A sheathed electric heater is an industrial heating device that isolates the electric heating element from the heating medium through a metal sheath, widely used in heating scenarios such as liquids, air, and molds.
What is a sheathed electric heater?
Its core structure encapsulates the resistance heating wire inside a metal sheath, filled with thermally conductive and insulating magnesium oxide powder, forming a solid whole.
Central layer: resistance wire (heat source)
Middle layer: magnesium oxide powder (thermal conductivity and insulation)
Outer layer: metal sheath (protection, heat transfer)
Main features
Long lifespan: The resistance wire is sealed inside the sheath, isolated from air, effectively preventing oxidation.
High mechanical strength: The structure is robust, capable of withstanding certain impacts, vibrations, and pressures.
High thermal efficiency: Magnesium oxide powder has good thermal conductivity, allowing heat to be transferred quickly and evenly to the heated object.
Safe and reliable: Magnesium oxide powder maintains good insulation performance even at high temperatures, and the metal sheath is usually grounded.
Flexible installation: It can be bent into different shapes as needed, meeting various installation requirements.
Main types and application scenarios
According to application needs, sheathed electric heaters mainly come in the following types:
Table
Type Main features Typical application scenarios
Liquid heater With threads or flanges, can be directly immersed in liquid Heating water, oil, acid and alkali solutions, electroplating solutions, etc.
Air heater With fins to increase contact area with air Ovens, drying ovens, air ducts, air conditioners, fan heaters, etc.
Mold heater Slender rod shape, can be directly inserted into heating holes of molds Temperature maintenance for injection molds, die-casting molds, hot press molds
Clamp-on heater Tubular heating elements bent into shape and embedded in cast aluminum sleeves Heat tracing and insulation for large pipelines, tanks, and instruments
Typical product models
Common models on the market include the SRY series and HRY series, which differ in power, dimensions, and applicable media.
SRY series: General-purpose immersion heater, suitable for heating mineral oil in open or closed oil tanks.
SRY series sheathed electric heater
HRY series: Sheathed tubular electric heater, suitable for heat transfer oil or oils with good heat absorption.
HRY series sheathed electric heater
Purchasing and usage precautions
Strictly prohibit dry burning: When heating liquids, ensure the heater is fully immersed in the medium. It is strictly forbidden to power on without a medium, otherwise the heater will burn out.
Choose appropriate material: Select the sheath material based on the corrosiveness of the heating medium. For example, when heating corrosive liquids, choose corrosion-resistant materials such as 316L stainless steel.
Regular maintenance: Regularly clean the sheath surface, check the tightness of wiring terminals, and periodically test insulation resistance to ensure safe and reliable operation of the equipment.
Sheathed electric heaters are widely used in the industrial heating field due to their safety, efficiency, and durability
