Improved external mix air atomizing spray nozzle assembly

Abstract

An external mix air atomizing spray nozzle assembly comprising a nozzle body having liquid and air flow passages, and an air cap formed with an air chamber communicating with said air passage and a plurality of angled pressurized air discharge passages communicating with said chamber at an angle to a central axis of said spray nozzle assembly for directing pressurized air onto a liquid flow stream discharging from said liquid passage. The angled air discharge passages each are defined by a conical indentation in a front face of the air cap and a cylindrical bore communicating in perpendicular relation to a side surface of the conical indentation. The design of the angled air discharge passages permits easy manufacture and design modification for particular spray applications.

Description

[0001] related application [0002] This application is a continuation-in-part of application Serial No. 10 / 252,194 filed September 23, 2002, the disclosure of which is incorporated herein by reference. technical field [0003] The present invention relates generally to spray nozzle assemblies, and more particularly to "external mix" air atomizing spray nozzle assemblies in which the discharged liquid stream is atomized and formed into a desired spray pattern by pressurized air outside the liquid discharge orifice. Background technique [0004] External mixed air atomizing spray nozzles are known to be able to control liquid particle size and spray distribution by pressurized air independent of liquid flow rate. The spray nozzle can also be used with a relatively low pressure air source, such as about 15 psi, which can be generated by an inexpensive blower rather than an air booster. However, such spray nozzles generally have to be formed with complicated gas flow passages ...

AI Technical Summary

Problems solved by technology

However, such a spray nozzle must generally be formed with a complicated airflow channel which communicates through the spray nozzle to a position downstream of the liquid discharge hole.

Such passages are expensive to manufacture, create pressure losses, and if not precisely and accurately formed, can create burrs and lead to misalignment of the passages, which cause pressure losses that further impair the efficient operation of the spray nozzles

Therefore, sometimes the source of pressurized air generated by the low-pressure blower is not sufficient for effective liquid particle breakdown and guidance

Also, when external mixing air atomizing spray nozzles are not used to generate a flat fan spray pattern, the spray nozzles have thus far not been effective at producing a full conical liquid spray pattern with a substantially uniform breakdown of the liquid particles

[0005] In particular, external air atomizing spray nozzles may also experience performance issues when spraying viscous liquids, grout, or other solids containing liquids

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