Medium and High-Pressure Atomization Technology - Part 3

Atomization Applied sciences Half Three Air-Assisted Airless and AirlessAir Assisted AirlessAir-Assisted Airless is taken into account a medium fluid strain know-how not like all of the beforehand talked about low fluid strain applied sciences. The principle pressure used for atomization in Air-Assisted Airless is fluid strain and never air strain. With this know-how, pumps are used to pressurize the coating to pressures within the 300 to 900 psi vary. Though that is the everyday vary for many coatings, some Air-Assisted Airless weapons are designed to function at a lot larger pressures for coatings which are tougher to atomize.The fluid is compelled by a tungsten carbide tip much like an Airless tip. The tip is minimize in an elliptical form, like a cats’ eye, at predetermined orifice sizes and spray angles. The orifice sizes decide the quantity of fluid that may be handed by the tip, or circulation fee, whereas the spray angle determines the width of the spray sample. Atomizing air is then launched into the pre-atomized fluid stream, which assists the Airless (hydraulic) atomization that happens from the medium fluid pressures. This blends away the tails on the finish s of the spray sample that might in any other case happen and enhances the general atomization. This air additionally permits for the sample to be manually adjusted however solely by about 30%, not like air spray applied sciences that ship totally adjustable spray sample widths.The benefit of this know-how is that it may be as environment friendly as HVLP or higher, particularly with larger viscosities or larger circulation charges. The principle drawback of this know-how is that you just should not have the flexibility to feather, management the circulation fee by how far again you pull the set off, because the fluid strain and the tip measurement management the circulation fee and never the journey of the set off and needle.One other benefit of this know-how is that it makes use of about one fifth the quantity of compressed air of an HVLP gun, thus lowering compressed air prices, air damming, turbulence and over spray. The spray particle velocity could be considerably decrease than HVLP. One other doable drawback is the shortcoming to alter the fan sample dramatically, with out having to alter the tip. Tip plugging will also be an issue with supplies which have combination in them akin to metallic crammed coatings. Nonetheless, correct filtration reduces or eliminates tip plugging with most different non-aggregate crammed coatings.AirlessThis know-how makes use of very excessive fluid pressures as its major atomization pressure. Usually, these pressures vary from about 1000 psi to 3000 psi however can go even larger if want be. It’s this know-how that was mixed with air spray that led to the event of Air-Assisted Airless know-how. Airless makes use of pumps to pressurize the fluid to those excessive pressures and forces the coating by an orifice that’s elliptical in form. The scale of the orifice and the diploma of the angle at which it’s minimize determines the guidelines circulation fee and the width of the spray sample. Due to the dangerously excessive fluid pressures operators should be extraordinarily cautious when working this gear.Airless know-how is predominantly used for terribly viscous coatings and for very excessive circulation charges. The atomized particles are usually extra course than these of different atomization applied sciences until particular wonderful end suggestions or warmth is used. Moreover Airless spray patterns are usually heavy on the ends not like Air-Assisted Airless and this could result in excessive construct areas when overlapping. One other drawback of excessive strain Airless software is the recoil or surge that may happen when triggering. The recoil can change the gun to half relationship, which can lead to variations in movie construct uniformity. Clearly a surge might create a run or sag.Airless is taken into account a compliant know-how however the effectivity tends to be decrease than HVLP and Air-Assisted Airless. The upper the fluid strain, the upper the spray particle velocity, and the decrease the switch effectivity can be. Using excessive strain additionally makes it tougher for customers to spray into corners, recesses or different complicated shapes with out runs or sags. Nonetheless, Airless can be utilized successfully by skilled finishers and when steps are taken to boost the atomization traits.