pump discharge pressure and flow rate
pump discharge pressure and flow rate
(OP)
To avoid calculations of pipe lenght, elbows, pipe id etc I placed a pressure guage on the discharge of my pump.
The guage reads 4.26Bar, approx 43meters, approx 130feet
Is it correct to infer this is the pump head loss ?
Fluid is DI water at 20C
Pump is 20Hp data attached.
Hz pump running: 50Hz
Pump rating 3500Hz
The pump forces the water through a loop back to the tank that feeds the the same pump, closed loop during pressure testing.
A vortex meter indicates 100 liters per min. I feel that this value incorrect, any observations confirm that the value of the vortex meter is incorrect?
The guage reads 4.26Bar, approx 43meters, approx 130feet
Is it correct to infer this is the pump head loss ?
Fluid is DI water at 20C
Pump is 20Hp data attached.
Hz pump running: 50Hz
Pump rating 3500Hz
The pump forces the water through a loop back to the tank that feeds the the same pump, closed loop during pressure testing.
A vortex meter indicates 100 liters per min. I feel that this value incorrect, any observations confirm that the value of the vortex meter is incorrect?





RE: pump discharge pressure and flow rate
The pump's head is the discharge pressure minus the suction pressure. Depending on the height of water in the suction tank, that can be close to a bar pressure plus whatever pressure the tank runs at.
I can't really say whether the flow is correct or not from the information you've posted. What makes you think the flow is wrong?
RE: pump discharge pressure and flow rate
RE: pump discharge pressure and flow rate
RE: pump discharge pressure and flow rate
Thus please note that the pump discharge pressure can be converted to feet of head, all in all if you know data on the media your pumping and pump characteristics.
your advise was very helpful!
Sanitary Friction Piping Loss Calculator Results
Based on the information you provided, we have calculated a friction loss of
42.92 m or 4.2 bar*.
Flow Rate: 280 (LPM)
Viscosity: 1 (cP)
Specific Gravity: 1
Temperature: 22° (C)
Tubing Type: Stainless Sanitary Tubing
Nominal Tubing Size: 2 (in)
Tube Length: 200 (M)
45º Elbows: 20
90º Elbows: 20
Tee Flow Through: 2
Tee Flow Branch: 2
Vertical Rise: 10 (M)
RE: pump discharge pressure and flow rate
If you want the pump head, measure the suction pressure and the discharge pressure, the head produced by the pump is the difference.
RE: pump discharge pressure and flow rate
RE: pump discharge pressure and flow rate
It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)
RE: pump discharge pressure and flow rate
"People will work for you with blood and sweat and tears if they work for what they believe in......" - Simon Sinek
RE: pump discharge pressure and flow rate
This is only true given a number of assumptions - 1. You ignore your frictional losses, which may or may not be reasonable. In reality, your pump head will be higher than the difference between discharge & suction head pressures. 2. Your pump nozzles are at the same elevation. 3. Your kinetic head energy is equal at both nozzles (same diameter nozzles ... this factor is often considered negligible)
RE: pump discharge pressure and flow rate
1. You ignore your frictional losses, which may or may not be reasonable. In reality, your pump differential head will be higher than the difference between discharge & suction head pressures.
No, or only very slightly, due to differences between suction and discharge velocity. Pipe friction losses do not enter into the pump head equation
2. Your pump nozzles are at the same elevation.
Again no. Pump differential head is indeed the difference between total suction head and total discharge head (assuming small velocities), which includes elevations.
3. Your kinetic head energy is equal at both nozzles (same diameter nozzles ... this factor is often considered negligible)
Not necessarily, but true only if velocities are the same at suction and discharge.
"People will work for you with blood and sweat and tears if they work for what they believe in......" - Simon Sinek
RE: pump discharge pressure and flow rate
A pressure gauge and a suction gauge is required is required to determine TDH. If it is under a flooded suction conditon subtract the suction reading from the discharge reading and then add the difference in velocity head between the suction and discharge if the suction and discharge flange sizes are different. If it is under a suction lift condition you will need a suction gauge that measures negative pressure. Add the two gauge readings and then add the difference in velocity head between the suction and discharge if the suction and discharge flange sizes are different. Make sure you make the correction for the gauge readings to the pump centerline datum.
Do a shut in head test and you should hit the shut in head point on the curve. Throttle the discharge valve to develop readings and plot it agains the pump curve and tell us what you observe.