Safetygram-8安全程序-8
Liquid Argon液态氩
General概述
Liquid argon is tasteless, colorless, odorless, noncorrosive, nonflammable, and extremely cold. Belonging to the family of rare inert gas, argon is the most plentiful of the rare gas, making up approximatel y 1% of the earth’s atmosphere. It is monatomic and extremely inert, forming no known chemical compounds.
液态氩无色，无味，无嗅，无腐蚀性，不可燃，温度极低。氩属于稀有惰性气体家族，是最丰富的稀有气体，占地球空气的约1%。它是单原子，极不活泼，没有已知的化合物。
Special materials of construction are not required to prevent corrosio n. However, materials of construction must be lected to withstand the low temperature of liquid argon. Vesls and piping should be designed to American Society of Mechanical Engineers(ASME) specifications or the Department of Transportation (DOT) codes for the pressures and temperatures involved.
不要求特殊的建材来防止腐蚀。选择的建材必须能抗液氩的低温。容器和管道系统要根据相关的压力和
温度按照美国机械工程师协会（ASME）或交通部（DOT）的规定来设计。
Although ud more commonly in the gaous state, argon is commonly stored and
trans-ported as a liquid, affording a more cost-effective way of providing product supply.
尽管通常作为气体使用，氮一般以液态存储和运输，这样产品供应成本更低。
When argon is converted to liquid form it becomes a cryogenic liquid. Cryogenic liquids are liquefied gas that have a normal boiling point below –238°F (–150°C). Liquid argon has a boiling point of –302.6°F (–185.9°C). The temperature difference between the product and the surrounding environment, even in winter, is substantial. Keeping this surrounding heat from the product requires special equipment to store and handle cryogenic liquids.
当氩转化成液态，就成为低温液体。低温液体是沸点温度一般在–238°F (–150°C)以下的液化气体。液氩的沸点是–302.6°F (–185.9°C)。因为产品和周围环境的温差即使是在冬天也非常大，保持液氩和周围环境隔离是很重要的。产品还要求专门的使用和储存设备。
A typical system consists of the following components: a cryogenic storage tank, one or more vaporizers, a pressure control system, and all of the piping re quired for fill, vaporization, and supply.
The cryogenic tank is constructed like a vacuum bottle. It is designed to keep heat away from the liquid that is contained in the inner vesl. Vaporizers convert the liquid argon to its gaous state. A pressure control manifold controls the pressure at which the gas is fed to the process. Physical and chemical properties are listed in Table 1.
一个典型的储存系统由一个低温储存罐，一个或多个汽化器，一个压力控制系统和所有的用于灌装、汽化、供给的管道系统组成。低温罐造得象个真空瓶。设计得使热量无法进入内罐中的液氩。汽化器把液氩转化成气态。压力控制管控制着输入到过程的气体压力。使用液氩的过程不要求有汽化器和压力控制管。物理和化学性质列于表1。
Manufacture生产
Argon is produced at air paration plants by liquefaction of atmospheric air and paratio n of the argon by distillation. The argon is then recovered as a cryogenic liquid.
在空气分离工厂，通过空气液化和蒸馏分离出氩。接着氩作为低温液体回收。
Us用途
欧式婚纱
夏季防晒Argon is most commonly ud in its gaous state. It is widely ud in the lighting industry for filling
bulbs and with combinations of other rare gas for the filling of special bulbs and tubes for special color effects. The welding industry us argon as a shielding gas to protect metal from oxidation during welding. Argon is also ud extensively in the miconductor manufacturing process as a purge gas.
