In the damage of the parts of the single-acting water ring vacuum pump, the damage of the shaft occupies a large proportion. Damage to the pump shaft includes bending, cracking and breaking.

The reason for the bending of the pump shaft is mostly due to the insufficient rigidity of the sleeve and the large unbalance of the impeller, which is caused by deformation during operation.

The cracked and broken parts of the pump shaft often occur in places where local stress is concentrated, such as the edge of the keyway, the sudden change of diameter, etc. The cause of damage is often due to vibration-induced fatigue failure.

If the pump shaft has fatigue cracks (a precursor to breaking), it should be replaced in time. If it is necessary to continue to use due to objective factors that cannot be replaced temporarily, the temporary remedy is to repair the crack. When using the pump shaft after repair welding, always pay attention to the changes in the repair welding area to avoid accidents.

When the single-acting water ring vacuum pump is in use, the frequent failure is the breaking of the pump shaft (especially the pump with larger air volume). The broken section is generally perpendicular to the axis line, very neat like a knife cut, most of the entire section is smooth and metallic luster, and a small part is rough. Obviously, this is the fracture characteristic caused by fatigue failure.

The main reason for fatigue damage is that the force of the gas in the pump cavity on the pump shaft is caused by the force of the pump shaft during operation, which is also called radial force.

The fatigue damage of the pump shaft, in addition to the fundamental cause of the radial force in the water ring vacuum pump, the unreasonable structure is also an important reason that cannot be ignored.

The general water ring vacuum pump shaft has not undergone heat treatment, so the fatigue strength is low. In order to prevent breakage, the pump shaft should at least undergo quenching and tempering treatment, and nitriding treatment should be carried out where conditions permit.

When designing, it is necessary to avoid too large abrupt changes in the cross-section. Instead of sharp corners at transitions, fillet connections are applied. The surface finish should not be too low, especially where the shaft is easily broken. During processing, the circumferential processing at the transition of different shaft diameters must ensure the quality, and be carried out in strict accordance with the size and finish required by the drawings. The surface of the pump shaft and the transition should not have knife marks, scratches, bumps and other defects.

The fatigue damage of the pump shaft is very harmful to production and is a problem that users are extremely concerned about. The solution is to check the fatigue strength of the pump shaft according to the magnitude of the radial force. When using corrosive gases and liquid rings, use corresponding corrosion-resistant materials. The pump shaft must be quenched and tempered, and must be processed during processing. To ensure quality and so on.