How do you read a pump performance chart?

How do you read a pump performance chart?

When you’re reading a curve, the pump’s flow rate will be on the top and bottom and its height to push is on the sides. You’ll want to select the flow rate your application requires by drawing a line up on the chart then select your desired height by drawing a line to the right.

How do you calculate NPSH?

Explanation: To calculate NPSH Available, take the source pressure , add the atmospheric pressure , subtract the losses from friction within the pipeline and subtract the vapor pressure of the fluid . The result equals the NPSHA (or Net Positive Suction Head Available) of your system.

What is pump capacity?

Pump capacity is a term used to define the flow rate through a pump at its designed conditions. It describes the volume of liquid that is allowed to travel through the pump in a given time. Some of the most common units of pump capacity are: Gallons per minute (gpm) Liters/minute (L/min)

How do you calculate the NPSH of a pump?

NPSH (A) = (Pressure on the liquid surface) (ha) ± (suction head/lift) (friction loss) (vapour pressure) (hvp) NPSH (A) = 9.02 + 4-1.2 – 0.25 = 11.57 Mts.

What is meant by NPSH?

NPSH stands for Net Positive Suction Head and is a measure of the pressure experienced by a fluid on the suction side of a centrifugal pump.

How can we prevent cavitation?

How to Prevent Cavitation

1. Reduce motor speed (RPMs).
2. Install an impeller inducer.
3. Incorporate a booster pump into your pump system.
4. If possible, reduce the temperature of your pump, liquid, and/or other components.
5. Increase liquid level around the suction area.

How do you maintain NPSH?

How to Increase the NPSH Margin to a Pump

1. Increase the liquid level in the suction vessel.
2. Eliminate any flow restrictions in the suction piping (such as a strainer)
3. Operate at a flow rate less than the pump bep (see figure 3).
4. Install an Inducer, if available.
5. Change to a low NPSHR impeller, if available.

Does NPSH change with pump speed?

NPSH-Required increases by the 4/3 power of the pump speed, for a given flow rate and Suction Specific Speed, so assuming that the value of the system NPSH-Available is fixed, lower pump speed can increase the NPSH-Margin, and therefore, pump reliability.

How does Suction Head affect pump performance?

Suction Head. These are two equal but opposite forces that affect the flow of water pumps. This is because the water entering the pump applies additional pressure at the suction. Conversely, if the pump is located above the water to be pumped, then the suction head is positive and the pump head will decrease.

What happens if NPSH is less than Npshr?

When the pump is running, the reading from this gauge will be equal to your NPSHA, less vapor pressure. If after subtracting vapor pressure this value is less than the pump’s NPSHR, you have confirmed that this is a cavitation problem.

What is difference between NPSHa and Npshr?

NPSHa is a value that expresses the absolute pressure acting on a liquid as it enters the pump. NPSHr is a value that expresses the minimum absolute pressure that must be acting on a liquid as it enters the pump impeller to avoid excessive cavitation and degradation of pump performance.

What is NPSH margin?

The NPSH Margin is the amount that the NPSH Available to the pump exceeds the NPSHR of the pump, see figure 3. Much higher NPSH Margins are required in High Suction Energy pumps when the pump is at low flow rates in the suction recirculation region. The suction energy determines how much margin is required.

How do you calculate the maximum discharge pressure of a centrifugal pump?

Discharge pressure = Head * density of the fluid. Discharge pressure is in kg/cm².

What is the maximum suction head for centrifugal pump?

approximately 15 ft