i have a centrifugal pump with 22-38 mtr head, outlet od = 1 inch, i am getting 3.2 bar after on pressure gauge after reducing it to 1/2 inch......i want increase the outlet pressure, can somebody help

i want t attain 5 bar pressure...is it possible

Pl. look at characteristic H-Q curve of pump. If the desired parameters are not in curve it is not possible. If full data furnished like pump model, system resistance curve etc may be some suggestion can be provided, But reducing pipe size is not the solution for your problem.My Mail:agrao@clikengg.com

Do not waste your time , if you have reduced outlet to 1/2 " that means you have throtled the discharge pipe and you are at the left side of the curve .
please learn the system needs and chuse the right pump fot it .

Just as Amnon said. All you are doing is throttling the pump. Depending on the HQ characteristic you might get 5 bar (although it is very unlikely), but even if you do the flowrate will be almost zero.

If you want more pressure from your pump either have it run at a higher speed or buy a bigger impeller.

this may work depending on pump and impeller type and current pump speed
try fitting an inverter to the motor and increasing the pump speed
regards Ernie Bower

If the pump curve indicates that 5 bar is on the curve then instead of decreasing the outlet from 1" to 1/2" increase it to say 2" Ø. By decreasing the outlet size you are increasing the friction losses and thus reducing the pressure due to increased friction loss.

My dear friends , in order to increase speed or impeller diameter we have to increase motor power . In our proffesion we have to be practical and offer Mr. Anish to buy a new pump , it seems to be a very small pump 1"/1 and might be also cheap to by .
VSD is not the right solution in a technical also economical to solve his problem .
Have a good day
Amnon Jablonsky - Israel

You will need to buy another pump that will give you the desired flow rate at 5 Bar. It sounds as if you are using a close coupled centrifugal pump here which can only achieve the max pressure as indicated.

thanks friends...i have installed the pump ( 1.5 hp , iinch outlet ) near to the tank bottom at a nearest dist 500mm...<.just a wild thought > by increasing the tank height ( suction head ) will this cause any change in the discharge pressure......

Hi Anish-

Sure, the greater suction head will "add" to the total discharge pressure you need, thus helping a lower powered pump achieve a higher discharge pressure. However, with this increased suction head in mind, you still need to plot a "system head curve" on top of the pump curve to see where the pump will operate (where the curves intersect). As another fellow indicated, if the flow is not sufficient at the intersection, a VSD may be used to alter the pump curve to increase output, but it would be best to consult with the pump manufacturer to determine the pump curve at various speeds before deciding whether to buy a new one.

Les Lattig