3 replies to this topic

[g3wtter]

Increasing Gauge Pressure In The Recycle Stream Of A Dissolved Air Flotation (DAF) Unit

 

The current gauge pressure of the side channel pump in the recycling stream is limited to 4bar and we would like to increase the pressure to between 5 and 7bar.

In the picture below point 1) is the actual operating point of this system assuming that the characteristic curve of this 20 year old pump hasn't changed.

 

now to my question:

 

lets say I would use the pump 1204 instead of 1203 would the new operating point result in point 2) marked in the picture or would it just change the volumetric flow and we end up in point 3) and the gauge pressure wouldn't change at all?

 

any feedback from a knowledgeable and kind soul would be greatly appreciate

Edited by g3wtter, 27 April 2017 - 07:47 AM.

[Saml]

The best answer to this question has been provided by Art Montemayor in another post

 

https://www.cheresou...iquid/?p=109159

 

I cite the most relevant part, for this case, of it:

 

"A pump doesn't create pressure.  A pump forces a flow of liquid through a conduit and it is the resulting downstream resistance to flow that produces the resulting discharge pressure on the pump"

 

So... basically, it depends on how your discharge pipe is configured, what control you have there, etc.

[g3wtter]

The best answer to this question has been provided by Art Montemayor in another post

 

https://www.cheresou...iquid/?p=109159

 

I cite the most relevant part, for this case, of it:

 

"A pump doesn't create pressure.  A pump forces a flow of liquid through a conduit and it is the resulting downstream resistance to flow that produces the resulting discharge pressure on the pump"

 

So... basically, it depends on how your discharge pipe is configured, what control you have there, etc.

so this means no matter what centrifugal pump I use I will only adjust the volumetric flow according to the pump characteristics and the resistance in the piping but I cant increase the gauge pressure. If I want to increase the pressure I need to install something like a backpressure regulator?

Edited by g3wtter, 28 April 2017 - 12:06 PM.

[Saml]

I don't know the downstream configuration you have.

 

If the main resistance downstream the pump is a nozzle or a sparger,  you may assume that the pressure drop throught it will be quadratic (a nozzle datasheet would be better). So with the new pump you will have both more flow and more discharge pressure, but not a vertical line at the same flow (point 2), or a horizontal line at the same pressure (point 3), but somewhere in between.

 

Check this link

http://www.peerlessx...head-curves.pdf