Quality control is very important for each product. And for tubular heating elements, there is also the manufacture standard to control the quality. The following are general standards of tubular heating elements in China. So when we manufacture the tubular heating elements, we must follow this standard and doing same test.
1. Heating time Under the test voltage, the time for the component to rise from the ambient temperature to the test temperature should not exceed 15min
2. Rated power deviation
2.1 Under the condition of sufficient heat, the deviation of the rated power of the component should not exceed the range specified below;
2.2 For components with rated power less than or equal to 100W: ± 10%.
2.3 For components with a rated power greater than 100W: 5% to -10% or 10W, whichever is greater.
3. Leakage current
3.1 Leakage current in cold state and leakage current after water pressure and sealing test should not exceed 0.5mA
3.2 The thermal leakage current at the operating temperature should not exceed the calculated value in the formula, but the maximum should not exceed 5mA
I = 1/6 (tT × 0.00001)
I—Heat leakage current mA
T—heating length mm
T-Working temperature ℃
When multiple electric heating tube components are connected in series to the power supply, the leakage current test should be conducted with this group of components as a whole.
4. Insulation resistance
The cold insulation resistance should not be less than 50MΩ during factory inspection
After the sealing test, the insulation resistance after long-term storage or use should not be less than MΩ
The thermal insulation resistance at working temperature should not be lower than the calculated value in the formula, but the smaller should not be less than 1MΩ
R = “(10-0.015T) / t” × 0.001
R—Thermal insulation resistance MΩ
T—heating length mm
T—Working temperature ℃
5. Dielectric strength
The component should be kept under the specified test conditions and test voltage for 1min without flashover and breakdown.
6. Ability to withstand power on and off
The component should be able to undergo 2000 power-on and power-off tests under the specified test conditions without damage.
7. Overload capability
The component should withstand 30 cycles of overload test under the specified test conditions and input power without damage.
8. Heat resistance
Electric heating tube components should withstand 1000 cycles of heat resistance test under the specified test conditions and test voltage without damage.