大多数情况下氩作为气体使用。氩在照明工业得到了广泛应用，填充灯泡，以及同其它稀有气体一起充入特殊灯泡和管子以获得特殊的颜色效果。焊接工业中，氩作为焊接过程中的保护气防止金属氧化。作为吹扫用的气体，氩也广泛应用于半导体制造工艺过程。
Health Effects对健康的影响
Being odorless, colorless, tasteless, and nonirritating, argon has no warning properties. Humans posss no ns that can detect the prence of argon. Argon is nontoxic and largely inert. It can act as a simple asphyxiant by displacing the oxygen in air to levels below that required to support life. Inhalation of argon in excessive amounts can cau dizziness, naua, vomiting, loss of consciousness, and death. Death may result from errors in judgment, confusion, or loss of consciousness that prevents lf-rescue. At low oxygen concentrations, unconsciousness and death may occur in conds and without warning.
由于无嗅、无色、无味、无刺激性，氩没有警告性特征。人类没有能够探测到氩的存在的官能。氩无毒且不活泼。通过取代空气中的氧，使之下降到维持生命所必须的水平以下，它可以成为简单的窒息物。过量吸入氩会导致眩晕、恶心、呕吐、失去知觉和死亡。死亡可能来源于错误的判断、精神混乱或者阻止了自救的失去知觉。在低氧浓度情况下，意识不清和死亡会在几秒钟内发生，而且没有警告。
Personnel, including rescue workers, should not enter areas where the oxygen concentration is below 19.5%, unless provided with a lf-contained breathing apparatus or air-line respirator.
除非备有自给式呼吸器（SCBA）或空气管呼吸器，任何人，包括救援人员，都不能进入氧浓度低于19.5%的区域。
For more information on oxygen-deficient atmospheres, consult Air Products’Safetygram-17, “Dangers of Oxygen-Deficient Atmospheres”. Extensive tissue damage or burns can result from exposure to liquid argon or cold argon vapors.
要得到关于缺氧大气的更多信息，请参考Air Products的安全程序-17，“缺氧大气的危险”。暴露于液氩或低温氩蒸气会导致大面积组织损伤或冻伤。
Containers容器
Liquid argon is stored, shipped, and handled in veral types of containers, depending upon the quantity required by the ur. The types of containers in u are the dewar, cryogenic liquid cylinder, and cryogenic storage tank. Storage quantities vary from a few liters to many thousands of gallons. Since heat leak is always prent, vaporization takes place continuously. Rates of vaporization vary depending on the design of the container and the volume of stored
product.
根据用户要求的量，使用高压钢瓶、管道或管道拖车来运输和储存液态氩。使用中的容器类型包括杜瓦瓶、低温液体钢瓶和低温储存罐。储存量从几升到成千上万加仑。由于热泄露总是存在，蒸发不断地发生。蒸发率随容器的设计和容量而变化。
Containers are designed and manufactured according to the applicable codes and specifications for the temperatures and pressures involved.
钢瓶的设计和制造是按照相应的压力和温度所适用的法规和规范。
Table 1: Liquid Argon Physical and Chemical Properties
表1：液态氩的物理和化学性质
Chemical For mula分子式Ar
Molecular Weight分子量39.95
Boiling Point沸点
Specific Gravity比重, Gas气体(air空气=1) @ 68°F (20°C), 1 atm 1.38
Specific Gravity比重, Liquid (w ater水=1) @ 68°F (20°C), 1 atm 1.40
Specific Volume比容@ 68°F (20°C), 1 atm 9.68 scf/lb @ 1 atm –302.6°F (–185.9°C)
Freez ing Point凝固点@ 1 atm –308.8°F (–189.4°C)
Critical Temperature临界温度–188.4°F (–122.4°C)
Critical P ressure临界压力705.8 psia (48.0 atm)
Density密度, Liquid液体, @ BP, 1 atm 87.40 lb/scf
Density密度, Gas气体@ 68°F (20°C), 1 atm 0.1034 lb/scf
Latent Heat of Vaporization汽化潜伏热2804 Btu/lb mole
E x pansion Ratio膨胀率, Liquid to Gas液体到气体, BP to 68°
F (20°C) 1 to 840
Dewars杜瓦瓶
Fig. 1 illustrates a typical, vacuum-jacketed dewar. A loo-fitting dust cap over the outlet of the neck tubes prevents atmospheric moisture from plugging the neck and allows gas produced from vaporized liquid to escape. This type of container is a non-pressurized container. The unit of measure for the capacity of a dewar is typically the liter. Five to 200 liter dewars are available. Product may be removed from small dewars by pouring, while larger sizes will require a transfer tube. Cryogenic liquid cylinders that are pressurized vess els are sometimes incorrectly referred to as dewars.
