The most intuitive way to verify the advantages and disadvantages of the electric heating tube is to wipe the surface of the electric heating tube, then connect the AC 220V power supply, dry burn in the air, turn off the power after the surface is red, wipe it with napkin after the electric heating tube is completely cooled, and there should be no black oxidation powder on the white paper (not reacting with oxygen in the air), indicating that it is a high-quality electric heating tube.

1. Power input test rated input power (W): power on at rated voltage, and its power deviation shall not exceed the following table

Rated input power (W)

Deviation

deviation

W≦200

±10%

W>200

Positive deviation: + 5% or 2

, negative deviation: - 10%

2. Electrical strength test:

a. Electrical strength under cold state: it shall be able to withstand 50Hz, 1min withstand voltage, cut-off current 5mA, and there shall be no breakdown and flashover.

Rated voltage test voltage

250V 1250V

b. Electrical strength at operating temperature: withstand 50Hz, withstand voltage for 1min, cut-off current 5mA, no breakdown and flashover.

Rated voltage test voltage

250V 1000V

3. Leakage current at operating temperature

Under the condition of full heat release, the electric heating tube is input at 1.15 times the rated power, and the leakage current is 0.5m a.

4. Overload test

Under the condition of full heat release, the electric heating tube shall be powered on for 1hrs at 1.27 times the rated power, and cooled for 0.5hrs to room temperature (forced cooling is allowed), so as to repeat 30 cycles without damage.

5. Sealing test of electric heating tube shell (pipe crack test)

Immerse the electric heating tube in acidified water (2% ~ 3% hydrochloric acid, sulfuric acid or nitric acid) for 3hrs, and both ends of the electric heating tube shall expose the liquid level for at least 5mm. After the test, it shall meet the performance requirements of items 2 ~ 3.

6. Sealing test

Place the electric heating tube in the environment with temperature of 60 ℃ and humidity of 95% for 24hrs. After placing, it shall meet the performance requirements of items 2 ~ 3.

7. Life test

Under the condition of full heat release, the electric heating tube shall be powered on for 1hrs at the rated voltage and cooled for 0.5hrs to room temperature (forced cooling is allowed), and the cumulative working time is 3000hrs.