API 610 clearances

[frostrobn]

I have a 3600 rpm, double suction, pump with impeller wear rings that are approximately 7.375" diameter. Can anyone tell me what the proper clearance should be in this application? Fluid temp. is 250F.

Thank you.

 

[JJPellin]

Standard API wear ring clearances for that size would be 0.019" to 0.028" on the diameter since the service is less than 500 °F. If the service was hotter than 500 °F, standard clearances would be 0.024" to 0.033" on the diameter.

Johnny Pellin

 

[frostrobn]

Thanks, Johnny!

 

[1gibson]

>500*F or materials with high galling tendency (316 for example) both require the extra 0.005". The API table is minimum clearances, but there is no reason you would want larger, you'd just lose efficiency.

You can go tighter with non-metallic (Vespel CR-6100 case rings for example) because the table only applies to metal on metal running clearances. That is where most of the improved efficiency claims come from for non-metallic rings.

 

[frostrobn]

Thank you.