Anyone can help how to solve my problem quickly?? 2

[lukitorio]

We had chiller unit to chill the water to provide 4 degC for Oil Fractionation system.
The chiller consist of two circuits, where one circuit has three compressors and the other has two compressors. The compressors are come from Carlyle Compr. 06EA599600 (it was 06EA299600 before).
Yes the compressors were installed in parallel system. However preventing process shutdown due to repetitive failure of the compressors, we now try to make a compressor work as individual as possible, by installing each compressor with individual oil separator and controls. However we still (due to evaps and condenser) we still at the end paralleling those such as after oil separators has a discharge manifold to condensor and having one suction accumulator at each circuit before entering compressors. Compressors are started in asequence according to the temperature ranging from 8 degC down to 4 degC. Our recent problem now is the oil migrate not from "run" unit to "off" unit, but rather from "off"(?) to "run" unit. In circuit having three compressors, the oil flooded was found in the middle one (a strange thing was not vice versa). We are not using the equalizing line as recommended due to the fact that preventing liquid flooded and shutdown the whole process just to repair on the compressor will cost a lot and loosing our company's opportunity. That process is our company's backbone product.

We need anybody advice to levelling the oil at the compressor, working in semi-parallel like we had. We need the answer urgently.
Thanks

 

[absrbrtek]

If you are using them in parralel youll need to add equalizer lines and do some internal compressor modifications. Or put an oil seperator in the common discharge line on with a resevoir and add floats to the sightglasses on each compressor.

The 06EA299 has a tendency to break up due to the size of the pistons and the stroke. They tend to be the weakest O6E compressors out there.

 

[imok2]

I don't see any good solution except to do as the manfg recommends. It is important that the oil equalizing line be connected to the compressor body at the minimum oil level line, so that a slight difference in crankcase pressure will not force the oil below a minimum operating level in the crankcase. The gas equalizing line should be pitched from the center toward each compressor or supported rigidly enough to prevent sags or traps which might fill with oil and restrict the passage of gas. These lines should be of ample size to allow free equalizing of the oil level. If the manufacturer has provided taps in the compressor for these lines, use the same size pipe as the compressor openings provided by him. Intall one valve in each line, and a means of disconnecting at each compressor, should be provided for the removal of either compressor without taking the other out of service.

cogito ergo sum "I think, therefore I exist"

 

[icer]

Lukitorio:

The answer of imok2 is very correct. Be also sure that all compressors are at the exact same hight. Not one compressor higher than another.
The oil ecualization line should not rise over the level of the connection.
I also suggest check valves after each oil separator.
If nothing works there is a much sophisticated system with oil reservoirs (an more expensive).
Be sure that the diameter of the gas icualization is big enough, normaly bigger than the oil line.

 

[lukitorio]

Thanks for the answers of my problem. However the equalizing line was there originally but lots of problems were happened befor I was joined with the company. The main problem was liquid entrance to the compressors and loss of oil due to migration from "run" to "off" line.
At present the only problem just a different oil migration from "off" to "run" unit, especially when the middle compressor is running; but the level will stays if the middle "off" and side comressor "run".
The piping arrangement was made as such that not directly parallel. Discharge compressor on each unit had oil separator installed, the ogas utlet of the oil separators then joined to go to condensor using common line. Leaving evaporator, there is a suction accumulator installed at the LP gas outlet of the accumulator then split to every compressor. We had checked both the dryers and accumulator there is no indication of oil entrainment. Therefore what we suspect was an equalizing check valve at the lock bolt at each compressor. We understand that direct parallel required an equalizing line, but now we are not using direct parallel of the system. Thank you - lukito