The pump is conveying liquid or causes the liquid turbo-charged machinery. It transmits the mechanical energy or other external energy transmitted to the liquid, causes the liquid energy increase, mainly used for conveying liquid, including water, oil, the sour lye, the emulsion, hangs the emulsion and the liquid metal and so on, also may transport the liquid, the mixture of gases as well as contains the suspended solid liquid. The technical parameters of pump performance can be measured in flow, suction, head, shaft power, water power, efficiency, etc.; According to the different working principle can be divided into volume pump, vane pump type, etc. Positive displacement pump is to use the studio volume changes to deliver energy; Vane pump is the use of rotary vane interaction with water to deliver energy, such as centrifugal pump, axial flow and mixed flow pump type.
One, the water pump vibration cause analysis
1, 28 sla - 10 domestic vertical water pump is composed of horizontal pump direct transformation. Motor base and the pump base between the vertical height of 4.3 m, the shaft is weighed 3 t. relative to the horizontal pump, it increased the root length is 3752 mm diameter is 140 mm in the middle of the shaft. On the structure, in addition to adding a bearing on the shaft in the middle, without any modification. The four pumps operating pressure is 0.7 ~ 0.85 MPa for a long time. Under high head and large flow conditions, such a high center of gravity, quality system at high speed, the centrifugal force is very big, will cause the vibration of large unit. Combined with stent and the water pump in and out of the water direction connection stiffness is insufficient, lead to the pump and the fittings have larger displacement. Runtime pumps on the displacement cause of the bearing force change, vibration increase, so easy to fever. If the correct pump displacement, improve bearing force condition, can reduce the system's vibration intensity.
2, for the rigid connection between pump and the shaft. Due to manufacture, installation, operation when the pump shaft and the shaft concentric, cause water pump vibration; Motor, drive shaft and other source of vibration is passed directly to the pump, the form of vibration superposition, further strengthen the pump vibration. In addition, such a rigid connection increase water pump bearing on the external force, the bearing is easy fever, affect the pump shaft.
Second, the transformation
For these reasons, we adopted the following two steps.
1, strengthen rigidity pipeline. Considering of the pump as it is difficult to reinforce adopted in the pump export steel pipe welding "reinforcement" way. Along the direction of in and out of the water, the water pump outlet divergent tube and the water valve flange on both ends of the connection between the steel tube, with eight is 32 mm, width is 100 mm thickness steel plate welding. Increase the stiffness of the steel tube, reduce the deformation and resistance to water pump displacement. Measured, after reinforcement, the pump displacement of point A dropped to 0.35 mm.
2, to modify the transmission system. To reduce the vibration of the motor, transmission shaft to the water pump, changing the rigid connection between the pump and the shaft to elastic connection. Use GB4323-84 column elastic sleeve pin couplings, centrifugal pump maximum compensation displacement is 0.6 mm, the compensation Angle of 1 ° 30? . In this way, motor, the vibration of the shaft can be obtained by elastic coupling compensation, not directly to the pump.
Three, reconstruction results
After modification, measured, pump vibration by the vibrating velocity of 4.3 cm/s lower before modification is 1.48 cm/s. can decide according to the vibration intensity ISO2372-1974 standard, the pump running in a good area. Smooth operation, at the same time, water pump, bearing on the normal maintenance, also did not have the pump shaft is wear phenomenon, explain the transformation was a success.
Hydraulic ejector is outlined
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