The main purpose of a helium gas, industrial helium (2N ~ 3N): mainly used for leak detection, filling balloons, helium airship, flying boats and the like. Second, pure helium (4N): for: special metal welding, diving breathing, special metal smelting. Third, the high purity helium (5N) for: standard gas production, low temperature superconductivity, scientific research, laser cutting, carrier gas chromatographic analysis. (2N refers to 99%, 4N means 99.99% 5N refers to 99.999%) First, understand, low pure helium (2N ~ 3N) usefulness due to the physical nature of his decision to use helium balloon, helium airship areas such as helium a low degree of awareness in China, we are essentially balloons and airships float using hydrogen as a gas, but because of frequent accidents, the state expressly provides that when the balloons and airships helium must be filled, so low purity Helium had its own arena, since the nature of the inert gas, and the density is very small, second only to hydrogen, so that the balloon and airship has been widely used, mainly the face of customer groups: advertising, wedding Companies and Meteorology. Now, talk about pure helium (4N) usefulness. Special metal smelting industry: He has great inertia and good thermal conductivity, in the rare metal smelting special titanium, zirconium and semiconductor silicon, germanium, use helium as a shielding gas. Special metal welding industry: the use of inert helium and good thermal conductivity, helium can be used as advanced alloys welding and cutting, Ar + He mixed gas for welding aluminum and aluminum alloys, magnesium and magnesium alloys, copper and copper alloys, titanium and titanium other metal alloys, and metal matrix (usually of aluminum, magnesium, titanium, etc.) composite material. Medical industry applications: in medical terms, 1: 4 mixture of oxygen and helium can quickly penetrate the lungs and speed up the exchange of oxygen and carbon dioxide, can treat asthma, airway, throat diseases, as well as diving disease. Diving industry applications: in diving operations, if ordinary air, at a depth of 50m or less dissolved nitrogen in the blood can cause anesthesia, diver life-threatening. Therefore, when the deepwater diver, you can not use pure oxygen, but need to use oxygen, helium gas mixture instead of air for divers to breathe, can guarantee the security 200m deepwater operations. Here, the focus explain high purity helium (5N) application in various industries. First, look at the helium leak detectors: helium leak detectors, mainly applied to the closed pipeline leak detection, when a pipeline project is installed, sealed the end of the pipeline, in another section of the connection helium leak detectors, pipe into a vacuum state, and to no one at the valve and interface blow helium, helium has a strong diffusion, penetration is particularly high, so if you find the leak, helium will penetrate into the tube Road, helium mass spectrometer leak detector detects the presence of helium, then that tainted point, on the contrary, the pipeline safety. Optical fiber industry: optical fiber manufacturer to include a long fly to Wuhan, Hangzhou Fortis, Jiangsu Zhongtian, Wuhan flames, Jiangsu Hengtong, Shanghai-Corning, Shenzhen idiopathic Drake, live in Chengdu, Jiangsu Fasten like. We know, from the optical fiber drawn from an optical fiber preform, and the optical fiber preform is usually using different production chemical vapor deposition process. The main raw materials include silicon tetrachloride, helium, hydrogen, etc., in which silicon tetrachloride and helium gas account for about 50% of the cost of production of optical fiber preform. Since the world's growing demand for clean energy and semiconductor "silicon" material market prices began to show a rising trend, while helium gas prices have risen in recent years, more than twice this optical fiber preform production costs increase, optical fiber preform prices was evident. Chromatography industry: common carrier gas of hydrogen, nitrogen, helium, etc. Hydrogen, helium, smaller molecular weight is often used as a carrier gas for packed column chromatography; molecular nitrogen is large, often as a carrier gas for capillary gas chromatography; gas chromatography-mass spectrometry using helium as the carrier gas. Because nitrogen gas chromatography with Ar and O difficult to distinguish, so, in gas chromatography mass spectrometry using helium as the carrier gas. Nitrogen and helium is chemically stable, low reactivity, gas chromatography carrier gas only play the role of carrier physical, reactive nitrogen helium as low as possible so the scope is broad.