图1说明了一个典型的带有真空夹层的杜瓦瓶。颈部出口上的宽松的防尘盖可以防止空气中的水蒸汽堵塞颈部，同时允许液体蒸发产生的气体逸出。这种容器是不加压的。测量杜瓦瓶的容积最常用的单位是升。5到200升的杜瓦瓶都有。液氧可以从小杜瓦瓶中倒出来，而较大尺寸的杜瓦瓶需要用传递管来取出液体。作为加压容器的低温液体钢瓶有时候被错误的称作杜瓦瓶。
Cryogenic Liquid Cylinders低温液体钢瓶
Fig. 2 shows a typical cryogenic liquid cylinder. Cryogenic liquid cylinders are insulated, vacuum-jacketed pressure vesls. They come equipped with safety relief valves and rupture discs to protect the cylinders from pressure build-up. The containers operate at pressures up to 350 psig and have capacities between 80 and 450 liters of liquid.
典型的低温液体钢瓶如图2所示。这是一个隔热的有真空夹层的压力容器。它们配备有减压阀和破裂盘，以保护钢瓶，防止压力积累。液体容器可以在压力小于350 psig的情况下工作，容积在80到450升液体之间。
Product may be withdrawn as a gas by passing liquid through an internal vaporizer or as a liquid under its own vapor pressure. For more details on the construction and operation of cryogenic liquid cylinders, consult Air ProductsSafetygram-27 “Cryogenic Liquid Containers.”
张国荣可以通过使液体流过内汽化器取出气态氩，或者直接取出在它自己的蒸气压下的液态氩。要得到关于低温气体钢瓶制造和操作的更多细节，请参考Air Products的安全程序-27，“低温液体容器”。
Cryogenic Storage Tanks低温储存罐
A typical customer installation (e Fig. 3)includes a tank, a vaporizer, and a pressure control manifold. Tanks may be spherical or cylindrical in shape. They are mounted in fixed locations as stationary vesls or on rail road car or truck chassis for easy transportation. Sizes range from 500 to 420,000 gallons and all tanks are powder- and vacuum-insulated in the annular space. Tanks are equipped with various circuits to control product fill, pressure build-up, pressure relief, product withdrawal, and tank vacuum. Tanks are designed to ASME specifications for the pressures and temperatures involved.
用户使用的设备一般包括储存罐、汽化器和压力控制管（见图3）。罐的形状可以使球形或柱状，作为固定容器安装在固定位置，或者安装在有轨车或卡车底座上，以便于运输。大小从500到420,000加仑的都有。所有罐都有真空环形隔热层。罐子配备有各种控制产品灌装、压力积累、减压、产品取出和罐子真空的回路。罐子根据相关的压力和温度按照ASME规范设计。
Transfer Lines转移管
A liquid transfer line is ud to safely remove liquid product from dewars or cryogenic liquid cylinders. A typical transfer line for dewars is connected to a bayonet that provides a means of using product vapor pressure build-up or an external pressure source to remove the liquid. For cryogenic liquid cylinders, the transfer line is connected to the cylinder’s liquid withdrawal valve.
液体转移管用于从杜瓦瓶或低温液体钢瓶中安全地提取液体产品。用于杜瓦瓶的典型的转移管连接到卡口上，利用产品积累的蒸气压或外部的压力源来取出液体。对于低温液体钢瓶，转移管连接到钢瓶的液体提取阀门上。
Liquid product is typically removed through insulated withdrawal lines to minimize thel oss of liquid product to gas. Insulated flexible or rigid lines are ud to withdraw product from storage tanks. Connections on the lines and tanks vary by manufacturer.
