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Which is better for positive and negative pressure of fan blades?

Update:01-11-2019
Summary:

  Although we have always suggested that the fan b […]

 

Although we have always suggested that the fan blades of industrial fans should not be colored, because the color of the fan blade surface will be easy to fall off after a long time, but in some specific scenarios, such as focusing on commercial occasions, there will still be customers requesting fan blades. Coloring is performed, that is, electrostatic spraying is performed. However, electrostatic spraying is divided into positive pressure and negative pressure. Which one is used for industrial fan spraying?

In theory, both positive and negative corona can be used for powder charging. However, electrostatic spraying of industrial fans mostly uses negative corona, because the breakdown voltage of the positive corona is lower, the corona current is relatively smaller, and the charging efficiency is low; and the initial potential of the negative corona discharge It is lower than the positive polarity, and the corona discharge formed is relatively stable, and it is not easy to break down, and it is easy to grasp and use. Therefore, negative polarity (negative high pressure) electrostatic spraying is often used in industrial fan blade coloring.

When performing negative high pressure spraying, the generator must be grounded during use. If the sprayer is not grounded during use, it will accumulate on the equipment casing (including the gun casing) when excessive static electricity cannot be released through the ground. It will make the spraying operator feel the electric shock when taking the gun, so that he does not dare to hold the gun and cannot spray normally. At the same time, excessive static electricity is also likely to cause damage to the electronic components of the voltage doubler, which shortens the service life of the equipment.

Therefore, in summary, when the fan blades of industrial fans are sprayed, negative polarity (negative high voltage) electrostatic spraying is used, and the generator must be grounded during use.

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