Re: compact screw oil carry over
hi
your piping and slope of pipe inside condenser is not right
what is the condenser brands you are using .
Also why you change the compressor ?
I think screw more better than piston type
for this type works .
Re: compact screw oil carry over
Quote:
Originally Posted by
l2embo
Dear friends
Thanks for your cooperation.
We have changed the compressor with a piston type copeland model 6RR2-400a-tsn the oil carry over problem still goes on.
The point is when we dried the ice maker drum before changing the compressor there was no oil in drum. What could be the problem? We are assuming the condenser is too big for system so the discharge gas easily pass oil separator because of the low condenser pressure. Is it possible?
Could the oil separator be defectivec
Quote:
Originally Posted by
l2embo
Dear Tycho
We did not drain any oil from the oil drain valve while we were changing the compressor. We are assuming that oil stayed in the condenser. Or is it possible that oil is in surge drum and the siphon under it ?
Dear l2embo,
if there was no oil in the drum after you "dried" it, which I think you mean you pumped the system down and trapped all the liquid in the condenser, than that means that the oil is staying in the condenser.
Looking at your pictures, I now see that the big blue tank below the compressor is the condenser/receiver.
And that condenser/receiver is so large that there is probably not a lot of turbulence in it, so the oil leaving the compressor will collect, like I said before oil is lighter than R-22, in an oil rich layer on top of the R-22 liquid.
Also, since you are controlling the liquid level in the surge/suction drum with a hand regulating valve, and not using the liquid level control valve, I am kind of unsure how to advise you on oil return. because if the oil is collected on top of the liquid in the condenser/receiver, then it's kind of trapped there.
What is the liquid level % in the condenser?
Re: compact screw oil carry over
Hi Tycho
if he pump down the system ,
oil should be on drum if there were oil
in pump down we sucking gas and oil were stay on drum
but to return oil ( oil is on top in flooded system in freion ) from drum he needs rectifier system .
I am family with those condenser's
design of pipes inside condenser is not right and oil especially POE oil were stay there .
Re: compact screw oil carry over
Quote:
Originally Posted by
mbc
Hi Tycho
if he pump down the system ,
oil should be on drum if there were oil
in pump down we sucking gas and oil were stay on drum
but to return oil ( oil is on top in flooded system in freion ) from drum he needs rectifier system .
I am family with those condenser's
design of pipes inside condenser is not right and oil especially POE oil were stay there .
Yes, but look at the size of the condenser in the picture.
it is a very big condenser.
if oil and gas comes in from top and the gas condenses...
The liquid outlet is on other side of condenser.
you have very slow movement inside condenser, so oil will stay on top of liquid in condenser.
is what I am thinking.
If he has smaller condenser, with higher gas and liquid flow, then oil and liquid will go quickly from condenser to LP drum.
l2embo, says that when they pumped out the ice drum and LP receiver, there was no oil.
But he oil has left the compressor, so it has to go somewhere, yes?
That is why I am saying the oil may be staying in the condenser :)
Now... if l2embo keep running the system until the condenser is 70% oil, then the oil will start to go out to icedrum and expansiontank along with liquid from condenser, but he will also see that level in LP drum increases, even if he didn't add any *****.
Now I agree with you, he needs to add a rectifier system, but personally, I don't know any rectifier that works on a system with a steady stream of HP liquid. it needs to alternate.
If l2embo want's I can draw up a piping diagram for that ice machine, and an electrical diagram, but it would also mean that he would have to change the control system, to properly control the liquid level in the LP drum
So mbc, I am not here to arrest anyone or to make anyone look bad... I am doing my best to give input and help, from sometimes very little information. but I am here to help :)
Re: compact screw oil carry over
Tycho
we pumped down the LP side and trap all the gas in the condenser. we did not drain any oil from oil drain valve of the drum. we assume maybe the oil has been trapped inside the siphon under the surge drum. we also add nitrogen about 8 bar to drum for draining the oil but still get nothing.
about your question for liquid level I should say it is a small percentage HP liquid in condenser. if we open the throttling valve more than 1 turn we see high pressure liquid travels very very fast to LP side from the sight glass.
do you offer thermostatic expansion valve for that?
I would like to have your suggestion for piping and electrical diagram for the ice machine.
please also include what kind of valve is could we use for HP liquid control.
Re: compact screw oil carry over
MBC
what do you think is wrong with the condenser?
I haven't heard about rectifier system before. please let me know. Is it the system with oil return from evaporator using an heat exchanger to avoid liquid come to the compressor?
if yes please note than we are not receiving the oil from Evaporator.
Thanks
Re: compact screw oil carry over
Sabroe Atlas 10 tons per day flake ice maker
Re: compact screw oil carry over
Re: compact screw oil carry over
Hi Tycho
please provide me with the diagrams if possible
regards
Re: compact screw oil carry over
Quote:
Originally Posted by
Tycho
Yes, but look at the size of the condenser in the picture.
it is a very big condenser.
if oil and gas comes in from top and the gas condenses...
