On the function of the rear check valve in cryogenic liquid filling pumps
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(ˇˍˇ) I’d like to ask an expert: what is the function of the check valve after low-temperature liquids (liquid oxygen, liquid nitrogen, liquid argon) are filled into a pump? Our company has a compressed air separation unit worth around 40,000 yuan. After liquid oxygen, liquid nitrogen, and liquid argon are filled into tanks, the residual liquid often freezes and damages the foundation of the ground. Therefore, we want to make modifications so that this residual liquid can be vaporized through return pipes and sent back to the storage tanks. However, there is one problem: the residual liquid between the check valve after the filling pump and the filling valve cannot be returned to the storage tanks. We plan to remove the valve core from this check valve, but we’re not sure what negative consequences this might have. We would appreciate it if everyone could help analyze this situation. :lol
The idea of returning it to the storage tank is not recommended, as it causes contamination of the tank and the costs outweigh the benefits.
:Lol, this check valve is mainly used to prevent the liquid inside the tank truck from flowing back into the pump, which could cause the pump to reverse! !
There is a drain between the check valve behind the charging pump and the charging valve. This drain is used to replace the filling pipeline every time the tank is filled. This check valve also prevents the gas inside the tank truck from flowing back into the pump, thereby avoiding pump reversal! !
As mentioned above, the main purpose is to prevent the pump from reversing direction; another consideration is the risk of contamination of the large storage tank by liquid from tank trucks in certain situations. It is recommended to install a return pipeline in front of the check valve. By the way, why wasn’t this included in the design? With this return pipeline, it is possible to perform pre-cooling via return flow, as well as to adjust the filling speed through return flow~~
Why not find a way to pump the liquid in the pipeline section behind the pump outlet valve into the tank truck? This wouldn’t overload the tank truck either; it’s a small amount compared to what would be lost if the liquid were discharged and caused damage to the foundation and ground. Water can be used to increase pressure through vaporization; it works well in the south over a long period of time, but not in the north during winter. It’s best not to remove the check valve; contaminating the large tank would be too costly, and there are precedents for this.