Reduce CO2 emissions with Slim-Line CF Flanges™

November 7, 2023

Break a 70-Year Tradition

The planning of a vacuum system often begins with the question of the type of flange connection required. This question is technologically determined by the quality of the required vacuum level (or the required absolute "emptiness") in the vacuum. It starts with rough vacuum at 103 mbar, goes through fine, high, and ultra-high vacuum (UHV) ranges down to 10^-10 mbar, and extends to the extreme ultra-high vacuum (XHV) range at 10^-14 mbar. Different vacuum ranges require specific flange designs that reliably guarantee vacuum conditions. One suitable vacuum flange design for the UHV range is the Conflat Flange (CF-Flange). These commercially available specialized vacuum flanges come in various stainless steel grades. The ISO standard for these flanges is ISO 3669:2017-08, "Vacuum technology - Bakeable flanges - Dimensions of knife-edge flanges," in the English language. The German standard ISO/TS 3669-2 has been withdrawn by Beuth Verlag.
A CF vacuum component typically consists of two identical flanges, with a soft gasket placed between them. The flanges are pulled together and the gasket is compressed using fastening screws.

The origin of this flange design can be traced back to the USA at the company VARIAN®. The basis for its development was to ensure secure vacuum flange connections under high-temperature conditions. Extensive testing was conducted, and CF flanges adopted their current appearance early on. This appearance was documented in the US standard ASTM E 2734/E 2734M:2010. The flanges described in this standard, with their specific knife-edge geometries and dimensions, have remained largely unchanged since the mid-1950s.

In the layout for the use of CF connections in vacuum systems, the relatively high weights and bulky appearance of these flanges have been accepted for over 70 years.

Ironclad climate protection

Six percent of global CO2 emissions – 4.4. billion tonnes per year – are currently produced by the steel and aluminium industry.

Modern societies would hardly be able to function without metals: alone 1.7 billion tonnes of steel and 94 million tonnes of aluminium are produced per year. They literally support industrial production, buildings, and transport as well as energy supply, telecommunications, and medicine. And by 2050, the amount of metallic materials produced and used annually could once again double – and even triple – for some materials. However, extracting metals from ores is extremely energy-intensive and produces huge amounts of CO2 emissions, thereby contributing to climate change.

Steel and aluminium producers emit 30% of the greenhouse gases emitted by industrial companies worldwide.

"We must reduce these industrial CO2 emissions”,
says Dierk Raabe, Director at the Max-Planck-Institut für Eisenforschung in Düsseldorf.
https://www.mpg.de/14127346/ironclad-climate-protection

The time is more than ripe to put CF flanges on a diet

In addition to the greenhouse gases problem, rising material costs for high-quality, high-alloy stainless steels, expensive storage space and increasing transport costs are other reasons for this step.

The company emios Technologies GmbH from Jena was able to gain support for the idea of the new CF Slim-Line Flanges™ from the German Electron Synchrotron (DESY) in Hamburg. A project was initiated in 2017 for this purpose. This project was carried out in close cooperation with the DESY ITT (Innovation and Technology Transfer) and MDI (Machine Diagnostics and Instrumentation) groups.