Air atomization

A special case of air atomization is high volume low pressure (hvlp) spray. In this case the air pressure at the spray gun is less than 70 kPa (10 psig) and there are relatively large (up to 0.32 cm) holes in the air cap to easily pass the low pressure air. This type of atomizer produces a soft or slow moving spray and is generally considered to be rather efficient in depositing the material on the workpiece. However, the use of low pressure air for atomization usually limits the viscosity and/or flow rate of the material that can be atomized. 

Airless spray uses hydrauHc pressure to deUver the paint. Paint is brought to the spray gun under 7—40 mPa (1000—6000 psi), where it is divided into small separate streams and forced through a very small orifice to produce the spray. Airless spray is faster, cleaner, and less wasteful than air atomization, but demands good technique because it deUvers paint very quickly. 

Air atomizing nozzles are commonly used to control the droplet-size distribution independently of the liquid feed rate and to minimize the chances of defluidization due to uncontrolled growth or large droplets. 

Fine water spray systems may be potentially superior to CO9 apphcations and may replace halon environments such as telephone central offices and computer rooms. In the fine spray dehveiy system, water is delivered at relatively high pressure (above 100 psi [0.689 MPa]) or by air atomization to generate droplets significantly smaUer than those generated by sprinklers. Water flow from a fine spray nozzle potentially extinguishes the fire faster than a sprinkler because the droplets are smaUer and vaporize more quickly. Preliminaiy information indicates that the smaller the droplet size, the lower the water flow requirements and the less chance of water damage. 

Figure 10-10. Low-pressure air atomizer. (Courtesy of General Electric Company.)...

MDHS 6/3 Lead and inorganic compounds of lead m air (atomic absoiption spectrometry)... 

Cadmium and inorganic compounds of cadmium in air (X-ray fluorescence spectroscopy) Chromium and inorganic compounds of chromium m air (atomic absorption spectrometry) Chromium and inorganic compounds of chromium m air (X-ray fluorescence spectroscopy) General methods for sampling and gravimetnc analysis of respirable and mhalable dust Carbon disulphide in air... 

Oil-, gas- and dual-fired boilers are available with a range of combustion appliances. The smaller units have pressure jet-type burners with a turndown of about 2 1 while larger boilers may have rotary cup, medium pressure air (MPA) or steam-atomizing burners producing a turndown ratio of between 3 1 and 5 1, depending upon size and fuel. The majority has rotary cup-type burners, while steam- or air-atomizing burners are used where it is essential that the burner firing is not interrupted even for the shortest period. 

MDHSIO Cadmium and inorganic compounds of cadmium in air (atomic absorption spectrometry). 

Figure 4. TEM for Au/Fe203 coprecipitate calcined at 673 K in air. Atomic ratio of Au/Fe is 1/19.

Air-Atomized Spray Airless Spray Pressure-Atomized Electrostatic Spray... 

Air-atmosphere furnaces, 22 290-291 Air atomization, in spray coating, 7 70-72 Air-atomizing sulfur burners, 23 659-660 Airbags, nylon, 19 766 Air-based balanced vinyl chloride process, 25 637, 640, 641, 645 Air-based ethylene oxidation, 20 643-646 Air bioremediation... 

Sulfur dioxide is manufactured mostly by combustion of sulfur or its iron sulfide mineral, pyrite, FeS2, in air. The flame temperatures for such combustion of sulfur in the air are usually in the range 1,200 to 1,600°C. Many types of sulfur burners are available and are used to produce sulfur dioxide. They include rotary-kiln, spray, spinning-cup and air-atomizing sulfur burners. Selection and design of burners depend on quality of sulfur to be burned, and rate and concentration of sulfur dioxide to be generated. Pyrites or other metal sulfides may be burned in air in fluid-bed roasters to form sulfur dioxide. 

Tests with Aerosol Sprays. One of the chief means of applying concentrated oil sprays is in aerosol form. An aerosol generally remains suspended in the air for some time and is carried by normal wind or air currents. Aerosols are probably best adapted to interior applications but have been used with some success outdoors. They may be produced by liquefied-gas formulations released through capillary nozzles, by steam and air atomization, by centrifugal disks and rotors, by extremely high pressure, and by heat vaporization. 

These nozzles are available as a single-port or multi-port design. Generally, the single port nozzles are adequate up to 100 kg batch, but for larger size batches a multi-port nozzle such as either a three port (Fig. 10) or six port (Fig. 11) nozzle is required. When these nozzles are air atomized, the... 

---