The liquid outlet is on other side of condenser.
you have very slow movement inside condenser, so oil will stay on top of liquid in condenser.
is what I am thinking.
If he has smaller condenser, with higher gas and liquid flow, then oil and liquid will go quickly from condenser to LP drum.
l2embo, says that when they pumped out the ice drum and LP receiver, there was no oil.
But he oil has left the compressor, so it has to go somewhere, yes?
That is why I am saying the oil may be staying in the condenser :)
Now... if l2embo keep running the system until the condenser is 70% oil, then the oil will start to go out to icedrum and expansiontank along with liquid from condenser, but he will also see that level in LP drum increases, even if he didn't add any *****.
Now I agree with you, he needs to add a rectifier system, but personally, I don't know any rectifier that works on a system with a steady stream of HP liquid. it needs to alternate.
If l2embo want's I can draw up a piping diagram for that ice machine, and an electrical diagram, but it would also mean that he would have to change the control system, to properly control the liquid level in the LP drum
So mbc, I am not here to arrest anyone or to make anyone look bad... I am doing my best to give input and help, from sometimes very little information. but I am here to help :)
Hi Tycho
Please provide me with you recommendation on diagrams.
Regards
Re: compact screw oil carry over
Quote:
Originally Posted by
l2embo
Hi RANGER1
1. Evaporator is a flooded flake ice drum ( with surge drum ) with an oil trap at the bottom of it and an oil drain valve. we regularly open and drain the oil which carried from the system. The oil is very dirty and not usable.
2.Evaporator superheat is 5 degree centigrade
3. The oil is suniso 4GS and refrigerant is R22
4. Oil separator pipe size and discharge line size are the same. Usually for screw compressors we use bigger oil separator than you can see in the picture but since the catalog doesn't mention any possibilities for using an external oil separator we use this.
5. Yes, the oil almost always foam in sight glass.
6. Discharge temperature is about 90 degree centigrade and discharge pressure is 150-165 psi.
7. We are mostly sure that the oil return from oil separator. but there is a doubt that oil could possibly migrate into 3 meter vertical suction line and to the surge drum because of the pressure difference. ( discharge pressure 150/suction pressure 25 psi) there is no connection embedded for the oil return so we used suction connection for that. there are also doubt for using oil cooler route for oil return which we again worries of oil wrong direction passage from oil cooler to oil separator due to little pressure difference.
The other point is that when we reduce the capacity from 100 to 75 and so on the oil foam will return in sight glass more.
this is the link for the instruction manual for this compressor for your reference.
https://www.hosbv.com/data/specifica...HandBook_E.pdf
your advises would be precious for me.
Regards
Originally you say you were draining oil from ice machine & was very dirty?
Now you get nothing.
You can return oil from evaporator automatically if set up correctly, but if in condenser, which I find hard to believe, then eventually it will pass into evaporator.
Pump out condenser, see if any oil in it like people suggest.
Better still, put R32 & air in it, then pump it down, but wear fire suit:off topic:
Re: compact screw oil carry over
1 Attachment(s)
Re: compact screw oil carry over
Quote:
Originally Posted by
l2embo
Hi Tycho
Please provide me with you recommendation on diagrams.
Regards
Sorry for my late answer, but I have been out of town :)
But here is the way to control the oil return from your LP side.
I have been looking fro a proper drawing so I didn't have to make one myself..
Attachment 15423
Now if you look at this picture.
On the left side is the oil return to the suction, there is a solenoid valve and a manual valve.
The solenoid valve should open 3-5 minutes after the compressor started. The manual valve should be a hand regulating valve, and after the hand regulating valve should be a sight glass, so you can correctly adjust the flow of oil/refrigerant going back into the suction.
If you look at the right side, there is a level control valve controlled by a simple regulator...
20 years ago when I worked on these machines, the level were controlled by a danfoss RT280, and they worked like a charm
https://assets.danfoss.com/documents...3586432642.pdf
Re: compact screw oil carry over
Quote:
Originally Posted by
Tycho
Sorry for my late answer, but I have been out of town :)
But here is the way to control the oil return from your LP side.
I have been looking fro a proper drawing so I didn't have to make one myself..
Attachment 15423
Now if you look at this picture.
On the left side is the oil return to the suction, there is a solenoid valve and a manual valve.
The solenoid valve should open 3-5 minutes after the compressor started. The manual valve should be a hand regulating valve, and after the hand regulating valve should be a sight glass, so you can correctly adjust the flow of oil/refrigerant going back into the suction.
If you look at the right side, there is a level control valve controlled by a simple regulator...
20 years ago when I worked on these machines, the level were controlled by a danfoss RT280, and they worked like a charm
https://assets.danfoss.com/documents...3586432642.pdf
There should be pipe connections sticking out of your surge drum at all the appropriate levels :)