Tubular Electric Heater
Analysis completed, with reference to 19 sources
Tubular electric heaters (also known as metal tubular electric heating elements) are the most basic and widely used electric-to-heat conversion elements in industrial heating. The core of selection lies in "medium adaptation, surface load control, and material matching." Based on your procurement needs, here are the core selection points and references for local and surrounding manufacturers:
Core Selection Parameters
During selection, the following parameters must be carefully matched to ensure heating efficiency and service life:
Heating medium and surface load (power density): This is the most critical parameter determining the life of the heating tube. Different media have greatly differing requirements for surface load:
Clean water/drinking water: surface load 6-8W/cm², single-tube power 0.5-15kW, optional 304 stainless steel material.
Oil/heat transfer oil: surface load 2-4W/cm², single-tube power 1-20kW; carbon-prone media such as heat transfer oil must be strictly controlled at ≤0.7W/cm² to avoid local overheating causing oil carbonization.
Heavy oil/asphalt: surface load 1-2W/cm², single-tube power 3-30kW. When melting solid asphalt, it is necessary to first use reduced voltage, then raise to rated voltage after melting.
Corrosive liquids (acid and alkali): surface load 3-5W/cm², single-tube power 0.5-10kW, requiring 316L stainless steel or titanium tube material.
Static air: surface load 1-3W/cm², single-tube power 0.5-8kW. It is strictly prohibited to dry-burn ordinary smooth tubes in static air; finned structures should be used to expand heat dissipation area.
Flowing air: surface load 3-5W/cm², single-tube power 1-20kW.
Mold/metal solids: surface load 5-15W/cm², single-tube power 0.1-5kW.
Material selection: Choose the sheath material according to medium temperature and corrosiveness:
SUS304: Suitable for 100-300℃ environments and ordinary water and oil heating, the first choice for general-purpose use.
SUS316/316L: Strong corrosion resistance, suitable for weakly acidic and weakly alkaline liquids, drinking water, and chemical environments.
SUS310S: Suitable for 600-850℃ high-temperature environments.
Titanium tube/zirconium tube: Used in strongly corrosive environments (such as electroplating solutions and seawater).
Copper tube: Mostly used for civil water heating; carbon steel tube is used for oil or air heating and is prohibited for water heating.
Structure and installation forms:
Shape structure: straight tube type (I type), U type, W type (M type), single-head heating tube (single-end wiring), flange type, etc., selected according to the internal space of the equipment.
Installation method: threaded connection (suitable for hydraulic oil tanks and lubrication systems), flange connection (suitable for reactors and large storage tanks), fixed brackets, etc.
Sheathed structure: The heating core is separated from the protective sleeve, so the core can be replaced during maintenance without draining the medium, suitable for high-reliability occasions.
Electrical parameters:
Voltage: mainly single-phase 220V and three-phase 380V; industrial scenarios also include high-voltage specifications such as 690V and 6kV.
Power: Single-tube power ranges from 50W to 140kW. The theoretical power must be calculated according to the medium's specific heat capacity, mass, temperature difference, and heating time, with a 10%-20% margin reserved.
Safety protection: Multiple protection mechanisms such as over-temperature protection, low liquid level/dry-burn protection, and short-circuit protection must be provided; explosion-proof occasions require a complete-machine explosion-proof certificate, and the explosion-proof grade can reach Ex d IIB T4 or Ex d IIC T4.
References for Local and Surrounding Manufacturers
Jiangsu is the core industrial belt for electric heating equipment in China. Yangzhou and its surrounding areas have many manufacturers specializing in tubular electric heaters, making on-site inspections and after-sales coordination convenient:
Yangzhou local:
Located in Yangzhou, producing the full series of tubular electric heaters such as SRY2/SRY3/SRY4/SRY6/SRY7, covering oil tank heating, sheathed heating, straight rod heating, and other scenarios. Explosion-proof grade can reach dⅡB and C, and pressure resistance can reach 20MPa.
Yangzhou Hengwei Electric Heating Technology Co., Ltd.: Located in Xiaji Town Industrial Development Zone. Its business scope includes R&D, processing, and sales of electric heating tubes and electric heaters, and manufacturing of explosion-proof electric heaters and temperature control equipment, supporting non-standard customization.
: Located in Baoying County Chengnan Industrial Concentration Zone, focusing on R&D, processing, and sales of electric heaters, heating tubes, and boiler heating tubes, with import and export qualifications.
Located in Baoying County Chengnan Industrial Concentration Zone, producing electric heating tubes, track-type heaters, bolt heating rods, and other products, with supporting thermocouples and temperature control equipment.
Located in Liubao Industrial Zone, producing electric heating tubes, oil bath heaters, temperature control cabinets, etc. Its product line covers supporting heating equipment for oil purifiers, ovens, and more.
Located in Xiaoguanzhuang Town, Baoying County, mainly engaged in infrared heating lamp tubes, quartz heating tubes, ceramic heaters, cast copper/cast aluminum/cast iron heaters, etc.
Located in Fanshui Town Industrial Concentration Zone, specializing in the manufacture of infrared heating tubes, double-tube heating tubes, ruby heating tubes, etc., with annual production capacity reaching the million-piece level, and products exported to Japan, South Korea, Europe, and the United States.
Surrounding areas:
Single-end electric heating tubes, stainless steel finned heating tubes, maximum temperature resistance 900℃, supporting 690V high-voltage specifications, single tube up to 11.6 meters long), Changzhou Weiken Filtration Separation Environmental Protection Technology Co., Ltd. (pipeline electric heaters, heaters for wind power gearboxes).
Yancheng direction: Yancheng Feiyu Alloy Electric Appliance Co., Ltd. (single-head heating tubes, strict surface load control, providing life design guidance).
Shanghai direction: Shanghai Yanyan Machinery (sheathed electric heating tubes, supporting full-parameter customization), Shanghai Haoyu Machinery Co., Ltd. (thread-mounted single-head electric heating tubes).
Selection Precautions
Surface load is the core of service life: The higher the surface load, the higher the internal operating temperature of the heating tube, and the faster the material deteriorates. During selection, be sure to calculate with the formula: surface load (W/cm²) = power (W) ÷ (tube diameter (cm) × 3.14 × heating section length (cm)).
Dry burning and empty burning are strictly prohibited: Liquid heating tubes must ensure that the heating area is completely immersed in the medium. If scale or carbon deposits are found on the tube surface, they must be removed promptly; otherwise, heat dissipation will be affected and service life shortened.
Explosion-proof compliance: If used in flammable and explosive environments, complete-machine products with explosion-proof certificates must be selected, and the explosion-proof grade must match the on-site hazardous area classification.
Voltage and power matching: When multiple groups of heating tubes are connected in parallel in industrial scenarios, attention must be paid to three-phase load balance to avoid single-phase overload.
