Reefer chamber compressor losing oil

[Pengze]

Good day.
I would like to have some advice regarding the following problem.
Our reefer chamber compressor is gradually losing oil in the crankcase but could not find any leakages. The system is still working fine with freon gas inside.
FYI, this system does not have oil separator.
Why is it that the oil does not re-circulate back to the compressor crankcase?
Would appreciate kind comments.

[Big Pete]

Before I joined one ship the crew were putting oil in the fridge compressor every day, they then orderd and fitted a new compressor (complete with oil seperator) and had to drain oil out every day, until the system stabilised with a constant amount of oil in the circulating gas. I think the only problem was with the float valve in the oil seperator, but that is another story.

There were problems with the Veg room temperature so we eventually cut out the evaporator and up ended it and got about 10 litres of oil out of it! After we re-connected it everything worked fine.

As I see it you have 2 problems, firstly why is the oil being carried over with the gas and secondly where is it going and how do you remove it?

I have never seen a fridge compressor without an oil separator, normally the gas suction is into the crankcase and the incoming gas carries oil from the crankcase into the cylinder to lubricate the moving parts, and is then removed by the oil seperator, if there is no oil seperator is the gas suction directly to the cylinder head?

Should you be using a special oil that is not miscible with the refrigerant gas?

Are the suction & discharge pressures normal?

Are the superheat levels at the evaporators normal?

Is this a new ship or installation or is it a new problem on an old plant?

Sorry, lots of questions but no answers, I am trying to visualise the situation.