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  1. pointsman

    Max allowable pressure drop for control triple eccentric butterfly valves

    Do you mean for use as a throttling valve? In this case the allowable pressure drop depends on a variety of factors (eg. the outlet pressure). Cavitation is a particular concern. What is your application?
  2. pointsman

    EPANET alternating nodes with base demand

    I don't think this can be automated in EPANET. One work around that comes to mind would be to set each node it's own demand pattern, such that only one node activates at a time. Then let the simulation run through all your nodes. Consider that your reservoir level must remain within the range...
  3. pointsman

    how to measure if HDPE flakes are clean?

    Droplet contact angle measurement can be done without specialized lab equipment. Clean vs oily HDPE will have different contact angles. This method could be worth a try if your flakes are large enough to support a droplet of water.
  4. pointsman

    ***LOW PRESSURE SEWER INFORMATION DESPARATELY NEEDED***

    If I'm reading your post correctly, the grinder pump and its check valve are located in your house, and the lateral connects to the outlet of the grinder pump? Grinder pumps are necessary when the downstream piping is pressurized. Otherwise, your lateral would not have a pump and your seweage...
  5. pointsman

    Valve at inlet side of pump

    In theory it could, but won't your valve have a control device (like a handle, or threaded stem) that controls the position of the valve? I think this would be a better solution that relying on the valve's weight to keep it in place. Have you ever seen a valve that uses its weight to stay in...
  6. pointsman

    Clogging potential: orifice vs. slot

    Having taken a look at the constructability side, I've come to the conclusion that a circular orifice will be the best fit for the project. That's a rather interesting method for anticlogging Swazimatt. The overflow equalizes pressure across the obstruction and then the crossflow velocity...
  7. pointsman

    Calculation for HP needed to operate a pump

    Here is a guide: https://www.engineeringtoolbox.com/pumps-power-d_505.html
  8. pointsman

    Clogging potential: orifice vs. slot

    The volume is taken care of, the slope is very shallow and we are only collecting from a width of a few meters along the tracks. Just need to sort out the maintenance on this hole.
  9. pointsman

    Valve at inlet side of pump

    Is the pressure inside the suction pipe less than atmospheric pressure? If so you will have a pressure difference across the cylinder, creating a force pushing the cylinder into the pipe. This assumes that the exterior face of the piston is exposed to atmospheric pressure. Conversely, if the...
  10. pointsman

    Clogging potential: orifice vs. slot

    Fellows, let's consider a concrete lined drainage channel conveying stormwater collected from a railway platform. It should be relatively free of debris, but obviously twigs leaves and branches are a possibility for clogging. The flow out of the channel must be regulated to 25 m3/hr, at the...
  11. pointsman

    Process pressure

    Regarding your 3rd question, EPANET is a free and fairly simple program (also used at the professional level) which can perform the functions that you list. It's geared toward civil engineering applications and will help you develop an intuition for how hydraulic systems behave.
  12. pointsman

    HEC-RAS- culvert modeling- huge jump upstream of culvert

    What is your upstream boundary condition?
  13. pointsman

    HEC-RAS- culvert modeling- huge jump upstream of culvert

    Your velocity in the culvert is quite high, so you should expect a high headloss. If we take the minor loss coefficient of the entrance as 0.5, then the headloss will be v^2 / 2g = 12.92^2 / (2 x 32) = 1.3 ft Which exactly agress with what HEC RAS found. If this disagrees with observations...
  14. pointsman

    HEC-RAS- culvert modeling- huge jump upstream of culvert

    Why is the bottom of the culvert above the channel bed? Not only do you have an entrace loss, you also have a vertical expansion followed by contraction. HEC RAS documentation states that the cross sections upstream and downstream of culvert openings needs to be far enough away from the end of...
  15. pointsman

    HDD, Duckbill Valve and Air Valve

    This cut sheet contains charts showing headlosses for valves of this type. https://www.redvalve.com/uploads/02_09_21_Revised_Brochures/The_Tideflex_Duckbill_Check_Valve_Advantage_Brochure_RV09.00-1_040424.pdf
  16. pointsman

    Fluid Mechanics

    Normally headlosses are calculated based on the velocity just upstream. One exception to this is contractions -- for contractions the higher velocity is used regardless of its position upstream or downstream.
  17. pointsman

    Slow sand filtration - sand supply and control of the filtration rate

    The primary filtering element of a slow sand filter is the biological layer that rests above the sand, which must be ripened (grown) before the filter becomes effective. If you are missing the biological layer then your filtration rate will be much higher than literature values obtained from...
  18. pointsman

    DIAPHRAGM PUMP

    If the application is chemical dosing, then a diapragm pump has a shorter expected life than a peristaltic pump. The advantage is that diaphragm pumps are much less expensive. We'll usually specify that spare pumps be provided and put in storage; this compensates for the reduced reliability.
  19. pointsman

    Environmental Engineer but want to pursue Civil/Structural

    A masters degree isn't a bad idea if you plan on making this your career. Imagine that one day you be on the job market again -- will a potential future employer take you at your word that you self-studied effectively? A masters degree would go a long way towards resolving those doubts.
  20. pointsman

    Troubleshooting High Vibrations in API 610 Multistage Pump Operating with Saltwater

    Is this a long coupled pump, and if so was the shaft realligned after the pump was moved?

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