SC - 04Feb'13 Cryo Heaters Review
Cryogenic Heaters Review
Operation use and wishes
S. Claudet - A. SuraciLHC Cryogenic Operation
SC - 04Feb'13 Cryo Heaters Review
Content
• Introduction
• Why/how we use heaters
• What we would like to have
• Summary
SC - 04Feb'13 Cryo Heaters Review
From LHC Magnet String testx 13.5
Sector 3.3km
Introduction to LHC Cryogenics
Pt 3
Pt 4
Pt 5
Pt 6
Pt 7
Pt 8
Pt 1
Pt 2
Pt 1.8
Cryoplant DistributionPresent Version
Cryogenic plant
Distribution
Magnets
8 x 18kW @ 4.5K24km & 20kW @ 1.8K
36’000 t @ 1.9K130 t He inventory
Heaters:
10-30 kW
600 kW
25 - 100 W - 1 kW
SC - 04Feb'13 Cryo Heaters Review
Cryogenic Line (QRL)
No bad experience with heater command
Level Control (PID)
Fixed value
SC - 04Feb'13 Cryo Heaters Review
Electrical Feed Boxes (DFBs) or Stand-alone magnets
No bad experience with heater command
Fixed value
SC - 04Feb'13 Cryo Heaters Review
Standard cells (magnets + beam screens)
Few mishaps with power kept ON, local intervention by specialists required !!!
To provide minimum
flow to CCs
So far 25 W,
Later on for bake-out (200W)
Temperature Control (PID)
SC - 04Feb'13 Cryo Heaters Review
What we would like to have• DO: ON-OFF independent from Analog request (New)
– Logic conditions to switch it ON/OFF (operators for special cases)
• DI: Safety switch ON/OFF (setting tuned by referent specialist)– If it comes once, temporary stop for both DO and AO– If it comes 3 times in less than 2 hours, full stop
• AO: Analog request for power– As done now
• AI: Analog measured power [AI]– Feedback of dissipated power (if it exists)
• + Regulation switch or value (independent from safety)– HW (iron-like) or SW(PID controler), tuned by operators or logic
SC - 04Feb'13 Cryo Heaters Review
Example No1
Power Request 0-100%
Power Measured 0-100%
Power Enable
Enable Validated (needed?)
Safety Thermal Switch
SC - 04Feb'13 Cryo Heaters Review
Example No2
Power Request 0-100%
Power Measured 0-100%Power Enable
Enable Validated (needed?)
Safety Thermal Switch
Circuit breaker
SC - 04Feb'13 Cryo Heaters Review
Safety switches part2
Safety Thermal Switch
No reset, simple Iron-like system
SC - 04Feb'13 Cryo Heaters Review
LHC CRYOGENICS - Overall Schedule LS1
Legendw Sector warm, cryo locked -out, ready for Interco consolidations
Helium logisticsI Cryo-installations locked-out, ready for maintenance & projectsl Maintenance done, ready for cryo re-commissioning testst Helium leak tests in sectorP Pressure testF Flushing of sector
Cool-down of a sector, cryo tuning
According to master schedule V2.2 => Most likely helium leak tests with lost helium => Time available for Re-commissioning cryo refrigerators (CD delayed by R2E)
2 0 1 3 2 0 1 4Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
S12 w I 7.5m t l P F
S23 !CSCM! w I 9.5m t l P F
S34 w I 10m t l P F
S45 w I 12m t l P F
S56 w I t 6.0m P F l l
S67 w I t 5.5m l P F l
S78 w I t 6.5m l P F
S81 w I 7.5m t l P F
Key dates for cryogenics
All magnets warm in LHC: End May’13
1st magnets cold in LHC for tests: >May’14
Global bake-out of 8 sectors: >Jan’15
SC - 04Feb'13 Cryo Heaters Review
Summary
• Large variety of heaters used in the cryogenic system– Some with PID loops with active control (beam-screens)– Some to empty liquid helium or warm-up
• Few mishaps with some heaters ON and out of control !• Strong wish to have an independent ON/OFF button for
each heater (at least > 100W)
• Internal needs for summer’14, for beams early 2015