Food-grade spiral wound tubular heat exchanger
This is a special-purpose equipment designed for food and beverage processing, meeting both strict hygiene requirements and high-efficiency heat transfer. It is widely used in sterilization, concentration, cooling and other processes.
Core Structure and Materials
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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.
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**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
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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.
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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).
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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
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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.
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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.
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Compliance
Material certificates, welding records, hygiene certification reports and leakage test reports must be provided.
Comparison with Traditional Heat Exchangers
Compared with traditional shell-and-tube and plate heat exchangers, its advantages lie in anti-fouling, high temperature and pressure resistance, and dead-end-free hygienic design. The disadvantage is higher one-time investment than plate heat exchangers, but lower long-term energy consumption and maintenance costs, especially suitable for high-viscosity and easily fouled food media.