Why choose Graco nozzles over competitors'?

The shape and material of a nozzle affects blast pattern and speed, service life, and job size.

The selection of nozzle has an important influence on the efficiency of a blasting operation.

The shape of a nozzle’s bore determines the blast pattern, which differs for each application.

When selecting a blasting nozzle, you should take into account its shape and material. While the shape influences the velocity and the blast pattern, the material depends on the blasting media to be used, the desired service life, and the size of the blast job.
 

Nozzle shape

Among the many types of blasting nozzles, three are widely used.

Straight bore nozzle

Straight bore nozzles

Standard venturi nozzle

Standard venturi nozzles

long venturi nozzle

Long venturi or high-performance nozzles

The shape of the nozzle affects the following characteristics:

·       Velocity

The long, tapered, converging entry of a venturi nozzle mixes the air and abrasive into the nozzle. The mix is then pushed into a narrow section in order to be forced out of the diverging exit end. These shapes greatly accelerate the air flow and particles/abrasives. The velocity of the abrasive as it exits the nozzle is nearly twice as high as in a straight bore nozzle (pos. 1).

The long venturi nozzle has a longer barrel, which gives the abrasive a higher speed and kinetic energy. Consequently, the impact is more aggressive and the long venturi nozzle works up to 10-15% faster than the standard venturi nozzle (pos. 2).

But nothing comes for free; long venturi nozzles (pos. 3) only work on full capacity when you fulfill the demands for compressed air. When there is too little air pressure, it is better to use standard venturi nozzles (pos. 2).

·       Blast pattern

A nozzle’s bore shape also determines its blasting pattern:

        o    Straight bore nozzles (pos.1) create tight, varied blast patterns. The blasting pattern shows a harsh impact in the centre and little impact on the perimeter. This type of nozzle is best used for blasting small surface areas.

        o    Venturi nozzles create wider and homogenous patterns and increase the velocity while lowering the abrasive consumption.

        o    Long venturi nozzles with little air pressure have a small blast pattern. Increasing the air pressure gives a wider and thus better pattern, even allowing you to stand further away from the blast object. Long venturi nozzles are thus best used when blasting larger surfaces.
 

Nozzle material

The nozzle material selection depends on several factors:
        o    the abrasive you choose
        o    how often you blast
        o    the size of the blast job
        o    the rigors of the job site

Below, we provide some general application guidelines for various materials.

·       Aluminium oxide ‘Alumina’ (ceramic) nozzles offer a reasonable lifetime at a lower price than other materials. They are a good choice for low-intensity applications where the unit price is a primary factor and the nozzle lifetime is less important.

·       Tungsten carbide nozzles offer a significant long lifetime and value when rough handling cannot be avoided and mineral or coal slag abrasives are used.

·       Silicon aluminium oxynitride (SiAlON) nozzles offer the same increased lifetime and durability as tungsten carbide but are only about half the weight. They are also better for handling aluminium oxide abrasives.

Nozzle material Steel shot/grit Slag Aluminium oxide
Ceramic 20-40 hrs 10-30 hrs 1-4 hrs
Tungsten carbide 500-800 hrs 300-400 hrs 20-40 hrs
SiAlON 500-800 hrs 300-400 hrs 50-100 hrs

Values given in hours (vapour blasting technology extends the service life by minimum two/three times). 

Conclusion: Why choose Graco blasting nozzles?

Graco uses only standard venturi nozzles and long venturi nozzles because they create wider and homogenous patterns and increase the velocity, while lowering the abrasive consumption. The long venturi nozzle works up to 10-15% faster than the standard venturi nozzle. They are the best choice for blasting larger surfaces with high air pressure.

Graco nozzles are made from silicon aluminium oxynitride (SiAlON) cores with aluminium jackets. They provide increased toughness over competitive lightweight ceramic nozzles and silicon carbide nozzles. SiAlON venturi nozzles are designed to replace both silicon carbide and silicon nitride. The nozzles resist breakage better than silicon carbide. They’re as durable as tungsten carbide but lighter in weight, reducing operator fatigue.

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