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  1. nondimensional

    Seizure of Multistage Vertical Centrifugal Pump

    Thrust reversal during coast down?
  2. nondimensional

    Pipe pressure class

    I figured out that this was depth of cover. Thanks for all the input. Appreciate your responses. PS: That was project specific numbering system.
  3. nondimensional

    Pipe pressure class

    I have a PCCP pipeline profile drawing showing pipeline pressure class as 100-6, 150-10, etc. I understand the first number is a pressure class. As in 100-6 means 100 psi pipe. But what does the second number mean - 6?
  4. nondimensional

    Pressure Relief Valve on a Force Main

    Draw a system curve from pump station to the high point only. Draw a second system curve from pump station to final discharge manhole ignoring the high point. At your rates flow, whichever gives you highest head is your pump TDH. If this happens on the first system curve then add a vent...
  5. nondimensional

    Minimum Flow in pump

    At higher head on an OH pump, bearing life may change.
  6. nondimensional

    Can a pumps suction gauge ever read below NPSHr, taking into account atmospheric pressure

    Bernoulli says that high velocity is low pressure. As fluid accelerates into the impeller right at the inlet, pressure drops locally creating a flashing effect. This may not be happening in the suction pipe where velocity is relatively constant and relatively low.
  7. nondimensional

    How to calculate mass moment of inertia

    If I may ask, what is the ultimate idea of calculating the moment of inertia of the water?
  8. nondimensional

    HI 9.6.6, E.2 Flow Straightening Devices

    Type of flow conditioning depends on the media you are pumping. What is your pump capacity, type and media? I have seen & used baskets on clean media pumps, single vanes on large sewage pumps, and diffusers on small end suction units.
  9. nondimensional

    Epanet not calculating D-W friction factor properly

    Friction factor is a function of the distance of the pipe, i.e., f in EPANET is f per 1000 ft of pipe because headloss is for 1000 ft of pipe.
  10. nondimensional

    HI 9.6.6 - Physical Model Study for Pump Inlet Piping

    All the measurements, swirl angle, rotations, time averaged rotations, etc are all laid out clearly in HI 9.8. This can be scaled to the existing model as long as the model has a minimum Weber and Reynolds. Then Froude number should be matched.
  11. nondimensional

    Diesel Driven Vertical Turbine Pump (875HP)

    Artisi, With all due respect, I have just one word - Boeing. They all worked, until they didn't.
  12. nondimensional

    Diesel Driven Vertical Turbine Pump (875HP)

    Are the engine and the right angle gear on the same baseplate with machined mounting surfaces? If not, I suggest you go with a flexible coupling instead of rigid shaft connection. For lateral and torsional analysis, HI 9.6.8 is a great start. Also, see API 610 section 6.9. With so many...
  13. nondimensional

    Diesel Driven Vertical Turbine Pump (875HP)

    In the US, if the engine is the prime mover then the engine will have to rated for Tier IV emissions. Check with local emissions requirements. I would start with dynamic lateral and torsional analysis for the whole pping unit as a requirement since there are too many moving parts. A rubber boot...
  14. nondimensional

    TOTAL HEAD CALCULATION

    For academic purposes, velocity head should NOT be ignored. Also, gauge elevation correction should be accounted for as well (z term in Bernoulli's).
  15. nondimensional

    Reverse osmosis permeate discharge pressure

    Ashtree, I will have to respectfully disagree. 1x water goes to tank. You indicated that 1.33X water will have to be pressurized. The .33X is brine reject. Whatever additional head you put into the additional 0.33X water is still retained by that water, and CAN be recovered. If the tank is...
  16. nondimensional

    Reverse osmosis permeate discharge pressure

    Instead of asking yourself why typical systems don't have more than 1 barg, ask why do I need anymore pressure. Agree with LittleInch here: Most of the time this water just goes into a tank - why do you need pressure? Also, agree with ashtree on higher energy consumption for feed water pump...
  17. nondimensional

    Allowable ANSI pump foundation tilt

    If piping does not move because of good harnessing, then the pump nozzle will see excessive moments. This will cause shaft deflection in excess of 0.002 in and potentially destroy mechanical seals - repeatedly. Based on pump size and type, it can cause high stresses in casing/discharge head and...
  18. nondimensional

    Fluid pass through centrifugal pump

    CheemaJ, To understand the answer to your question well, please read about FOUR QUADRANT CURVES in publications by R.T.Knapp (1930s). This knowledge gives you an understanding of what the pump (overall as a unit) is doing when it is spinning - no matter which direction, no matter whether there...
  19. nondimensional

    Estimate energy cost for small pump-injector system for Ozon treatment

    When you say a venturi pump, are you talking EDUCTOR? If so, the eductor manufacturer should give you the requirements for this. This below is based on the assumption that you are using an eductor/venturi for extracting Ozone. See image below. In this image, you know a given required Ozone...
  20. nondimensional

    Estimate energy cost for small pump-injector system for Ozon treatment

    Pump headloss calculation is no different in any other situation. Downstream of the injector, you will need a mixer - usually a static mixer by Mazzei, Sta-ti-Flo or equal - followed by the rest of the pipe. Static mixer adds about 5 to 7 psi of head to the pp besides the piping friction and...

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