GB-Didcot: 10 Multi-stage root pumps

The final date and time for submission of bids is the 06th January 2021 at 14:00 All tenders information must be submitted through the Delta eSourcing Portal Breif description of the requirement; The ISIS Neutron and Muon Source supports around 800 experiments per year, with almost 70% of these involving Cryogenic Sample Environment. One of the most common ways to provide a Cryogenic Sample Environment is using a pumped helium 4 cryostat. Such a cryostat features a liquid helium 4 bath at 4.2K. From this bath a small amount of liquid helium is drawn through to a heat exchanger, at which point a room temperature vacuum pump is used to reduce the vapour pressure above the liquid helium, giving cooling. The minimum temperature with such a system is around 1.4K. The ability to provide such a cryogenic environment is critical to ISIS operations. In addition, pumped helium gas is recovered by the facility and re-liquefied. In order for this process to be successful there must be no contamination of the helium gas due to the pumping process. Currently this service is provided by scroll pumps. These are no longer suitable for this purpose due to the continuous ejection of tip-seal particulate material, the frequent maintenance required, and the noise & heat generated. They also lack the pumping capacity to deal with our more demanding equipment. To this end we require 10 multi-stage roots design vacuum pumps which are able to pump this cold helium gas at the required rate, and which do not allow the helium to come into contact with significant contaminants (e.g. oil). The pumps should also be quiet, easily transported, and low maintenance. For more information about this opportunity, please visit the Delta eSourcing portal at: https://www.delta-esourcing.com/tenders/UK-GB-Didcot:-10-Multi-stage-root-pumps/89P42Q2443-0000m,m