Fluidic Switch

Active redirection. The principle of fluidic switches.

Although there were already preliminary works from the beginning of the 19th century, the first fluidic switches were not invented until the 1950s (references at the end of the page). These were intended to serve as amplifiers in (fluidic) logical circuits. The idea behind it is to redirect larger fluid mass flows (e.g. water or air) with a small mass flow. We have taken up this concept and refined it further. Our switches are very similar to fluidic oscillators (like the OsciJet nozzle), only that they can be actively switched by a valve. In the adjacent figure such a switch is shown. For active switching, a small pressure signal is applied to one of the pressure ports, which pushes the fluid jet (gases or liquids) to the opposite side. This condition remains stable even without a further pressure signal. A change of the state is however at any time possible by activating the opposite pressure port. The switches offer a few unbeatable advantages. First of all, they are extremely robust, because the absence of any mechanics means that they can not fail. So the switches can be operated even in very harsh environments with for example corrosive or very hot media. Secondly, fast switching valves can be used and so even very large mass flows can be switched very fast, because the switches switch very fast.

Reliable, fast and versatile. An example application.

For the first time we had dealt with these switches in a very exciting project. The project was about switching a very hot gas mass flow quickly back and forth between two outlets. In the beginning we were looking for fast switching valves that are able to switch an air mass flow with at least 25 kg/h at a temperature of 900°C in a thousandth of a second. We found several valves that could meet one or the other requirement, but none that fulfilled all of them. So we came up with the idea of the switches, since these were able to work with two conventional quick-switching valves and a very low and above all cold air flow to switch the hot main mass flow. The resulting switch was able to switch a hot mass flow with up to 80 kg/h reliably and permanently with 900 Hz between the two outputs.

Application. Characteristics.

Fluidic switches can be used in a variety of applications and show their strength especially in environments where conventional valves cannot be used. This means especially in particularly harsh environments with high temperatures or corrosive media or where very fast switching times are required. The switches can be scaled almost arbitrarily and adapted to almost any operating condition. Since no moving parts are used, the components are maintenance-free and offer very fast response times that a mechanical system cannot achieve. If you are interested in a fluidic switch, please contact us at any time.

We advise you gladly


Harsh Environments

Corrosive Fluids

Fast Switching

Harsh Environments

Corrosive Fluids

Fast Switching

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Links. References.

  • R. W. Warren. Some parameters affecting the design of bistable fluid amplifiers. In Fluid Jet Control Devices; Papers presented at the winter annual meeting of the ASME, 1962.