CO2 supermarket Refrigeration Question

[turtle stato]

hey guys
was just wondering if i could pick your brains....
i am a third year refrigeration mechanic in Australia and am in the middle of putting a oral presentation together to present to my class.

the questions i have are..

is there any maintance schedules that need to be carried out on these system?
if changing a drier (i understand that there is manual hand valves and check valves to allow pressures to escape the isolated area) is it as easy as isolate the area and then removing the drier letting the co2 go to atmosphere or is it a pump down method as in more common refrigeration?
And when re-installing a new drier is there a way of purging the air or placing it under a vaccum?

also have to discuss some safety and regulations guidelines but that will be more specific to australia

if you have any web sites or information/pictures that may be able to help me with my presentation that would be much appreciated

thank you all in advance look forward to reading up on all the new technology


turtle

[cool runings]

Maintenance should be no differant.

Change filters and oil as you would with HFC refrigerants.

As for valves and by-passes, yes most commercial and industrial systems
provide for changing the filters and oil without stopping the whole system
so all you need to do is familiarise yourself with the system.

The only thing to be very aware of is you are allowed to vent Co2 but if you let
the liquid pressure drop too low it will instantly freeze to dry ice!!!!!!

All the best

cool runnings

.

[RONB]

The procedure I do to change a liquid core on a Co2 system is as follows. Connect a suitable gauge line to the drier shell and then connect the other end of the line to the vapour side or the system. Open the bypass valve across the liquid drier, shut the out going and the inlet valve to the drier and open the accsess valve on the vapour side of the gauge line. Then slowly crack the drier side access valve and gently bleed the remaining liquid from the drier through to the vapour side of the system. Once the pressures are equalized shut both access valves on the gauge line and remove the gauge from the vapour side of the system, then gently open the access valve on the drier shell and release the vapour in the shell. Once you have changed the drier core vac out the drier shell,connect your gauge line up as before and open the vapour side of the line and the open the valve on the gauge line on the drier to introduce vapour into the shell ( PRESSURE SHOULD BE ABOVE 5/6 BAR VAPOUR) then leak test. Then open the inlet/outlet valves to and from the drier and close the bypass..

[turtle stato]

thank you guys for all your help, i will defently use this information in my assigment ..

thank you again for your time turtle