Helium is widely used in military, scientific research, petrochemical, refrigeration, medical, semiconductor, pipeline leak detection, superconductivity experiments, metal manufacturing, deep-sea diving, high-precision welding, optoelectronic product production, etc.
1. Low temperature cold source: Utilizing the low boiling point of -268.9C for liquid helium, liquid helium can be used for ultra-low temperature cooling. The ultra-low temperature cooling technology is widely used in superconducting technology and other fields, and the superconducting material needs to be at a low temperature.
The superconducting characteristics can be exhibited only (about 100K). In most cases, only liquid helium can achieve such extremely low temperature relatively easily. Superconducting technology has great applications in magnetic levitation trains in the transportation industry and nuclear magnetic resonance imaging equipment in the medical field.
2. Balloon inflation: Because the density of helium is much smaller than that of air (the density of air is 1.29kg / m3, the density of helium is 0.1786kg / m3), and the chemical properties are extremely inactive, safer than helium (helium can be in the air It may cause an explosion), helium is often used to fill the spacecraft or advertising balloons.
3. Inspection and analysis: The superconducting magnet of the nuclear magnetic resonance analyzer commonly used in instrument analysis needs to use liquid helium to cool down. In gas chromatography analysis, helium is often used as a carrier gas. The helium gas has good permeability and non-flammability. Used in vacuum leak detection, such as helium mass spectrometer leak detector.
4. Shielding gas: Utilizing the inactive chemical properties of helium, helium is often used as shielding gas for welding metals such as magnesium, aluminum, titanium, etc.
5. Other aspects: Helium can be used as a high-vacuum device, and nuclear reactors can be used as pressurized gases for transporting liquid propellants such as liquid hydrogen and liquid oxygen on rockets and spacecraft. Helium is also used as a cleaning agent for atomic reactors, in the gas mixture for breathing in the field of marine development, as a filling gas for gas thermometers, etc.