1. First, determine the on-site working conditions
1. Confirm the heating medium, distinguishing between clean water, thermal oil, circulating air, corrosive chemicals, and saline wastewater, while noting the viscosity and presence of acids, alkalis, or chloride ions.
2. Verify the operating temperature, including the ambient starting temperature and the maximum long-term operating temperature of the equipment.
3. Confirm the pressure-bearing capability of the cavity. For normal-pressure tanks, use standard sealing; for pressurized vessels, thicken the pipe walls and equip with standard flanges.
4. Measure the installation space, determine the pipe fitting position and insertion depth, and use U-shaped or custom bent structures for confined spaces.
2. Power Calculation and Surface Load Management
1.The power calculation is based on the heat capacity of the medium. For water eplenishment and storage heating, it is calculated according to the water volume and heating duration. Due to the higher thermal resistance of oil heating, the power is increased by approximately 30%. For air duct hot air heating, the values are determined by combining airflow and temperature rise. A unified power margin of 1.2 to 1.3 times is reserved for all operating conditions to compensate for heat dissipation losses.
2. Controlling the surface load of the pipe wall is key to extending service life. For clean water under normal conditions, it should be 3 to 5 watts per square centimeter, reduced to 2–3 watts for heavy scaling conditions; thermal oil should be maintained at 1.5–3 watts, with further reductions for high-temperature oil; natural air convection should not exceed 2 watts per square centimeter, while forced air blow with finned heating can be relaxed to 4–8 watts; corrosive liquids must be strictly limited to 1–2 watts.
3. Select the protective pipe material as needed
1.304 stainless steel, suitable for general water, ambient air, and neutral oils, offers high cost performance with a service temperature range of up to 600°C.1.
2.316L stainless steel, suitable for seawater, chlorine-containing aqueous solutions, and weak acid/alkali media, with priority selection in the food and pharmaceutical industries.
3.310S high-temperature stainless steel, specifically designed for heating with high-temperature hot air, thermal oil, and flue gas, capable of withstanding dry burning at around 1000°C.
4. Titanium material, with excellent corrosion resistance in environments with high chloride ion content such as electroplating solutions and seawater, is suitable for medium to low-temperature liquid applications.
5. Nickel-based alloys, resistant to strong corrosion and acids, suitable for harsh chemical environments, exhibit high-temperature and corrosion resistance, and are commonly used in specialized chemical equipment.
6. Purple copper, low-temperature water purification heating, fast heat conduction, not resistant to acid and alkali corrosion.
4. Select and Install Fixed Structures
1. Flanged plug-in type, widely used in large-capacity storage tanks, reactors, and thermal oil furnaces, featuring excellent pressure resistance and convenient disassembly for maintenance.
2. Threaded screw-in type, small fuel tank, small water tank, threaded seal, commonly used for low-pressure small equipment.
3. Finned casing model, air and duct drying heating, with external heat dissipation fins installed to increase heat exchange area.
4. Sanitary flange type, suitable for food and pharmaceutical tank bodies, with a quick-release structure for easy disassembly and cleaning.
5.Electrical parameters and safety selection
1. Distinguish between single-phase 220V and three-phase 380V voltage, prioritize three-phase wiring for high-power heating tubes, and reasonably match star or delta connections.
2. The factory insulation resistance is greater than 1 megohm, the withstand voltage test meets the standard, and an IP65 protective junction box is selected for humid outdoor environments.
3. Explosion proof sheathed heating tubes should be used in flammable and explosive environments, with built-in overheating fuses or temperature probes, linked with temperature controllers to prevent air and dry burning, and the metal shell should be properly grounded.
6. Simplified selection reference for different scenarios
1. Ordinary domestic water tank: made of 304 material, installed with threads or small flanges, with medium to low surface load.
2. Hydraulic press oil tank: made of 316 material, with flange insertion, low surface load to prevent oil surface carbonization.
3. Drying room air duct heating: 310S finned heating tube, flange fixed, suitable for flowing hot air.
4. Saltwater and seawater tanks: titanium sheathed heating tubes, low load flange structure.
5. Water for food production line: 316L sanitary grade pipes, chucks or sanitary flanges.
7. Key Points for Selection Attention
The heating section of the liquid immersion heating tube must be completely submerged in the liquid surface, and local empty burning is prohibited; Priority should be given to reducing surface load in working conditions with severe scaling and dust accumulation; Mark the four key parameters of size, voltage, medium, and temperature before placing an order.
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Post time: Jun-15-2026
