What is helium used for

Hydrogen could be used as a substitute for helium in this application, but there are concerns about both safety and hydrogen embrittlement of the material being coated.

Plasma-arc melting is used to make specialty metal billets, such as titanium billets for jet-engine components. The process provides superior uniformity and composition control and has effectively replaced electron-beam melting, which used to be the main method.

Furnaces operate in a helium atmosphere, with a helium plasma melting the titanium. There are no known substitutes for helium in this application. Argon does not have sufficient specific heat to produce the desired depth of melt. In this process the helium is recirculated during furnace operation but is vented at the end of a run because it is highly contaminated. In principle it should be possible to recover and purify the helium after a run. Some industrial heat treatments are conducted in helium atmospheres because helium's high thermal conductivity allows the cooling of thick sections.

For example, nickel-base superalloys are rapidly cooled in helium atmospheres. Helium can be replaced with argon in all but special applications. The use of helium for leak detection is a relatively small but critical industrial application. Helium is an excellent leak detector because of its low viscosity and large diffusion coefficient.

The amount of helium used for leak detection was about million scf 3. Leak testing using helium-tuned mass spectrometers is the most sensitive method of detecting leaks before they reach a critical stage and thus is ubiquitous in science and technology. It is critical in the manufacture of large rocket engines; the manufacture and maintenance of vacuum equipment in all aspects of industrial processing, including the electronics industry and the advanced materials industry; and in scientific research.

Indeed, helium leak detection is the standard in any activity requiring leak-tight systems. Helium leak detectors were developed during World War II and can detect and measure leaks that are thousands of times smaller than the leaks that can be located by other procedures. Equipment can be calibrated to detect leaks that are smaller in volume than the equivalent of one drop of water per year.

The usual procedure in leak testing is to spray the area on the outside of the system being tested with helium and then try to detect its presence on the inside, using a vacuum environment attached to a mass spectrometer.

The development of any replacement technology for helium is problematic because its use is based on its combination of unique size and inertness. Inert gases other than argon, which is excluded because it exists in the atmosphere at the 1 percent level, could be used in principle, but comparable sensitivity might require more elaborate mass spectrometers than are currently employed in helium leak-detection systems.

Some degree of conservation through gas recovery might be possible using ''sniffer" technology. In this approach, helium is introduced under pressure into the device being tested, and a sniffer, connected to a helium-tuned mass spectrometer, detects leaks by sensing helium leaking out of the helium-pressurized apparatus. Helium used in this manner could be recovered. Mixtures of helium and oxygen are used as breathing gases for deep-sea divers and for individuals working under high atmospheric pressures for extended periods of time.

The advantage of helium over nitrogen in these mixtures is that it is absorbed and released by human tissue faster than nitrogen, making longer dives possible with shorter decompression times. The amount of helium used was about 56 million scf 1. Given the diving industry's increasing reliance on robot replacements for humans, however, the amount of helium used for diving is expected to remain relatively stable, or even decline. Each dive consumes very little helium because "rebreathers," which recirculate the gas, are commonly employed.

One obvious use of helium is as a lifting gas. Unfortunately, this usage is no longer reported separately, making the amount of helium used for this purpose unknown. Because it is the most visible use of helium, however, it deserves mention in a separate section of this report. Hydrogen is the lightest gas, but helium's chemical inertness makes it the safest lifting gas.

Helium replaced hydrogen for blimps in the s after a number of tragic accidents involving hydrogen-filled airships. Nowadays, party balloons are probably the application with which most people are familiar. Helium is used as well in blimps that bear advertising e. Helium-filled balloons are also used in various types of atmospheric and astrophysical research. One future use of helium is as a lifting gas in devices to lift heavy loads for construction. Other uses of helium include minor medical uses and uses in lasers not covered in previous sections.

The total amount of helium used for these purposes was about million scf 8. This section discusses potentially important applications that could rely on the availability of helium at a low price: magnetic levitation, superconducting magnetic energy storage, energy conversion systems, cryogenic wind tunnels, and superconducting electronics.

In this technology, trains are levitated above their tracks, eliminating wheels and permitting very high-speed operation without frictional losses. The Japanese version of MAGLEV is based on the magnetic repulsion between a conducting track and high-power, helium-cooled, superconducting magnets on the vehicle. The highest speed achieved by a full-size test vehicle was mph. A scaled-down, non-passenger-carrying vehicle attained mph kph in Although superconducting MAGLEV technology was pioneered in the United States, there has been almost no domestic effort to develop it over the past 30 years.

