The most important decision to make is to decide whether you have to protect the process from the pump, or vice versa. When the oil vapor or migrating hydrocarbon is too much for the process to handle, it’s just reasonable to protect it from the pump. The oil can move or migrate to the chamber in two ways: either by surface creep along the walls of the pump line or by backstreaming of vapor into the pump chamber. On the contrary, when the process generates gases that will negatively affect the oil of the pump, it’s important to protect the equipment from the process itself. But this scenario alone is not a solid ground to make the shift to an oilless vacuum pump right away.
Both the oil-sealed or lubricated rotary vane and rotary piston vacuum pumps have been refined and where improvements allow for diminishing returns. The application must be carefully analysed first to know if an oilless vacuum pump is really necessary and more beneficial for the entire operation. The inclusion of ancillary equipment or quick change in operating method can provide sufficient protection against contamination, discounting the need for replacement. But if the process won’t allow any of the possible protection options, including those two mentioned, then the final decision to opt for an oilless vacuum pump has to be made.