Spraying manual

Flame Spray < Manual Torch Press,Sinter,Wrought P/M... 

The presence of a powder as an aerosolized mist may be used so that testing will be by an electronic eye. Manual methods include listening devices for sound inspection or sprays for visual inspection of sprays. Hoods or spray booths are used online where inspectors manually actuate units and observe for defective sprays. Manual actuation for sound may be performed into vacuum setups with microphones that amplify the valve actuation noise. The usual number of actuations for testing is between three and five. At least two are considered as priming shots, followed by a test fire. Rejection rates vary from lot to lot and supplier to supplier but are usually less than 0.1%. The rejection rate, classified by defect, and the testing method should be documented for the validation lots. Rejected units should be closely examined for any false results and may be used to improve the valve manufacturer s quality control. 

The specimens are sprayed manually with a spray bottle once daily five times a week with an artificial seawater, the droplet size and distribution being required in the specification along with exposure time. 

Spray, manual, automatic, airless. Low to high Moderate to high Moderate to high Moderate to high Good Low to high... 

Coatings Coatings are mixtures of fine refractory aggregates and bonds. They contain higher water content than mortars and are supplied in a ready-to-use form. The bonds may be ceramic, hydraulic, chemical, or organic. They can be applied manually, pneumatically, by mechanical projection, or by spraying. Manual application involves the use of a brush or trowel. 

Enclosed agitated filters are useful when volatile solvents are in use or when the solvent gives off toxic vapor or fume. Another significant advantage is that their operation does not require any manual labor. Control can be manual or automatic, usually by timers or by specific measurements of the product. Most filters are made of mild steel, with the exposed surfaces protected by lead, tile, mbber lining, or by coating or spraying with other substances as necessary. Filtration areas up to 10 m are available and the maximum cake thickness is 1 m. Apphcations are mainly in the chemical industry for the recovery of solvents. 

Manual painting occurs mostiy during touch-up or repair, and is best suited for piping, railings, and other hard to spray places. The conventional tools for manual apphcation are bmshes, rollers, paint pads, and paint mitts. These methods are very slow but are suitable for unskilled appHcators and allow the painter to work the coating deeply into the surface being painted. 

The principal factors affecting transfer efficiency are the size and shape of the object, the type of apphcation equipment, the air pressure to the spray gun, and the distance of the spray gun from the object. The transfer efficiency becomes lower as the object becomes smaller or more complex. The transfer efficiency increases when the spray gun is brought closer to the object and when the atomizing pressure is reduced. The transfer efficiency of different types of apphcation equipment in descending relative order is manual > electrostatic spray > airless spray > conventional atomized air spray. 

If the regenerator temperature eontinues to rise, additional quantities of steam will be added in the form of water spray by either manual or automatie means—first, through one set of injeetion nozzles in the overhead line, then through another set elsewhere. It may beeome neeessary to add steam to the eyelones in order to maintain 1,300°F to the expander. Spray nozzles in the dilute phase might also be used if the temperature eontinues to rise. 

The Manual processes cover methods such as hand lay-up, spray-up, pressure bag and autoclave moulding. 

Rail cars, tank trucks, and some reactors and storage tanks were cleaned manually by personnel who entered the vessel fatalities occurred from unexpected or undetected low oxygen content or toxicity. An inherently safer system is a rotating pressurized water spray head that does the cleaning without vessel entry. 

The same applies to the use of spray pistols (spray guns and aerosol cans), the frequency of whose use ought probably to be reduced on account of the propellant gas (chlorofluorohydrocarbons) employed Manual depression of the button valve of the vertically held spray can shoots the propellant gas through a fine jet and drags the sucked-up reagent solution with it onto the vertically held chromatogram (water pump pnnciple)... 

Because when operated manually the spray unit can never be moved so uniformly that the chromatogram is homogeneously covered with reagent and the amount... 

The distribution of the reagent is no longer influenced by the manual dexterity of the operator, the performance of the spray apparatus, the viscosity of the reagent or the drop size of the spray mist. 

Self-induced spray wet collectors This is the most common type, and relies on its separating action by the induced air from the fan pulling the contaminated air through a curtain of water. It is simple in operation with no pumps or moving parts except for the fan, which is set on the clean side of the collector. The scrubbing action is dependent on the pressure drop across the collector. When set, this is constant and is determined by the water level within the collector. The removal of sludge is either by automatic ejection or manual drag-out. 

The more automatic the method of coating application, the more economical and efficient it is, since automation lends itself more readily to more even coatings than do manual methods, e.g. large surface areas lend themselves more readily to spraying techniques, whereas open work structures are more suitable for dipping methods. The coating should also be applied to a specified minimum thickness which is adequate for the service conditions and life envisaged. 

Either system can be used manually or as part of an automated plant. Many modifications of the basic spray guns are available, widening the engineer s potential choice of designs. Some equipment allows paint to be sprayed hot, facilitating the application of very thick coats. 

Improvements of the manual pistols have made it possible to use a much thicker wire which can be up to 8 mm dia for the softer metals. Recently, the range of the wire pistol has been extended by the spraying of plastic cords containing the material to be sprayed as a fine powder. This development, as yet, is not much used in the anticorrosives field. 

The vision of the late W E Ballard ensured that this chapter is still very relevant but there have been some changes in emphasis. Of the spraying techniques, the electric arc process is now generally more economical in operation than oxy-fuel gas processes. The rate of spraying is proportional to the current used and several types of equipment are available ranging from 200 to 1 000 A capacity. For manual operation, pistols using currents up to... 

Coatings up to more than 500 /im (3 200 g/m zinc) can be applied to suit requirements, but with aluminium it is usually best to spray 100-200/xm more than 200 /xm is unnecessary. In manual spraying, the uniformity of the coating depends on the skill of the operative. Spraying in horizontal overlapping lines gives more uniform thickness than the cross-hatch technique. 

Oeshsle, S. J. and Childs, J. N., Thermal Sprayed Coatings, in Steel Structures Painting Council Manual, Vol. 1, pp. 456-464 (1982)... 

Spray-up Popular system with reinforced plastic production. An air spray gun includes a roller cutter that chops usually glass fiber rovings to a controlled short length before being blown in a random pattern (manually or automatically) onto a surface of the mold simultaneously the gun sprays catalyzed TS polyester plastic. The chopped fibers are plastic coated as they exit the gun s nozzle. The resulting, rather fluffy, RP mass is consolidated with serrated rollers to squeeze out air and reduce or eliminate voids. A closed mold... 

Wiping Paint is applied conventionally, then paint is wiped off Paint is either totally removed, remaining only in recessed areas, or is partially removed for special effects such as woodgraining. Standard spray-paint setup with a wipe station following. For low production, wipe can be manual. Very highspeed, automated equipment available. 

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