VectorFridgeShutDown260912

Unexpected shutdown of vector fridge on 26 09 2012

IMG_20120926_095100.jpg

Magnet temperatures as I found them. Magnets are hot!

IMG_20120926_095111.jpg

Fridge temperatures as I found them. Fridge is hot

IMG_20120926_095125.jpg

IGH front panel as I found it. All valves are shut. Mixture is behind He3 pump and in He4 dump?!

IMG_20120926_095137.jpg

IGH panel again. Notice P3=243! . Most likely mixture.

IMG_20120926_095144.jpg

Pressure gauges as I found them. Probe>1500 mbar and IVC no Ident -> IVC is vented !? Gas in the OVC due to warming of the fridge. Still>1500. There is mixture in the fridge.

IMG_20120926_100006.jpg

IGH front panel after recovery. After recovery pressures don't match previous values + He3 and He4 are mixed in the dumps. Fridge Crash Sept2012 Pressure Logs MG2-MG5.
See VectorFieldFridgeMixturePressureLog for details of the fridge dump pressures, but usually they are 990mB & 1153 mB, and we are now getting 985 & 919 mB.

So there is some mixture missing -- maybe this is in the IVC (-- AlexHamilton - 27 Sep 2012) ?

Switched off both compressors.

Waiting to warm up.

Oleh wrote that he pumped the IVC into the dumps and now the dumps pressures make sense: P6=1160 and P7=989. This is basically the same as the historical values, which says that the extra gas in the IVC may well have been mixture - but how on earth did it get there?

He Leak Detection

Hooked up Leak detector to Aux Port-1, to leak check the still lines and both condensing lines.

*done whilst waiting for fridge to warm up (Magnet temperatures ~ 242K).

VectorFridgeShutDown260912_leak_check_IMAG1040.jpg

VectorFridgeShutDown260912_leak_check_IMAG1043.jpg

*Note: Here we're used the leak detector's rotary pump as a substitute for pump S4.

VectorFridgeShutDown260912_leak_check_IMAG1044.jpg

Result of leak checking:
IVC is holding pressure so no leakage between IVC and fridge lines (still and both condensing lines).

Perhaps it is due to a blockage.

VectorFridgeShutDown260912_leak_check_IMAG1045.jpg

VectorFridgeShutDown260912_leak_check_IMAG1046.jpg

Cleaning Mixture via Fridge Attempt

The following attempts at cycling the mixture was repeated a couple of times, and the same result was obtained every time - inidicating a blockage in the condenser lines.

Blocked_condenser_lines.doc

Pressure Tests (5/8/12)

The following tests were conducted as per Giorgio's suggestion.

pressuretests2.png

Fridge Logs of the Event

Plots of the fridge pressures & temperatures are provided below.

Crash occurred between 8:31am to 8:34am:

- Sudden heat load applied to all Plates of the fridge.

- Flow rate dropped from 177 to 0.

- Mixture was auto dumped in to P6 (He4 dumps rose from 18mbar to >500mbar)

- Mixture also auto dumped into IVC (P3 rose from ~0bar to 250mbar, MG2 and MG4 rose >1500mbar)

Pressure_Logs_P3-P7.png

Pressure_Logs_MG2-MG5.PNG

CH6_TMC.PNG

Magnet temperatures also increase.

Compressor Logs during that time period show no change - ie power was still on at that time and the compressors were in normal operation:

C:\Liquefier Logs\CompressorState 2012_09_24 1549.txt
Timestamp Low side PSI High side PSIIn water temp C
Out water temp CHe gas temp C
Oil temp C
Motor Amps
Diode temp K
08:31:18 082.7 264.5 070.5 087.8 134.6 081.7 15.0 NaN
08:36:26 090.0 273.9 070.9 088.5 135.0 082.4 15.0 NaN

C:\Liquefier Logs\CompressorState 2012_09_24 1551.txt

Timestamp Low side PSI High side PSIIn water temp C
Out water temp CHe gas temp C
Oil temp C
Motor Amps
Diode temp K
08:03:24083.2 268.3073.0 090.0 133.0 085.3 15.0 NaN
08:08:33082.7 268.4073.2 090.0 133.0 085.3 15.0 NaN

Access Control

Previously the default template was set up so that all pages were visible by the whole world, and we relied upon authors to use access control to limit access to sensitive pages. That hasn't worked, so now pages are by default only visible to QED group members. Delete the following line if this page is meant to be visible by the whole world.

