Cause analysis and solution for pump vibration

A water pump is a machine that delivers or pressurizes a liquid. It transfers the mechanical energy of the prime mover or other external energy to the liquid, and increases the energy of the liquid. It is mainly used to transport liquids including water, oil, acid and alkali, emulsion, suspoemulsion and liquid metal, and also to transport liquids and gas mixtures. And a liquid containing suspended solids. The technical parameters for measuring the performance of the pump include flow, suction stroke, lift, shaft power, water power, efficiency, etc.; according to different working principles, it can be divided into volume pump and vane pump. The volumetric pump uses its change in the volume of the working chamber to transfer energy; the vane pump uses the interaction of the rotating blades with water to transfer energy, such as centrifugal pumps, axial pumps and mixed flow pumps.
First, the pump vibration analysis of the reasons 1, the domestic pipeline centrifugal pump ISG is directly transformed from the horizontal pump. The vertical height between the motor base and the pump base is 4.3m, and the drive shaft weighs 3t. Compared to the horizontal centrifugal pump, it adds an intermediate drive shaft with a length of 3752 mm and a diameter of 140 mm. Structurally, no modifications were made except for the addition of a bearing to the intermediate drive shaft. The operating pressure of the four centrifugal pumps is 0.7 to 0.85 MPa for a long time. Under the conditions of high lift and large flow, such a system with high center of gravity and high mass rotates at high speed, and the centrifugal force generated is very large, which will cause large vibration of the unit. In addition, the joint rigidity of the bracket and the water pump in the direction of water inlet and outlet is insufficient, resulting in a large displacement of the water pump and each connecting piece. The displacement of the centrifugal pump during operation causes the upper bearing to change its force condition, and the vibration is increased, so it is easy to generate heat. If the displacement of the centrifugal pump is corrected and the bearing stress condition is improved, the vibration intensity of the system can be reduced.
2. A rigid connection between the centrifugal pump and the drive shaft. Due to manufacturing and installation reasons, the pump shaft is concentric with the drive shaft during operation, causing the pump to vibrate; the vibration generated by other sources such as the motor and the drive shaft is also directly transmitted to the water pump to form a superposition of vibrations, further increasing the vibration of the pump. In addition, this rigid connection increases the external force on the bearing on the water pump, causing the bearing to be prone to heat and affecting the pump shaft.

Second, the pump vibration solution analysis For the above reasons, we have taken the following two steps to transform.
1. Strengthen the rigidity of the pipeline. Considering that it is difficult to reinforce the centrifugal pump, the method of welding the "reinforced ribs" at the outlet of the centrifugal pump is adopted. In the direction of the inlet and outlet water, the flanges at both ends of the connecting steel pipe between the centrifugal expansion pump outlet and the outlet valve are welded by 8 steel plates having a thickness of 32 mm and a width of 100 mm. Increase the rigidity of the steel pipe, reduce the amount of deformation, and resist the displacement of the pump. After measurement, after the reinforcement, the displacement of the pump A point is reduced to 0.35mm.
2. Transform the transmission system. In order to reduce the vibration of the motor and the drive shaft to the water pump, the rigid connection between the water pump and the drive shaft is changed to an elastic connection. The GB4323-84 elastic sleeve pin coupling is used. The maximum compensation displacement of the centrifugal pump is 0.6mm and the compensation angle is 1°30?. In this way, the vibration of the motor and the drive shaft can be compensated by the elastic coupling and will not be directly transmitted to the water pump.
Third, the pump vibration solution results After the transformation, after the measurement, the pump vibration was reduced from the vibration speed of 4.3cm / s before the transformation to 1.48cm / s. According to the vibration intensity standard ISO2372-1974, the pump operation is in an excellent area. At the same time, the pump runs smoothly, the upper bearing only needs normal maintenance, and the pump shaft is worn out, indicating that the transformation is successful.

Wolfberry Juice Vermicelli Bag

Wolfberry Juice Vermicelli Bag,Wolfberry Juice Vermicelli Plastic Bag

Ningxia ZhaiXianSong Commercial and Trading Co.,Ltd. , http://www.nxupin.com