In petrochemical enterprises,explosion-proof electric heating tubes protect the surrounding of the internal connecting conductors and are equipped with sturdy terminals for power connection, thus fully withstanding mechanical external forces such as vibration and impact. The production structure must use sealed metal.
Design features of explosion-proof electric heating tubes:
(1) The distance between the heating element and the internal connecting conductor, as well as between them and the metal protective tube, should be at least 2mm.
(2) The connection between the internal conductor and the heating element is crimped.
(3) The end of the metal tube should be fully moisture-proof treated.
(4)Explosion-proof electric heating tubes design principles must also meet the following test conditions:
1. Under 1.1 times rated voltage and rated power, power on for 1 minute and power off for 4 minutes as one cycle. After repeating 2000 cycles, apply AC voltage for 1 minute, which should withstand 1600V.
2. After powering the component for 5 minutes at 1.1 times rated voltage and rated power, immerse it completely in water while power is off, with 25 minutes as one cycle. After repeating 50 cycles, place it in the air for 40 minutes, then it should withstand the AC voltage shown earlier for 1 minute.
(5) The explosion-proof structure of explosion-proof electric heating tubes must adopt one of the following explosion-proof structures during manufacturing:
1. Pressure-resistant explosion-proof structure: The metal tubular electric heating element is cast integrally with the sealed shell, and the metal shell has sufficient thickness and strength.
2. Increased safety explosion-proof structure: The sealed electric heating element is installed in a protective shell, part of which is made of stamped steel structure. The mesh must be less than 12mm, but at a distance of 100mm from the conductive part, the mesh can be less than 20mm.
(6) Temperature rise limit: The part of theexplosion-proof electric heating tube that may contact explosive gas (for pressure-resistant explosion-proof structure, it is the temperature rise limit of the shell surface).
Production process of explosion-proof electric heating tubes:
Explosion-proof electric heating tubes are made by welding multiple heating tubes onto a flange for centralized heating. They are mainly used for heating in open or closed solution tanks and circulation systems. They have the following advantages: High surface power, 2 to 4 times the surface load of air heating. Heavy oil explosion-proof flange electric heating tubes are highly dense and compact. Due to the overall short and dense structure, they have good stability and do not require brackets for installation. The combined type mostly uses argon arc welding to connect the electric heating tube to the flange, or it can use a fastening device, where each electric heating tube is welded with a fastener. Then it is locked with a nut on the flange cover. The tube and fastener are argon arc welded, ensuring no leakage. The sealing part of the fastener uses scientific technology. Single tube replacement is very convenient.
