Tip #9 Blast cabinets - Pressure blast vs. vacuum injection

Pressure Blast
Pressure blast cabinets use a pressure vessel to pneumatically push the blast media through a single abrasive hose and out the blast nozzle. An easy way to understand is the pressure blast systems drop the abrasive into an air hose and pneumatically push the abrasive out through an air jet. These two items are often referred to as abrasive hose and blast nozzle but they are really an air hose and air jet due to the direct pressure delivery configuration.

Pressure blast systems concentrate the abrasive which creates a bigger hotspot on the surface. Because the pressure blast system pneumatically pushes the blast media, it is possible to clean into blind holes and pockets.

All pressure blast cabinets double the particle velocity over the vacuum injection systems at any given pressure. Processing with the pressure blast system requires lowering the blasting pressure by 50% over vacuum injection to prevent exceeding the maximum abrasive impact velocity. Because of the concentrated pattern, the pressure blast system operates with more frictional heat on the partPressure blast models do something that vacuum injections can’t and the applications listed below are reasons the choice would be pressure blast.

Advantages

• Greater media velocity. A pressure blast system produces greater abrasive particle velocity than a vacuum injection system which means faster cleaning of tough contaminants.
• Heavy abrasives or large abrasives, steel shot for shot peening etc.
• Removal of heavy thick coatings that require additional frictional heat on the surface to be removed.
• Blind holes or deep pocket cleaning.
• Moves more media. More abrasive particles are propelled against the work surface per minute. This translates into greater productivity, particularly on difficult applications.
• As a general rule of thumb, pressure abrasive blast machines are four times as productive as suction abrasive blast machines.
   

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