How to solve pipeline vibration
Thread Content
From the outlet of the pump at the bottom of the negative-pressure tower, the fluid flows to the heat exchanger for heat exchange before entering the tower again; the water temperature is still around 70°C. The 250 mm long pipeline experiences severe surge vibrations in this section – how can this problem be solved? Seeking advice.
Ensure there are no issues with the process operation by adding pipe supports.
It is likely that there is air in the liquid; improve exhaust, reduce the outlet valve to maintain pressure, and secure the pipes.
Is there an inverted U-shaped bend? If there is one, it is likely that the vibration is caused by air at the top of the inverted U-shaped pipe not being able to escape.
The pipeline should be fitted with additional support to ensure outlet pressure
Adding support is not an effective way to solve the problem; making adjustments is the key.
Adding support is useless; it’s the liquid shock inside that’s the problem, and the key to solving it is to reduce the liquid shock
The fluid temperature inside the pipe is high; when water comes into contact with low pressure, it vaporizes and bubbles are formed, resulting in liquid slugging
Solution: First, from a design perspective, select a pump type that can meet the net positive suction head available in the surrounding environment； Assume that the pipeline resistance is sufficient for the pump to operate properly ； The design takes into account the ability to remove the gas from within the pump (for example, by venting it to a reflux tank equipped with a vacuum pump). Second, the inlet pressure during operation should be slightly higher than the designed pressure ； Third, purge the gas from the pump before operating it ； Fourth, the pump must be sealed before starting. Fifth, secure the pipelines properly (cover the pipelines with thin asbestos sheets beneath the pipe clamps to enhance stability) ； Sixth, pipeline support load and pipeline stress design ； Seventh, the backflow control valve is installed near the backflow equipment to prevent the medium pumped by the pump from vaporizing.
It’s circulating water, right? The shock waves in the pipes indicate a problem: there is steam present, which means the water has been vaporized (the same principle as water hammer caused by steam condensation). In other words, a phase change has taken place. At this temperature, the most likely reason for such a phase change is that the pressure has reached the saturated vapor pressure of water. It’s recommended to check the process parameters first and adjust them accordingly. If the problem persists even after adjusting the process, then consider installing compensators; U-bends can also be used for this purpose.
It is recommended to add some kind of buffer device at the pump inlet, equipped with a vent valve