Gear pump noise and instrumentation issues
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This post was last edited by uenpyvhu on 2019-8-23 at 11:12. The unit’s oil transfer system uses a KGB-300 type gear pump; the nameplate is shown in the attached image. The length of the oil inlet pipe varies depending on the location of the product. When the pipe is short, the noise level is very low, but it becomes high when the pipe is long – the maximum length of the pipe is 70 meters. The pipes are all laid horizontally, with the gear pump positioned about 1 meter above them. In my opinion, the reason for the noise is the excessive length of the oil inlet pipe. I’m not sure if this is correct; if so, how can this issue be resolved? Can a booster pump be added at the middle of the oil inlet pipeline? What type of booster pump is better to choose? Another question is, what does the required net positive suction head of 5 meters for gear pumps mean? Is the maximum suction pressure 0.5 MPa? If that is the case, what range should the vacuum gauge for the inlet pipe have? I’m a complete novice when it comes to gear pumps; I hope experienced users will be kind enough to offer their guidance
This post was last edited by uenpyvhu on 2019-8-23 10:38
The longer the pipeline, the greater the pipeline losses, which can lead to insufficient suction at the inlet! Although gear pumps are a type of positive-displacement pump and do not cause vacuum, doing this will affect the proper operation of the pump.
Try increasing the inlet pressure, raising the oil temperature, or lowering the pump’s installation height; or install a new pump with a higher head starting from 70 meters to modify the flow process
Increase the inlet pressure, or add a horizontal expansion bend
The requirement of a NPSH of 5 meters means that, under normal atmospheric pressure, it is theoretically possible to draw water up to a height of 10 meters; therefore, this pump can only lift water up to a height of 10 – 5 meters
Should another pump be added at the middle of the oil inlet pipeline, for example, 50 meters away from the gear pump? What type of pump should be used? Can a vortex pump be used?