Help!!! Many problem with single- screw compressors

[rusholod]

Good day colleagues!
I'm a engineer from Russia, the city of St. Petersburg.


Our company is relatively recent works with compressors J & E Hall. For a while until we are working with them we have a problem with data compressors. Operation fully satisfies the requirements of the manufacturer. The main problem with mass flow and discharge temperature. Please help find the cause of data breakage.
If we can't identify it, then we will have to renounce the use of data compressors.

[Magoo]

Hi rusholod.
Welcome to the forum,can you give more information of compressor conditions. Refrigerant and pressures.

magoo

[savoc]

discharge temperature on a screw compressor. have you checked the oil level, oil pressure. More info needed pressures, type of condenser, application of plant.

[rusholod]

Yes. R22. Mobil Arctic oil 300.
Delivery pressure
15 bar
Suction pressure
0.5 bar
Oil pressure 13.2 bar
In the hermetic compressor unit are 3 J & E Hall. They work in 4 rooms with a temperature of-18 degrees. The oil level is maintained constant in oil separator. The oil is in the air oil cooler located above the installation at 8 meters. Oil cooler with bottom feed oil. After the oil cooler, it is mixed with termostatic valve and served in the compressor with a temperature of 50 degrees Celsius

[savoc]

i may have miss under stood. oil going in a termostaic valve? is that valve used for oil cooling? that oil pressure may be a little low are the filters blocked? can you change oil temp. what model compressor? what do you mean data and mass flow? what is your discharge temp? what is your super heat? can you raise the suction pressure are unloaders working? 0.5bar = -30? if your pressure is to low it may cause problems? record all your pressures, temps, refrigerant level, pressure before filters and after filter, pump pressures more info you give us the better we may be able to help you.

[rusholod]

compressor J & E Hall. 4223 HSL model.
Oil cooling is used valve firm DANFOSS ORV. Oil filter clean. Pressure drop on the filter very small. Discharge temperature 76 degrees on one side and 100 degrees.
Load compressor is not uniform. Overheated steam inlet to the compressor to about 25 degrees.
Due to ongoing problems with electricity constantly compressor stops under load. Next run occurs when a load of 100 per cent. Can run under load disable compressor? There is also suspicion that oil dissolves R22 too much!

[chillerman2006]

Yes. R22. Mobil Arctic oil 300.
Delivery pressure
15 bar
Suction pressure
0.5 bar
Oil pressure 13.2 bar
In the hermetic compressor unit are 3 J & E Hall. They work in 4 rooms with a temperature of-18 degrees. The oil level is maintained constant in oil separator. The oil is in the air oil cooler located above the installation at 8 meters. Oil cooler with bottom feed oil. After the oil cooler, it is mixed with termostatic valve and served in the compressor with a temperature of 50 degrees Celsius

Hi Rushold,

(If I am thinking of the right type of compressor here)

Then you are loosing oil pressure somewhere probaly filters

Your oil pressure should be discharge pressure(15bar) minus suction pressure(0.5)

So I would be expecting 14.5bar oil pressure(or closer than you have), you only have 13.2bar

First I would change the filters (all - any external + internal)

And when was the oil last changed ?

Change the oil if its due or there is no record of change

Mineral based oils can start to react over time, even though they have not reached their 'pour point' releasing a 'wax' that builds up and blocks the sytem, this is due to their 'floc point' which is increased with volume

A quick search has revealed it is almost wax free, but over time the large volume you have in your system can still build up,

R's chillerman

[rusholod]

The producer admits drop of oil pressure to 4 bar. The internal filter is removed after 500 hours. Hydraulic cylinders compressor, which control its performance, operate. Compressor performance changes without any problems. And most important, both discharge temperature varied by more than 30 degrees.

[sweimaker]

2.8 oil differential is high... blocked filter perhaps....

oil pressure can be affected by low suction, .5bar on r22,

ouchyyyy.

id go with oil an filter change, and weigh gas out, also check for moisture and acid!!!

