SONDEX® / Danfoss Spiral Heat Exchangers
SONDEX® SonSPV spiral heat exchangers utilize two helical flow channels instead of a tube bundle. This configuration is suitable for fluids with viscosity, solids, fibers, or increased fouling tendency, such as sludges, slurries, wastewater, and process streams with particulates.
Operating Principle
The spiral path creates a single-channel flow with increased shear stresses. When deposits begin to form, the local reduction in cross-section increases velocity and helps limit accumulation. This does not eliminate the need for cleaning but affects maintenance intervals depending on the medium.
Applications
Typical uses:
- wastewater, biogas, and sludges,
- pulp and cellulose fibers,
- chemical and petrochemical streams,
- heavy industry,
- molasses, vinasse, and viscous sugar streams.
Technical Selection Data
Key parameters:
- exchange area: 1–500 m²,
- connections: DN25–DN300,
- operating pressure: up to 10 bar, with higher pressures upon design,
- operating temperature: -20 °C to 200 °C,
- media: liquids, steam, and gases.
Materials and Configurations
Spiral and shell materials include P355GH, AISI 304, AISI 316L, and AISI 904L. Gaskets are available in NBR, EPDM, PTFE, or graphite. Channels can be with spacers or Free Flow without spacers for media with solids and fibers. Construction can be openable for mechanical cleaning or welded for clean fluids.
Standards
Design covers EN 13445, PED 2014/68/EU, and ASME Section VIII Div. 1. Connections can be customized to known industrial standards per project.
FAQ
When is a spiral heat exchanger selected?
When the fluid easily clogs or fouls conventional exchangers.
When is an openable version needed?
When frequent inspection or mechanical cleaning is anticipated.
What data is required for sizing?
Flow rates, temperatures, pressure, viscosity, solids, allowable pressure drop, and cleaning schedule.