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Hydrostatic Testing

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  • #16
    Re: Hydrostatic Testing

    Originally posted by bartnc37 View Post
    go to the local tractor supp;y company or something of that nature. Actually an equipment dealer might be a better bet(backhoes, bobcats etc.) Those rams and hoses run at a couple thousand psi. heck better idea, think log splitter, they run a high psi hydraulic pump and are pretty cheap. you could rig up a injection cylinder to the end of the ram and be off like a prom dress
    Could you elaborate on the injection cylinder more?

    I can envision a moving hydraulic cylinder attached to something.

    I can't envision the device the hydraulic cylinder would attach too in contact with the water at 1000psi.

    Thanks.

    J.C.

    Comment


    • #17
      Re: Hydrostatic Testing

      a small pressure washer pump, with a check valve, the key to hydrostatic pressure testing is low volume and High pressures, the low volume is so if it does blow is so it does not have any volume to cause danger, thus with Hydrostatic, or liquid testing liquids do not compress, so you could have 1000 psi with less than 1/4 of a cubic inch of volume behind it, so all it will do is basically tear not explode, so using a nitrogen cylinder or similar is not wise, as the compressed gas will expand, causing or potentiality causing a explosive type damage,

      I would think some type of a low gallonage pressure washer pump, with a check valve, and possibly even slowed down via pulley or even a hand crank. so one can control the volume, but a pressure by pass should be able to control the pressure,

      fill with normal water pressure then shut it off and then finish pumping up to PSI,

      the cylinder would work but I do know of any "hydraulic cylinders" that are water compatible, but once you have removed all the air you will only need to stretch the hose out until pressure is reached.

      (all a pressure washer pump is normally a small set of cylinders that are on a crank and is water compatible)

      any water compatible pump that is positive displacement should work.

      I did a quick Google search and stainless steel Hydraulic cylinders are made, if you want to make your own hand pump, use a small piston, so you can get the leverage to reach your pressure,

      check this link, http://www.catpumps.com/pumps-hydros...id+-+Cat+Pumps they may have jsut the set up your wanting,
      Last edited by BHD; 01-13-2010, 01:12 AM.
      Push sticks/blocks Save Fingers
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      Comment


      • #18
        Re: Hydrostatic Testing

        Originally posted by JCsPlumbing View Post
        Thanks. Similar to what's being done now but it's taking too long. Remember, the volume. Bringing 500 gallons up to 1000psi reasonably quick is what's needed.

        J.C.
        Water does not compress. If you have minimal air in the hose when you press it up it should not take long to reach 1000 PSIG.

        If these are new assemblies you are testing then I would consider applying pressure in stages and hold for a couple minutes.

        Say start at 100, hold for 2 minutes, then 400 with a hold, then 700 and on up to full pressure.

        That way if you have a bad assembly it will more than likely pop at a lower pressure.
        Last edited by Bob D.; 01-13-2010, 05:20 AM.
        ---------------
        Light is faster than sound. That's why some people seem really bright until you hear them speak.
        ---------------
        “If I had my life to live over again, I'd be a plumber.” - Albert Einstein
        ---------
        "Its a table saw.... Do you know where your fingers are?"
        ---------
        sigpic http://www.helmetstohardhats.com/

        Comment


        • #19
          Re: Hydrostatic Testing

          Originally posted by Bob D. View Post
          Water does not compress. If you have minimal air in the hose when you press it up it should not take long to reach 1000 PSIG.

          If these are new assemblies you are testing then I would consider applying pressure in stages and hold for a couple minutes.

          Say start at 100, hold for 2 minutes, then 400 with a hold, then 700 and on up to full pressure.

          That way if you have a bad assembly it will more than likely pop at a lower pressure.
          I believe water does compress a certain amount & volume causes longer times to produce pressure.

          Would a 5 inch hose 1 foot long take the same time to bring to x pressure as a 5 inch hose 1000 foot long using the same system for pressure?

          J.C.

          Comment


          • #20
            Re: Hydrostatic Testing

            Originally posted by JCsPlumbing View Post
            I believe water does compress a certain amount & volume causes longer times to produce pressure.

            Would a 5 inch hose 1 foot long take the same time to bring to x pressure as a 5 inch hose 1000 foot long using the same system for pressure?

            J.C.
            For hydrostatic testing or plumbing in general, water cannot be compressed. There are some circumstances (which we would never be exposed to in plumbing) where water could be compressed but it is very hard to do and the results are minimal.

            Mark
            "Somewhere a Village is Missing Twelve Idiots!" - Casey Anthony

            I never lost a cent on the jobs I didn't get!

            Comment


            • #21
              Re: Hydrostatic Testing

              Originally posted by ToUtahNow View Post
              For hydrostatic testing or plumbing in general, water cannot be compressed. There are some circumstances (which we would never be exposed to in plumbing) where water could be compressed but it is very hard to do and the results are minimal.

              Mark
              I was told 1% to 2%.

              But I'll propose a question just for my learning.