一般通过隔热提取管来取出液体产品，以尽量减小液体汽化的损失。使用隔热的弹性或刚性管道来从储存罐中取出液体产品。管道和储存罐上的接头随制造商的不同而不同。
NOTE: Liquid cylinders designed to dispen gaous argon have valves equipped with standard Compresd Gas Association (CGA) outlets. Suitable pressure regulating equipment may be attached. Valves provided for the withdrawal of liquid product are also equipped with standard CGA outlets, but are different than the connections ud for gaous withdrawal. This is to prevent cross connections between process using the liquid or gaous product.铭记那份美好
中国人体摄影注意：设计来输出气态氮的液体钢瓶上装有配有标准的压缩气体协会排气口的阀门。或许还附带着合适的压力调节器。用于液体产品提取的阀门也配有标准的CGA的排气口，但它不同于用于气体提取的
also造句排气口。这就避免了在使用液体或气体产品之间的交叉连接。
Shipment of Liquid A rgon液氩的运输
Containers ud for transporting liquid argon at less than 25 psig (40 psia) pressure are
UN/DOT authorized containers. The are containers built to other than DOT specifications, but are authorized by the DOT for u in the transport of approved products. Containers ud for transporting liquid argon at pressures greater than 25 psig (40 psia) need to be designed, manufactured, and tested to DOT specifications.
用于运输压力小于25 psig (40 psia)的液态氩的容器是UN/DOT认可的容器。这些容器的制造不必遵守DOT规范，只是得到了DOT的用于运输已核准产品的授权。用于运输压力大于25 psig (40 psia)的液态氩的容器需要按照DOT规范设计、制造和检测。
For air shipments all packages must be incompliance with International Air Transport Association/International Civil Air Organization(IATA/ICAO) Dangerous Goods Regulations, as well as DOT regulations.
对于空运，所有包装还要遵守国际空运协会/国际民航协会（IATA/ICAO）危险货物的规定，以及DOT
的规定。
DOT Hazard Class危险等级: 2.2
DOT Shipping Label运输标志:: Nonflammable Gas
(Fig. 4), except none for cargo tanks under 23 psig（图4）不排除23 psig以下的货物容器Identification Number鉴别号: UN1951
DOT Shipping Name货物名称: Argon, Refrigerated Liquid, 2.2, UN1951氩，冷冻液体
Safety Considerations对安全的考虑
The hazards associated with liquid argon are exposure to cold temperatures, which can cau vere burns; over pressurization due to expansion of small amounts of liquid into large volumes of gas in inadequately vented equipment; and asphyxiation due to displacement of oxygen in the air in confined work areas.
同液氩相联系的危险有：会导致严重冻伤的低温暴露；在通风不充分的设备里，小量液体汽化成大量气体造成的过压；取代狭窄工作空间内的氧造成的窒息。
If oxygen-deficient atmospheres are suspected or can occur, u oxygen monitoring equipment to test for oxygen-deficient atmospheres. Review the liquid argon Material Safety Data Sheet (MSDS).
如果怀疑空气中缺氧或缺氧可能发生，使用氧检测设备来测试缺氧空气。可以参考合适的材料安全数据表（MSDS）。
Fig. 1 A typical dewar.图1一个典型的杜瓦瓶
Fig. 2 Typical cryogenic liquid cylinder. Side view, top. Overhead view, bottom.图2 典型的低温遗体钢瓶。侧视图，上。俯视图，下。
Fig. 3 A typical customer station with a cryogenic storage tank.图3 一个典型的带有低温液体储存罐的用户站
Fig. 4 Nonflammable gas shipping label. 图4 不可燃气体运输标志
柴犬优缺点Buildings建筑物
Becau of the large expansion ratio of liquid to gas, it is very important to provide adequate ventilation in areas using liquid argon. A minimum of six air changes per hour are suggested in the areas.
养肺的食物
因为液体到气体的大膨胀率，为正在使用液氧的地方提供充分的通风非常重要。建议每小时最少换气6次。
