Spiral Heat Exchangers

Spiral heat exchangers are used for heating, cooling, and heat recovery in services involving fouling fluids, high-viscosity media, suspended solids, fibres, slurries, and process effluents. This category includes Sondex/Danfoss spiral heat exchangers, based on two metal plates formed into a spiral to create two separate flow channels for the process media. The geometry supports true counter-current flow and close temperature approach without a tube bundle arrangement.

Selection is based on heat duty, flow rate, viscosity, solids loading, fouling tendency, allowable pressure drop, temperature programme, material compatibility, and access requirements for inspection and cleaning. The single-channel flow path increases local velocity in areas where deposits typically form, which can reduce fouling in many duties. For heavily contaminated media, hinged covers with C-clamps provide direct access to the heat transfer surface for inspection and mechanical cleaning.

Typical applications include food and beverage processing, biogas plants, wastewater treatment, pulp and paper, heavy industry, and petrochemical and chemical process systems. Published technical limits include DN32 to DN300 connections, shell and spiral materials in carbon steel or stainless steel, design pressure up to 16 bar with higher pressure ratings available on request, and operating temperatures from -20 to 200 °C. Mechanical design is referenced to PED 2014/68/EU, EN 13445, and ASME Section VIII Division 1.