Prsentation PowerPoint

FOTO24/11/2011PS FWS RELIABILITY1IMPROVING THE PS FWS RELIABILITY

PS fast wire scanner:why the instrument reliability has become an issue24/11/2011PS FWS RELIABILITY2The fast wire scanner is a beam profile monitor 5 instruments are installed in the PS ring (SS54, SS64, SS65, SS68, SS85), 3 horizontal and 2 verticalInstruments usage increased significantly over the last few yearsBellows failure leads to the loss of vacuum, stops the PS complex and so also the physics programme in the SPS and LHC

Reliability problems24/11/2011PS FWS RELIABILITY3Transmission of the movement via two edge welded bellows

Bellows lifetime much shorter than was foreseen: less than 10000 cycles instead of 100000 as specified on drawing

Looking for a solution to significantly improve the PS FWS reliability

Analysis of the problem24/11/2011PS FWS RELIABILITY4The bellows have to compensate a lateral movement(y,y1) as well as an axial stroke(x)

Problem found in the bellows design: number of convolutions too small, bellow length too short. Those bellows were designed, calculated and made at CERN at the beginning of the 80s

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24/11/2011PS FWS RELIABILITY5With such a design the bellows cannot comply with what was requested: 100000 cycles lifetimeCalculation and design have improved a lot: a very powerful software for CAD 3D design of dynamic system, and also improvements in bellows analysis

24/11/2011PS FWS RELIABILITY6Very little space for modifications: the instrument main design cannot be modifiedCERN metallurgy specialist strongly suggested to use 316L stainless steel that is the best material to resist pollution and corrosion.Asked to two bellows manufactures a proposal for a new bellow fitting the newly calculated stroke and lateral movement with a lifetime of 100000 cyclesBoth companies offered almost identical solutions: the proposed bellow is produced with a very similar membrane to the existing one, it is longer and with more convolutionsDesign modifications due to the new bellowsOrdered and received new bellows

Solution to the problemValidation test24/11/2011PS FWS RELIABILITY7A FWS has been equipped with the new bellowsThe instrument has been installed in its PS tank in our lab and put under vacuum.The FWS will be used as in normal operation(same measure speed but with 1 cycle every 2 seconds)The test is in progressThe first test will validate the bellows design, more test are foreseen to precisely define the new lifetimeConclusions24/11/2011PS FWS RELIABILITY8The five PS FWS will be equipped with new bellows during the next WSD assuming the validation test is succesfulA new preventative maintenance policy will be developped to avoid instrument failure in the machineMore studies and test are planned for a general improvement of the PS FWS

8W.ANDREAZZAOther shutdown activities24/11/2011PS FWS RELIABILITY9Installation of 4 new FWS tanks in the SS 54, 64, 65 and 85

Installation of the 2 pick up in the SS 54 and 64

Acknowledgemets24/11/2011PS FWS RELIABILITY10I would like to thank all the people who helped for these studies and in particular R. Sautier, D. Gerard, M. Hamani, F. Camba, S. Leblanc, J. Emery, A. Guerrero and R. VenessA special thanks to Jurgen Enzinger from Comvat for his willingness to quickly find a new bellows for our applicationA big thanks also to EN-MME-AF section and to 40-30 air liquide for their prompt reaction to have our instrument ready within a very short delay