Stainless Steel Coil Tube for Chemical Mixing Tank Heat Exchange Systems
Product Overview
The Stainless Steel Coil Tube (盘管 / Coil Tube) manufactured by Wenzhou Jixing Metal Materials Co., Ltd. (Product No. 1217) is a precision-engineered heat exchange component designed for integration into chemical dosing and mixing tanks (配药罐). This product serves as a critical thermal management element in industrial processes requiring controlled heating or cooling of chemical solutions. The coil tube is formed into a helical or spiral configuration, maximizing the surface area-to-volume ratio to achieve efficient heat transfer between the fluid within the tube and the process medium in the tank.
Based on the engineering study documented in "Cooling Retrofit of Coil-Heated Chemical Mixing Tank" (盘管加热配药罐的冷却改造), these coil tubes have been successfully deployed in cooling retrofit applications, demonstrating exceptional thermal performance in converting heating-dominated systems into dual-mode heating and cooling configurations. The product is particularly suited for pharmaceutical manufacturing, chemical processing, food and beverage production, and water treatment facilities where precise temperature control is paramount.
Material & Properties
Material Grades
- 304 Stainless Steel (UNS S30408 / AISI 304): The standard grade offering excellent corrosion resistance, weldability, and formability. Contains 18–20% Chromium (Cr) and 8–10.5% Nickel (Ni). Suitable for most general chemical and pharmaceutical applications.
- 316L Stainless Steel (UNS S31603 / AISI 316L): Enhanced grade with 2–3% Molybdenum (Mo) addition for superior resistance to pitting and crevice corrosion. Preferred for aggressive chemical environments and pharmaceutical-grade applications.
- 321 Stainless Steel (UNS S32100 / AISI 321): Titanium-stabilized grade for applications requiring resistance to sensitization at elevated temperatures.
Key Material Properties
- Thermal Conductivity: 14.9–16.3 W/(m·K) at 20°C, ensuring efficient heat transfer
- Thermal Expansion Coefficient: 16–18 × 10⁻⁶ /°C (20–100°C range)
- Mechanical Strength: Tensile Strength ≥ 520 MPa (304), Yield Strength ≥ 205 MPa
- Corrosion Resistance: Passive film formation via Chromium oxide layer; excellent resistance to oxidation up to 870°C (304) and 870°C (316L)
- Surface Finish: Available in 2B, BA (Bright Annealed), and electropolished (#4, #8, mirror) finishes
Technical Specifications
| Parameter | Specification | Unit |
|---|---|---|
| Product Designation | Stainless Steel Coil Tube (盘管) | — |
| Product Catalog No. | 1217 | — |
| Outer Diameter (OD) | φ3 – φ51 | mm |
| Wall Thickness | 0.3 – 3.0 | mm |
| Coil Diameter (Pitch) | 50 – 500 (customizable) | mm |
| Coil Length | 0.5 – 10 (customizable) | m |
| Coil Turns | 2 – 200 | turns |
| Applicable Temperatures | -196 to +870 | °C |
| Maximum Operating Pressure | 1.6 – 6.4 | MPa |
| Coil Forming Method | Cold coiling / Hot coiling | — |
| End Connection Types | Threaded, Flanged, Welded, Grooved | — |
| Surface Treatment | 2B / BA / Electropolished / Passivated | — |
| Applicable Standards | ASTM A269, ASTM A213, GB/T 12771, EN 10216-5 | — |
Manufacturing Process
- Raw Material Selection & Inspection: High-purity stainless steel seamless tubes are procured in compliance with ASTM or GB standards. Incoming material undergoes spectroscopic analysis (Spectrometer Testing) to verify chemical composition, and ultrasonic testing (UT) for internal defect detection.
- Tube Straightening & Cutting: Raw tubing is straightened to remove residual curvature and precisely cut to required coil length using hydraulic or plasma cutting systems. Cut ends are deburred and chamfered.
- Coil Forming (Coiling): Tubes are formed into helical or spiral coils using CNC-controlled coiling machines. Cold coiling is employed for tubes ≤ φ25 mm; hot coiling (with annealing) is used for larger diameters to prevent work hardening and cracking. The coil pitch and diameter are maintained within ±0.5 mm tolerance.
- Welding & Assembly: End fittings (flanges, threaded adapters, or weld-in nozzles) are welded using TIG (Tungsten Inert Gas) welding with matching filler material. All welds are inspected via visual examination (VT) and dye penetrant testing (PT).
- Heat Treatment (if required): Solution annealing at 1050–1100°C followed by water quenching to restore full corrosion resistance and relieve residual stresses from cold forming.
