Tek-Tips is the largest IT community on the Internet today!
Members share and learn making Tek-Tips Forums the best source of peer-reviewed technical information on the Internet!
-
Congratulations cowski on being selected by the Eng-Tips community for having the most helpful posts in the forums last week. Way to Go!
Minimum sumergible level - NPSH available
- Thread starter PalomaP
- Start date
The minimum liquid level in your sump must be above the pump intake by the vortex prevention depth. Minimum distances from pump intake to sump walls and to sump floor should also be maintained.
NPSHa should be calculated from that same minimum liquid level to the pump centerline.
NPSHa should be calculated from that same minimum liquid level to the pump centerline.
GregLamberson
Petroleum
NPSH is a function of the system, which is its sucton head or lift, frictionas, and the vapor presure of the liquide being handled. NPSH for a new system can be calculated, if it is anexisting installation can be determined by pressure/vaccuum gauge.
By definition, NPSH is the net positive suction head above the vapor pressure of the liquid at the suction flange of the pump top maintain a liquid state.
You can use NPSHa = Hp +/- Hs - Hf - Hvp
Basi8cally NPSH = static suction head (if any)+ atmospheric pressure (if open tank) or the psitive pressure (if closed pressurized tank) which is Hp above. Then subtract the vapor pressure (Hvp), friction losses (Hf) and static suction lift (Hs).
The NPSHa is directly dependent on the suction conditions and in turn defines the required suction characteristics of the pump. You haven't provided any detaiuls, but when you consider a typical application of NPSH as it affects the system, the keys are head-capacity and pump suction size.
Greg Lamberson, BS, MBA
Consultant - Upstream Energy
Website:
By definition, NPSH is the net positive suction head above the vapor pressure of the liquid at the suction flange of the pump top maintain a liquid state.
You can use NPSHa = Hp +/- Hs - Hf - Hvp
Basi8cally NPSH = static suction head (if any)+ atmospheric pressure (if open tank) or the psitive pressure (if closed pressurized tank) which is Hp above. Then subtract the vapor pressure (Hvp), friction losses (Hf) and static suction lift (Hs).
The NPSHa is directly dependent on the suction conditions and in turn defines the required suction characteristics of the pump. You haven't provided any detaiuls, but when you consider a typical application of NPSH as it affects the system, the keys are head-capacity and pump suction size.
Greg Lamberson, BS, MBA
Consultant - Upstream Energy
Website:
- Thread starter
- #4
GregLamberson
Petroleum
My apologies, BigInch as usual has nailed it.
Greg Lamberson, BS, MBA
Consultant - Upstream Energy
Website:
Greg Lamberson, BS, MBA
Consultant - Upstream Energy
Website:
![[poke]](/data/assets/smilies/poke.gif "[poke] [poke]")
I could never take advantage of you Quark. Actually
asked a number of NPSH questions just a couple of days
ago.
asked a number of NPSH questions just a couple of days
ago.
- Status
Similar threads
