Currently there are a wide variety of industrial vacuum pumps available to suit most applications. Oil-sealed pumps have been a workhorse in the industrial markets for decades, but more applications are seeing the benefits of dry vacuum pumps in both performance and maintenance costs.
Oil-sealed pumps – rotary vane, piston, and flooded screw – are reliable and durable when maintained as required. The mechanisms are simple and routine maintenance can be accomplished without having to send the pump back to a rebuilder. These pumps perform well from atmosphere to base pressures and adapt well to booster pumps for increased capacity and range. On the contrary, management of waste oil from the often frequent changes can be a problem as it can contain toxic materials that must be handled carefully. As the pumps get older, spare parts and service can become more difficult to find. However, there are a few sources that can provide parts and materials to squeeze a bit more time from an “old reliable” pump that’s reaching the end of its lifecycle.
Dry pumps also perform well from atmosphere to base pressures but not with the same consistent flow that you’d get with wet pumps. Dry pumps minimize contamination of the process from oil and other chemistries, keeping the product chemistry pure. Dry pumps can also be fitted with booster pumps to achieve higher capacities and wider vacuum ranges. One distinct advantage is the absence of oil in these mechanisms. Any lubrication is normally contained away from the pump swept volume and is less susceptible to contamination. Oil changes are less frequent and capacities on these pumps are smaller than similar sized oil-sealed pumps. Maintenance is usually reserved to oil changes but overhauls for bearing changes require specialist tools and know-how. Which type of pump you choose depends on the aspects that cause the most pain – is it performance or maintenance?