My recommendation is Gülich's book Centrifugal Pumps. See the link below.
It is a worthy successor to Igor Karassik's book and (in my opinion) far surpasses it in terms of technical depth.
http://www.amazon.com/Centrifugal-Pumps-Johann-Friedrich-G%C3%BClich/dp/3642128238
You end up with the same answer either way. I just expressed it differently.
Try a worked example:
Suction pressure = 1.5 barg
Pump differential head at shutoff = 120m (maximum differential head)
Density = 1000 kg/m3
g =9.81 m/s2
Maximum differential pressure = 120 x 1000 x 9.81 / 100000 =...
That part is understood, however just buying 2 pumps with >10% head rise to shutoff will not assure successful parallel operation.
The matching of the curve shapes of the two pumps is at least as important and is something that sadly API 610 doesn't currently provide guidance on.
Bowl efficiency is typically quoted on vertical turbine type pumps like a VS1 type.
It is the efficiency attained by the pump when measured immediately after the final pump stage.
The pump efficiency is the efficiency of the pump when measured at the discharge flange of the pump.
In the...
The pump vendor will confirm he maximum differential head (or shutoff head)
Max differential pressure = rho x g x h where
rho = the fluid density in kg/m3
g = the gravitational constant - normally 9.81 m/s2
h = the maximum differential head supplied to you by the pump supplier
The answer with...
Just to mirror the other comments:
The selection point is kind of bad. Your life cycle cost will be significantly higher as a result.
The 10% API 610 requirement is a bit of a fudge IMO. What matters at least as much is the matching between pumps in parallel (when they are fixed speed). I...
I agree with JJPellin in that cavitation is an uncommon cause for shaft fatigue.
Before we all launch into possible root causes, is it possible to share some information that might help focus discussions:
Where the pump is operating relative to BEP and NPSH margin
What the vibration spectrum...
Nick, just for the sake of clarity when you quote an Nss of 12,000 is that in US units (USGPM,ft) or metric (m3/hr, m) ?
Additionally I'd recommend you go direct to the Goulds aftermarket central engineering office in Glasgow UK. They might be more responsive to the request for a different...
JJPellin does bring up a good point. Where you measure the pulsation when you have a resonance does matter. The pipe tappings need to coincide with the expected location of the pulsation and not be at a node. Having 2 sets of tappings spaced apart is a definite advantage. MSI claim they can...
Here is my favourite acoustic/vane pass study. I remember being astounded when it was presented.
Basically it is a checklist of what not to do...
http://turbolab.tamu.edu/proc/pumpproc/P27/Rotor%20Retrofits%20Improve%20Pump%20Station%20Vibration.pdf
We've used MSI (Mechanical Solutions Inc) in the past. They are pretty good with tricky pump problems. Since it looks like you are outside the US, they may not be your lowest cost source however.
If acoustic resonance is found to be the cause, the solution generally involves either changing...
Since the vibration band of interest is vane pass and temperature dependent the two things that come to mind are:
1. Changes in support stiffness as the structure heats up. It may be that the thermal expansion provisions on the pump/baseplate and/or pipe loadings is changing with temperature...
I'm not sure if it helps you but:
ITT Goulds does offer a VFD (PumpSmart) that will achieve flow control to a claimed accuracy of +/- 5% using the measured power. Obviously this would require neither a pressure sensor or a flowmeter. The main drawback is that it won't work in applications...
electricpete, if you do what FLS recommend, you basically end up with an oil bath arrangement with the slinger augmenting the oil circulation in the sump. My personal experience with shafts of 65-70mm is that churning losses will be significant at 3560 RPM. My OH2 bearing designs would not...
The link below talks about standing waves.
http://phys.strath.ac.uk/12-156/12156PDF/wwol10.pdf
Or you can just google the topic in relation to standing waves excited by pumps. The second link covers the application of standing waves to pumps...
