Here are different pump mechanisms, the main ones listed for you:

• Scroll pumps are extremely robust and easy-to-handle vacuum pumps. They are particularly well-suited for a variety of applications, ranging from general laboratory and light industrial applications to specific chemical applications.
• Multi-stage rotary vane pumps have been specifically designed for use in quiet and clean environments such as analysis and research laboratories. They offer stable vacuum performance over many years without requiring maintenance.
• Diaphragm pumps have been designed, among other things, for use in laboratory operations in chemistry as well as for pre-pumping for (wide-range) turbomolecular pumps.