Pneumatic cleaning method

Scope. This paragraph applies to all operations where an abrasive is forcibly applied to a surface by pneumatic or hydraulic pressure, or by centrifugal force. It does not apply to steam blasting, or steam cleaning, or hydraulic cleaning methods where work is done without the aid of abrasives. 

There is a wide variety of methods for particle size measurement which measure different types of particle size. When selecting a method, it is best to take one that measures the type of size which is most relevant to the property or the process which is under study. Thus, for example, in powder elutriation, pneumatic conveying or gas cleaning, it is most relevant to use one of the sedimentation methods which measure the Stokes diameter, i.e. the diameter of a sphere of the same density as the particle itself, which would fall in the gas at the same velocity as the real particle (assuming Stokes law). In flow through packed or fluidized beds, on the other hand, it is the surface-volume diameter (or diameter... 

Hydraulic drive is probably the least used compression method. Although it provides tremendous power, it is difficult to maintain and fluid leakage is a problem. Pneumatic and electric compression are popular and successful. Electric drives are easy to control, but become expensive and/or slow when larger forces are required (as in the case of larger grids). Pneumatic systems are fast and powerful, but require a good supply of clean, dry, compressed air. With any method, accurate compression control is critical to reliable fixture performance. 

The two types of pressure testing are hydrostatic and pneumatic. Hydrostatic pressure testing with clean water is the preferred method. The test section should be completely filled with the test medium, taking care to bleed off any trapped air. Venting at high points may be required to purge air pockets while the test section is filling. 

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