ALICE Recovering the cryogenic system from major contamination.
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Transcript of ALICE Recovering the cryogenic system from major contamination.
ALICE
• Energy Recovery Linac
• 2 x 1.3GHz 9 Cell SCRF Modules
• Operating temperature - 2K
• Pressure stability ± 0.1mbar
Cryogenics Plant• Linde TCF50
Liquefier• 1500 Litre Dewar
(Wessington Cryogenics)
• Linde 2K Recouperator
• Leybold Ambient Pumps
• Transfer Lines manufactured by DEMACO
Breox Oil!!!!
• Historical oil contamination from Breox oil
• Formaldehyde Contamination• Changed to CPI 4601-46 in 2009
Contamination – Part 1
• Adsorber replaced October 2013
• Evidence of oil and carbon dust found on Hx E3110
• Solvent flush performed on E3110
Contamination – Part 2
• Feb 2014 Liquefier inoperable again!!• Heated Nitrogen purge at 100°C• Oil found from purge!!!!• New adsorber now contaminated
with oil??• Decided to remove the adsorber and
replace with pipework.
Contamination – Part 2
• March 2014 Liquefier opened to remove adsorber.
• Adsorber constructed from carbon pellets with a coarse mesh filter and Rockwool discs.
Contamination – Part 2
• Visited Linde June 2014• X-ray tests of faulty adsorber
inconclusive• Adsorber cut open for inspection
Contamination – Part 3
• July 2014 Capacity of the 2K system started to reduce
• Instrumentation failures• 2K pumps trips due to low oil level• Unable to maintain pressure stability
so forced to shutdown for repair
Contamination – Part 3
• Oil drained and Recouperator box cleaned.
• U-bend estimated to have contained at least 10 litres of oil.
• Still had persistent pressure drop in 4K box – Hydrocarbon from Compressor!!!!
Repair
• September 2014 started repairs.
• All oil contaminated pipework cleaned with Petroleum Ether.
Conclusions
• Find and fix your leaks.• Test as much of your new equipment
off-line.• Service your equipment regularly.• Don’t Rush!!!