UNIWELD NV1 NitroVue simplifies the purging of nitrogen during the brazing of copper tubing in Air Conditioning and Refrigeration systems with an "easy" to read flow indicator label and a precision adjustable valve to control the low flow of nitrogen gas. The bright orange float ball and tube are fortified and protected in the aluminum body with wide open windows for a clear view. The easy to see orange float ball visually confirms the nitrogen is flowing and allows the technician to first "PURGE" the copper lines at 20+ scfh and then reduce the flow to "BRAZE" at 3-5 scfh during the brazing process thus conserves its consumption and reduces operating cost. The nitrogen must be flowing to displace the oxygen inside the tubing during the brazing process, preventing internal oxidation and the resulting scale. Scale build up inside the tubing can cause blockage in the TXV and within the Air Conditioning and Refrigeration system resulting in premature failure. If the ball does not rise in the tube there is no flow of nitrogen only static pressure and oxygen is not being displaced. The NV1 must be connected to a Nitrogen Regulator with the delivery pressure set at 60 PSI to control the nitrogen gas pressure. The NV1 is protected from over pressure with a reseatable safety blow off that opens at 200+ PSI.