Perforated Pipe Question
Perforated Pipe Question
(OP)
Im looking to do some calculations on a pump hooked up to a perforated pipe in a tank. The reason is purely for recirculation and agitation. I cannot find any formulas or guides as to how many hole and what size is a safe range( or desirable range) for a given pump and tank size.
Any help or guidance to formulas and/or text would be greatly appreciated.
Any help or guidance to formulas and/or text would be greatly appreciated.





RE: Perforated Pipe Question
The total cross-sectional area of all orifices together is defined based on pressure drop (backpressure) you can afford for the pump, and considering agitation requirements as well. Higher pressure drop increases discharge velocity from each hole, but it imposes higher backpressure on the pump. So you must balance the system accordingly.
See some info at http://www.mottcorp.com/resource/pdf/sparger_desig...
Dejan IVANOVIC
Process Engineer, MSChE
RE: Perforated Pipe Question
I should make it clear as well that I am recirculating the fluid into itself. There is no gas or air used.
RE: Perforated Pipe Question
- How much pressure drop can you afford? --> this will define the size/number of the sparger orifices
- What controls are available on the pump discharge? Is there a net discharge flow out of the system, or everything get recirculated back to the tank? --> if there are no other controls, you have to match the circuit+sparger pressure drop with the pump curve in order to have the desired flow, and also to prevent from pump off-the-curve conditions.
Dejan IVANOVIC
Process Engineer, MSChE
RE: Perforated Pipe Question
I am unsure of the exact pressure drop I can afford but a rough estimate would be 7-10 psi.
Also all fluid is discharged back into the tank, a control valve is in place for flow control but all fluid is routed back to the tank.
The data I have so far is
Pump:
Max flow- 15gpm
Max Pressure- 100psi
Pipe data:
1 1/4"
80 holes, 3/16"
24 foot long
RE: Perforated Pipe Question
You want to size the holes so that the pump runs at it most efficient point. This isn't just to save power, pumps last longer when you operate them this way.
If the holes are oversized, then you will need to throttle the pump discharge to keep it running in range, then the velocity out of the holes will be very low and you will get little mixing.
Will the level in the tank vary? you may meed to allow for this also.
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P.E. Metallurgy, Plymouth Tube
RE: Perforated Pipe Question
Also refer to Perry's ChE Handbook, Section 6, perforated pipe distributors.
Dejan IVANOVIC
Process Engineer, MSChE
RE: Perforated Pipe Question
I believe this is exactly the calculation I am looking for.
I appreciate you're guidance.
RE: Perforated Pipe Question
You have left out many details.
1. Is the sparger on the suction or discharge.
2. Volume of tank to be mixed.
3. Fluid properties.
RE: Perforated Pipe Question
but for your information:
1, Discharge
2, 4200 GAL
3, Caustic soda approx. 30% solution
RE: Perforated Pipe Question
Make sure to look at trace impurities.
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P.E. Metallurgy, Plymouth Tube
RE: Perforated Pipe Question
RE: Perforated Pipe Question
I have determined that I will replace the existing perforated pipe and install a new one.
It will be 2.5" diameter pipe with 60 3/16" holes and 24 feet long.
Currently with a 20 GPM pump I am getting a average orifice velocity of 3.87 ft/s.
Any literature or guidance is appreciated
RE: Perforated Pipe Question
Katmar Software - AioFlo Pipe Hydraulics
http://katmarsoftware.com
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