VACUUM SCIENCE BLOG

As applications using vacuum technologies evolve and become ever more precise, the vacuum systems and pumps used have even less margin for error than ever before. In every operation that uses vacuum – particularly where incredibly precise instruments are involved (R&D, mass spectrometry) – the preservation of the vacuum is of the utmost importance.

The reality is that unforeseen problems in a vacuum can be catastrophic for the process, the environment and the operator, and one which can prove tricky is a vacuum leak.

Given the situation with COVID-19, many questions are being asked about how vacuum technology (specifically mass spectrometers) can help with health diagnostics and research.

With this in mind, in this short blog we’ll explore how mass spectrometers can be used in the medical field to tackle pandemics like COVID-19.

Oil diffusion pumps have been the workhorse in high-vacuum pumping for many decades and remain the standard for industrial applications like brazing/soldering, E-Beam welding and large-area coating. Their investment costs are relatively low, and they can provide pumping speeds of up to 50.000 l/s. In this blog, we will explain the working principles of oil diffusion pumps, including how to apply and control them in vacuum systems, the typical dos and don'ts, and provide several application examples.

According to the Union of Concerned Scientists (UCSUSA) about 2,200 active satellites orbit our planet and an additional 100 are launched every year. Most of these satellites are used for telecommunication and, with GPS projects like the European GALILEO and the SPACE-X Starlink (which intends to bring internet connection to every spot on earth) on the horizon, their number will continue to grow.

Secondary pumps require a primary pump to initially ‘prime’ them for operation and/or to support their continuous operation. There are several factors which need to be considered for the correct combination or ‘matching’ of primary and secondary pumps to ensure safe and optimized performance.

Cryopumps offer several advantages compared to other high-vacuum pumps. For instance, their pumping speed for water vapour is up to 4x higher than any other vacuum pump with the same inlet diameter. Furthermore, unlike gas transfer pumps, i.e. turbomolecular pumps or oil diffusion pumps, cryopumps condense all the gasses within them. The goal of this blog is to explain to you how they operate and where their capabilities are beneficial to the vacuum process. 

Screw pumps belong to the family of dry compressing gas transfer pumps. (Learn more about the origins of dry pumps here) They are positive-displacement pumps that use two screw shaped intermeshing rotors to move gas along the screw’s axis. They are frequently used in industrial vacuum applications, often in combination with roots blowers and as oil-free roughing pumps in high and ultrahigh vacuum systems.

The presence of gaseous molecules, whether slow or fast moving, is what gives rise to pressure. A vacuum is created by reducing the number of molecules that exist within, for example, a chamber or a flask. However, by reducing the number of molecules that exert a pressure on the internal surface of such a chamber, one reduces the pressure. Unfortunately, this causes “additional” molecules to enter into play.

There are several types of pumps that can deliver high and ultra-high vacuum pressures; diffusion pumps, cryo pumps; ion getter pumps (IGP); titanium sublimation pumps (TSP); non-evaporable getter (NEG) pumps; and turbomolecular pumps (TMP).

The methods whereby these pumps are capable of producing high and ultra-high vacuum pressures (between 10^-3 and 10^-11 mbar) are either by momentum transfer of gas molecules or by capturing them (either physically or chemically).

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.