Tech Tip 7: Rotary Pump Maintenance | Oil changes & use of the Ballast Valve
Most GC-MS vacuum systems comprise of a two-stage pumping arrangement – an initial low-vacuum, high capacity stage consisting of a rotary oil pump or diaphragm pump; and a second high stage, low capacity vacuum pump such as a diffusion or turbo-molecular pump. The first stage or low-vacuum pump requires maintenance to ensure optimum pumping performance. Two aspects that are often overlooked are the use of the ballast valve on the vacuum pump and replacement of the pump oil at the correct intervals.