Centerifugal Pump Pipe Design for 24hrs.

[nasirqa1407]

Recentely, we faced problem when we run our water supply sestem to our tank. Our system consists of 5 tanks which they can be suction/return tanks depending in the valves. The suction lines of each tank connected to the suction header then to the pump suction inlet. The discharge lines connected to the suction line befor the suction header. Now, if we operate the system in circulation mode from the same tank, we have problem that the pump & pipes become very hot. But if we transfer a water from tank to different tank there is no problem. Our desire is to continued pumping 24hrs from the tank & returned back to the same tank. Could you please help in this issue?

 

[nasirqa1407]

This is the drawing for this thread.

 

[micalbrch]

How big (volume) are your tanks and how big (capacity) your pumps? If you circulate a certain amount of water continuously, you will of course heat up the water. And that will heat up your pump and the pipes. How much depends a lot upon the tank size. When your pump gets water from tank A and transfers it to tank B it is not a circulation. Therefore the water is not heated up.

 

[nasirqa1407]

The Pump Capacity is 400 GPM & the tanks have various volumes from 3000 to 10000 Gallons. Yes if there is transfer no heat existed but if we circulate from/to the same tank.

 

[micalbrch]

You can calculate how long it takes to get the whole volume of the tanks circulated. From 7.5 to 25 minutes. Keep in mind that you transfer energy to the fluid and that creates heating. What can you do? I guess there are not many possibilities. Increase the tank volume or take a smaller pump or install a cooler. All that is not cheap. You did not tell us yet why you circulate the water.

 

[Compositepro]

It looks like you are using only one nozzle connection to each tank for supply and return. When you supply and return to the same tank you do not actually have any flow though the tank. You are simply circulating water in the piping. This relatively small volume will heat up.

 

[nasirqa1407]

micalbrch: This water supplied to mixing process which needs water in 24hrs.

 

[TenPenny]

As compositpro has mentioned, it looks like you are not circulating the water in the tank, if I follow you correctly. Is there only one connection to the tank, and it's in the suction manifold where the discharge connects? If so, when you are circulating, the only water you are circulating is what is in the pipe loop, not the tank. That's why it heats up so much.

In order to have circulation through the tank, you need one nozzle for the inlet to the tank, and one nozzle for the outlet. Without that, you'll have no circulation through the tank.

 

[nasirqa1407]

Gents,
In this case does our system suffer from cavitation due to high fluid temperature? What extera causes if its true.