What are the performance requirements of electric heating tubes?

What are the performance requirements of electric heating tubes?

 

1. Heating time

Under the test voltage, the time for the heating tube to rise from the ambient temperature to the test temperature should not exceed 15 minutes.

2. Rated power deviation

Under the condition of sufficient heating, the deviation of the rated power of the electric heating tube should not exceed the following specified range:

For electric heating tubes with rated power less than or equal to 100W: ±10%.

For electric heating tubes with rated power greater than 100W: +5%~-10% or 10W, whichever is greater.

3. Leakage current

① The cold leakage current and the leakage current after water pressure and sealing test should not exceed 0.5mA.

 

② The thermal leakage current at working temperature should not exceed I=1/6tT*10-5, but the maximum should not exceed 5mA. (In the formula: I is the thermal leakage current, mA; t is the heating length, mm; T is the working temperature, ℃.)

 

When multiple components are connected in series to the power supply, the leakage current test should be performed on this group of components as a whole.

4. Insulation resistance

① The cold insulation resistance should not be less than 50MΩ during the factory inspection.

② The insulation resistance after sealing test, long-term storage or use should not be less than 1 MΩ.

③ The thermal insulation resistance at working temperature should not be lower than R=(10-0.015T)/t*1000, but the minimum should not be lower than 1 MΩ. (In the formula: R is the thermal insulation resistance, MΩ; t is the heating length, mm; T is the working temperature, ℃.)

5. Insulation compressive strength

The electric heating tube should be kept for 1 min under the specified test conditions and test voltage without flashover and breakdown.

6. Ability to withstand power on and off

The electric heating tube should be able to perform 2000 power-on and power-off tests under the specified test conditions without damage.

7. Overload capacity

The electric heating tube shall be able to withstand 30 cycles of overload test under the specified test conditions and input power without damage.

8. Heat resistance

The electric heating tube should be able to withstand 1000 cycles of heat resistance test without damage under the specified test conditions and test voltage.

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