Eccles:cell culture CO2
CO2 for cell culture
We have two cell culture incubators in Hercus 203, each with their own CO2 tank connected to the "Tank 1" inlet of the respective incubators. Both incubators have a feature called "Gas Guard" that allows a second backup tank to be connected (Tank 2). We have one Gas Guard backup tank to supply both incubators - there is a Y-junction that connects the Gas Guard tank to the Tank 2 inlets of each incubator. When gas pressure falls too low in Tank 1, it automatically switches to the backup supply connected to the Tank 2 inlet, sounds an audible alarm (press "Silence" to silence), flashes "Tank 1 low" on the screen until the alarm is manually silenced, and illuminates the "Tank Low" light on the incubator console. When this happens, the "Tank select" option under System config switches from 1 to 2, indicating that the incubator is now getting supplied by Tank 2 (the backup tank), and the "Tank Low" light remains on as a visual reminder that something needs to be done. The empty tank now needs replacing.
Changing CO2 tanks
- Get a replacement tank from the Animal Feed Store in the Hercus Loading Bay (key is in the Braithwaite Lab key container). Use the manky old tank barrow from the Feed Store, or the tank barrow in the Supply Store area adjacent to the Path Museum. Tanks must be secured with the top-chain on the Feed Store barrow, or both leather straps on the red barrow (one higher, one lower). Travel in the Service Lift only.
- Two replacement tanks are kept in the Feed Store. It there are none in the Feed Store, then the incubator will have to run on the backup tank until replacement tanks arrives from BOC. In this case, simply take the empty tank to the loading bay, and see Lynne about getting a replacement.
- Close the supply tap on the empty tank.
- Remove the regulator, leaving the regulator tap position untouched i.e. open.
- Wiggle the empty tank out of the tank cradle.
- Wiggle the new tank into postion, taking care not to bump the regulator of the adjacent tank in the cradle - angle the tank outlet toward the back to keep the regulators and hoses as much out of the way as possible.
- Replace the safety chains.
- "Crack" the new tank:
- remove the yellow plastic cap on the tank outlet.
- quickly open and close the tap to blow any dirt, dust, and debris from the outlet before connecting the regulator.
- Re-connect the regulator, taking care not to over-tighten.
- Gently open the tap on the tank - tank pressure should be about 4000-5000 kpa; regulator outlet pressure must be set at a little over 100 kpa.
- Listen for leaks - the regulator connection to the tank outlet is the usual culprit, although sometimes the incubator hose connection to the regulator can work loose.
- Switch the supply from Tank 2 back to Tank 1 using the system config option on the incubator console - see the manual, in the draw under the incubator bench, for instructions. If you forget to do this step, the backup tank will be used as the primary tank for that incubator until it runs out, then the Gas Guard will switch to the new Tank 1. However, this will leave no backup for the other incubator if, by chance, the other incubator's Tank 1 runs out.
- take the empty cylinder back down to the loading bay, and place in the empty cylinder cradle in the loading bay landing area. If after hours, and the landing door is locked, then leave the tank in front of the Full Tank cradle outside the Feed Store door. It is a hazard to leave the tank free-standing, but if you cannot get access to the Empty Tank cradle on the loading bay, or the cradle is full, then there is no choice to leave the tank free-standing.
Ordering replacement CO2 tanks
- See Lynne, the Purchasing Officer, to initiate a replacement from BOC.
- Keep an eye out for the replacement tanks on the landing, and replace where necessary i.e. back into the Feed Store, or up to cell culture room.