These Edwards nXDS gas ballast control knobs are used with the nXDS-i "standard" and nXDS-ic "chemical resistant" series dry scroll vacuum pumps. The gas ballast is a control valve that intentional introduces a small room-air leak into the second stage of the vacuum pump, producing a positive flow throughput, and sweeping out vapors from volitale compounds, such as, water and others. When pumping volitale compounds, like water vapor, they are compressed inside the pump and condense into a liquid. When condensation happens the ultimate vacuum pressure of the vacuum pump is now limited to the vapor pressure of the volitale contamenting compoud, for example, the room temperature vapor pressure of water is around 23.8 Torr. The gas ballast should be opened while the pump is warmed up to help evaporate and sweep out the volitale vapors. It is often good to leave the pump running overnight with the gas ballast open to rid it of volitale compounds. The gas ballast should not be used when pumping flamable, as the gas ballast introduces air which contains oxygen. The gas ballast should also not be used when pumping toxic compounds, as the gas ballast introduces a leak into the room air, if the pump is turned off, a small amounts of vapors from inside the pump could potentially leak out through the gas ballast port into the room air. These replacement Edwards nXDS gas ballast control knobs have part number A735-01-759.

Works With Edwards nXDs Series Dry Scroll Vacuum Pumps:

• Edwards nXDS6i
• Edwards nXDS10i
• Edwards nXDS15i
• Edwards nXDS20i
• Edwards nXDS6ic "Non-Flamable and Non-Toxic Gases"
• Edwards nXDS10ic "Non-Flamable and Non-Toxic Gases"
• Edwards nXDS15ic "Non-Flamable and Non-Toxic Gases"
• Edwards nXDS20ic "Non-Flamable and Non-Toxic Gases"