compact screw oil carry over

[l2embo]

l2embo,

I'd like to see a picture of the surge drum and the pipe arrangement around the surge drum.
Oil will form an oil rich layer on top of liquid R22, so I would like to see the oil drain arrangement as well

-The discharge temperature seems a bit high for that load on the compressor, what is the ambient temperature?


I agree with this

Looking forward to more pictures

Dear Tycho

I attached some photos for your reference. Ambient temperature is about 33 but we are using water-cooled condenser with the working pressure of 150 psi.
About the oil drain arrangement I have to say we do not return the oil from the evaporator to the compressor since the evaporator is a second hand flake ice drum. Actually most of the oil stay in the condenser.

[RANGER1]

Dear Tycho

I attached some photos for your reference. Ambient temperature is about 33 but we are using water-cooled condenser with the working pressure of 150 psi.
About the oil drain arrangement I have to say we do not return the oil from the evaporator to the compressor since the evaporator is a second hand flake ice drum. Actually most of the oil stay in the condenser.

No no ice on float leg?

[Tycho]

No no ice on float leg?

I think we should all note that, as l2embo said. HP liquid is fed into the flooded system through the hand regulating valve that can bee seen in the middle of the attached picture, that feeds into the bottom of the drum.

Also in the same (last picture), connected into the middle of the "drop leg" pipe, is a pipe that is ice and frost free, connected to a level control valve, that is apparently not in use.

The last ice machine I worked on was a North Star, and it was identical in design as this one.

And the Liquid level in the surge drum was controlled by a danfoss RT thermostat (I forget what kind of RT, but it had a heating element), when the RT read a high delta T it would signal the level control valve to add liquid.

Liquid from the HP receiver was added in the drop leg, exactly as shown in these pictures exept it was using the level control valve and not a hand regulated valve.

and there was a functioning oil return by heat exchange from hp liquid.

so to stop beating about the bush and just lay it out:

So no offence to l2embo, but the oil temperature is too high, this again makes the discharge temperature too high, this again makes the oil less dense and more susceptible to follow the gas out of the compressor, the oil separator mounted on the discharge is too small (it would probably work on a small piston compressor, but it's much to small for the screw compressor). While I salute you for having managed to keep the correct level in the surge drum by using the hand regulating valve, you have to install an oil rectifier, and pipe the liquid feed through the level control valve if you want this system to work optimal and also have oil return to the compressor.
Oh and also to minimize oil loss, lower the discharge temperature to below 90C