Automatic Spraying

I. Deviation from these distances requires l pro tective installations such as fixed focm system-., water spray, automatic sprinklers, fire-system grading yf 4 or better, or superior construction. 

The B6580/81 automatic sprinkler system also sen/es the HCF. Standard spray automatic sprinklers are provided in occupied areas of the basement, including Rooms 100,104,105,106, 107, 111, 112,113,113Aand114. The HCF is equipped with an independent fire-alarm control panel, located against the south end of the west wall of Room 107 that monitors all areas of the HCF. Water that may be released during fires is captured and routed to holding tanks. This capture system is described in Section 2.9.5. Any sprinkler-water flow will activate the TA-V... 

In the automated lay-up system, each layer of veneer (with exception of the top surface veneer) passes under an automatic adhesive appHcation system. This may be a spray appHcation, a curtain coater, or an extmder, each of which is designed to apply a uniform adhesive spread on the upper face of each veneer. After all except the top veneer have been spread with adhesive and laid together, the top veneer is added. The me of the veneer—adhesive assembly at this point should be about 8%. 

The main features in which the Radford process differs from the batch operation are in thermal dehydration and compounding. Water-wet nitrocellulose on a continuous vacuum belt filter is vacuum-dried followed by hot air transfusion (80°C) to reduce the moisture to less than 2%. After cooling, alcohol is sprayed on the nitrocellulose to a concentration of 15—20%. The alcohol-wet nitrocellulose is then transferred from a surge feeder to a compounder by a continuous weigh-belt along with the other ingredients of the composition, which are also weighed and added automatically. 

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. 

Fig. 1. An automatic spray-coating system, where air-automized electrostatic spray guns are mounted on reciprocators.

Phospha.tes, Pentasodium triphosphate [7758-29-4] sodium tripolyphosphate, STPP, Na P O Q, is the most widely used and most effective builder in heavy-duty fabric washing compositions (see also Phosphoric acid and phosphates). It is a strong sequestrant for calcium and magnesium, with a p c of ca 6, and provides exceUent suspending action for soils. Because of its high sequestration power, it also finds extensive appHcation in automatic-dishwashing detergents. Sodium tripolyphosphate forms stable hydrates and thus aids in the manufacture of crisp spray-dried laundry powders. 

If an ethyl ether fire occurs, carbon dioxide, carbon tetrachloride, and dry chemical fire extinguishers meeting National Eire Prevention Association Code 1 and 2 requirements may be used successhiUy (23). Water may also be effectively appHed (see Plant safety). Hose streams played into open tanks of burning ethyl ether serve only to scatter the Hquid and spread the fire. However, ether fires may be extinguished by a high pressure water spray that cools the burning surface and smothers the fire. Automatic sprinklers and deluge systems are also effective. 

Gearing is single hehcal or spur gear lubrication usually is an automatic spray type. Single drives are used up to 150 kW. Kilns requiring more than 150 kW may be equipped with dual drives, i.e., two driving... 

Provision and use of appropriate health surveillance, e.g. for signs of dermatitis, asthma, effects of specific solvent exposures. Full use of any spray booth, enclosure, exhaust ventilation or dilution systems, and automatic handling equipment. (The efficiency of all local exhaust ventilation and other control systems should be maintained, and checked by testing.) Where appropriate, atmospheric monitoring of airborne pollution levels. 

Regarding fires, water is the primary extinguishing agent, and it should be available in adequate supply and pressure at all of the locations in the plant. The layout for various types of installations and the appropriate recommendations are found in the standards of the National Fire Protection Association. Fire hydrants, hose lines, automatic sprinkler and water spray systems should all be a part of the permanent equipment facilities of the plant. 

Sprinkler and water spray installations-Many process and storage area buildings should be protected by automatic sprinkler systems. The size and arrangement for water supply are dependent upon the nature of the hazard and the degree of protection desired. Water spray installations are particularly adapted for cooling uninsulated steel structures, elevated pipe lines, vessels, spheres, and similar plant installations. 

The usual protection for large installations is to provide a water-spray system. For small bulk storage, fire hoses or monitors are often adequate. However, for installations over 50 tons of storage (and all major cylinder-filling plants) it is accepted that a fixed water-spray system needs to be provided which is automatically initiated by a system capable of detecting a fire threatening the vessels... 

Few plant operators need to be told of the problems caused by water in compressed air. They are most apparent to those who operate pneumatic tools, rock drills, automatic pneumatic powered machinery, paint and other sprays, sandblasting equipment, and pneumatic controls. However, almost all applications, particularly of 100-psig power, could benefit from the elimination of water carryover. The principal problems might be summarized as ... 

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. 

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... 

Full use of any spray booth, enclosure, exhaust ventilation or dilution systems, and automatic handling equipment. Full use, where appropriate, of ventilation, e.g. by opening doors, windows. 

---