Rated pressure
Nominal air pressure in the spray gun.
The general meaning of this parameter depends on the type of instrument (see above). So, in pneumatic models, nominal pressure data is required for connection to an external compressor. It is this pressure that this compressor must create at the inlet to the atomizer; too low values will lead to a decrease in efficiency, too high are fraught with breakdowns and even accidents with injury to others.
In turn, for electric models, the nominal pressure is the air pressure created by the unit's own compressor; the complete atomizer was originally designed for the same pressure. So in this case, this parameter is more of a reference than practically significant; it may be useful only for connecting replacement nozzles to the compressor (or vice versa, for using an existing nozzle with a third-party compressor).
As for specific pressure values, they are primarily determined by the spray system (see below). The diversity here is quite high: the most modest units give out
less than 2 bar,
2-5 bar compressors are quite popular
, 5-10 bar models are relatively rare, and some powerful performance solutions provide a pressure of
100 bar or more.
Air consumption
Nominal air flow rate when the spray gun is operating in normal mode.
This parameter is of key importance for a pneumatic tool (see "Type"): the compressor to which such a sprayer is connected must provide the appropriate air supply rate, otherwise normal operation will not be possible. In turn, in electric models, this indicator is more of a reference — the complete compressor, by definition, corresponds to the characteristics of the sprayer, and it makes sense to pay attention to the flow rate only if the working nozzle of the electric spray gun is planned to be used with a "non-native" compressor.
Nozzle size
The diameter of the nozzle at the outlet of the spray gun.
It is from this nozzle that paint or other working material comes out. And the productivity and spot size at the exit depend on the diameter. Accordingly, larger nozzles are better suited for processing large surfaces, while smaller nozzles provide greater precision and accuracy. Thus, this parameter is directly related to the type of device (see above). There are also
spray guns with a replaceable nozzle, when more than one nozzle is provided in the kit, which expands the possibilities of using the device.
Spray system
The type of spray system used in the device. Different spray systems differ in the format of work and, as a result, in individual practical nuances of use:
—
HP (High Pressure) / CONV (conventional). One of the most famous and popular spray systems. The air pressure at the inlet and outlet of such spray guns is approximately the same. The advantages of HP systems are the simplicity of design, large working width, high paint application speed and relatively low air consumption. At the same time, the percentage of paint transfer in such sprayers is very low — more than half of the applied material bounces off the surface due to high speed and settles on surrounding objects. Another disadvantage is that the flow from the HP atomizer picks up fine dust and other "flying debris" heavily; because of this, additional grinding and polishing of the painted surface is often required.
—
RP (Reduced Pressure). Modification of conventional (HP) atomizers, characterized by a slightly reduced outlet pressure. This allowed for some improvement in the transfer coefficient and reduced debris levels while maintaining the advantages of good performance, uniformity and low air consumption. Nevertheless, according to these indicators, such devices are still inferior to low-pressure models.
—
HVLP (High Volume Low Pressure). Spray system with reduced outlet pressure (a
...pprox. 0.7 bar) and large air volumes. One of the key advantages of such devices is a high ink transfer coefficient of at least 65%. In addition, the low speed of the paint supply reduces the level of debris: there are relatively few turbulences that “pull” debris along with them. The main disadvantage of HVLP systems can be called high air consumption; not every compressor can handle such an atomizer. In addition, they require additional filters to protect against oil and moisture entering the air during high compressor loads; and you can work with such a device only at a short distance (usually up to 15 cm), and in order to avoid drips, a certain skill is required.
— HVLP-II (New High Volume Low Pressure). The second generation of HVLP (see the relevant paragraph), which has a number of improvements compared to the original, but is generally similar.
— LVLP (Low Volume Low Pressure) / Trans-Tech. Spray systems developed as an improvement to HVLP. With the same advantages (high transfer coefficient, minimum debris), they consume much less air and have softer requirements for compressors and hoses. In addition, LVLP systems are less sensitive to pressure drops, and the effective spraying range in them reaches 25 – 30 cm. Of the notable disadvantages of this option, one can only mention a rather high cost.
— HVMP (High Volume Middle Pressure). Spray systems with high air flow and medium outlet pressure. Compared to HVLP, due to the higher pressure, they give a slightly lower ink transfer efficiency, but greater uniformity and range.
— LVMP (Low Volume Middle Pressure). Spray systems with low air consumption and medium pressure; a kind of modification of LVLP, characterized by higher pressure. Due to this, the cost is somewhat reduced, productivity, uniformity of application and capture width are increased; however, paint consumption is higher and the finished surface is rougher than original LVLP.
— HTE (High Transfer Efficiency). This marking is used in spray systems for which a high transfer coefficient is claimed by the manufacturers. In terms of characteristics, they are most often similar to LVLPs (see the relevant paragraph) — in particular, they have a rather large effective range. However, specific features in each case should be clarified separately.
— EA (Excellent Atomization). The main feature of such systems, in accordance with the name, is a very high degree of atomization of the material. Other performance characteristics in such systems may be different, these points should be clarified separately.
— HEA (High Efficiency Airless). Proprietary airless spray technology (see "Spray") used in the Wagner brand technique. Reduces paint wastage by more than 50% compared to more traditional systems, as well as more even material distribution, according to the creators. Suitable for water and oil based coatings.
MP (Middle Pressure). Transitional option between the HP and RP described above: it provides a slightly lower working pressure compared to HP, but not as low as in RP. For a number of reasons, it did not receive distribution.
HD (Heavy Duty). A marketing designation used on individual sprayers, typically high-capacity, high-volume sprayers. The specific characteristics of such systems should be clarified separately.
