On October 20, 2026, the University of Helsinki in Finland announced a device that guides liquid through the air using ultrasound, without a solid tube. A total of 256 ultrasonic transducers arranged in a cylindrical device form a sound field around the liquid stream, allowing it to flow horizontally without touching any pipe wall. By changing how the ultrasound is controlled, the team can also alter the shape and direction of the path while the liquid is flowing. The technology could make it possible to transport substances that cause problems in ordinary piping, such as adhesion or corrosion, without contact with a solid wall. However, the prototype is only 8 cm long, and its transport distance and stability will need to be verified before it can be used in real factories or research facilities.
The results were published in the Proceedings of the National Academy of Sciences (PNAS) in a paper by Dmitrii Nikolaev and colleagues titled "Contactless continuous guidance of matter in its main states using curved elongated Bessel-like acoustic fields" (DOI: 10.1073/pnas.2614959123). Researchers from the Public University of Navarre in Spain and the University of Michigan in the United States also took part, in addition to the University of Helsinki. The device specifications and experimental results described below are based mainly on the University of Helsinki's official announcement; we have not been able to check detailed measurement conditions in the paper itself or its supplementary materials.
256 ultrasonic transducers form an "invisible tube" that can change shape
The device developed by the research team has a cylindrical structure surrounding the liquid stream, with 256 small ultrasonic transducers arranged on its inside. Each transducer emits ultrasound at about 40 kHz, forming a specific sound field around the liquid that guides the flow without touching any solid wall. According to the university, the liquid stream is about 5 cm from the surrounding cylindrical device, and there is no physical tube wall between them. In the experiment, the team succeeded in supporting a liquid flowing horizontally through the air with ultrasound and moving it along a set path.
A key feature of the device is that the liquid's path can be changed without being constrained by the shape of a physical tube. In ordinary piping, changing the direction of flow requires bent pipes or valves, but with this method the flow path itself can be adjusted by changing the ultrasound control. Dmitry Nikolaev, the postdoctoral researcher at the University of Helsinki who led the team, said in the university's announcement, "By changing how the transducers are controlled, we can alter the shape and orientation of the tube as needed." The direction can be changed even while the liquid is flowing, and the liquid can also be dispensed one drop at a time when needed.
The targets of ultrasonic transport are not limited to liquids. The University of Helsinki says gases, powders, and plasma can also be guided with this technology. However, the sound field required differs depending on the state of the substance, and not every material can be transported with the same settings. Nikolaev also noted that moving a solid requires forming a different sound field than for a liquid or gas.
The team also showed that an electrical discharge can be guided along a chosen path. This involves using ultrasound to control the discharge path through the air; it does not demonstrate how efficiently electrical energy can be delivered. Videos released by the university show the device guiding liquids, powders, mist-like substances, and discharges, but no data has been presented comparing transport volume or stability for each material under the same conditions.
The idea began with eliminating tube walls where dirt builds up
This technology grew out of research on cleaning the inside of pipes with ultrasound. According to Ari Salmi, professor of electronics at the University of Helsinki who led the development, the team had previously built a device that used ultrasound to remove dirt stuck to the inner surface of tubes. While discussing that work with colleagues, the idea arose that it would be convenient if there were no surface for dirt to stick to in the first place. Salmi recalled that he came up with the idea of forming a tube from ultrasound instead of a solid wall while walking his dog afterward.
Turning the idea into a working device was not easy, however. The team repeatedly experimented with how to control the 256 transducers to form a sound field that could guide liquid stably. Researchers from the Public University of Navarre and the University of Michigan also joined the development, and the team ultimately completed a prototype that can guide liquid continuously through the air.
The university cites the transport of corrosive or sticky substances as a future use. In ordinary piping, corrosive substances can damage the inner surface of the pipe, and highly adhesive materials can stick to the walls and obstruct flow. Avoiding contact with a solid wall could help reduce such problems. It is also considered an advantage for contamination-sensitive substances, which could avoid contact with other materials left on the inner surface of pipes.
These are, however, only anticipated applications at this stage, and no performance results have been published for transporting corrosive liquids or highly adhesive materials over long periods. There are also no quantitative comparisons showing how much adhesion or contamination can be reduced relative to conventional piping. Furthermore, not touching a solid wall is not the same as being free from contamination during transport. Because the material moves through air, the influence of the surrounding environment must also be considered, and evaluation for each target substance and operating condition would be essential before use in an actual manufacturing process.
From an 8 cm, 50 W prototype toward practical use
The completed prototype is 8 cm long, shorter than the diameter of the device. According to the University of Helsinki, operating this 8 cm section requires about 50 W, comparable to a conventional incandescent bulb. It is significant that a specific power consumption figure has been given for a device that guides matter with ultrasound, but this number alone does not show that it is more efficient than conventional pumps or piping. The university's announcement gives no flow-rate data on how much liquid was transported in a given time, so energy consumption per unit of transported volume cannot be compared.
Nikolaev expects that modules with the same structure can be connected in series to build an ultrasonic tube of the required length. If each module can form a continuous sound field, the approach could develop into a system that transports matter over longer distances without installing physical piping. However, the results published so far are a demonstration with an 8 cm prototype, and transport distance and stability with multiple modules connected have not been confirmed. Whether the flow can be maintained at the boundaries between modules, and how much the required power increases with longer distances, also remain issues for future verification.
There are also unconfirmed points in assessing reproducibility. The university's announcement does not disclose the detailed composition of the transported samples, the particle size of the powders, or the number of experimental trials. It is therefore impossible to judge how stably the device operates with different materials and flow rates, or how much variation there is in the measurements. Although the research was published in the peer-reviewed journal PNAS, we have also found no information indicating that an independent research team has completed a replication of this device.
Safety also needs to be considered. The roughly 40 kHz ultrasound the device uses is normally above the range of human hearing, but being inaudible does not mean its effects on people and the surrounding environment can be ignored. Nikolaev explained that the ultrasound inside the device is very intense and, though inaudible to humans, could affect animals. The university's announcement, however, gives no quantitative sound pressure measurements, exposure conditions, or comparisons with safety standards, so safety for use in factories or research facilities has not been confirmed.
The significance of this research is that it shows ultrasound can support a liquid stream in the air and dynamically change its path. A transport method without solid tube walls could offer a new option for materials that are difficult to handle with conventional piping. However, developing the 8 cm prototype into practical transport equipment will require confirming flow stability over longer distances, the range of materials it can handle, and power consumption per unit of transported volume. Whether these performance figures are presented as concrete measurements, and whether they can be reproduced in independent experiments, will be important in judging the prospects for practical use.