Announcement Announcement Module
Collapse
No announcement yet.
Still more on the theory of water... Page Title Module
Move Remove Collapse
X
Conversation Detail Module
Collapse
  • Filter
  • Time
  • Show
Clear All
new posts

  • Still more on the theory of water...

    thanks for all your answers regarding my previous post... i've got another one for you...

    say i have a 3/4" pipe with 50 psi pushing water. i have a second 3/4" pipe with 20 psi pushing water.

    if at some point i join these 2 pipes with a Y... would the resulting pressure at the end of the Y be 20 psi? 50 psi? 70 psi?

    thnaks all!

  • #2
    Re: Still more on the theory of water...

    survey says 50

    are you trying to fool us or educate yourself?

    let me give you the 3 golden plumbing rules

    payday is friday

    $hit flows downhill

    don't chew your fingernails

    do you have anything else to add

    rick.
    phoebe it is

    Comment


    • #3
      Re: Still more on the theory of water...

      I'm scratching my beard before i chew my fingernails... since i've got plenty of bristles there they're clean before they reach my mouth!!!

      seriously, i'm trying to educate myself on the theory of water... if i have an engine that has 50 hp i can go at a certain speed. if i add 20 hp to that engine, i'll go a little faster... so i think the same would apply to psi...

      now why would the resulting psi at the end of the Y would be 50 since it's got 20 psi more added to the stream?

      Comment


      • #4
        Re: Still more on the theory of water...

        If you capped the end of the wye, the pressure at that point would be 50, AND water would flow from the 50 PSI side into the 20 psi side, if there was a path for flow.

        PSI will not add up. The part you are overlooking is that PSI is measuered with respect to some point. Usually, we are referring to PSIG, but you could also measure PSIA and I think there is another .

        Comment


        • #5
          Re: Still more on the theory of water...

          If you know more about electricity than water it may help you to think of a plumbing system as if it was an electrical system. Water behaves very much like electricity

          Comment


          • #6
            Re: Still more on the theory of water...

            think of two water tanks one 100 feet, and one that is 40 feet, now you know water seeks it own level, the 100 foot tank would be close to 43 psi, and the 40 foot tank would be close to 17.2 psi, lest for the fun it put in check valve so water can not flow back into the tanks,

            you have a pipe for your illustration 150 foot tall,

            where will it seek it own level, 100 feet, 40 feet, or at the 140 foot level,

            I hope you can see the 40 foot tower and the 100 foot tower can not work as a team to push the water up to 140 foot,

            but it can seek it own level at 100 foot, or about 43 psi,

            If we would not have put in the check valves in the true answer would have been 40 feet as the 100 foot tower would have over filled the 40 foot tower, and sooner or later you would have only had 40 foot of water. as the 100 foot tower would have emptied it self into the 40 foot tower over flowing the 40 foot towers tank,

            (I think in your engine illustration you could relate psi to Rpm, if you have engine one running at 1800 rpm and engine two running at say 1000 rpm, and put a direct coupling between them your not going to 2800 rpm, your probably only going to get 1800 at the most and in the process over rev the 1000 rpm engine (unless you would put in a over run clutch, check valve), (just like the 40 foot tall tank and over flow it),
            Push sticks/blocks Save Fingers
            ~~~~~~~~~~~~~~~~~~~
            "The true measure of a man is how he treats someone who can do him absolutely no good."
            attributed to Samuel Johnson
            ~~~~~~~~~~~~~~~~~~~
            PUBLIC NOTICE: Due to recent budget cuts, the rising cost of electricity, gas, and oil...plus the current state of the economy............the light at the end of the tunnel, has been turned off.

            Comment


            • #7
              Re: Still more on the theory of water...

              going back to psi and height,

              your measuring the psi at the base of the tower, or base of the height of it,

              say you have 100 foot tower, at the base of it you would have about 43.3 pounds of pressure, but if I climb or go up on a near by hill at the elevation of 50 feet, and measure the pressure of the water there it will only be about 21.6 pounds of pressure,
              and at the top of the tower if I would put a gage there it would be "0" psi.

              the force of gravity is the or the amount of pull it has on it, if your at the top of the tower there is no weight or pull on top of the water at the surface, now down 50 feet there will be enough pull to create 21.6 pounds of pressure, and at one 100 foot 43.3 pounds, if you would run it down the hill (via pipe) another 50 feet you would now have a total drop of 150 feet or 65 psi. (this would be static pressure not taking in for pipe friction or any other losses that would happen in flow),
              Push sticks/blocks Save Fingers
              ~~~~~~~~~~~~~~~~~~~
              "The true measure of a man is how he treats someone who can do him absolutely no good."
              attributed to Samuel Johnson
              ~~~~~~~~~~~~~~~~~~~
              PUBLIC NOTICE: Due to recent budget cuts, the rising cost of electricity, gas, and oil...plus the current state of the economy............the light at the end of the tunnel, has been turned off.

              Comment


              • #8
                Re: Still more on the theory of water...

                Sh*t flows down hill, not because it wants to but because its the path of least resistance. Water doesn't know where its going, only that it doesn't like to be pushed.

                Comment


                • #9
                  Re: Still more on the theory of water...

                  Everything is cool and clear now!

                  many thanks to you all!

                  now... where's my umbrella... in case **** falls down(hill) on me?

                  cheers!

                  Comment

                  Working...
                  X