Inverted trap

[A.Mortezania]

Dear Friends,
How are you ?

Would you please someone tell me why we use "Inverted P trap" at outlet of evaporators ? I know it is for prevent returning liquid to compressor, But danger of liquid return when compressor and system is in running situation or when system is off or both of these situations ?

Sincerely yours.
15031

[Brian_UK]

During the "off" cycle it stops oil draining down or pooling in multi-evaporator systems.

[RANGER1]

This is book that picture is from & is self explanatory.

https://inspectapedia.com/aircond/AC_Guide_McQuay.pdf

[A.Mortezania]

This is book that picture is from & is self explanatory.

https://inspectapedia.com/aircond/AC_Guide_McQuay.pdf

Thanks Brian_UK and RANGER1 for replies,
Regarding MCQuay documents, I read it completely and my sent photo was form this document.
Regarding "Inverted trap" at outlet of evaporators, Brian_UK said it is for stopping oil draining, But at this photo below evaporator and condenser is almost in same height, Even evaporator is at higher situation instead condenser. Why twice MCQuay suggested to use this inverted trap ????
I think it is for prevent of liquid migration to compressor.

Am I right ?

15032

[Brian_UK]

Okay, if you like.