Location of balance drum in a compressor.

[rQuestionEngineering]

Noted some balance drum are located on the suction end of a compressor, some are on the discharge end of a compressor ? What is the design consideration of locating a balance drum ?

 

[JJPellin]

I don't recall ever seeing a balance drum on the suction end of a compressor. It is sometimes on the inboard end and sometimes on the outboard end. But, for our machines, it is always on the discharge end. A machine cross-section would be helpful.

Johnny Pellin

 

[rotw]

Think there might be a little confusion.
For a straight-through configuration, the balance drum is on the casing end / discharge side ALWAYS.
The thrust bearing is on the discharge side; in some special cases the thrust bearing can be on suction. This is called reversed flow path. For back to back arrangements, the balance drum is on suction side (of 2nd stage). The thrust bearing is on suction side and that can be either 1st (exceptionally) or 2nd stage.
There is also two stages machine, with inline arrangements which I wont cover here. These are rarely supplied; but it can also have its specifics.