How to judge whether the heating tube is good or bad?
1. Design the size and power according to the working environment;
2. Choose the appropriate shell material according to the working environment;
3. Electric heating pipes have been purchased, and the electric heating pipe project is tested whether it meets the national standards.
4. The cold leakage current is less than or equal to 0.5 mA;
5. The cold insulation resistance is greater than or equal to 50 megaohms;
6. The thermal leakage current is less than or equal to 0.12 mA;
7. The thermal insulation resistance is greater than or equal to 3 megaohms;
8. Thermal withstand voltage experiment 50 Hz, 1500 volts, 1 minute should not have flashover breakdown phenomenon.
In addition, supplemental electric heating tubes:
Electric heating tube, is a kind of electrical components that specialize in converting electrical energy into heat energy, is a metal tube as the shell, along the center of the tube axial uniform distribution spiral electric heating alloy wire its void filling compacted magnesia with good insulation and thermal conductivity, both ends of the pipe mouth sealed with silicone, this metal armored electric heating element can heat air, metal molds and various liquids;
Common electric heating tubes are finned electric heating tubes, finned electric heating tubes, finned electric heating tubes, Teflon electric heating tubes, quartz electric heating tubes, etc., which are cheap, easy to use, easy to install, pollution-free, and are widely used in various heating occasions.
1. The pipe body leaks
2. There is no obvious damage to the tube body, and the resistance value of the heating tube measured by a multimeter is 0, which must be broken
3. There are obvious holes, trachoma, cracking and bursting pipe phenomenon on the surface of the pipe body.
Measure two aspects with a multimeter ohmic file:
1, the resistance of the two outlets should be normal, 220V, 1000W about 48 ohms, 1500W about 32 ohms, and so on.
2. The (insulation) resistance of any outlet and the shell is more than a few megaohms. Those who can pass the above two steps are good.
Multimeters are relatively sophisticated instruments, and if used improperly, they can cause inaccurate measurements and are easily damaged. However, as long as we master the use of the multimeter and precautions, and exercise caution, then the multimeter can be durable. When using a multimeter, you should pay attention to the following:
1. The measurement current and voltage cannot be rotated in the wrong gear. If the resistance or current file is mistakenly used to measure the voltage, it is easy to burn out the meter. When the multimeter is not in use, it is best to rotate the gear to the highest level of AC voltage to avoid damage due to improper use.
2. When measuring DC voltage and DC current, pay attention to the polarity of "+" and "-", do not connect it wrong. If the hand is found to be reversed, the watch stick should be replaced immediately to avoid damage to the pointer and the watch head.
3. If you do not know the size of the voltage or current to be measured, you should use the highest gear first, and then choose the appropriate gear to test, so as to avoid excessive deflection of the watch needle and damage to the meter. The closer the selected gear is to the measured value, the more accurate the measured value will be.
4. When measuring resistance, do not touch the two ends of the naked body of the element (or the metal parts of the two watch rods) with your hands, so as to avoid parallel connection between the human resistance and the measured resistance, so that the measurement results are inaccurate.
5. When measuring resistance, if the two watch rods are short-connected, adjust the "zero ohm" knob to the maximum, the pointer still does not reach 0 point, this phenomenon is usually caused by insufficient battery voltage in the meter, should be replaced with a new battery to accurately measure.
6. When the multimeter is not in use, do not rotate in the resistance file, because there is a battery inside, if you are not careful, it is easy to make the two watch rods touch each other for a short circuit, which not only consumes the battery, but even damages the meter head in serious cases.