Hot spray

On increasing the temperature of the adhesive, its viscosity decreases. Many adhesives may be heated to 40-70°C before spraying. Fig. 26 shows the installation of such a system the adhesive passes through a heating element (electric or hot water heater). Only a small part of the adhesive circulates in the heated section (the volume contained in the hose) and is heated. 

When the worker starts spraying, the pump sucks in a certain amount of cold adhesive from its container, but the temperature at the gun remains almost constant because this amount is quickly heated in the heater and mixed with the hot adhesive which circulates. 

The heater must be close to the gun so that there is no loss of heat between these two elements. 

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Wti cyclonic Individually controlled Gas introduced at hot- Spray or orifice wear,... 

Leclercq, M., The Electrochemical Determination of the Proportions of Metal and Metal Oxide in Zinc-base Coatings Obtained by Hot Spraying , Anii -Corr. Methods Mater., 25 No. 9, 5 (1978)... 

Hot spray The paint is heated to 60-80°C. The hot paint flows better and gives better coverage. Transfer efficiency is increased and drying time is shortened. 

Thermosetting epoxy and polyurethane chemically-cured liquid resins can provide, among other characteristics, superior abrasion resistance coatings. Solvent-free formulation applied by hot spray techniques can achieve film thicknesses of up to 5 mm. 

At this stage, the spread of combustion from grain to grain is by a hot spray of molten potassium salts. 

Several spraying methods can be used to apply adhesives, including conventional air spray, hydraulic cold airless spray, hot spray, and hot airless spray. The main types of spray equipment are summarized in Table 17.1. 

Generally unsuitable for small parts. Maintenance is high due to nozzle clogging and overspray. Several passes necessary for thick coating buildup Hot spray Adhesive is first heated, permitting the use of high-viscosity materials. Heavier... 

Polymer films can also be deposited on solid particles by vapor phase reaction or from a melt. The best example of vapor phase reaction is the deposition of Union Carbide s Parylene , a derivative of p-xylylene. In this process, di-p-xylylene, or more commonly a halogenated derivative of it, is vaporized in a vac and therm-mally dissociated into the very reactive monomer, a diradical. The monomer is allowed to condense on the surface of the particles to be coated, where it instantaneously polymerizes to form a high molecular weight, polymeric film (Ref 10). Less reactive, vaporizable or meltable polymers can be applied by hot spraying onto agitated particulates or by deposition in a fluidized bed or in liq suspension (Ref 2). Wax is a common example of wall material applied in all three ways... 

The penultimate section covers special subjects chimneys, uses of chemical resistant masonry materials in the nuclear power field, a short discussion of the uses and limitations of hot sprayed sulfur coatings, and the use of chemically resistant materials in the pulp and paper industry. The final section is devoted to the related subjects of inspection and faiiure analysis. 

Use of application methods that can use relatively high-viscosity paints is advantageous. Appropriate methods include roller coating, special electrostatic spray equipment, hot-spray techniques, and two-nozzle spray guns. 

InterseaL [Porter Int L] High build hot-sprayed high-solids qx>xy. 

The slurry is discharged from the tumblers onto vibrating screens and washed with hot spray water to remove oversized solids and undigested oil sand lumps. This process may also provide additional air entrainment and hence further aeration of bitumen. Additional hot water is added to the slurry, which is then pumped to primary separation vessels. The rejected solids (about 5% of the original oil sand) are conveyed out of the plant for disposal. 

InterseaL [Prater IntT.] High Id hot-sprayed high-solids qx)xy. 

Most of the transparent conductive coatings are produced by vacuum evaporation and sputtering. Other techniques are hot spraying and chemical vapour deposition, as manufactured by Corning, Pittsburgh Plate Glass (PPG) and others [162]. 

Paints have widely differing viscosities that depend on their application conditions low-viscosity paints are processed by dipping and spraying methods, while high-viscosity paints are used in casting, rolling, and hot-spraying methods. The correct choice of solvents serves to optimize the paint properties [14.200], [14.201]. 

Methyl butyl ketone [591-78-6] (MBK, 2-hexanone) is slightly soluble in water, miscible with organic solvents. Being a medium boiler it dissolves cellulose nitrate, vinyl polymers and copolymers, and natural and synthetic resins. It increases the dilutability with non-solvents and diluents. As a paint solvent, methyl butyl ketone is important only in hot-spraying and coil-coating paints. It has a very low MAK value and is recommended as a solvent because it is photochemically inactive and does not, therefore, contribute to the formation of photosmog. ... 

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