Among the many inventions of Nikola Tesla (1856-1943) is a particularly fascinating one: the so-called ‘Tesla valve’ or, as the Serbian-born, American-nationalised inventor called it, the ‘valve conduit’. It is a hydraulic structure, or conduit with no moving parts that allows the flow of a fluid in one direction whilst restricting, or hindering its passage in the opposite direction. The patent application (US 1329559), dated 1919, describes the device as follows: “the interior of the conduit is provided with enlargements, recesses, projections baffles or buckets which, while offering virtually no resistance to the passage of the fluid in one direction, other than surface friction, constitute an almost impassable barrier to its flow in the opposite direction, by reason of the more or less sudden expansions, contractions, deflections, reversals of direction, stops and starts and attendant rapidly succeeding transformations of the pressure and velocity energies”.
One of the relevant aspects of this hydraulic device is the efficiency of its design, which controls the fluids without the need for external mechanisms. Moreover, as Tesla emphasises in the patent application, its valve operates in a wide variety of conditions and can be manufactured on many different scales, from industrial systems to tiny devices.
Indeed, although the Tesla valve went unnoticed for decades, in recent years, with advances in materials and computer simulations, it has come back to the attention of engineers, technicians and scientists. They find its potential in a variety of technological applications, such as microfluidic systems, heat pumps and medical devices.
A recent example of its application is in the design of high-efficiency cooling systems. Its use has also been explored in industries such as aerospace and automotive, where minimising weight and maintenance is important. In 2021, the Xiaomi Corporation – a Chinese manufacturer of phones, home electronics and electric cars – announced that some of its mobile phone models would use liquid loop cooling technology. Well, this technology uses a Tesla valve to ensure that the flow of coolant flows unidirectionally.
A computational fluid dynamics simulation using the Tesla valve showed that the resistance to flow in the blocked direction was about 15 times in the 2-segment design and about 40 times in the 4-segment design, compared to the unimpeded direction. These parameters were in line with those given in the patent application. However, the steady flow experiments show smaller ratios, in the range of 2 to 4.
In any case, the simplicity of Tesla’s valve is testament to the genius of its creator. In a world looking for sustainable and efficient solutions, his invention could have relevance as a tool for meeting the technological challenges of the future. Therefore, Tesla’s valve, thanks to its ability to restrict flow without the need for electricity or moving parts, has become a sustainable solution in terms of energy consumption.
If you would like to know more and find out how the Tesla valve works, you can satisfy your curiosity with this video:
Header image: Cmglee – CC BY-SA 4.0
