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The reverse rotation of roots blower will lead to failure. How to solve it?

Source: Roots blower manufacturer Published on: March 4, 2022 Hits:

Roots blower Why is it reversed? For boilers equipped with two forced draft fans or two induced draft fans, because the inlet guide vanes are not tight, one fan is in operation and the other standby fan is in reverse. Dang Roots drum What to do if the fan reverses?

Roots drum Fan reversing is because the rotation direction of the impeller is opposite to the direction of the rotating magnetic field of the motor nail, the starting current is larger, and the inertia of the impeller is much larger than that of the static one, so that the current and time for fan starting exceed the action current and time set by the current relay for motor safety, so the reversing fan cannot be started. To start the reversing Roots blower, first stop the reversing impeller, for example, add a barrier at the inlet of the reversing blower, or use external force to stop the rotation of the impeller before starting.

Roots blower is not allowed to suddenly reverse in the case of positive transmission. The fan is suddenly powered off or the fan gear and coupling are broken due to the reverse rotation of the fan caused by the pressure return of the outlet, forward inertial rotation and outlet backpressure. In serious cases, the rotor or the whole fan may be damaged. The reversing rotor of the former two blade fan will be broken immediately, and the three blade roots drum The gear of the fan will also be damaged.

Generally, Roots drum The fan can be reversed, but it will start when the fan stops. In case of long-term reverse operation, the fan shall be adjusted for the front and rear end clearance before leaving the factory. Sudden power failure of the fan or reverse rotation of the fan caused by pressure return of the air outlet, forward inertial rotation and outlet back pressure may break the fan gear and coupling, or even the rotor or the whole fan may be damaged in serious cases. Therefore, it is generally required to disconnect from the original pipe before reversing, and the reversing can only be performed after the fan is completely stopped. When the fan is powered off and trips, the rotor and coupling are always broken. It is better to install a check valve in front of the fan outlet or at the fan outlet to prevent the impact of back pressure in the pipeline on the fan itself.

Resolve Roots drum The way to reverse the fan is to install a check valve and ensure that the check valve can be closed safely. In general, Roots drum The fan can be reversed, but it must be started when the fan stops. In case of long-term reverse operation, the fan shall be adjusted for the front and rear end clearance before leaving the factory. For the fan blade reversal caused by sudden power failure, the Roots blower tripped after power failure, and the rotor and coupling were always damaged. The solution is to install a check valve in front of the fan outlet or at the fan outlet to prevent the back pressure in the pipeline from affecting the roots fan itself.

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