pump discharge size

[cams1975]

Hi

Why would a pump manufacturer design a pump with a 50mm outlet when the pump can generate 14 l/s.
If the pump was connected to 50mm pipe then the velocity would be high an cause problems with noise in the pipe.

Yes ive asked the manufacturer, but still waiting for an answer.

 

[dabluffrat]

50mm discharge at 14 l/s is roughly 1.6 ft/s after converting... this isn't a high velocity for pump discharge.

Did you know that 76.4% of all statistics are made up...

 

[cams1975]

i work out 23 ft/s??

 

[itsmoked]

I find those kinds of speeds coming out of a lot of pumps.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[JohnGP]

It is definitely not unusual to have a larger size pipe connected to the pump discharge (or suction). In fact in the plant I am in I doubt that there are any with same size piping attached. (Makes mental note to see if one can be found.) There are many more factors involved in pump design then just the fluid velocity at the entrance and exit points, and it makes sense to adjust connected piping size to achieve desired velocities.

And dabluffrat, you need to revise your conversion calculator.

 

[wimple]

normally for inline pump, divergent should be installed between pump flange out and discharge pipe, this good practice. same for inlet by the way where a convergent is in between suction pipe and pump flange In.

 

[Artisi]

If the pump was connected to a 50mm line you could say that the velocity in the pipeline would be too high - but there is no rule to say that the pump has to be connected to a 50mm line - you can connect to what ever size pipeline you elect to use based on the pump requirement, friction losses likely to be incurred etc etc.

 

[GPRnD]

25 ft/s is a pretty traditional limit for the design of many pump discharges.

Personally I don't like it. A better approach is to limit the kinetic energy of the fluid at the discharge to a % of the discharge head.

 

[DaveB442]

In my pump course I was told the reason the size of the pump discharge is small is due to cost. It is much more expensive to increase the size of the casting of the pump housing as opposed to just adding a concentric spool to the discharge.

 

[Artisi]

Sure that maybe a valid reason, but if the pump was to be run at half speed then the discharge velocity would be a lot less and could be accommodated in a 50mm line without excessive velocity /friction losses, which at the end of the day is all that is important.

 

[rmw]

A pump doesn't build pressure, it accelerates the fluid. The pressure increase occurs outside the pump when the high velocity of the accelerated fluid is converted to static head right after the exit of the pump as the velocity reduces in the pipe.

rmw