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Tubular heating element basics and structure

1. What is the heating part of electric heater?

Electric heater heating body is resistance heating wire, the main ones are iron-chromium aluminum (Cr25A15) and nickel-chromium alloy wire (Cr20Ni80). The price of iron-chromium aluminum is relatively cheap, generally no special instructions, electric heaters are usually used in the iron-chromium aluminum alloy heating wire. Nickel-chromium alloy wire is more expensive.

The difference between iron-chromium-aluminum (Cr25A15) and nickel-chromium alloy wire (Cr20Ni80): the iron-chromium-aluminum system of alloy materials can reach a working temperature of 1400 ℃, enough to meet the needs of electric heating tubes. But nickel-chromium wire flexibility and oxidation resistance is better.

2. Is the surface of the electric heating tube electrically charged?

We all know that the heating body electric heating wire is charged, so the surface of the electric heating tube charged? The answer is no. Electric heating tube is because the surface is not charged, so it is widely used in heating liquid.

So why is the surface of the electric heating tube is not charged? That is because the gap between the electric heating wire and the electric heating tube shell is generally filled by magnesium oxide powder, magnesium oxide powder filling both insulation and thermal conductivity is very good.

3. How to ensure that the internal insulation of the electric heating tube does not absorb moisture?

We know that the electric heating tube due to insulation filler makes the surface of the electric heating tube is not charged, so how to do the internal insulation of the electric heating tube does not absorb moisture?

First, choose high purity modified magnesium oxide powder (insulating filler).

Second, that is, the electric heating tube port to use the proper sealing (as for how to choose the electric heating tube sealing material, we will further detail later).

4. The difference between electric heating tube and electric heating wire?

The main difference between electric heating tube and electric heating wire is that the surface of the electric heating tube is not charged, and the surface of the electric heating wire is charged.

The reason we have explained above, then this issue, I want to expand the difference between electric heating tube and electric heating wire is also that the electric heating tube is a metal tube sheath, the main one is stainless steel (SUS201, 304, AISI321, 316L, 310S, etc.), purple copper, carbon steel.

According to the different working environment choose different metal sheath tube. From this point, we can get the electric heating tube basic structure of four: metal tube sheath.

Electric heating tube basic structure we can understand through the following picture：

In addition to the 4 main aspects introduced above, from this diagram, we can also see that the basic structure of the electric heater also includes: insulators, lead rods, terminals and other components.