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Recent content by 77JQX

  1. 77JQX

    PE Exam for specialized field

    You should take the exam you can pass and that will benefit you most in the future, including futures where you no longer are employed by the utility. Also, I believe in my State, regardless what experience one has, one can be reprimanded for stamping electrical drawings with a civil license.
  2. 77JQX

    VFDs for Water Well?

    VFDs can have a place in matching pumping rates to well conditions. As you are probably aware, well capacity can change for many reasons, including interference from nearby wells, reservoir depletion, recharge conditions, etc. I have done the energy savings calculations for several municipal...
  3. 77JQX

    angled surface to ball connection

    The vertical force on B from A is equal to the weight of A less the frictional resistance (in the upward direction) caused by the connection of A to the rails.
  4. 77JQX

    Water Cross Restraint Necessary?

    One normally installs valves at crosses. Wherever there is a valve, restraint should be included, so the valve may be closed without damage to the system.
  5. 77JQX

    Approver on professional documents

    I would argue that if in the act of signing the document you can direct changes to your satisfaction, then the document was prepared under your direct supervision, regardless of where you and they fit in the company's org chart.
  6. 77JQX

    Affinity law question

    What TenPenny said
  7. 77JQX

    Conduit across Concrete Drainage Channel

    Why is relocation of the conduit not an option? What does the conduit owner have to say about leaving it hanging in space above an open channel?
  8. 77JQX

    Verify a water tank capacity

    I think you should model a pressure sustaining valve at the inlet to the lower tank, and set the sustain pressure to the HGL of the lower end of the fill pipe. Connect the PSV to the lower tank with a short large diameter pipe. That should allow you to model the hydraulic performance of the...
  9. 77JQX

    Do I need a surge valve or a surge vessel for small sewage lift pumping station with same elevation?

    From a maintenance standpoint I would strongly prefer to upgrade pipe class to handle any surge (or increase diameter to reduce velocity and surge magnitude)rather than installing anti-surge hardware in a sewage line.
  10. 77JQX

    System Head Curve Question

    If I understand correctly, the two system curves were developed (1) with flow through one pump branch to the manifold and then in a single pipe to the tank, and (2) through the two pump branches (in parallel) to the manifold and then in the single pipe to the tank. With the parallel flow found...
  11. 77JQX

    12" Watermain Freeze

    I would suggest that you present the insulating value of your insulating board in terms of equivalent feet of soil, and compare to the standard burial depth of the municipality.
  12. 77JQX

    Object Tracker

    How about this technology? Used to track small frogs in the wild. Might be too expensive for a 12 year olds science project though.
  13. 77JQX

    Sizing distribution main for fire pumps

    Our agency allows for up to 18 fps during fire flows. While I've seen lots of surge issues with pump trips, I don't recall one on the suction side - always the discharge side on pump trips. We would allow the 8-inch pipe.
  14. 77JQX

    Submersible vs. Vertical Line Shaft Turbine Pumps and difference in efficiencies

    We prefer lineshaft where well construction allows. Reasoning is based on differences in the motors: (1) we can change an above ground motor in a day with our service truck cranes, while a submersible requires a drill rig to trip the pump out of the hole (resulting in about a week's outage)...
  15. 77JQX

    centre of gravity, load and footprint

    For similar stability against tipping due to a horizontal disturbing force applied at maximum extension (OP post of 10 May 06:52), I think the weight needs to INCREASE to proportional to the height of the horizontal disturbing force.

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