The design of electric heating tubes is a system engineering that requires comprehensive consideration of the application of thermodynamics, materials science, and process technology. The following is a detailed breakdown of the core design ideas:
1、 Technical parameter determination
Power Calculation
It is necessary to specify the volume of the heating medium, the target temperature difference (Δ T), and the heating time, and estimate the total power demand through the formula. For example, in the design of a paint baking room, when the volume is 39m ³, the temperature difference is 40 ℃, and the heating time is 40 minutes, the total power is about 120kW.
Matching of working condition requirements
Determine the shape (straight pipe/U-shaped/spiral) and size of the electric heating tube based on the working environment (temperature 25-55 ℃, humidity ≤ 90%), medium type (liquid/air/solid), and installation space limitations.
2、 Material selection and performance optimization
Core materials
Electric heating wire: Nickel chromium alloy (working temperature>600 ℃) or iron chromium aluminum alloy (≤ 600 ℃) are commonly selected, and it is necessary to balance electrical resistivity and high temperature resistance.
Pipe material: stainless steel (corrosion-resistant), copper (high thermal conductivity), or titanium alloy (special medium), choose 26 according to the characteristics of the heating medium.
Insulation filling
The purity of magnesium oxide powder should be greater than 96%, and the particle size should be ≤ 0.4mm to ensure thermal conductivity uniformity and insulation stability.
3、 Structural Design and Thermal Distribution
Layout strategy
Adopting a uniform layout strategy to avoid local overheating. For example, in the design of a paint baking room, straight finned tubes are arranged alternately on both sides and at the bottom, with a column spacing of 15cm to ensure a uniform thermal field.
Pipe body optimization
The diameter and length of the pipe need to be adapted to space limitations, and the heat dissipation area can be increased by using structures such as fins and ripples to improve heat transfer efficiency by 25.
Sealing and Interface
The vacuum shrink tubing process is used to ensure a dense internal insulation layer, and the lead out rod needs to be double sealed to prevent oxidation and corrosion.
4、 Control system integration
Temperature control method
Combining PID algorithm with temperature sensor to achieve closed-loop control, the fluctuation range can be controlled within ± 1 ℃.
Security protection
Integrated overload protection, leakage detection, and over temperature fuse device, in compliance with safety standards such as IEC60335.
5、 Process and Testing Standards
Manufacturing process
Follow the process of "cutting tube → winding wire → adding powder → shrinking tube → sealing → testing", with a focus on controlling the magnesium oxide filling density (≥ 3.1g/cm ³) and the compression ratio of the shrinking tube (15-20%).
Quality verification
Through withstand voltage testing (1500V/60s), leakage current detection (≤ 0.5mA), and lifespan testing (>2000h continuous operation) 68.
6、 Economy and maintainability
Cost balance
Optimize the thickness of the pipe and the diameter of the heating wire while meeting performance requirements, and reduce redundant power design.
Modular design
Adopting a detachable connection structure for quick replacement in case of local damage, reducing maintenance costs by 38%.
Through the multi-dimensional collaborative design mentioned above, efficient, safe, and long-lasting operation of electric heating tubes can be achieved. During specific implementation, simulation verification and prototype testing iteration optimization should be carried out in conjunction with application scenarios