Glossary
Air / steam atomizer
Definition
Atomizer in which compressed air or steam supplies part of the atomizing energy, giving the widest turn-down at a constant spray angle.
An air or steam atomizer adds a second fluid to the nozzle. A fast stream of compressed air or steam shears the fuel film into droplets, so the atomizing energy no longer comes only from the fuel pressure. That decoupling is what makes the design attractive on burners with a very wide modulation band.
Because the spray angle is set by the air or steam geometry rather than by the fuel pressure, it stays constant while the fuel output is modulated — Fluid Control Instruments Ltd publishes a turn-down of 1:5 – 1:10 at a constant spray angle, over a flow range from 2.5 to 5000 kg/h and spray angles from 20° to 120°.
The trade-off is the need for an air or steam supply at the burner. Where that is available anyway — on industrial furnaces, kilns and heavy-fuel-oil installations — the air/steam atomizer gives the widest control range of the whole Fluid Control Instruments Ltd range.