Balancing holes resulting in reduced performance?
Balancing holes resulting in reduced performance?
(OP)
We have a pump (high temp service 350 deg C)- sp gr 0.8; flow: 160m3/hr' diff head: 35 mts; etc.
This pump had a history of bearing failures. A decision was taken (after due consultations with OEM, i guess) to drill balancing holes in the impeller to reduce loads on the bearing.
After installation, the pump was reported to be not delivering the required head (ie "poor performance" according to operators).
Can anyone tell me what could be happening here.
We recently took this pump to workshop and inspected the internals: Wearing ring clearances are about 0.5 ~ 0.6 mm; impeller diameter appx 205 mm. Casing and impeller good condition (internally). Bearing condition was good.
Regards
This pump had a history of bearing failures. A decision was taken (after due consultations with OEM, i guess) to drill balancing holes in the impeller to reduce loads on the bearing.
After installation, the pump was reported to be not delivering the required head (ie "poor performance" according to operators).
Can anyone tell me what could be happening here.
We recently took this pump to workshop and inspected the internals: Wearing ring clearances are about 0.5 ~ 0.6 mm; impeller diameter appx 205 mm. Casing and impeller good condition (internally). Bearing condition was good.
Regards





RE: Balancing holes resulting in reduced performance?
Mike Halloran
Pembroke Pines, FL, USA
RE: Balancing holes resulting in reduced performance?
If postioned in the eye of the impeller the function is to try and balance the "suction pressure" to be the same on each side of the impeller, this minimises the axial load on the bearings.
The impeller eye is at inlet pressure which could can be either positive or a negative pressure depending on the inlet conditions.
How was the "not delivering the required head" measured - by direct measurement or by "ëye".
RE: Balancing holes resulting in reduced performance?
Regards
RE: Balancing holes resulting in reduced performance?
RE: Balancing holes resulting in reduced performance?
RE: Balancing holes resulting in reduced performance?
A very astute observation and important star -award comment re the casing/impeller wear rings. I overlooked the fact assuming that the pump had back-side wear rings or else an impeller with close impeller/back cover (casing) running clearance and pump-out vanes.
RE: Balancing holes resulting in reduced performance?
RE: Balancing holes resulting in reduced performance?
The balance holes can be small. As long as they don't clog they will work.
= = = = = = = = = = = = = = = = = = = =
Rust never sleeps
Neither should your protection
http://www.trent-tube.com/contact/Tech_Assist.cfm
RE: Balancing holes resulting in reduced performance?
RE: Balancing holes resulting in reduced performance?