Bleeder style spray guns have a continuous flow of air through the air cap when the HVLP turbine is “on”. Bleeder spray guns are the original style HVLP spray gun supplied with Apollo turbine spray systems. They are simple in design, extremely reliable, and very easy to clean and maintain. The perception that the continuous air flow will displace dust and dirt in the spray area and workshop, or in any way affect the performance when spraying is incorrect. It originated when HVLP manufacturers began offering non-bleeder style HVLP spray guns and circulated inaccurate information to promote the alternative non-bleeder concept. HVLP manufacturers continue to successfully offer bleeder style spray guns. Apollo 5000 Series bleeder style spray guns have a proven history and proven performance and have even been copied by other HVLP manufacturers.
Non-Bleeder HVLP spray guns do not bleed air when the HVLP turbine is “on” until the trigger on the spray gun is pulled back. These style guns operate more like traditional compressed air spray guns. When you pull the trigger the first stage is to release the air, the second stage then releases the material into the air stream. Non-bleeder spray guns are slightly more complex than bleeder style HVLP spray guns. Non-bleeder HVLP spray guns require a turbine system to have some form of air relief to prevent back pressure to the motor. This air relief can be internal or external. Apollo only uses external bleed ports on their turbines as this is the best way to push the hot air outside the turbine box and not exasperate the heat inside the box. There is no advantage or disadvantage to using a non-bleeder HVLP spray gun. It is a matter of preference and/or choice.
Generally, HVLP bleeder spray guns are less expensive than non-bleeder HVLP spray guns. If you are operating an older turbine system without back pressure relief built into the turbine you can still use a non-bleed spray gun, but you do have to install an external air relief. Apollo makes an air relief that can be installed on most brands of turbines, which will allow the operator to use a non-bleed spray gun without damaging the turbine motor.