Lordfintube-Continuously Welded Spiral Fin Tubes
In the harsh environments of modern industry---be it the fiery exhaust of a power plant boiler, the corrosive atmosphere of a chemical reactor, or the high-vibration setting of offshore operations---conventional heat exchanger elements often fall short. Engineers routinely grapple with inefficient heat transfer, premature fin loosening, tube bundle leakage, and accelerated corrosion. These failures lead to unscheduled downtime, soaring maintenance costs, and compromised plant safety and output.
The selection of the fin tube, the very heart of most air/gas-to-liquid heat exchangers, is a critical decision that determines long-term reliability and Total Cost of Ownership (TCO). Among the options, one technology stands out for its resilience and efficiency: the Continuously welded spiral fin tube.
What are the continuously welded spiral finned tubes?
What sets this fin tube apart is not just the spiral form, but the metallurgical bond created by the High-Frequency Welding (HFW) process.
- Spiral Finned Tube: This refers to tubes where fins are continuously wound around the outer wall of a base tube (plain tube) at a specific angle (usually the helix angle), resembling a spiral. This significantly increases the tubes external surface area.
- Continuous Welding: This is the core technological feature. It refers to the continuous, uninterrupted metallurgical bond between the fin roots and the base tube along its entire length through welding. This is fundamentally different from mechanical connection methods such as "L"-type or "LL"-type interlocking.
Continuously welded spiral fin tube is a high-efficiency, high-strength, and long-life heat exchange element formed by continuously welding spiral steel strips onto a base tube using a high-frequency resistance welding process. It is one of the preferred finned tube types for solving heat exchange needs under harsh conditions such as high temperature, high pressure, high wear, strong corrosion, or strong vibration.
Advantages of HFW process
Zero Contact Resistance: Unlike mechanical attachments, the HFW process fuses the fin root to the base tube along a continuous spiral seam. This creates a monolithic metal structure, eliminating the microscopic air gaps that cause significant thermal contact resistance. The result is near-perfect heat conduction from the base tube to the fin surface, maximizing the effectiveness of the extended surface.
Structural stability: This continuous weld transforms the fin-tube interface into a unit capable of withstanding severe thermal cycling and flow-induced vibration. There is no risk of fin loosening or "belling out" over time, a common failure point for tension-wound fins.
Comparative Analysis of Continuous Spiral Welded Finned Tubes and Several Other Types of Finned Tubes
Choosing the right fin type is a trade-off between performance, durability, and cost.
| Feature | Continuously Welded Spiral Fin Tube | L/LL Type Tension-Wound Fin Tube | Integral Extruded / Rolled Fin Tube | Embedded Fin Tube |
|---|---|---|---|---|
| Thermal Efficiency | Excellent (Zero Contact Resistance) | Moderate (Resistance increases with temperature) | Superior (One-piece construction) | Good (Lower than welded) |
| Anti-Vibration & Mechanical Strength | Exceptional (Welded bond) | Poor (Prone to loosening) | Exceptional | Good |
| High-Temperature Limit | High (Limited by material only) | Low-Moderate (Limited by solder/braze) | High | Moderate |
| Anti-Fouling & Cleanability | Excellent (Smooth weld seam) | Fair (Interface traps debris) | Good | Fair-Good |
| Corrosion Resistance Flexibility | High (Base & fin materials can be independently selected) | Low-Moderate | Low (Same material for both) | Moderate |
| Initial Cost | Moderate-High | Low | High | Moderate |
| Ideal Application Profile | Demanding Environments: High temp/pressure, corrosion, vibration, cycling (e.g., Boilers, HRSGs, Chemical Processing) | Clean, non-cycling, low-temp gases (e.g., Air conditioners, mild HVAC) | Where ultimate strength in clean service is critical | Moderate corrosion/erosion environments where thermal performance is key |
Our Tailoring the Solution
At Shanghai T.S. Industrial Co.,Ltd, our HFW process unlocks unparalleled customization to meet your exact process conditions.
