Helium cylinders

For distributing larger quantities of gaseous helium, argon, and occasionally neon, a number of large, horizontal, compressed gas cylinders are manifolded on tmck semitrailers (called tube trailers) or railroad cars. Like individual cylinders, these serve both as transport containers and rental storage containers. Capacities of tube trailers range from about 300 to 5,000 m (10,000—175,000 fT) of gas. 

Use compatible pipe fittings. (Flammable gas cylinders have valves with left-hand threads cylinders for oxygen and nonflammable gases, except occasionally helium, have valves with right-hand threads. Certain liquefied gas cylinders have two supply lines, one for gas and one for liquid, dependent on cylinder position.)... 

Sketch a cylinder with ten molecules of helium (He) gas. The cylinder has a movable piston. Label this sketch before. Make an after sketch to represent... 

Precautions also have to be instituted to protect against the inherent properties of the cylinder contents, e.g. toxic, corrosive, flammable (refer to Table 8.1). Most gases are denser than air common exceptions include acetylene, ammonia, helium, hydrogen and methane. Even these may on escape be much cooler than ambient air and therefore slump initially. Eventually the gas will rise and accumulate at high levels unless ventilated. Hydrogen and acetylene can form explosive atmospheres in this way. 

A sample of helium gas is held at constant temperature inside a cylinder whose volume is 0.80 L when a piston exerts a pressure of 1.5 atm. If the external pressure on the piston is increased to 2.1 atm, what will be the new volume ... 

Gases were supplied to the infrared cell from a gas manifold. 4.99% NO in He and 2.14% CH4 in He were obtained from Matheson. Oxygen and helium were obtained on-site. The He, NO, and CH4 cylinders were passed through an oxysorb trap, an ascarite trap, and a molecular sieve trap, in that order, for additional purification. The O2 was passed through an ascarite and a molecular sieve trap. 

Fig. 5.3. Distribution of helium mnetastable atoms concentration along cylinder at different pressures of He[39] ( / - 1.310 2 Torr 2- 2.510-2 3- 710-2 Torr)...

Fig. 5.14. Flow diagram of the Linde TCF series of turbine helium liquefiers. C denotes the screw compressor, OF the oil filter, Ej 2 3 the heat exchangers, T12 the turbo-expanders and JT the final Joule-Thomson stage. Cylinder B is for pure He gas storage and Gas He is the normal He gas input to the purifier [60],...

Nitrous oxide (N2O 99.0 %) and helium (He 99.999 %) from commerical cylinders were purified through a dry ice-methanol trap to remove water vapor. 

The reactor used consists of a Pyrex glass tube containing 260.6 g catalyst and was immersed in an oil bath. The temperature of the catalyst bed remained constant within + 0.1°C of the desired temperature. Oxygen (0 99.9%), nitrogen (N 99.9%), nitrous oxide (N ,0 99.99%), carbon dioxide (99.9%) and helium (He 99.999%) from commercial cylinders were purified through a dry ice-methanol trap to remove water vapor. 

Apparent near the bench on which the GC unit sits are pressure-regulated compressed gas cylinders of hydrogen and air (in addition to the carrier gas, helium or nitrogen). Metal tubing, typically ]/8-in. diameter, connect the cylinders to the detector. A needle valve is used for flow control. These valves are located in the instrument for easy access and control by the operator. 

Helium sparging refers to the vigorous bubbling of helium gas through the mobile phase. This can be done while it is contained in the reservoir by using a metal bubbler with tubing attached to a cylinder... 

Alternatively, helium may be separated from natural gas by diffusion through permeable barriers, such as high silica glass or semipermeable membranes. The gas is supplied commercially in steel cylinders or tanks. The United States is the largest producer of helium in the world. 

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