Analysis of the cause of roots blower failure

Friction between the rotor and the casing or rotor is a common problem in roots blowers, and if this problem is shown during operation, it may have serious mechanical vibration and noise. After a long period of shutdown, the roots blower frequently appears impeller jamming, and we sort out the main causes of the problem into the following categories.
(1) There is a problem with the gap between the rotor lobe and the hinge

There is a problem with the blade and hinge gap of the rotor, and the gap between the lobes and hinges changes during operation. When the two rotors rotate at low speeds, they collide, causing friction or even jamming between the rotors.
Once this mechanical failure occurs during operation, it will cause the two rotors or the rotor and the casing to collide, emitting a strong impact sound; The vibration becomes larger, and even the foundation can be vibrate; At the same time, the temperature of the friction part rises in a short period of time, and even the casing heats up and burns red.
(2) Bearing damage

Poor operating conditions of the fan, damage to the oil seal, and excessive assembly clearance will lead to bearing damage, and bearing damage will cause the temperature to rise, the temperature of the bearing seat will also increase, and the bearing seat will be deformed in serious cases.

Especially when the inner and outer rings of the bearing are locked, the bearing seat and the side cover plate are subjected to a large additional force, and the temperature will be very high, and the bearing seat and the side cover plate are heated unevenly, which causes the side cover plate to deform and crack in serious cases.

Shaft diameter wear, so that the shaft and the bearing inner ring clearance is too large, bearing seat wear makes the bearing seat and the bearing outer ring clearance too large, will cause rotor jamming or friction. In particular, the fan connected by the belt, the driving shaft is affected by the belt tension force, resulting in a large unidirectional force on the bearing seat, and the bearing seat of the belt side driving shaft is prone to unilateral wear.
(3) Gear wear

Gear wear and gear side clearance increase, which will cause the position of the two rotors to change, so that the hinge gap between the driving rotor and the driven rotor will become smaller, and the blade clearance will increase, causing the two rotors to collide and friction with each other.
(4) Deformation of the rotor or housing

If the rotor or housing is deformed, the gap between the outer diameter of the rotor and the casing will be too small, resulting in rotor friction and jamming.The gap between the end face of the rotor and the side cover plate is smallIf the gap between the rotor and the side cover plate is too small, there are debris squeezed into the rotor and the side cover; Or after the axial positioning bearing is worn, the axial channeling of the rotor becomes larger, which causes friction between the rotor and the side cover, causing the rotor to jam.