[sweimaker]

liquid dryer too. that blocked and you ll get a stupidly crazy low suction, suprised lp has tripped, surely its not set to 0bar/psi

[chillerman2006]

The producer admits drop of oil pressure to 4 bar. The internal filter is removed after 500 hours. Hydraulic cylinders compressor, which control its performance, operate. Compressor performance changes without any problems. And most important, both discharge temperature varied by more than 30 degrees.

Ok, you have all that covered, good

Is this unit low temp water system,? (if not please explain your system)

The reason I ask is,(if Yes) the condition of the water vessel is often over looked, this gives the impression of water flow or txv, but is often a build up of minerals in the vessel, which prevents good heat transfer & low suction pressure.

Let us have as much info as you have & this will then be resolve-able

R's chillerman

[rusholod]

Dear Colleagues,
Possible assumptions associated with the low pressure is not important for solving problems with the compressors. Pressure is 0.5 bar for 22 is the evaporation temperature -32 degrees. The machine operates at low temperature warehouse storage with a high turnover. The problem stems from the fact that the bearings are out of order for main and auxiliary rotors.

[rusholod]

There are suspicions that the compressor starts after it stops at 100% performance lead to shock loads on the bearings of compressor. under the influence of these shocks and bearings are displaced, they do not provide the correct relative position of the shafts.

[chillerman2006]

[QUOTE=rusholod;237888]Dear Colleagues,
Possible assumptions associated with the low pressure is not important for solving problems QUOTE]

If you will not give us the full details of the system, then all I have is a short saying

Jog on

[Plank!]

Are the compressors controlled by a carrel controller?
have had issues before, the controller does not measure the slide position, just counts the number of pulses open/closed.
I doubt that starting the compressor under full load will damage the bearings, the rotors are designed to deal with that.

You may have "hydraulic lock" - if the compressor spins backwards when it stops I've seen oil enter the compressor when stopping at full load. Re-starting without letting it drain will destroy the bearings (and the star wheels)

This is where you should be looking. Don't re-start without proper drain down time.

[savoc]

Discharge temperature 76 degrees on one side and 100 degrees where are you reading these temps? the DANFOSS ORV is used to mix hot/cold oil to maintain a constant temp. lets assume that vavle is working correctly. what do mean by Overheated steam inlet to the compressor to about 25 degrees. Are you referring to superheat? (The problem stems from the fact that the bearings are out of order for main and auxiliary rotors) if you believe the bearings are faulty carry out a end float test or even take a oil sample and send it for testing. have found oil testing to be very helpful and can save a expensive rebuid. Are you sure that the control circuit is working correctly? check the start up, anti recycle timer,unloader, are the room solenoids cycle correclty, dose the loader steps work correctly, what about defrost? hot gas or electric? even check the shut down when all rooms are down to temp. Sound like your plant is all over the place. Very poor commissioning from day one. I would start fresh, start as if you were commissioning plant from brand new.

[Plank!]

what do mean by Overheated steam inlet to the compressor to about 25 degrees.

I think it's supposed to be superheat but lost in translation somewhere via an online translation program :/

I'm also curious about the term "data compressor" would be interesting to see winzip compressing R22

[chillerman2006]

Off topic - needed removing

[RANGER1]

Have read post but can't understand exact problem.

Is one compressors discharge temp much higher compared to the other?

Have seen a few instances on Hall mono screw where drain from compressor housing has ball bearing non return valve (assuming this is similar to what you have).
This is located in compressor itself & is for draining of excess oil when off.

I suggest you remove both inspection covers & inspect star wheels as well as any slack in star wheel bearings ie lift up/down & check clearances with feeler gauges.
Bearings are solid & very little movement of star wheel/rotor , if any at all
While covers are off chek for ball bearing non return valve. Sometimes circlip holding them in fall out into discharge line.
Check valve is difficult to find but is in bottom of casing & angles towards discharge port.
If it is missing expect crazy thing like poor performance,hot, little frost on suction line

[mohmmad thapet]

please I have problem with compressor type Indianian manufacturing. KIRLOSKAR. the problem is abnormal vibration please hilpe me.