Air actuated nozzles for coating

Air actuated nozzles are not air atomising nozzles so they do not use compressed air to break the liquid into small droplets. Atomisation is achieved purely by the fluid being sprayed under pressure through the nozzle orifice and/or nozzle swirl chamber.  The problem air actuated nozzles overcome is the slow responsiveness of purely hydraulic nozzles.  When a nozzle starts up, even if an activation valve is quite close to the nozzles, there will be a small period of reduced flow through the nozzle as the liquid builds up.  Similarly when the nozzle is deactivated there will be a small amount of reduced flow through the nozzle as the remaining liquid between the nozzle and the nearest valve is removed.

For non-precision spraying applications these periods of poor fluid flow will not be very important but for coating applications they can result in dripping that will impoverish the final product.  This problem is solved by air actuation at the nozzle.  A spring loaded shut-off pin is incorporated into the nozzle.  The fluid pressure is always maintained so liquid is ready to spray at the desire pressure right up to nozzle orifice.  Once air pressure is applied to the shut-off spring the pin moves out of the nozzle orifice allowing the spray to be ejected.  This mean a more or less instantaneous full spray pattern is achieved with no 'build up' period of poor spraying.

As air is far more responsive than fluid these nozzles can be cycled on and off 3 times per second meaning they are suitable for a wide variety of precision coating spray systems.  Air actuation can be added to a variety of our flat fan nozzles.


Coating engineering considerations

Coating nozzles


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