surge vessel design

Not enough information. Most designs are done with the system parameters known.

Most designs are done by someone who is getting paid and has a stake in the outcome.

What are you pumping from and too? You do not have much energy here, so I would not expect a surge drum to be necesary unless the sytem is strange. Do you have any quick shut-off valves, NRV's etc or do you merely stop the pump?

I assume a centrifugal pump and water as the fluid?

I agree with Guest. This system may not require surge vessel. Do proper piping layout.

Can you please provide some more information? Will this surge tank be piped to the suction side of the pump, or to the discharge? The number of starts per hour seems unusually high; is the tank intended to reduce this number by allowing the pump to run longer each time? What is the fluid being pumped?

Thanks for reply,

I can reduce pumps starts up no. so pump can run longer time.

Also fluid is water and surge vessel will be discharge side of pump.

Operational function is ,when pressure in the vessel will equal to pump discharge pressure( 3 bar) the pump will automatically shut off.Again when pressure will decrease gradually up to 1.5 bar then pump will start again.

Thanks

Soumen

You still do not give any details of the system. A little pump like this pumping into a pressurised vessel is most unlikely to require a surge vessel on the discharge of the pump. One would assume that there is an "air cushion" in the vessel to minimise start stops?

same old guest

As a preliminary design, I would want the pump to start not more than about 6 times per hour, but it could be more than that if the pump motor is rated to be started more frequently. With this in mind, each start of the pump would pump 2.5 m³ of water into the system. Estimating that the working volume of the expansion tank is 1/3 of the total volume, the total volume would need to be about 7.5 m³. This is a fairly large tank, and as it is on the discharge side of the pump, it is a 3-bar pressure vessel, and will need to be designed and certified accordingly.

I am trying to think of a way around this, but I haven't come up with a good plan yet. I am guessing that the present pump design is centrifugal, but I wonder if there is a better choice.

Hello Tornado - that's not correct. To get maximum 6 starts/h at 15m³/h, tank volume (between start and stop) needs to be 15/6/4 = 0.625 m³. A bit of elementary calculus shows that max starts/h occurs when outflow from the tank = 1/2 pump flow, with tank volume requirement as above.

But apart from that, it's quite common to limit start frequency of booster sets using expansion tanks by a minimum-run timer for the pump. If this is set to 10 minutes, 6 starts/h cannot be exceeded. If the outflow from the tank falls to zero the pump runs at dead-end condition, but that is OK for a limited time.

Cheers.......Codey