Tubular Electric Heater
Tubular electric heaters are the most widely used basic heating elements in industrial heating equipment. Their core structure consists of a metal sheath tube, spiral electric heating alloy wire (nickel-chromium/iron-chromium-aluminum), and high-purity crystalline magnesium oxide powder filled in the gaps. Through the tube reduction process, the filler reaches a high-density state. They feature simple structure, high mechanical strength, thermal efficiency close to 100%, and easy installation. The designed service life generally exceeds 10,000 hours, and the maximum operating temperature can reach 850°C.
I. Core Selection Logic: First Determine the Medium, Then Determine Surface Load and Material
1. Surface Load — The Key Indicator Determining Lifespan
Surface load (W/cm²) refers to the power density per unit heating area. Incorrect selection is the primary cause of electric heating tube burnout. Recommended values for different media are as follows:
Heating Medium Recommended Surface Load Single Unit Power Range Typical Application Scenarios
Clean Water/Drinking Water 6~8 W/cm² 0.5~15kW Water tanks, water heaters
Oil/Heat Transfer Oil 2~4 W/cm² 1~20kW Oil tanks, heat transfer oil furnaces
Heavy Oil/Asphalt 1~2 W/cm² 3~30kW Asphalt storage tanks
Corrosive Liquids (Acid/Alkali) 3~5 W/cm² 0.5~10kW Electroplating tanks, pickling tanks
Static Air 1~3 W/cm² 0.5~8kW Ovens, molds
Flowing Air 3~5 W/cm² 1~20kW Air ducts, hot air circulation
Molds/Metal Solids 5~15 W/cm² 0.1~5kW Injection molding machines, die-casting molds
Steam/High-Pressure Water 4~6 W/cm² 5~30kW Steam generators
Pitfall Warning: For media prone to carbon buildup such as heat transfer oil, the surface heating power must be strictly controlled at ≤0.7~2.0 W/cm²; otherwise, localized overheating will cause coking and carbonization, significantly shortening the lifespan.
2. Sheath Material — Selected According to Medium Corrosiveness
Clean Water/Ordinary Oil: SUS304 stainless steel (most commonly used, cost-effective)
High-Temperature Air/Weak Corrosiveness: SUS321 (contains titanium, resistant to intergranular corrosion)
Strong Acid/Alkali/Seawater/Chloride Ion Environment: SUS316L or titanium tube (Ti)
High-Temperature Oxidizing Environment (>600°C): Incoloy 800/840 (high nickel-based alloy)
Food-Grade/Drinking Water: SUS304 or copper (must comply with GB/T 23150-2024)
3. Structural Form — Selected According to Installation Method
Structure Type Lead-Out Method Typical Applications Advantages
Single-Head Heating Tube (Single-End Lead-Out) One-end lead-out Molds, injection molding machines, packaging machinery Small installation space, high power density
U-Shape/W-Shape/Straight Rod Type Double-end lead-out Water tanks, oil tanks, air ducts High versatility, low cost
Flange Immersion Type Flange-fixed multi-tube combination Large storage tanks, reactors No need to empty medium for replacement, easy maintenance
Finned Type Double-end/Single-end Air heating, drying rooms Fins increase heat dissipation area, high heat exchange efficiency
Threaded Type (Threaded Tube) Threaded fixing Small water heaters, pipelines Easy installation, good sealing
II. Key Parameters: 5 Hard Indicators That Must Be Verified
1. Voltage and Power
Voltage: Conventional 220V (single-phase)/380V (three-phase); special scenarios can use 12V/24V/48V/110V/690V
Power Deviation: Industry standard is +5%~-10%; high-end products can be controlled within ±5%
Power Calculation: Initial heating power must consider container mass, medium specific heat, temperature rise, and heating time; engineering practice reserves a 1.2x safety factor
2. Electrical Performance
Cold-State Insulation Resistance: ≥100 MΩ (some standards require ≥1 MΩ/500V)
Dielectric Strength: Cold state 1500V/1min without breakdown; hot state 1000V/50Hz without breakdown