              If I had a 5 inch stainless steel tube as long as the United States, would the time to bring it to x psi be the same as the time it would take to bring a 5 inch stainless steel tube 10 foot long to the same psi? Filled with water with all air purged?

              I know these are exaggerated questions but if water is not compressable then any pump should always take the same amount of time to reach a certain psi irregardless of volume. Provided you have a solid wall container without any expansion.

              Right?

              Thanks.

              J.C.

              Comment


              • #22
                Re: Hydrostatic Testing

                Originally posted by JCsPlumbing View Post
                I was told 1% to 2%.

                But I'll propose a question just for my learning.

                If I had a 5 inch stainless steel tube as long as the United States, would the time to bring it to x psi be the same as the time it would take to bring a 5 inch stainless steel tube 10 foot long to the same psi? Filled with water with all air purged?

                I know these are exaggerated questions but if water is not compressable then any pump should always take the same amount of time to reach a certain psi irregardless of volume. Provided you have a solid wall container without any expansion.

                Right?

                Thanks.

                J.C.
                Pleeeease, this makes my head hurt just thinking about it. This may help give you an idea:

                "For each atmosphere increase in pressure, the volume of water would decrease 46.4 parts per million."

                or

                " At the bottom of the Pacific Ocean at a depth of about 4000 meters, the pressure is about 4 x 107 N/m2. Even under this enormous pressure, the fractional volume compression is only about 1.8%"

                The amounts are so minimal you and I would never be able to afford the equipment sophisticated enough to measure the differences.

                Mark
                "Somewhere a Village is Missing Twelve Idiots!" - Casey Anthony

                I never lost a cent on the jobs I didn't get!

                Comment


                • #23
                  Re: Hydrostatic Testing

                  Originally posted by ToUtahNow View Post
                  Pleeeease, this makes my head hurt just thinking about it. This may help give you an idea:

                  "For each atmosphere increase in pressure, the volume of water would decrease 46.4 parts per million."

                  or

                  " At the bottom of the Pacific Ocean at a depth of about 4000 meters, the pressure is about 4 x 107 N/m2. Even under this enormous pressure, the fractional volume compression is only about 1.8%"

                  The amounts are so minimal you and I would never be able to afford the equipment sophisticated enough to measure the differences.

                  Mark
                  Oh, it's not over. I've got millions of questions Paw-Paw......

                  J.C.

                  Comment


                  • #24
                    Re: Hydrostatic Testing

                    Okay I just did some rough math for you. If you exerted 815,755.38 psi on water you would loose 1.8% of the volume of the water as the density of the water increases. That 1.8% would in fact be compression.

                    Mark
                    Last edited by ToUtahNow; 01-13-2010, 12:12 PM.
                    "Somewhere a Village is Missing Twelve Idiots!" - Casey Anthony

                    I never lost a cent on the jobs I didn't get!

                    Comment


                    • #25
                      Re: Hydrostatic Testing

                      By the way, I guess if you exert 815,755,380 psi on water it would disappear.

                      Mark
                      "Somewhere a Village is Missing Twelve Idiots!" - Casey Anthony

                      I never lost a cent on the jobs I didn't get!

                      Comment


                      • #26
                        Re: Hydrostatic Testing

                        Originally posted by ToUtahNow View Post
                        By the way, I guess if you exert 815,755,380 psi on water it would disappear.

                        Mark
                        Thanks for the tip. This is what we're planning to do next Tuesday.

                        J.C.

                        Comment


                        • #27
                          Re: Hydrostatic Testing

                          I'll bring My back Hoe over. Please give Log. and Lat. for Nuna
                          I can build anything You want , if you draw a picture of it , on the back of a big enough check .

                          Comment


                          • #28
                            Re: Hydrostatic Testing

                            if you are testing hose then I would guess it is expanding somewhat under the pressure, so that would account for some of your time in coming up to pressure, an increase in volume.

                            too bad you can't use nitrogen to press it up after filling with water. that could get expensive with the number of tests you want to do.
                            ---------------
                            Light is faster than sound. That's why some people seem really bright until you hear them speak.
                            ---------------
                            “If I had my life to live over again, I'd be a plumber.” - Albert Einstein
                            ---------
                            "Its a table saw.... Do you know where your fingers are?"
                            ---------
                            sigpic http://www.helmetstohardhats.com/

                            Comment


                            • #29
                              Re: Hydrostatic Testing

                              Originally posted by Bob D. View Post
                              if you are testing hose then I would guess it is expanding somewhat under the pressure, so that would account for some of your time in coming up to pressure, an increase in volume.

                              too bad you can't use nitrogen to press it up after filling with water. that could get expensive with the number of tests you want to do.
                              Thanks Bob. I too hypothesized that the expansion rate on the hose is a large factor in any time delay.

                              I've been talking to the Cat people since yesterday morning.

                              Pressure setup is currently being used with a 15 minute time to test pressure and I'm trying to get that down to 5 minutes or less.

                              Thanks for everyone's input and ideas.

                              J.C.

                              Comment

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