Limitless Material Combinations
The base tube and fin strip are selected independently.
| Component | Material Options |
|---|---|
| Base Tube Options | Carbon Steel (A106 Gr.B), Stainless Steels (304, 316, 321, 347H), Alloy Steels (P5, P11, P22, P91), Duplex Steels, Nickel Alloys |
| Fin Strip Options | Carbon Steel, Stainless Steels, Corten (Weathering Steel), Nickel Alloys |
Fin Types: Solid & Serrated fins
- Solid fins: Primarily used in environments with high dust levels, strong abrasion, or extremely high structural strength requirements.
- Serrated fins: Primarily used for applications with cleaner flue gas, higher heat exchange efficiency, or where a larger heat exchange area is needed but installation space is limited.
Size
Our continuously welded spiral finned tubes are highly flexible in size to meet the needs of most industries. Standard sizes range from small diameter to large diameter. Fin height, thickness, spacing, etc., can all be customized to meet specific requirements.
Conquering Extreme Environments
High-Temperature & Creep: We utilize alloys like P91 or TP347H for superheater sections in boilers and advanced power cycles.
Severe Corrosion: For Waste-to-Energy plants or highly corrosive chemical processes, we offer the continuously welded fin tubes made of nickel alloys (Alloy 625, C276, etc.).
Critical Applications of Continuously Welded Spiral Finned Tubes
- Energy & Power Generation: Used in boiler economizers and air preheaters, serving as core components for enhancing boiler thermal efficiency.
- Petrochemical Industry: Employed in the convection sections of cracking furnaces, reformer furnaces, and various process heaters to recover waste heat from high-temperature flue gas.
- Industrial Manufacturing & Heating: Functions as the core of hot air heating radiators for large industrial plants and greenhouses; also used in grain and food drying equipment.
- Other Fields: Also finds applications in central air conditioning systems, refrigeration equipment, rail transportation, waste heat recovery systems, and numerous other areas.
The suitability of HFW spirally finned tubes for the aforementioned applications stems from their specialized design for the following demanding operating conditions:
1. High-Temperature and High-Pressure Environments
- Key Features: Utilizes seamless steel tubes as the base pipe, which have no longitudinal weld seam, offering greater pressure-bearing capacity. The high-frequency welding creates a metallurgical bond, resulting in high connection strength (fin pull-off strength can exceed 275 MPa) and the ability to withstand thermal shock from frequent start-up and shutdown cycles.
- Typical Applications: Utility boilers (operating pressure can reach 3.82 MPa and above), steam superheaters, high-pressure process heaters.
2. Corrosive Environments
- Key Features: Both the base tube and the fin strip can be made from materials such as stainless steel (e.g., grades 304, 316L), heat-resistant steel (e.g., 12Cr1MoV), or ND steel. The integral welded construction avoids crevice corrosion at contact points. Studies indicate that in flue gas containing hydrogen chloride, the annual corrosion rate of 316L stainless steel finned tubes is significantly lower than that of carbon steel.
- Typical Applications: Chemical waste heat recovery (handling sulfur- or chlorine-containing flue gas), environmental protection desulfurization and denitrification units, equipment in coastal or high-humidity environments.
3. Environments Prone to Abrasion and Fouling
- Key Features: The welded structure is robust, eliminating the risk of fin loosening. Optimizing the fin spacing (e.g., using a larger pitch of 8-15 mm) can effectively prevent dust blockage, facilitate soot cleaning, and maintain low flue gas flow resistance.
- Typical Applications: Tail-end ducts of coal-fired boilers, biomass boilers, cement kilns, and circulating fluidized bed (CFB) boilers.
4. Scenarios Requiring Compact and Efficient Heat Transfer
- Key Features: The fins can expand the heat transfer surface area to several times or even tens of times that of a bare tube, resulting in exceptionally high heat transfer efficiency. For the same heat duty, this allows for a significant reduction in equipment volume, saving space and material.
- Typical Applications: Marine boilers with space constraints, modular package boilers, various types of compact heat exchangers.