Spillback nozzles are single-fluid nozzles that atomize liquid in the form of a hollow cone. Unlike conventional single-fluid nozzles, water is supplied to the nozzle at a constant feed pressure (e.g., 35 bar) – independent of the actual atomized flow rate.
The regulation of the injected quantity is controlled by a control valve in the return line. By opening this valve, part of the supply flow is directed back into the water tank. The maximum atomized volume flow is achieved when the control valve is closed. The liquid atomization remains uniform over the entire control range.
By reducing the droplet size D32 at 35 bar,g across the operating points of the entire RS II-4 series to 120 – 165 µm, new possibilities emerge.
Several case studies have analyzed the replacement of spillback cluster head nozzle lances. The previously used RS 3 cluster head lance operate at an operating pressure of 35 bar, leading to high energy demand and excessive power consumption. In addition, the maintenance of numerous nozzles requires significant time and resources, while the heavy weight of the lance bundles complicates handling for maintenance personnel.
RS 3 cluster head nozzle lance (left) and new RS II-4 nozzle lance
The use of innovative nozzle technology significantly enhances system efficiency. Replacing cluster head nozzle lance with more efficient RS II-4 single nozzle lances offers the following advantages:
- Optimized evaporation: Finer droplets increase efficiency and enable capacity enhancements
- Energy savings: Lowering pump pressure to 25 bar reduces energy consumption
- Simplified maintenance: Fewer nozzles and reduced lance weight ease the burden on maintenance personnel
- Minimal retrofitting: Only lances, control valves, and pumps need to be replaced – existing mounting connections and most valve stand components remain unchanged
Additionally, the redesign of Lechler spillback nozzles has resulted in further design improvements, such as flow-optimized geometries, less individual parts and assembly with standard tools.
Overview