Troubleshooting Common Faults of Electric Heating Tubes & Heating Principles

Common faults of electric heating tubes include external leakage, fluid cross-leakage and excessive pressure drop. Timely troubleshooting for heating temperature failures is essential to avoid safety hazards.

External leakage of electric heating tubes mainly occurs at sealing joints between plates, secondary sealing leakage grooves of plates, and inner sides between end plates and compression plates. Excessive pressure drop means the pressure difference between medium inlet and outlet far exceeds design specifications, severely affecting system flow and temperature control. In heating systems, excessive pressure drop on the hot side leads to insufficient primary-side flow and inadequate heat source, failing to meet the required outlet temperature on the secondary side.

Electric heating tubes shall be firmly fixed, with all effective heating sections fully immersed in liquid or solid metal. Dry burning is strictly prohibited. Scale and carbon deposits on tube surfaces must be cleaned thoroughly in time to prevent poor heat dissipation and service life reduction. When heating fusible metals, solid saltpeter, alkali, asphalt, paraffin and other substances, lower the operating voltage first, and raise it to rated voltage only after the medium melts.

For air heating, arrange heating elements in staggered and even layout to ensure good heat dissipation and sufficient air heating. Magnesia powder at the wiring end shall be protected from dirt and moisture infiltration to prevent electric leakage accidents.

Wiring terminals shall be installed outside thermal insulation layers, kept away from corrosive, explosive media and water. Lead wires shall withstand long-term operating temperature and heating load; avoid over-tightening wiring screws. Store tubes in dry environment. If insulation resistance drops below 1MΩ after long-term storage, dry them in an oven at around 200℃ or apply reduced voltage for heating until insulation performance recovers.

Cast electric heaters adopt tubular heating elements as heat sources and high-quality aluminum alloy shells via integral casting. Their applicable temperature ranges from normal temperature to 350℃, widely used in plastic machinery, die heads, cable equipment, chemical, rubber, petroleum and other industrial facilities.

The heating principle of electric heating tubes is simple: it converts electric energy into thermal energy efficiently via Joule effect to heat materials. It is divided into direct resistance heating and indirect resistance heating for different application demands.

In direct resistance heating, power voltage is directly applied to heated conductive objects with high resistivity, which generate heat by themselves, achieving extremely high thermal efficiency.

The spiral heating resistance wire inside stainless steel electric heating tubes generates different heat output according to coil spacing: closer spacing means higher temperature, while wider spacing leads to lower temperature. Uniform coil winding and even resistance wire distribution are critical in production; uneven wire spacing caused by poor-quality heating wires will result in uneven heating.

Fill sufficient magnesia powder inside stainless steel heating tubes for dense packing, then compress tubes with tube shrinking machines. Featuring metal shells (stainless steel, red copper), evenly arranged spiral nickel-chromium or iron-chromium heating alloy wires and compacted insulated thermally conductive magnesia filler, with both ends sealed by silica gel, such metal-sheathed heating elements are applicable for heating air, metal molds and various liquids.

Stainless steel electric heating tubes boast over 30% higher thermal efficiency and faster heating speed than ordinary metal heaters. As pure blackbody heating components, they feature rapid temperature rise, low thermal lag, uniform heat emission, long-distance thermal radiation and fast heat exchange, with far lower luminous flux during operation.

Quality Inspection Method

Wipe the tube surface clean, connect to 220V AC power and conduct dry burning in air. Power off after the tube turns red. After full cooling, wipe the surface with napkin; qualified products leave no black oxide powder on the paper.

Repeated Usage Specifications

Firmly fix the tubes and avoid dry burning. Remove scale and carbon deposits regularly. Keep wiring parts away from harsh media and moisture. Arrange elements reasonably for air heating and protect terminal magnesia powder strictly against contamination and dampness to ensure safe and stable operation.