Acceleration losses in Diaphragm Pump running in Parallel

[bmw318be]

Hi,

I am studying a case of the metering pump running in parallel with the following service

1. 1056 GPH
2. 3 Pumps running in parallel at the same time
3. Suction line is about 40 Meter:
Section 1: From tank outlet nozzle is 3", 16 feet
Section 2: From 3" to common header is 6", 98 feet (This meant to be sharing suction header)
Section 3: From 6" to pump suction is 2", 7 Feet

4. Atmospheric Tank
5. Stroke Per Minutes is 120 SPM


Using the metering pump manufacturer guides, the Acceleration losses through all Pipe section is 30.73 PSI or 2.11 Bar or 21 meter This based on 1056 GPH.
Link

https://www.dropbox.com/s/w0onpq84u...GLE-PUMP-APPLICATION-Rev-B 1056 GPH.xlsm?dl=0

If i running the pump in parallel, shall we considered 1056 x 3 = 3168 GPH Total Flow, this turned out to be very large acceleration losses of 92.19 PSI or 6.35 Bar or 60 meter.
Link

https://www.dropbox.com/s/atmuf9fsc...GLE-PUMP-APPLICATION-Rev-B 3168 GPH.xlsm?dl=0

For this types of pumps, the NPSHr = 5 meter so the NPSHr < NPSHa

Can I get your opinion of the following

1. if the losses shall be multiple by 3 ? would install the inlet dampener bladder help to reduce the acceleration losses by 3 to 4 psi according to Blacoh inlet stabilizer.

https://www.blacoh.com/downloads/literature/Solving_Pump_Inlet_Problems_P21E11_010.pdf

Would the calculated if dampener was installed, we just need to calculate the lines losses after the dampener

2. Currently maximum pipe size is considered 6 " with the space constraints. Bringing the pump closer is also not feasible as this is the retrofitting jobs.

P& ID layout

https://res.cloudinary.com/engineer...ketch_4000_LPH_3_pumps_in_parallel_lyijhy.png

]

 

[georgeverghese]

There are many engineers who have had their fingers burnt assuming they could rely on a suction pulsation dampener, and there will continue to be many more.

 

[bmw318be]

Hi,

George, can you share in whatways the suction dampener does not help. As i know the atmospheric pressure help to pushed the fluid. When the inlet stabilizer or suction dalpener installe, The nitrogen was fill with lower pressure than atmospheric. It create positive head to compensate the losses near the pump when installed.