Issues with the check valves installed on the nitrogen pipelines used for driving or zero-hour purging
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Issues with setting up check valves on the nitrogen pipelines used for driving or zero-hour purging? Now it's the front valve, blind flange, backflow preventer, and rear shut-off valve. Do you need to add a check valve? The process gas pressure is higher than that of nitrogen.
A check valve is a safety measure; you can’t be sure that the pressure in the nitrogen pipeline will always be higher than that of the process medium, for fear that the process medium might enter the nitrogen pipeline
Since it is intended for use in driving the process or for zero-hour purging, it is not necessary to install a check valve; instead, a blind flange can be used directly or a three-valve assembly – “two valves and one drain valve” – can be employed.
Installing a vent between the two valves can prevent process gas from flowing back into the nitrogen pipeline network. However, I still recommend installing a check valve as a precautionary measure, as some accidents are impossible to predict. I have requested that a check valve be installed on one of the safety nitrogen branches~