A: Generally speaking, nitrogen is not too dangerous, but the pressure you fill should not exceed the withstand pressure of the furnace. If you connect between the nitrogen cylinder and the furnace body with not a metal pipe but a general hose pressure pipe, first open the valve between the pressure reducing valve and the furnace, and then open the pressure reducing valve, because the general pressure hose only has 15 kg of pressure resistance, if it is connected with the cylinder and does not enter the furnace, I am afraid of bursting the pressure pipe.