# Set ALLOWTOPICVIEW = QedGroup

Tags

create new tag

Comments

 
Topic attachments
I Attachment Action Size Date Who Comment
26-09-2012_10-59am_MagTemp.PNGPNG 26-09-2012_10-59am_MagTemp.PNG manage 209 K 26 Sep 2012 - 08:15 LaReineYeoh fridge crash sept2012 magnet temps
Blocked_condenser_lines.docdoc Blocked_condenser_lines.doc manage 22 K 04 Oct 2012 - 07:23 LaReineYeoh Vector fridge shut down 26/9/2012 - blocked condenser lines
CH6_TMC.PNGPNG CH6_TMC.PNG manage 129 K 26 Sep 2012 - 07:16 LaReineYeoh Fridge Crash Sept2012 Tmc
IMG_20120926_095100.jpgjpg IMG_20120926_095100.jpg manage 202 K 26 Sep 2012 - 03:31 OlehKlochan  
IMG_20120926_095111.jpgjpg IMG_20120926_095111.jpg manage 157 K 26 Sep 2012 - 03:31 OlehKlochan  
IMG_20120926_095125.jpgjpg IMG_20120926_095125.jpg manage 142 K 26 Sep 2012 - 03:31 OlehKlochan  
IMG_20120926_095137.jpgjpg IMG_20120926_095137.jpg manage 163 K 26 Sep 2012 - 03:31 OlehKlochan  
IMG_20120926_095144.jpgjpg IMG_20120926_095144.jpg manage 94 K 26 Sep 2012 - 03:31 OlehKlochan  
IMG_20120926_100006.jpgjpg IMG_20120926_100006.jpg manage 143 K 26 Sep 2012 - 03:31 OlehKlochan  
IMG_20120926_101208.jpgjpg IMG_20120926_101208.jpg manage 161 K 26 Sep 2012 - 03:32 OlehKlochan  
IMG_20120926_101219.jpgjpg IMG_20120926_101219.jpg manage 171 K 26 Sep 2012 - 03:32 OlehKlochan  
Pressure_Logs_MG2-MG5.PNGPNG Pressure_Logs_MG2-MG5.PNG manage 22 K 26 Sep 2012 - 07:15 LaReineYeoh Fridge Crash Sept2012 Pressure Logs MG2-MG5
Pressure_Logs_P3-P7.pngpng Pressure_Logs_P3-P7.png manage 21 K 26 Sep 2012 - 07:16 LaReineYeoh Fridge Crash Sept2012 Pressure Logs P3-P5
VectorFridgeShutDown260912_leak_check_IMAG1040.jpgjpg VectorFridgeShutDown260912_leak_check_IMAG1040.jpg manage 895 K 02 Oct 2012 - 06:54 LaReineYeoh Pressures IVC, Still
VectorFridgeShutDown260912_leak_check_IMAG1043.jpgjpg VectorFridgeShutDown260912_leak_check_IMAG1043.jpg manage 739 K 02 Oct 2012 - 06:54 LaReineYeoh Gas handling cabinet valves
VectorFridgeShutDown260912_leak_check_IMAG1044.jpgjpg VectorFridgeShutDown260912_leak_check_IMAG1044.jpg manage 1 MB 02 Oct 2012 - 06:55 LaReineYeoh He leak detector rate
VectorFridgeShutDown260912_leak_check_IMAG1045.jpgjpg VectorFridgeShutDown260912_leak_check_IMAG1045.jpg manage 1 MB 02 Oct 2012 - 08:20 LaReineYeoh Pressures after leak checking
VectorFridgeShutDown260912_leak_check_IMAG1046.jpgjpg VectorFridgeShutDown260912_leak_check_IMAG1046.jpg manage 1 MB 02 Oct 2012 - 08:20 LaReineYeoh leak detector after leak checking
pressuretests.pngpng pressuretests.png manage 149 K 05 Oct 2012 - 03:56 LaReineYeoh Vector fridge pressure tests 5/8/12
pressuretests2.pngpng pressuretests2.png manage 183 K 05 Oct 2012 - 06:10 LaReineYeoh 5/8/12 vector fridge pressure tests
Topic revision: r10 - 09 Sep 2014, RoyLi
This site is powered by FoswikiCopyright © by the contributing authors. All material on this collaboration platform is the property of the contributing authors.
Ideas, requests, problems regarding Foswiki? Send feedback