Helium: is a colorless, odorless, non-flammable gas, the air content of about 5.2 parts per million. chemically inactive, the usual state does not combine with other elements or compounds. Role: low-temperature cold source, balloon inflation, balloon inflation, protection gas and other aspects.
Toxicity of helium:
1. If a large amount of helium is inhaled, it will cause oxygen to be replaced by helium in the body, and thus hypoxia will occur (the respiratory reflex is driven by excess carbon dioxide in the body and is not sensitive to hypoxia), and in severe cases, even death.
2. If helium is inhaled directly from a high-pressure cylinder, its high flow rate can severely damage lung tissue. Large amounts of helium and oxygen at high pressures can cause Highpressurenervoussyndrome (HPNS), although small amounts of nitrogen can deal with this problem. Inhalation of helium in large quantities and over long periods of time can lead to brain damage and even death.
3. A small amount of helium is also found in most bags of French fries, but it is not harmful.
Expanded Information
Applications of Helium
Helium is widely used in the military, scientific research, petrochemicals, refrigeration, medical care, semiconductors, pipeline leakage detection, superconductivity experiments, metal fabrication, deep-sea diving, high-precision welding, and production of photonics products.
1, low-temperature cooling source: Using liquid helium's low boiling point of -268.9℃, liquid helium can be used for ultra-low temperature cooling. And the ultra-low temperature cooling technology has a wider application in the field of superconducting technology and other fields, superconducting materials need to be in low temperature (about 100K) in order to show superconducting properties, most of the time only liquid helium can be relatively easy to realize such extremely low temperature.
Superconducting technology has large applications in the transportation industry for magnetic levitation trains and in the medical field for nuclear magnetic **** vibration imaging equipment.
2, balloon inflation: because helium density is much smaller than air (air density of 1.29kg/m3, helium density of 0.1786kg/m3), and the chemical nature of the extremely inactive, safer than hydrogen (hydrogen can be burned in the air, which may cause an explosion), helium is commonly used in airships or advertising balloons in the filling of the gas.?
3, inspection and analysis: instrumental analysis of commonly used nuclear magnetic **** vibration analyzer superconducting magnets need to use liquid helium cooling, gas chromatography analysis of helium is often used as a carrier gas, the use of helium permeability is good, non-combustible characteristics of helium, helium is also used in vacuum leak detection, such as helium mass spectrometry leak detector.
4, protective gas: the use of helium inactive chemical properties, helium is commonly used in magnesium, zirconium, aluminum, titanium and other metal welding protective gas.
Baidu Encyclopedia - Helium