The melt-blown process requires a large amount of hot air. The compressed air from the air compressor is transported to the air heater for heating after dehumidification and filtration, and then to the melt-blown die assembly. Air heater is a pressure vessel, and it should resist the oxidation of high temperature air, so the material must be stainless steel. The heating element of air heater is stainless steel electric heating tube. A plurality of baffles are arranged in the inner chamber of the heater, which can prolong the air retention time in the inner chamber of the heater and improve the heat exchange efficiency. Appropriately increasing the number of heating tubes and increasing the installed power of air heater can shorten the start-up time of production line. The precision of temperature control of draft air heater is required to be high in melt blown process, and the temperature of draft air should be stable in the range of (+) 1 C.

Working principle

A primary coil with more turns and a secondary coil with less turns are mounted on the same core. The voltage ratio of input to output is equal to the ratio of coil turns, while the energy remains unchanged. For large heating platform manufacturers, the secondary coil generates high current under low voltage conditions. For the induction heater, the bearing is a short-circuit single-turn secondary coil, which passes through a large current at a lower AC voltage, thus generating a great deal of heat. The heater itself and the yoke remain at room temperature. Because this heating method can induce current, the bearing will be magnetized. It is important to ensure that the bearings will be de-magnetized in the future so that they will not absorb metal magnetic debris during operation. The FAG induction heater has automatic de-magnetization function.

It uses the eddy current produced by metal in alternating magnetic field to heat itself. It is usually used in metal heat treatment and so on. The principle is that when a thicker metal is in an alternating magnetic field, it will generate current due to electromagnetic induction. When a thick metal produces current, the current will form a spiral flow path inside the metal, so that the heat generated by the current flow will be absorbed by the metal itself, which will lead to the rapid heating of the metal.

High temperature resistance wires are evenly distributed in seamless tubes of high temperature resistant stainless steel, and crystalline magnesia powder with good thermal conductivity and insulation performance is compactly filled in the gap. This structure is not only advanced, but also has high thermal efficiency and uniform heating. When current passes through the high temperature resistance wires, the heat generated diffuses to the surface of metal tubes through crystalline magnesia powder, and then transfers to the heated parts. Or in the air to achieve the purpose of heating.

Repair of folding failure

Failure 1: Digital display meter does not work.

Check whether the air switch is closed and the control circuit is in good condition.

Fault 2: Heater temperature does not rise.

Check whether the fuse is in good condition and the air heater is damaged.

Fault 3: Three-phase unbalance.

(1) Check whether the three-phase inlet voltage is missing.

(2) Open the protective cover of the air heater and check whether a single electric heating element is open with a multimeter.

Skilled technicians should be consulted (or the manufacturer) for troubles that cannot be eliminated by themselves.