High-pressure water blasting

High-pressure water blast has been used for prebond surface treatments to eliminate hazardous materials. The combination of high-pressure water abrasion with subsequent application of an adhesive promoter/primer has been found to provide high strength and durable aluminum bonds. 

Cleaning procedures for refinery/petrochemical equipment will continue to emphasize less toxic chemicals, high-pressure water blasting (with water recovery), and considerations for the disposal of the waste materials. Continued use of analytical methods (such as FTIR) may reduce the time necessary to develop an appropriate cleaning sequence. 

Surface preparation typically takes place concurrently with joint termination demolition. Surface preparation can be performed by ultra-high-pressure water blasting, abrasive blasting, or pneumatic sponge blasting. 

Energetic compounds can be collected for reuse by processing to reject binder, impurities, and other inert components. Explosives such as high-blast explosive (HBX), HMX, research department explosive (RDX, or hexahydro-l,3,5-trinitro-l,3,5-triazine), tetryl, TNT, NG, and NC are dissolved or suspended by steaming, high-pressure water jet cutting, or solvent extraction. Filtration, selective extraction/precipitation, vacuum evaporation, and other purification methods then separate the explosives from the binders and impurities, such as metal fragments and decomposition products. 

The paint peeling methods specified in (b) are divided into a mechanical peeling method and chemical peeling method. For the mechanical peeling method, shot-blast and waterjet methods were evaluated. The shot-blast method is to spray particulate agents on a painted TP bumper surface by means of compressed air in order to peel off the paint film. The water-jet method uses high pressure water instead of particulate. Both of them are unsuitable for the treatment of such bulky products with complex geometries as bumpers. 

Clean the outside of the radiant tubes onstream. This is best done by blasting the tubes with nutshells or with a thin jet of high-pressure water. The trick is to hit the tubes—and not the easily damaged refractory. 

Product ion/removal rates for some commonly used floor and wall concrete removal techniques are shown in Table 4. In general, the most productive techniques are also the crudest and generate the most waste Application of concrete decontamination in a relatively sensitive environment is easier to control but will typically require much slower production equipment such as that used in shot blasting. For heavy industrial applications with large floor spaces and limited impediments to movement, grinding or high pressure water techniques can be employed (Woodyard, 1985). 

Excellent surface preparations for porous surfaces include blasting with oil-free compressed air, abrasive media, or high pressure water (dry time is a must in this case) and grinding or wire brushing followed by oil-free dry compressed air blasting. For nonporous substrates, solvent wiping with clean cloth followed immediately by a clean cloth dry wipe is the preferred approach. 

For laymen, the production of steel shot seems more complicated. Steel (often scrap) is first annealed to the desired hardness and then melted, the molten steel being subjected to atomization - blasting it into tiny fragments - by a jet of high-pressure water. This is followed by a series of thermal and mechanical treatments to give the product final characteristics. It is dried, screened for size, spiraled to remove irregular shapes, quenched and tempered. 

Grit blasting is a relatively simple process. Hard grit is propelled by compressed air, or occasionally by high-pressure water, directed at the substrate that needs cleaning or roughening. 

Wet blasting uses a high pressure water stream (to 50000psi) or an air-blasted slurry of fine abrasives in chemically treated water. The liquid slurry is sometimes called liquid honing since it is often used when dimensional tolerances have to be maintained. 

Power Washing. Power washing is similar to steam cleaning, except that the cleaner is injected into a high pressure (6.9—35 MPa (1000—5000 psi)) water blast in power washing. The water can be cold, warm, or hot, because the power washer is fed from a water tap. 

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