Our company has two French Cryostar LNG cryopumps, but the pumps do not generate pressure as liquid flows from the LNG storage tank in the direction of loading.
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Our company has two French Cryostar LNG cryopumps. However, once the pumps are started, from the LNG storage tank towards the loading direction, no pressure is generated, which prevents the LNG from being loaded into the vehicles. The liquid coming out of the LNG storage tank flows into the pre-cooling pump; the temperature of the pump is sufficient, but still no pressure is produced. The liquid level in the LNG storage tank is also sufficient.
The pipeline distance from the tank to the pump is too long; change the pipe.
It’s probably still due to excessive vaporization. Additionally, it is recommended to check whether there are any \"air pockets\" in the piping.
We encountered this situation before; we just changed the pipes and moved the pump closer to the tank, and that solved the problem.
One possibility is cavitation; another could be the impact on the medium-sized machine itself after maintenance, or an improper sealing.
If the pipeline is not a vacuum tube, it needs to have insulation measures
If there is no U-turn, it’s likely that the pipeline between the pump and the storage tank is too long. We encountered the same issue in one of our previous sites; by moving the pump below the storage tank, the pump was able to generate pressure successfully. If it is a pressurized tank, one could try increasing the pressure first before starting the pump, but doing this every time results in excessive vaporization, which is not cost-effective. It is still recommended to completely eliminate this pipeline issue.
It has already been produced; it’s definitely impossible to change the pipes now!
Make sure to check the insulation properly; if the pipelines are too long, inadequate insulation may lead to cavitation.
1. Verify whether the pump’s net positive suction head meets the requirements. 2. Check whether there is an air pocket at the pump inlet, which could cause air locking of the pump. 3. If it is a low-temperature barrel pump, ensure that the liquid level in the pump barrel and the exhaust from the pump barrel meet the requirements.
1. Is the frequency of the variable-frequency pump being increased?； 2. Circuit wiring ； 3. Pump cavitation.