Preview

Calculating Npsh of Pump

Good Essays
Open Document
Open Document
393 Words
Grammar
Grammar
Plagiarism
Plagiarism
Writing
Writing
Score
Score
Calculating Npsh of Pump
NPSHA in the system is calculated as :
NPSHA = Terminal Pressure in the vessel (in guage)
(+) Static Head of fluid above pump centre line (see note).
(+) Atmospheric Pressure
(-) Vapour Pressure of liquid at pumping temperature
(-) Friction loss in suction piping up to pump centre line consisting of the following :
• Entrance and exit losses
• Loss in suction strainer
• Loss in control valves, instruments, exchangers etc. if any
• Line losses
Note : a) The height of liquid in the vessel should be taken to be at the vessel bottom tangent line.
b) Height of the pump centreline is calculated as follows :
HPC = HPB + F where
HPC = height of pump centreline above finished floor level
HPB = height of pump centreline above pump baseplate
F = height of pump foundation above finished floor level
HPB is estimated from the following table based on typical vendor information :
Pump Flow Rate Height of Pump Centreline
(m3/hr) above Base Plate HPB (mm) upto 200 450
200 - 300 650
300 – 400 750
The height of foundation F is typically taken at 300 mm.
Calculate NPSHA carefully considering all Conditions i.e. start-up, original fill of lines, winter operation, all control valve pressure drops, summer operation, piping conditions, exit and entrance losses. Provide
NPSHA at 1 meter over worse conceived NPSHR curve by the manufacturer. In general, NPSHR of pumps should be considered as 3.0 meters, though the exact requirement, will be specified by the pump manufacturer. In case of submersible pumps, the available submergence should be specified.
NPSH is a function of flow, it should always be determined at design capacity regardless of the total head required. It is not uncommon for NPSHR curve to turn upward at low flows. Low flow effects can often be amplified by selecting too large a pump which forces re-circulation within the pump.
When liquids at their bubble points are pumped from closed vessels, NPSHA is only the static liquid head above the pump

You May Also Find These Documents Helpful

  • Satisfactory Essays

    Excercise 5 Activity 1

    • 553 Words
    • 2 Pages

    2. Explain the effect that the flow tube radius change had on flow rate. How well did the results compare with your…

    • 553 Words
    • 2 Pages
    Satisfactory Essays
  • Good Essays

    Physio 9.0 Cardio Lab Report

    • 2277 Words
    • 10 Pages

    2. Explain the effect that the flow tube radius change had on flow rate. How well did the results compare with your prediction?…

    • 2277 Words
    • 10 Pages
    Good Essays
  • Satisfactory Essays

    2. Explain the effect that the viscosity change had on flow rate. How well did the results compare with your prediction?…

    • 556 Words
    • 3 Pages
    Satisfactory Essays
  • Satisfactory Essays

    7. To properly measure liquids you read from the bottom of the meniscus which is the slightly concave surface of the liquid.…

    • 739 Words
    • 3 Pages
    Satisfactory Essays
  • Powerful Essays

    a. A column of liquid is found to expand linearly on heating 5.25 cm for a 10.0oF rise in…

    • 1644 Words
    • 7 Pages
    Powerful Essays
  • Good Essays

    Dish Soap Lab

    • 916 Words
    • 4 Pages

    b. Pour the milk from the beaker into the graduated cylinder, so that the markings on the cylinder show that there are twenty (20) milliliters in the cylinder, where the markings line up with the meniscus.…

    • 916 Words
    • 4 Pages
    Good Essays
  • Satisfactory Essays

    c. Control the flow rate to prevent the sample from becoming too spread out on…

    • 553 Words
    • 2 Pages
    Satisfactory Essays
  • Good Essays

    level pool routing report

    • 1215 Words
    • 35 Pages

    The inflow into the tank was then graphed to show the Inflow vs. Time, the results obtained had some outliers in the initial negative trend so a linear interpolation of the part of the data set was instead used. The amendment via linear interpolation can be found in Appendix A, the graph is displayed below in Figure 1.…

    • 1215 Words
    • 35 Pages
    Good Essays
  • Good Essays

    Basic Hydraulics

    • 3586 Words
    • 18 Pages

    Main relief valve is part of the power unit, causes system pressure and it’s a safety valve!…

    • 3586 Words
    • 18 Pages
    Good Essays
  • Satisfactory Essays

    ISSUE FOR DESIGN (modified par 4.4) ISSUE FOR DESIGN ISSUE FOR DESIGN ISSUE FOR APPROVAL DESCRIPTION…

    • 8158 Words
    • 33 Pages
    Satisfactory Essays
  • Good Essays

    Series and Parallel Pump

    • 682 Words
    • 3 Pages

    The objective the experiment is to determine the flow rates and pressure head of a single pump and of two identical pumps. In this experiment, centrifugal pumps have been used to determine the flow rates and the pressure head. This experiment is conducted in series and parallel to identify the pressure different in both pumps. Centrifugal pump is known as one of the most widely used pumps for transferring liquids. It’s also known as a device to transfer mechanical energy from a prime mover into fluid energy to produce the flow of liquids. The pump is connected in 2 ways; in series and another as parallel pump. Centrifugal pump are connected in parallel because to provide enough flow rates compare to centrifugal pump that connected in series, the function is to provide enough head for the flow of liquids.…

    • 682 Words
    • 3 Pages
    Good Essays
  • Satisfactory Essays

    are a pump and an electric motor (that is the motor needed in order to drive the pump); the analysis provides…

    • 1038 Words
    • 5 Pages
    Satisfactory Essays
  • Better Essays

    Lm-37

    • 4396 Words
    • 18 Pages

    o Direct pumping o Indirect pumping o Bypass pumping However in all variants of the processes, the basic methodology remains the same. Water is pumped at a sufficiently high pressure, 200-400 MPa (20004000 bar) using intensifier…

    • 4396 Words
    • 18 Pages
    Better Essays
  • Satisfactory Essays

    TRAINING PROGRAM ON GAS PIPELINE NETWORK ANALYSIS & SYSTEM MODELING Organized by: Bangladesh Petroleum Institute (27th August, 2013) COURSE PLAN • System Modeling of a Transmission System • System Modeling of a Distribution System • Selection of Appropriate formula • MODEL CALIBRATION • Discussion PRESENTED BY: ENGR. KAZI MD. ANWARUL AZIM 2 GAS MARKETING SYSTEM PRESENTED BY: ENGR.…

    • 5514 Words
    • 23 Pages
    Satisfactory Essays
  • Satisfactory Essays

    Conduction Heat Transfer

    • 403 Words
    • 2 Pages

    This problem is important in the process industries, but we do need to make the distinction between thick and thin walled pipes. In general thin walled pipes can be considered by the previous analysis – but assuming that the pipe wall is effectively unwrapped so that it looks like a flat plate, with the process fluid on one side and the ambient condition on the other. The situation for thick pipes is, however, more complex.…

    • 403 Words
    • 2 Pages
    Satisfactory Essays

Related Topics