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RANGER1
08-08-2010, 09:36 AM
In newer Howden compressors it indicates 0.003mm
movement axially in thrusts , as being maximum allowable before replacement .

Interpret this as only using a "T" bar pushing in & out by hand , checking reading with suitable dial indicator .

Anybody have any thoughts or experience on this ?

Grizzly
08-08-2010, 09:58 AM
In newer Howden compressors it indicates 0.003mm
movement axially in thrusts , as being maximum allowable before replacement .

Interpret this as only using a "T" bar pushing in & out by hand , checking reading with suitable dial indicator .

Anybody have any thoughts or experience on this ?

All sounds reasonable to me, most other Makes are tested by "clocking" the physical movement present!
The only other usual thrust bearing measurement method is with feeler gauges. Although using gauge is more prone to error!


Maybe Howden themselves will answer, I note they have for you in the past?

Good Luck Grizzly

Andy
08-08-2010, 03:14 PM
In newer Howden compressors it indicates 0.003mm
movement axially in thrusts , as being maximum allowable before replacement .

Interpret this as only using a "T" bar pushing in & out by hand , checking reading with suitable dial indicator .

Anybody have any thoughts or experience on this ?
Hi Ranger:)
from memory the trust is measured by letting off the retaining plate. When running a screws rotors don't float on the trust like a recip shaft. The bearings are preloaded.

Kind Regards Andy:)

Grizzly
08-08-2010, 05:46 PM
Hi Ranger.
Andy is correct.
I have sent you mail.
Below is the relevant page without the picture.
Due to size!


To check the Thrust Bearing Float
Insert a piece of ½" UNC (5/8" UNC on 321 Compressor) screwed rod into the tapped hole in the end of the rotor at the thrust end. Set the clock gauge to Zero, ensuring the clock gauge spindle is touching the end of the rotor. By using a pull and push action while gripping the screwed rod, note the movement on the clock dial. (Fig. 41) This movement is the thrust bearing float. It should not exceed the figure quoted in the table below. (Fig. 42)
Any increase on this figure will necessitate replacement of the thrust bearings, the procedure for which is described per Section 8.2-8.3 or 8.4-8.5.
Fig. 41
NOTES:
It is extremely important that the fasteners on the thrust bearing retaining plates of the 163 compressors are torqued exactly to the specified setting 10lbs ft. (1.4 kgm). Over torquing will not permit correct operation of the thrust bearing, resulting in premature failure.
Should the thrust bearing float be within limits, no further work on the rotors is recommended i.e. journal bearing clearances would not necessarily be measured. Where the thrust bearing float is outside limits and, therefore, the thrust bearings have to be slackened off and removed, the opportunity would then be taken to measure journal bearing condition, and proceed as for major overhaul.
Where a compressor is fitted with condition monitoring, no check on the thrust bearings would be required and a 2 yearly check on the guide block wear and PTFE seal condition would be all
Maximum Thrust Bearing Float
Please note that due to a change in bearingselection, which now means that bearingsare fitted with a pre-load condition, themaximum float permitted is 0.003mmregardless of compressor size.
IF FLOAT OR MOVEMENT IN EXCESS OFTHIS FIGURE IS RECORDED, THRUSTBEARINGS MUST BE CHANGED.

I hope this helps!
If I had got off of my backside this morning you would of had your answer sooner.
Cheers Grizzly

RANGER1
08-08-2010, 08:45 PM
Thanks Grizzly for detailed answer .

It interests me in the description of checking as some people are stronger , heavier etc & may get a different result for changing bearings in a thrust check situation .

If you set up a push - pull bar & do it lightly you can get a different answer , especially for 321.

I find a lot of manuals you can have your own interpretation to a certain degree .

Regards Ranger