Leakage Current: Normal operation ≤3mA (required by the new national standard GB/T 23150-2024 for tubular heaters used in water heaters)
3. Dimensional Specifications
Tube Diameter: Commonly Φ8mm, Φ10mm, Φ12mm, Φ14mm, Φ16mm, Φ18mm, Φ20mm, Φ25mm
Length: Single-head tubes 21mm~2500mm; U-shaped/straight rod types can reach over 6000mm
Cold-End Length: The non-heating zone at the lead end is typically 5~25mm; during installation, ensure the heating zone is fully immersed in the medium
4. Lead Wire Method
High-Temperature Fiberglass Lead Wire: Temperature resistant to 400°C, standard length 300mm, most commonly used
Silicone High-Temperature Wire: Temperature resistant to 200~250°C, good flexibility
Ceramic Terminal/Bolt Connection: Suitable for high-temperature environments, convenient for external wiring
5. Compliance Certification
General Industrial: Complies with JB/T 4088.1-2022 "Daily-Use Tubular Electric Heating Elements," GB/T 11713-2008 "Electric Heating Tubes"
For Water Heaters: Must comply with GB/T 23150-2024 (implemented April 1, 2025, adding technical requirements for anti-corrosion, dry-burn rapid cooling, and voltage step-up)
Explosion-Proof Applications: Requires complete machine explosion-proof certificate (Exd IIB/IIC T4~T6), complying with GB 3836 series standards
Export Projects: CE, UL, RoHS certification
III. Mainstream Brands and Manufacturer Recommendations
International First-Tier Brands
Table
Zoppas Italy/Hangzhou Founded in 1963, global leader in electric heating elements, most complete product line High-end home appliances, industrial equipment supporting
BACKER HTS Sweden/Shenzhen 60 global factories, full range of heating tubes/films/belts, stable quality Export projects, high-end industrial
Watlow USA/Shanghai Founded in 1920, temperature control system + heater integration, semiconductor-grade precision Semiconductors, medical equipment, high-end laboratories
Thermowatt Italy/Wuxi Major manufacturer of plug-in heating tubes and thermostats Home appliances, industrial ovens
SJH Taiwan/Xiamen Founded in 1965, one of the world's larger electric heating element manufacturers Home appliances, commercial equipment
Domestic High-Quality Brands (Mainly from Jiangsu/Zhejiang/Guangdong Industrial Belts)
Dongfang Electric Heating (TANK) Zhenjiang Listed on Shenzhen Stock Exchange (300217), drafting unit of industry standards, 10KV high-voltage direct connection technology, ATEX explosion-proof certification New energy, petrochemical, explosion-proof high-end
Heatwell (HEATWELL) Hangzhou Listed on Shanghai Stock Exchange (603075), specialized and sophisticated "little giant," annual output of nearly 100 million pieces Home appliance supporting, industrial equipment
Headway (HEADWAY) Guangdong Annual output of 50 million pieces, new energy vehicle air conditioning and battery thermal management systems New energy vehicles, home appliances
SANA Ningbo 400+ types of heating elements, heating elements for steam ovens/medical ventilators Home appliances, medical equipment
XMT Changzhou Drafting unit for thermostat/electric heating tube standards, founded in 1975 Home appliances, industrial temperature control
TAMMAN Zhongshan Large domestic manufacturer of electric heating tubes for home appliances/industrial equipment Home appliances, commercial equipment
High-Quality Manufacturers in Jiangsu Region (Including Around Yangzhou)
Considering your location in Yangzhou, the following enterprises are worth noting:
Zhenjiang Dongfang Electric Heating (TANK): About 1 hour drive from Yangzhou, listed on Shenzhen Stock Exchange, main drafting unit of domestic electric heating industry standards, full coverage of explosion-proof electric heaters and tubular electric heating elements, industry-leading 10KV high-voltage direct connection technology, suitable for industrial scenarios with high quality requirements.
