Pneumatic spraying

Concretes made with Portland cement have a specific weight of 140 to 150 Ib/ft (2,242 to 2,400 kg/m ). Concrete absorbs the heat of a fire when chemically bound water is released from a crystalline structure and is reduced to lime. Dense concretes can be formed in place, or pneumatically sprayed to the required thickness using steel reinforcement. The corrosive effect of chlorides on the steel surface in moist saline environments (coastal or other chloride environments) dictates the use of protective primers and topcoat sealers. Major advantages of dense concrete are ... 

Figure 1. Schematic cross section of sonic spray ion source. Liquid sample is pneumatically sprayed by the coaxial gas flow. The cross section of the gas flow in this source is restricted to 0.017 mmh...

The negative exponent on the Reynolds number of -0.32 indicates that Re has a medium effect on the mean diameter. This result is about in accordance with those obtained by Gretzinger and Marshall [801 in their investigation on the external mixing pneumatic spray nozzles. 

Atmospheric pressure chemical ionization a solution of the sample is pneumatically sprayed at atmospheric pressure and the solvent is ionized by a coronary discharge from a needle. The monocharged ions produced cause the chemical ionization of the analyte and the ions are accelerated towards the vacuum region. 

Faced with potential leak that could cause gaskets of the pneumatic spraying columns rotation system of CIP, Serail has developed a system in which the inlet column of the cleaning agent is fixed. The spraying column makes its rotation through a magnet system. 

Figure 3. Flow diagram of system for supplying sulfur to pneumatic spray...

Other temperatures and conditions not associated directly with the application of the sulfur and wax (e.g., cooling) remain the same as in the pneumatic spraying process. 

Generally a very narrow droplet spectrum is obtained and the relative uniformity of the coating is improved accordingly. A further advantage of this method is that the gas flow rate is independent of the aerosol flow rate, which is not the case with pneumatic spraying. A modern spray deposition process can be described by relatively few parameters such as flow of carrier gas Q, concentration of the solution C, solution flow q, droplet radius r, distance between nozzle and substrate d, temperature of the gaseous environment Te, temperature of the substrates Ts and their speed... 

FIGURE 25.3 Microscopic images of carnauba wax microparticles produced by spray congealing under following conditions melt temperature 115°C, pneumatic spraying system with air pressure 1 bar, air nozzle internal diameter 1 mm (unpublished data). 

Antkowiak, W., and Heim, A., Investigation of Pneumatic Spray Nozzle for Wetting Granulate Fine Material, Inzynieria Chemiezna i Procesowa (Chem. Process Eng.), Vol. 8, No. 1, 1987, pp. 57-65 (in Polish). 

To overcome the rather qualitative and poorly reproducible corrosion test methods, a new method, which allows quantitative assessment, was developed by us. Body panels (150 x 80 x 1.5 mm ) from Mercedes-Benz were used as substrates. The panels were sand blasted and degreased with a 1 1 1 mixture of acetone, ethylacetate, and xylene. The polyaniline containing primer CORRPASSIV was applied using pneumatic spray units, the thickness after drying averaged 28 + 3 p,m. The topcoats were sprayed on after the primer had dried for 24 h. 

Some rare works also report on the AASG deposition of sub-micron films from a pneumatic spray. Either the authors concluded to a lower quality of AASG-derived films (Lin, 1997), compared to more traditional sol-gel deposition techniques, or precursor spray solutions had to be specifically processed with respect to viscosity (Kololuoma, 2001) or solvent boiling point (Fink, 2000). 

Fig. 12.40. APCI source. The liquid flow is pneumatically sprayed into a heated vaporizer where ionization is initiated by a corona discharge at atmospheric pressure. The sampling orifice and interface region behind remain unaltered by ESI.

The powders resulting from spray drying experiments with PVP K30 solutions showed comparable characteristics to conventional pressure or pneumatic spray dried powders. 

Fig. 10 Aluminum- or mica-flake orientation in HR-bell and pneumatic spray.

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