VACUUM SCIENCE BLOG

Multistage roots pumps are dry vacuum pumps used in low, medium, high and ultra-high vacuum systems to produce “dry” conditions. The simple (single-stage) roots pump is most commonly employed as a booster pump for several types of fore-pumps (such as rotary vane pumps, screw and liquid ring pumps) to improve ultimate pressure and pumping speeds. When multistage roots pumps are employed, no fore pump is required and they can operate from atmospheric pressure. Roots pumps are suitable where a dry and clean atmosphere is important or more likely essential. Consequently, they are frequently used in the manufacture of semiconductors and solar panels, as well as for coatings and other industrial applications.

Vacuum simulation (or modelling) is an essential part of vacuum system design. It is now a well-established practice and is primarily concerned with the prediction and calculation of how vacuum pumps and systems will perform in specific scenarios. These simulations enable engineers to identify anomalies in the design stage and acquire the right components, rather than building a vacuum system that later needs to be redesigned.

For a vacuum pump system, a vital consideration in its design is the conductance. Conductance in vacuum systems is the characteristic of a vacuum component or system to readily allow the flow of gas and can be thought of as the inverse of resistance to flow. Its units are that of the volumetric capacity of gas flow in a passive component (or aggregate component of a vacuum system), such as an opening or a pipe, divided by time.

When working with high vacuum (HV) and ultra-high vacuum (UHV), there are specific aspects to consider to ensure an efficient and safe system. To clarify, the pressure range of UHV conditions are defined as between 10-7 and 10-12 mbar, whereas HV conditions are defined as between 10-3 and 10-7 mbar. Some of the main applications of HV include metallurgical processes, nuclear physics, space simulation and analytical instruments. On the other hand, UHVs are used for surface analysis, in high-energy physics and Molecular Beam Epitaxy (MBE).  In this blog, we discuss the three main considerations you need to bear in mind when working under HV or UHV conditions.

working principle  Turbomolecular pumps (TMPs) are kinetic vacuum pumps which operate using a very fast spinning rotor (usually rotating at between 24,000 and 90,000 RPM). Their typical operating pressures are in the high to ultra-high pressure range between 10-3 and 10-11 mbar, employing pumping speeds of between 10 and 4,000 l/s.

Wherever and whenever a vacuum needs to be created, it is essential to ensure its integrity (i.e. the “tightness” of the system). If the system is not tight, then time is squandered and effort is pointlessly spent trying to create a vacuum in an “open system” which could never support a vacuum in the first place. 

Described as ‘a space in which the pressure is below surrounding atmospheric pressure’, vacuum science is a subject and concept that has stimulated many great minds for millennia. The origins of vacuum science can be traced back to as early as the 4th century when Aristotle stated that ‘nature abhors a vacuum’.