Food-grade spiral wound tubular heat exchanger

Core Structure and Materials

1. Overall Structure

   Composed of a central cylinder, multi-layer reversely spiral wound threaded tube bundles, stainless steel shell, inlet/outlet flanges and sealing system. Adjacent tube bundles are reversely wound to form continuous spiral flow channels, realizing pure counter-current / multi-stream heat transfer between tube side and shell side. It features an all-welded sterile structure to avoid tube plate detachment and cross-contamination of media.
2. **Food-grade Material Standards

• Heat exchange tubes: usually 316L stainless steel (tube diameter 8–12 mm, spiral angle 3°–20°), resistant to acid and alkali cleaning without heavy metal precipitation; titanium material is optional for high-end working conditions.

• Internal and external surfaces: mirror polished (Ra ≤ 0.8 μm), no dead ends, easy for CIP/SIP cleaning.

• Complies with food hygiene certification standards such as FDA, EHEDG, 3-A and GMP.

Working Principle and Performance Advantages

1. Enhanced Heat Transfer Mechanism

   Fluid produces secondary circulation under centrifugal force in the spiral channel, forming strong turbulence and destroying the thermal boundary layer. The heat transfer coefficient can reach 12000–14000 W/(m²·K), 2–3 times that of traditional shell-and-tube heat exchangers. It has a large heat transfer area per unit volume, only 1/10 of traditional equipment under the same load.
2. Anti-fouling and Self-cleaning

   High shear stress (15–20 Pa) of spiral flow inhibits the deposition of protein, pectin and sugar scale, with low fouling factor and significantly extended cleaning cycle (up to 6 months in some cases).
3. Precise Temperature Control

   Suitable for Ultra-High Temperature (UHT) sterilization. Rapid heating and cooling reduce the loss of food nutrition and flavor. Supports simultaneous heat transfer with large temperature differences and multiple media.

Typical Applications

• Dairy products: pasteurization, UHT sterilization of milk and yogurt, whey concentration and cooling;

• Beverages and juices: concentrated juice evaporation and cooling, instant sterilization of tea drinks, carbonated drinks cooling;

• Brewing: wort cooling, fermentation liquid temperature control, fine beer cooling;

• Sauces and condiments: tomato paste concentration, syrup heating/cooling.

Key Selection and Maintenance Points

1. Selection Parameters

   Processing flow rate, inlet and outlet temperature, pressure, viscosity, particle content, CIP cleaning medium and temperature. Pressure drop and heat transfer area shall be checked to avoid material shear damage.
2. Cleaning and Validation

   Standard equipped with CIP (Clean-In-Place) and SIP (Sterilize-In-Place) ports. Regular microbial testing and surface roughness re-inspection are required. Cleaning agents with excessive chlorine content are strictly prohibited to prevent corrosion of 316L.
3. Compliance

   Material certificates, welding records, hygiene certification reports and leakage test reports must be provided.

Comparison with Traditional Heat Exchangers