Screw Compressor Axial Float

Do you mean: you have a chiller which uses a screw compressor, it has an alarm/protection function of axial floating of the bearing of the compressor?

If it is the situation I mentioned, then there're two possibilities:

1)False alarm: the detector of the bearing is loosen or floated away;

2)True floating: the thrust bearing of the compressor failed; (limit of the life, or wear & tear too much)

It is often seen at the situation of using a open type(non-hermetic) compressor chiller, like open type centrifugal, screw compressor, and the lubrication is not good enough.

it is not used for chiller I am not sure what type of gas operation are use it for. we have checked the proximity probe and it is ok as per inst. This compressor has male and female rotor. it has a sleeve bearing. it has only tow months on service. temp of the bearing is ok

Only two months... sorry to hear that, sympathize with you...

Only the sleeve bearing can not work alone, because the differential between the discharge and suction pressure generate the axial force, which needs to be resisted by a thrust bearing or cover (maybe with carbon seal and spring or anything else). You can find it refers to the manual or else. If the probe is normal, the microboard is normal...

I...I'm afraid you may need to change the component...it's high cost...

you are right, Sleeve bearing is used for radial, for sure there is thrust bearing and it is tilting pad type. But if the bearing at 3.8 bar maintaining a good axial while design pressure is 5.0 bar and when we increase the pressure the axial float will increase accordingly that mean the bearing is defected and need to be replaced? waiting for your reply...

Dear Fahad, it's just about work condition. As you mentioned, if the discharge pressure increased but it still has not reached the standard design pressure while much lower than the limit pressure, and it cut out. My opinion is some components must be broken. Why? The bearings are often designed or selected to bear a force that 2 or 3 or even more times of the standard conditon in a short time.

Though I am not sure what kind of machine you are using. As far as I know, every compressor or an equipment that uses a compressor should be intergrated a protection of "High discharge pressure" and other protection of "Currency overload" or "High discharge/Oil temperature". All of these "protection" often cut the equipment out because of the too too high discharge pressure. That's the normal logic. So if the thrust fail to resist the bearing and screw floating before your compressor reach the standard or limit pressure, it's unnormal and dangerous. ( Don't hurt the compressor housing, or you will only to have it discarded)

I can understand your situation...It has been only two months...wish your "baby compressor" is still under the quality guarantee. Then you can make a complaint phone call to claim the service. Or it will cost you much! Good luck my brother.

thanks a lot dear, we will approach the vendor

You are welcome. Good Luck! Bro

Wait for your good news good night!

Fahad,

I took a moment to review your previous posts, they all seem to be around compressor troubles in one form or another.

Is this all the same little Atlas unit?

You may need to sit down and look closely at the initial installation and start up procedure, as these problems (may) have been self inflicted.

It looks like you had immediate issues overheating the motor and now experiencing air end premature failure???

Is this all the same little Atlas unit?

No, it is not

Thanks to Tim :-)

Reading and following the manuals about installation and start up procedure intensively is always necessary and important whateve how familar we get with the equipment.

Fahad's compressor can run at 90% load, oberviously, he succeeded in starting up the equipment. So I exclude those problems at once (operation procedure, installation and so on). If the level, the parallel of the installation is not good enough, will this problem result in the axial floating? (basic position is not correct) Supposed the parallel is really terrible, then firstly the noise of the compressor will sound different, sometimes it will even higher than 120 db for twin screw compressor. But it seems Fahad never mentioned the unnormal noise and the temperature of the bearing keeps well. It's not bad to checking the parallel, it is easy to do and get a exclusion. And adjusting the vibration dampers can modify the parallel of the installation.

I still doubt the bearing problems. It may be the assemble tolerance is not good.

How did the phone calls to the original equipment manufacturer go?

This post was published quite a while ago. I would like to know if you have already resolved this issue? If so, could you please share how you solved it?