oil behavior at differant temps R507

[costa]

I am erecting a freezing tunnel -40c .It will be a pumping system. My problem is I am not sure how the oil behaves in the pump vessel.ie isthere an oilrich layer does the oil sink to the bottem or does mix with the refrigerant?

[oldesky]

R507 has a specific gravity of 1.07 and RL32 has a specific gravity of .987 so the oil should float on top of the refrigerant depending on the turbulance and miscibility in the vessel at that temperature.