Function of demister and labyrinth in centrifugal chiller

[Mechya]

Hi to all

I appreciate any responses from our group of experts. Can anybody explain the function of demisters and the labyrinths in the centrifugal chillers.

Thanks in advance

 

[imok2]

In every process involving contact between liquid and flowing gas, as in a centrifugal refrigeration compressor tiny mist droplets are carried away with the gas. This phenomenon is called entrainment.
So special devices were developed to remove mist from gas streams. known as mist eliminators, these devices provide a large surface area in a small volume to collect liquid without substantially impeding gas flow. Unlike filters, which hold particles indefinitely, mist eliminators coalesce (merge) fine droplets and allow the liquid to drain back to the oil sump and to further maintain the oil integrity of the oil system. We need to make sure that all the oil used is returned to the oil sump, so a labyrinth seal, which is a mechanical seal that fits around a rotating shaft is installed to prevent the leakage of oil or other fluids

 

[quark]

A labyrinth seal is a mechanial seal with no. of grooves on the inner periphery (tortured path) to reduce the pressure difference of flowing fluid from one groove to another groove and thus creating resistance to the flow. Centrifugal force and gravity assist the cause.

The main drawback with labyrinth seals is that they can't seal if the shaft is not rotating.

 

[imok2]

"The main drawback with labyrinth seals is that they can't seal if the shaft is not rotating". Quote
True but in a Centrifugal machineat rest the pressures equalize so the leakage is minimal at best.