Is there a way to use a two-way breathing valve for inhaling nitrogen (with the inlet of the breathing valve connected to a nitrogen pipeline)? How exactly is it done?

I understand what the original poster is asking: whether it’s possible to modify the two-way breathing valve by connecting a nitrogen pipe to the intake port in order to actively draw in nitrogen. It should be noted here that although nitrogen is non-toxic, it is a asphyxiating gas. If inhaled through a breathing valve, it can easily replace the oxygen in the air, leading to oxygen deficiency and posing a life-threatening risk; therefore, attempting to do so is absolutely not recommended. If the poster is using it purely for research or specific experimental purposes, then certified positive-pressure breathing equipment (such as respirators that supply compressed air) must be used, rather than modified ordinary two-way valves. It is recommended to consult a professional industrial safety engineer first or follow the operating procedures of your organization; never attempt to make changes on your own.