The closing pressure of the nitrogen seal valve should be less than 75% of the set pressure value of the breather valve
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Which specification states that the closing pressure of the nitrogen seal valve should be less than 75% of the set pressure value of the breather valve? Or what could be the reason? Could someone explain this to me? Thank you
It’s similar to the SV value of a control valve – it can be adjusted at any time; an initial value is sufficient, and adjustments can be made during actual use. Such considerations are mainly due to the fear of overpressure; the damage caused by overpressure to storage tanks is likely to be much greater than the harm resulting from negative pressure. But on the other hand: under normal conditions, you’ll find that the pressure can be kept quite stable; however, in the event of sudden heavy rainfall, it may increase rapidly and there won’t be enough time to compensate for it.
Thank you very much. Also, I would like to ask whether there is any specific standard that outlines this clearly
Generally, when a nitrogen seal valve and a vent valve are used together, if the pressure on the secondary side of the nitrogen seal valve is 0.5 KPa, the discharge pressure of the vent valve is usually set at 0.8–1.0 KPa. The vent valve starts to function at around 80% of this pressure; when the pressure remains consistent with or slightly lower than that of the nitrogen seal valve, the vent valve will keep operating. For outdoor storage tanks, certain variables and safety values are taken into account, so that extreme weather conditions causing temperature differences do not result in the nitrogen seal valve not having enough time to replenish the gas. Additionally, there is also the protection provided by the vent valve