Applications of the Air Gases

A further hazard exists when compressed air jets are used to clean machine components in workplaces flying particles have caused injury and blindness. Cylinders may fail if overpressurized or weakened by the application of heat. Liquefied gases, e.g. butane or propane, respond more rapidly to heat than the permanent gases such as nitrogen or oxygen. Cylinders are normally protected by pressure relief valves, fusible plugs or bursting discs. 

By far the most important practical use of this sensor is for automotive applications, namely for the control of the air to fuel ratio. It compares favorably with the surface conductivity or high temperature potentiometric sensor (Logothetis, 1987). Other gases could be detected on the same principle provided that the right materials for the electrochemical pump were used. The electrode materials/solid electrolytes used for the construction of potentiometric high temperature sensors (see Table 6.7) could serve as guidance. 

ASTM D 2856 is the method used to determine the open-cell content of rigid cellular plastics by use of the air-pycnometer. This method is used where porosity of the cellular plastic has a direct bearing on the end use involved. For example, in thermal insulation, a high percentage of closed cells is essential to prevent the escape of gases and thereby promote low thermal conductivity. Also, in flotation applications high closed-cell contents generally prevent water absorption. 

The term ionizing wet scrubber was first used by the Ceilcote Co., located in Berea, Ohio, and has found wide application in the air pollution control field. This system is a proven means for the removal of pollutants from industrial process gas streams. The IWS combines the established principles of electrostatic particle charging, image force attraction, inertial impaction, and gas absorption to collect submicron solid particles, liquid particles, and noxious and malodorous gases simultaneously. The IWS system requires little energy and its collection efficiency is high for both submicron and micron size particles. 

Many factors enter into the experimental determination of flammable limits of gas mixtures, including the diameter and length of the tube or vessel used for the test, the temperature and pressure of the gases, and the direction of flame propagation—upward or downward. For these and other reasons, great care must be used in the application of the data. In monitoring closed spaces where small amounts of gases enter the atmosphere, often the maximum concentration of the combustible gas is limited to one-fifth of the concentration of the gas at the lower limit of flammability of the gas-air mixture. 

The first application of the gas turbine principle to a ground system was in 1906 when waste heat from furnace gases was used to operate a turboblower which compressed air for a blast furnace. Developments in metallurgy and compressor design after World War I led, in 1937, to the first... 

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