Turbomolecular

Turbomolecular refers to turbomolecular pumps, a class of high-vacuum pumps that use rapidly spinning blades to impart momentum to gas molecules, directing them from the inlet toward the exhaust. They are widely used to achieve high or ultrahigh vacuum in scientific instruments and industrial equipment.

Operation relies on a multistage rotor-stator arrangement. Each stage consists of angled rotor blades and stator blades that transfer momentum to gas molecules as the rotor spins at tens to hundreds of thousands of revolutions per minute. Gas molecules are progressively directed toward the exhaust, increasing the pump’s effective pumping speed at low pressures. A backing pump is required to remove gas from the system and maintain the pressure differential, with dry scroll or diaphragm pumps commonly used in dry systems.

Design and construction typically emphasize oil-free operation and low particle generation. Modern turbomolecular pumps often use magnetic or other non-contact bearings to minimize contamination and reduce wear. The drive motor is usually magnetically coupled or isolated, and the pump connects to vacuum hardware via standard flange interfaces. Inlet and exhaust handling, gas compatibility, and vibration control are important considerations, as performance depends on clean gas flows and minimal particulates.

Performance and applications: Turbomolecular pumps provide high pumping speeds in the high and ultrahigh vacuum ranges, generally down to the 10^-9 Torr level when paired with an appropriate backing pump. They are essential in electron microscopes, mass spectrometers, surface science setups, thin-film deposition systems, and semiconductor manufacturing equipment.

Advantages include oil-free operation and fast pump-down, while limitations involve sensitivity to particulates, dependence on a backing pump, and the need for controlled startup and maintenance.