Superconducting magnetic energy storage SMES devices store energy in magnetic fields. These systems are highly efficient and could be used for equalizing energy distribution in power systems on small scales, e. The devices consist of closed coils of superconducting wires. The coils can be fed and discharged by means of a switch that connects the winding with the power grid. Superconductors are the only appropriate materials for SMES devices because they have no electrical resistance and thus can be operated in a persistent current mode without being connected to a power supply.

A SMES device is the only method of storing electrical energy without first converting it to mechanical or chemical energy.

The energy density in superconducting coils is comparable with that in flywheels i. Their short cycle times make them competitive with batteries, however. SMES units can be large scale i. Superconducting technology is considered to be an important secondary technology for plasma confinement fusion.

Helium would play a critical role in cooling the superconducting magnets that would provide the magnetic containment environment. This kind of fusion technology would become widespread only in the very distant future, if ever. Nevertheless, it is essential to mention it as a potential user of helium as a refrigerant for superconducting magnets, which would probably require liquid-helium temperature refrigeration even if they were made from high-temperature superconducting wire.

A possible nearer-term use for gaseous helium in the energy conversion enterprise is in the high-temperature gas-cooled reactor. This type of fission reactor is fueled with a mixture of graphite and fuel-bearing elements. The coolant consists of helium gas pressurized to about atm. Helium, which is radiologically inert, passes through interstices in the array of fuel and graphite elements. These reactors can operate at extremely high temperatures, as graphite has a high sublimation temperature and helium is chemically inert.

The hot helium can then be directly used either as the working fluid in a high-temperature gas turbine or as the heat source to generate steam. The advantages of such a reactor are that it is meltdown-proof, nearly 50 percent more efficient than current water-cooled reactors, more proliferation-resistant since it uses ceramic fuel, and an efficient plutonium burner, and also that it produces less high-level waste.

A joint U. Each reactor would require an inventory of , scf 2, scm of helium and a reserve of , scf 5, scm. The inventory is expected to be drawn down at 25 percent per year.

Depending on scenarios for deployment, the cumulative requirement for helium by could be as high as 75 million scf 2. These facilities would require liquefiers of the scale used by the Relativistic Heavy Ion Collider at Brookhaven National Laboratory, so they could become large-scale users of helium.

The Reynolds number is a figure of merit that characterizes the flow of a fluid around an object such as an airplane or a ship. It is proportional to the product of a length of the object, the density of the fluid, and its velocity, and is inversely proportional to the fluid's viscosity. When a scale model is tested in a wind tunnel, the test is realistic only if the flow over the model is the same as the one the real plane would experience in flight.

To achieve this, the Reynolds numbers of the real object and the test object must be the same. This can be difficult if the real object is much larger than the model, because the Reynolds number depends on the size of the object under test. One solution to the problem has been to increase the speed of the gas passing over the model. Indeed there are supersonic wind tunnels that use helium gas.

There are limits to this approach, however. Building larger models and larger wind tunnels is too expensive, and thus the highest number achieved is typically 10 million. A submarine moving in water can have a Reynolds number as high as a billion. Liquid helium just above its superfluid transition has a very low viscosity and can be used to achieve very high Reynolds numbers.

Standard wind tunnels achieve Reynolds numbers of 10 6. A liquid-helium flow tunnel can achieve values of 10 9. Using cold, gaseous helium, Rayleigh numbers of 10 16 to 10 20 can be achieved, depending on the scale.

The Rayleigh numbers of the atmosphere, ocean, and Sun are 10 9 , 10 20 , and 10 21 , respectively. Medical Applications : Helium gas can be used for respiratory ailments to treat conditions such as asthma and emphysema. Liquid helium also has medical purpose as it is used as a cooling medium for magnets and process use in MRI scanners and NMR spectrometers.

It is also used to inflate airbags as helium can diffuse quicker than most unreactive gases. The Department of Energy's Jefferson Lab uses large amounts of liquid helium to operate its superconductive electron accelerator. Helium is an inert gas and does not easily combine with other elements. There are no known compounds that contain helium, although attempts are being made to produce helium diflouride HeF 2.

Number of Stable Isotopes : 2 View all isotope data. Electron Shell Configuration :. Helium Previous Isotopes Next. History and Uses : Helium, the second most abundant element in the universe , was discovered on the sun before it was found on the earth.

Citation and linking information For questions about this page, please contact Steve Gagnon. Imperial Helium has developed strategic relationships supporting the marketing and distribution of Helium to the end market. Read more. Back What is Helium Used For? December 8, by Imperial Helium.

Why helium is so important Helium has many qualities that make it irreplaceable. What is helium used for?