Lines 5-6 were replaced by lines 5-7 |
- Handling cryogenic liquids should only be done by trained people. Fear is a bad teacher \\ |
- and you should always consult a more experienced instrument scientist or [the sample environment team|http://lns00.psi.ch/sinqwiki/Wiki.jsp?page=SampleEnvironment]\\ |
+ Handling cryogenic liquids should only be done by trained people. The following instruction are by no means a replacement for a certified cryogenics course. They are meant as a reference for how to handle cryogenics at the Neutron guide hall. \\ |
+ Fear is a bad teacher |
+ and you should always consult a more experienced instrument scientist or [the sample environment team|SampleEnvironment], |
Line 18 was replaced by line 19 |
- [LN2_dewar_schematics|cl_clpb.gif] |
+ [LN2_dewar_schematics|LN2.png] |
Lines 22-23 were replaced by lines 23-24 |
- The filling hoses have a metallic protection sleeve. The valves and the hose get very cold during a nitrogen transfer. |
- *Make sure that you wear protective leather gloves when handling cold parts. |
+ The filling hoses have a metallic protection sleeve. The valves and the hose get very cold during a nitrogen transfer. |
+ *Make sure that you wear protective leather gloves when handling cold parts, however the gloves should never be soaked with LN2 or LHe. |
At line 24 added 1 line. |
+ |
Line 30 was replaced by line 32 |
- Liquid Helium dewars are provided by the sample environment staff at the sample preparation area.\\ |
+ Liquid Helium dewars are provided by the sample environment staff at the preparation area.\\ |
Line 34 was replaced by lines 36-37 |
- *Always measure the Helium level in the dewar before you take a Dewar away |
+ *The Level meter in the preparation area shows the level in litres. Make sure that there is sufficient helium for filling. The dewars |
+ should be returned with a level of at least 10-15 litres. |
At line 36 added 1 line. |
+ |
Line 39 was replaced by lines 43-52 |
- __Helium Transfer:__\\ |
+ __Helium Dewar Transport:__\\ |
+ Helium dewars are brought into the experimental area with the 1T crane. |
+ *Only instructed people are allowed to use the crane. (A short training is offered by the LDM mechanics personal.) |
+ *Only dewars with pre-installed transport straps are allowed for crane transportation. |
+ *To extend the straps please use the proper extensions as shown in the picture below. |
+ |
+ | [transport extensions|HeDewartransport.png] | [dewar with transport fixtures|transportstraps.png] |
+ |
+ |
+ __Helium Transfer:__ |
Line 43 was replaced by line 56 |
- *slowly lower the siphon into the dewar observe the pressure rise in the dewar (try to stay below 0.2bar) |
+ *slowly lower the siphon into the dewar and observe the pressure rise in the dewar (try to stay below 0.2bar) |
Lines 47-50 were replaced by lines 60-65 |
- *continue to lower the siphon into the transport dewar until you reach the bottom and lift it up by 10 cm |
- *switch on the compressed Helium gas line and connect the gas hose to one of the pressure release valves\\ |
- and open it. The dewar is now pressurized to 0.2bar over pressure. |
- When the transfer is finished:\\ |
+ *continue to lower the siphon into the transport dewar until you reach the bottom. |
+ *switch on the compressed Helium gas line and connect the gas hose to one of the pressure release valves |
+ and open it. The dewar is now pressurized to 0.15 bar over pressure. |
+ *make sure not to empty the vessel completely, the people running the liquefier will love you. On the transfer line, normally there is a prolongation with a hole at 10 cm above the end. If not, you should lift the transfer line by 10 cm after inserting. |
+ When the transfer is finished: |
+ |
Line 53 was replaced by lines 68-69 |
- *make sure that the extraction and filling ports are properly sealed |
+ *make sure that the extraction and filling ports are properly sealed. It might be necessary to |
+ use a hair dryer to remove the ice. |
Line 57 was replaced by lines 73-84 |
- |
+ !Returning Liquid Helium Dewars |
+ please return dewars to the dewar station as soon as possible after the transfer |
+ *connect the dewar to the rubber hose of the dewar station |
+ *open the manual valve to the recovery |
+ *open the manual pressure release that is connected to the recovery on the dewar |
+ *check the other manual pressure release. it MUST be closed |
+ *retighten the locking nut of the Helium extraction port |
+ *connect the level probe |
+ |
+ IMPORTANT: |
+ recheck that all valves are in the right state and the level is reading before you leave |
+ [afterfill.png] |
At line 58 added 1 line. |
+ In case you are unsure about certain procedures, please contact sample environment staff |