centrifugal pump piping 1

[jajoum2]

We want to install a centrifugal pump in our workshop for water circulation. The pump is a single stage and the suction nozzle is 5" while the discharge is 4". The suction and discharge pipes are same size 6". What are the consequences of having both lines to the same size?

 

[UtilityLouie]

I don't think it matters if the system is a closed loop - you don't have to worry about NPSH issues. That's typically why you make the suction piping larger - the flow is the same into the pump as out of the pump.

If you are pumping out of a resevoir or tank at some pressure - you want to minimize the pressure drop in that line by making the line size bigger and not installing suction strainers to make sure you have enough Net Positive Suction Head (NPSH)to prevent cavitation in the pump impeller.

If you are circulating in a closed loop - no worries....

 

[WebWizz]

In general the suction piping would have a larger diameter than the discharge. What really counts though is the calculation of the whole piping system including pipe lengths etc.
For the suction side avoiding cavitation (sufficient NPSH) is the most important factor.

To do these calculations a useful website is

http://www.engineeringpage.com

Choose > pumps > pump conditions

 

[TBP]

If it's a closed-loop, say for hot water heating or chilled water for air conditioning, it's virtually impossible to cavitate the circulating pump. The biggest problem, by far, is selecting a pump with too much discharge head, especially in applications with a big change in elevation. The intial fill supplies the pressure to put water to the top of the system. The weight of the water coming down is the same as the water going up. It's like a ferris wheel. All the circ pump has to do is move the GPM required in a circle. Relatively low horsepower drive and corresponding ly low head.

 

[rmw]

Give us some more information about what the water conditions are. A 5 X 4 centrifugal pump is a serious pump. Either your pump is real big, or your use of the word "workshop" connotes something smaller to me than it really is.

rmw

 

[PAN]

UtilityLouie,

I understand that suction strainer is required in typical installation of pump. Please comment.