The Delavan AL air atomising series spray nozzles offer the user a wide variety of spray patterns, flow rates and atomisation. Unlike hydraulic or pressurized nozzles where the energy from the pressure of the liquid is used to atomize, the AL series of nozzles use the energy or a pressurized gas (typically air) to atomize the liquid. This allows the liquid to be fed under lower pressure and still achieve fine atomisation. This is also advantageous for abrasive or high viscosity liquids.
The nozzles are so designed that flow rates from almost no flow, as in the siphon-fed, to over four liters per minute can be achieve. (For higher flow rates in an air atomized spray, refer to Delavan '92s Swirl-Air series)
The low flow rates and air atomization combine to give the AL series extremely fine atomization. Droplet sizes below 50 microns Sauter Mean Diameter can be expected. In the lower flow rates, droplet sizes below 20 micron SMD are not uncommon.
The mechanics of the atomisation in the AL series are of two types. The internal mix nozzle design provides for the gas and liquid to mix internally in the nozzle. For a given liquid pressure an increase in gas pressure will result in a decrease in liquid flow and decrease in droplet size. A decrease in gas pressure will do the reverse to the liquid.
The external mix nozzle has the gas flow intersect the liquid flow at the face of the nozzle. The liquid flow can remain constant while the atomization and spray pattern can be modified with adjustments in gas pressure. The liquid supply can be siphoned, gravity or pressure fed.