The selection of flange-type electric heating tubes should be based on parameters such as flange standards, power density, and medium characteristics. On-site operation and maintenance personnel should verify flange specifications, sealing face forms, and materials according to flange standards such as HG/T 20592 or JB/T 4700 to ensure compatibility with pipeline or equipment interfaces.
Common flange standards for flange-type electric heating tubes include HG/T 20592 and JB/T 4700, with sealing face forms such as raised face (RF) and male-and-female face (MFM). During selection, it is necessary to confirm that the pipeline flange standard is consistent with the heating tube flange to avoid installation difficulties caused by standard mismatch. Flange materials are usually similar to pipeline materials, such as carbon steel and stainless steel, to meet the corrosivity requirements of the medium.
Power density refers to the power per unit heating area and must be determined according to the medium type and flow rate. For low-viscosity media such as water and oil, the power density can be appropriately increased; for high-viscosity or scaling-prone media, the power density should be reduced to avoid surface overheating. The surface load of the heating tube is generally controlled within the range of 2~5 W/cm², and the specific value should refer to the process conditions.
The heating tube can integrate a temperature sensor to detect the medium temperature or tube wall temperature and provide over-temperature protection. In applications such as hot blast stoves and mixed air, the installation position of the temperature sensor must represent the mainstream temperature to avoid local overheating. The sensor signal should be connected to the control system to achieve over-temperature alarm or cut off the heating power supply.
During installation, ensure that the flange gasket material is compatible with the medium and that the bolt preload is uniform. Regularly check the sealing condition of the wiring cavity to prevent oil leakage or moisture intrusion. For equipment in long-term operation, it is recommended to check the surface scaling of the heating tube every quarter and clean it promptly to maintain heat exchange efficiency.