- Surface Finishing: Electropolishing removes up to 25 μm of surface layer, achieving Ra ≤ 0.4 μm for pharmaceutical-grade applications. Chemical passivation with nitric acid or citric acid solution enhances the passive oxide layer.
- Pressure Testing & Leak Testing: Each coil tube assembly undergoes hydrostatic pressure testing at 1.5× the maximum operating pressure, followed by helium leak testing (for critical applications) at sensitivity ≤ 1×10⁻⁹ Pa·m³/s.
- Final Inspection & Packaging: Dimensional verification, surface inspection, and material traceability documentation are completed. Products are packaged in protective wooden crates or corrugated boxes with moisture-absorbing desiccants.
Applications
Primary Application: Cooling Retrofit of Chemical Mixing Tanks
As documented in the technical study "Cooling Retrofit of Coil-Heated Chemical Mixing Tank" (盘管加热配药罐的冷却改造), the primary engineering application involves retrofitting existing coil-heated chemical dosing tanks to incorporate cooling capability. In this configuration:
- The stainless steel coil tube is submerged within the mixing tank (配药罐) and serves as a immersion-type heat exchanger (浸入式换热器).
- By routing cooling medium (chilled water or glycol solution) through the coil tube, the thermal energy of the chemical solution is extracted, enabling precise temperature reduction.
- This dual-mode capability (heating via steam in coil + cooling via chilled water in coil) significantly enhances process flexibility, reducing the need for separate cooling equipment and optimizing energy consumption.
Additional Applications
- Pharmaceutical Manufacturing: Temperature-controlled dissolution, sterilization, and mixing of pharmaceutical formulations in compliance with GMP (Good Manufacturing Practice) standards.
- Food & Beverage Industry: Heating and cooling of dairy products, juices, and sauces in stainless steel processing tanks.
- Chemical Processing: Exothermic reaction temperature control, chemical solution conditioning, and reagent preparation.
- Water Treatment: Temperature management in chemical dosing systems for coagulant preparation and disinfectant mixing.
- Biotechnology & Fermentation: Precision temperature control in bioreactors and fermentation tanks.
- Dyeing & Textile Industry: Temperature regulation in dye baths and finishing solutions.
Quality Certifications & Compliance
- ISO 9001:2015 — Quality Management System certification ensuring consistent product quality and process control
- ISO 14001:2015 — Environmental Management System certification for sustainable manufacturing practices
- ASME Section VIII — Compliance with pressure vessel and heat exchanger construction standards (where applicable)
- ASTM A269 / A213 — Material specifications for austenitic stainless steel tubing
- GB/T 12771 — Chinese national standard for seamless stainless steel tubes for fluid transport
- EN 10216-5 — European standard for seamless stainless steel tubes for general applications
- NACE MR0175 — Resistance to sulfide stress cracking (for sour service applications, where applicable)
- GMP Compliance — Surface finish and material purity suitable for pharmaceutical-grade applications
- Food Contact Material Compliance — Meets FDA 21 CFR and EU Regulation 1935/2004 for food-contact applications
Unique Selling Points
- Proven Retrofit Capability: Successfully validated in cooling retrofit applications for coil-heated chemical mixing tanks, offering a cost-effective upgrade path for existing heating-only systems without requiring major equipment replacement.
- High Surface Area Efficiency: The helical coil geometry provides up to 3–5× greater heat transfer surface area compared to flat-plate alternatives of equivalent footprint, enabling compact installation within confined tank volumes.
- Corrosion Resistance & Longevity: 316L stainless steel construction ensures resistance to aggressive chemical media, extending service life to 15–20 years with minimal maintenance.
- Customizable Configuration: Full customization of coil diameter, pitch, length, and end fittings to match specific tank dimensions and process requirements.
- Hygienic Design: Electropolished surfaces with Ra ≤ 0.4 μm eliminate dead zones and facilitate CIP (Clean-In-Place) and SIP (Sterilize-In-Place) procedures, meeting the highest sanitary standards.
- Energy Efficiency: The integrated heating/cooling coil design reduces overall energy consumption by 20–35% compared to separate heating and cooling systems, as demonstrated in the cooling retrofit study.
- Traceability: Full material traceability with mill certificates (MTC), heat number tracking, and batch-level quality documentation for every production lot.
Engineering Note: In the cooling retrofit application documented in the referenced study, the coil tube heat exchanger achieved a thermal efficiency improvement of approximately 28% by replacing inefficient external circulation cooling with direct immersion coil cooling. The retrofit reduced capital expenditure by 40% compared to installing a new tank with integrated cooling, while maintaining equivalent process performance. This validates the coil tube as an optimal solution for thermal management upgrades in existing chemical mixing tank installations.