Changzhou Weiken Filtration Separation Environmental Technology: Focuses on tubular electric heaters, covering wind power gearboxes and pipeline-type non-standard customization, surface load design strictly references JB2379-93 standard, suitable for petrochemical, steel metallurgy, and other heavy industry scenarios.
Wuxi Hengye Electric Heating: Main supplier of electric heat tracing cables in East China, fluoroplastic sheathed self-regulating heat tracing cable failure rate below 0.8%, provides complete electric heating system design services (including cable selection, explosion-proof junction box configuration, and grounding resistance calculation sheets).
Yangzhong Shenzhou Chemical Power Equipment / Hengda Electric Heating Appliances: Yangzhong is just across the river from Yangzhou. Shenzhou focuses on far-infrared heating technology and explosion-proof/pipeline heaters, compatible with DCS/PLC; Hengda specializes in high cost-performance customization, prices 10%~15% lower than industry average, suitable for bulk procurement.
Yancheng Hengneng Technology / Xuanyuan Heating Equipment / Yuheng Electric Heating: Yancheng is a major town in Jiangsu's electric heating industry. Hengneng Technology has independent production across the entire industry chain, PID temperature control ±0.8°C; Xuanyuan has fixed pressure vessel A2 qualification, complete CE/RoHS certification; Yuheng focuses on flange immersion heaters, tube diameters Φ8~16mm, flange DN50~DN800 optional, supports customization.
IV. Scenario Selection Quick Reference
Water Tank/Water Heater Heating U-shaped/straight rod type, SUS304, surface load 6~8W/cm², complies with GB/T 23150-2024 Heatwell/Zoppas/SANA
Heat Transfer Oil Furnace/Oil Tank Heating Flange immersion type, SUS304/321, surface load ≤2.0W/cm², HRY series low surface power design Dongfang Electric Heating/Zhenjiang Sanwei/Yancheng Hengneng
Mold/Injection Molding Machine Heating Single-head heating tube, SUS304, surface load 5~15W/cm², Φ8~16mm Zoppas/Headway/TAMMAN
Oven/Air Duct Air Heating Finned type, SUS304, surface load 1~3W/cm² (static)/3~5W/cm² (flowing) Changzhou Weiken/Wuxi Hengye
Electroplating Tank/Acid-Alkali Liquid Heating Titanium tube or SUS316L, surface load 3~5W/cm², or Teflon-coated tube (≤1.5W/cm²) Shaanxi Ruite/Yangzhong Shenzhou
Explosion-Proof Environment (Zone 1/Zone 2) Exd IIB/IIC T4~T6 flameproof type, complete machine explosion-proof certificate Dongfang Electric Heating/Zhenjiang Sanwei/Yifeiyang Tian
High Cost-Performance Bulk Procurement Standard U-shaped/single-head tube, SUS304, surface load matched to medium Yangzhong Hengda/TAMMAN/SANA
V. Installation and Maintenance Key Points
Dry Burning Strictly Prohibited: The effective heating zone of the electric heating tube must be fully immersed in the heated medium or closely attached to metal solids; static dry burning in air will cause instant burnout
Reliable Grounding: The metal sheath must be grounded, grounding resistance ≤4Ω
Regular Descaling: In areas with hard water, scale must be cleaned regularly; otherwise, it affects thermal efficiency and causes localized overheating
Insulation Testing: After long-term storage, measure insulation resistance before use; if below 1MΩ, dry in a 200°C oven for several hours to restore
Secure Wiring: Lead terminals must be tightened with double nuts to prevent vibration loosening causing poor contact and arcing
Melting Solid Media: When melting asphalt, paraffin, etc., use reduced voltage; after melting, increase to rated voltage to prevent heat concentration
