Injector system works on the principle of an airbrush. Air supply of the gun is attached to air nozzle. Electronic effect causes suction of an abrasive medium from a mixing device on the bottom of a cabinet. The mixture accelerates in the main nozzle. The mode of a working cycle is continuous.
In pressure systems a pressure sandblasting tank is incorporated into media delivery system. The pressure sandblasting tank is filled with appropriate amount of blast medium. During the blasting process, a sealing cone is automatically closed in a filler cap and the tank is pressurized. Abrasive material is pushed through a transmitting nozzle in a mixing head into a rubber abrasion-resistant hose, where it is mixed with air and gets out through the main nozzle. Even though the mode of a working cycle is discontinuous, its blast effect is approximately three times higher than with injector system. The pressure tank is filled automatically after every pause in the blasting process.
Both systems play important role in the discussed field and their use is very often similar. On the one hand the effect of injector system is lower than pressure system, on the other it is easily controllable and not that demanding on operator´s experience. Actually any abrasive media can be used in injector system and as such is suitable for blasting of thin-walled components and for mineral abrasive use for treatment of non-ferrous metals. Its role is irreplaceable e. g. in glass bead blasting. Advisable is its use even for continuous automatic processes.
Pressure system, due to its performance, is applicable especially for steel grit blasting of larger ferrous workpieces.
We supply versions of manual blast cabinets with adjustments for quick interchange of both systems.
|Height of workspace
|70 x 50 cm
|90 x 70 cm
|120 x 90 cm
|150 x 110 cm
|200 x 150 cm
Speaking of injector cabinets, you can use almost any type of blast media. It depends on what quality and surface conditions you need to reach.
Steel grit is more convenient for pressure units as it makes the best use of its potential including economical aspect. Of course that for special purposes such as blasting of non-ferrous metals, glass bead blasting, or soft non-abrasive cleaning it is necessary to use appropriate type of abrasives. Do not hesitate to contact us in case of any uncertainties, we will help you with the right choice.
We strongly recommend not to use silica sand as a blast medium. The sillica sand quickly brakes down and its service life lasts just few cycles. As a result it also increases the level of dust in workspace.
Moreover, silica sand is the only material which is dangerous to your health. It is the only blast material which causes a lung disease called silicosis.
In many countries is using of silica sand for blasting strictly prohibited.
The chart below displays approximate air consumption of injector system with set pressure. Diameter shows dimensions of internal air nozzle.
|Air nozzle diameter
Air consumption in pressure system with nozzle of corresponding parameter is c. 20% lower than in injector system.
Actually, the higher quality the better. If air contains condensation from compressor, it may lead to defects or oil leakage on the surface of a treated component. To some extent it also depends on the type of used system. Manual version of injector system with mineral abrasives is less demanding on air quality and works properly even when using cyclonic separators with filters for air cleaning. Of course, regular condensation relief etc. is necessary.
Pressure system is a bit more difficult as there is the risk of water condensation inside the pressure tank and subsequent moisture of abrasive media, which may lead to improper function of blasting device. In particular, steel grit may corrode or get sticky inside the tank; then it is essential to take it into parts and clean it properly.
Air quality is especially important for automatic machines controlled by pneumatic components. Air quality in terms of moisture for pressure and automatic blasting cabinets should be in accordance with stage no. 4 in ISO 7583. These conditions are realized e.g. by refrigerated air dryers with dew point under +3°C.