow

Mark Fletcher takes a look at a technology that, borrowing a concept from the
natural world, simplifies the creation of miniature fluid flow manifolds

May 2002 notebook: Ants plot the best paths for fluid flow Miniaturisation, a key buzzword in many industries, can now be applied to fluid control manifolds, thanks to an approach dubbed Ant Farm Technology. The technology allows complex patterns and flow channels to be created in manifolds without a big increase in overall size - enabling them to be used in space critical applications. It supersedes existing methods that require numerous cross-drilling operations, followed by superfluous construction passages being plugged - a process that also presents further quality and construction problems as complexity increases. Ant Farm manifolds are currently being used in non-invasive blood pressure modules as well as respirators, ventilators, medical analysers and blood analysis machines. Non-medical applications include their use in gas detection systems, semiconductor processing equipment and portable hardware. According to Lee Products, the manifolds can be used for inflation and deflation operations, pinch valve actuation and gas distribution. And, using pulse-width modulation in combination with a High Density Interface (HDI) valve, an analogue response can be provided for less cost and complexity than proportional valves. From a basic flow schematic, a series of intricate flow paths or channels (resembling tunnels in an ant farm) are plotted and then milled out of the face of an aluminium block. After the milling operation an aluminium plate is bonded over the milled face, closing off the open face of the channels - effectively completing the circuit. For more complex applications, requiring far more paths or channels per manifold size, additional channels can be milled into more than one face. Once the construction operation is completed, the whole aluminium assembly is then anodised for increased corrosion resistance. The manifold can be outfitted with specific inlet and outlet ports. These can be brass barbs, stainless steel hypo tubes or any other port that is needed. Every port is typically screened to prevent contamination and the finished manifold can then be fitted with all the necessary sub-components. The manifolds can be used in conjunction with the company's HDI valves, which can be customised to special requirements such as power consumption, flow rate, leakage and pressure, making the whole package suitable for power and space-sensitive applications. Once a manifold is fully assembled with valves and sub components, the complete assembly can then be tested to comply with the necessary parameters. Precision channel creation removes the need to block unwanted fluid paths Further channels can be created by milling other faces of the manifold block In combination with miniature valves the manifolds can be matched to a multitude of different applications