Centrifugal pump outlet buffer tank
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Every time a barrel is filled in the company’s barrel-filling workshop, once a barrel is full and the pneumatic valve shuts off the pipeline, vibration in the pipeline occurs. This is because the filling pump is designed to draw the fluid from the tank and send it to the barrel-filling machine; the barrel-filling machine represents the end of the pipeline, and thus a complete cycle back to the tank is not established. As a result, when the pneumatic valve of the barrel-filling machine is closed, the pump operates as if its outlet is closed. Although this situation lasts for only a short time, the vibration in the pipeline is quite severe. The measure taken now is to install fixing brackets, but the effect is not very noticeable. The manager wants to add a buffer tank between the barrel filler and the pump outlet in order to address the pipeline vibration that occurs after the pneumatic valve of the barrel filler is closed. I wonder if any of you sea friends have had similar experiences? ? ? ! ! ! Reciprocating compressors and reciprocating pumps have buffer tanks at both the inlet and outlet, but these are mainly used to address pulsation at the outlet ； But centrifugal pumps do not have similar experience.
First of all, I would like to correct that the proper procedure for shutting down a centrifugal pump is to close the pump’s outlet valve first and then shut off the pump itself. Similarly, when starting the pump, one should first turn it on and then open the outlet valve; there is a brief period during which pressure builds up. Could the shaking of your pipelines be due to the pump not being properly secured?
This is considered a minor water hammer effect: the pneumatic valve closes, the pump continues to operate, the outlet section becomes blocked, pressure rises, and oscillations occur. A branch pipe is connected on the pump outlet pipeline to the tank at the pump inlet.
Such phenomena are due to inertial momentum! Impact force is the inertial momentum of the fluid. That is the outlet pulsation phenomenon you see. Such problems can be initially resolved through operational measures: close the pneumatic valve slowly, rather than quickly, thereby avoiding the inertial momentum of the fluid. Regarding the pressure buildup issue mentioned by the poster, it doesn’t matter if the centrifugal pump is driven by an inverter-driven motor ； If it is not an inverter-driven motor, a buffer tank needs to be installed. Reconsider the specific structure of the buffer tank.
A low-flow return line should be added to the pump.
The pump is fixed properly. It’s the vibration of the pipeline
I would like to add here that a high frequency of material impact can cause fatigue failure in the pipeline welds and supports. If the pipeline is less than 50, there is no need to install any equipment; if it is greater than 80, then it is necessary to consider adding equipment or carrying out technical upgrades.
This situation is similar to the constant-pressure water supply system used in residential areas; a pressure tank can be connected in parallel at the pump outlet to serve as a buffer and for energy storage. Pressure sensors are used to control the start, stop, and operation of the pump.
The correct procedure for shutting down a centrifugal pump involves closing the pump’s outlet valve first and then turning off the pump itself. Similarly, to start the pump, one must first turn it on and then open the outlet valve; there is a brief period of pressure buildup during this process. As long as the pipes are properly secured, there should be no problems.
Normal pump shutdown is a manual process and is relatively slow, while bucket fillers use pneumatic valves, allowing for a much faster speed.
Consider installing shock absorber joints as well as expansion joints.