The ZNHW electric heating sleeve is made of alkali free glass fiber as insulation material, with Cr20Ni80 alloy wire spring installed in it. It is insulated with a hemispherical insulation body formed by vacuum shaping with aluminum silicate cotton. The shell is injection molded in one go, and the upper cover adopts electrostatic spraying technology. Due to the use of spherical heating, the heating area of the container can reach more than 60%. The temperature control adopts a computer chip as the main control unit, multiple digital filtering circuits, and fuzzy PID control algorithm. It has high measurement accuracy, small temperature surge, single key touch operation, dual screen display, internal and external thermocouple temperature measurement, thyristor control output, 160-240V wide voltage power supply, and has a break protection function. It has the characteristics of fast temperature rise, high temperature, easy operation, and durability. It is an ideal instrument for accurate temperature control and heating tests.