There’s a wheel barrow in my pipeline!

Rob Welke, from Adelaide, South Australia, took an uncommon cellphone from an irrigator in the late 1990’s. “Rob”, he mentioned, “I assume there’s a wheel barrow in my pipeline. Can you find it?”
Robert L Welke, Director, Training Manager and Pumping/Hydraulics Consultant
Wheel barrows have been used to hold package for reinstating cement lining throughout mild steel cement lined (MSCL) pipeline construction within the old days. It’s not the first time Rob had heard of a wheel barrow being left in a large pipeline. Legend has it that it happened in the course of the rehabilitation of the Cobdogla Irrigation Area, near Barmera, South Australia, in 1980’s. It can be suspected that it may just have been a plausible excuse for unaccounted friction losses in a brand new 1000mm trunk main!
Rob agreed to help his client out. A 500mm dia. PVC rising major delivered recycled water from a pumping station to a reservoir 10km away.
The drawback was that, after a 12 months in operation, there was about a 10% discount in pumping output. The client assured me that he had examined the pumps and so they have been OK. Therefore, it just needed to be a ‘wheel barrow’ within the pipe.
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Rob approached this drawback a lot as he had throughout his time in SA Water, where he had extensive expertise finding isolated partial blockages in deteriorated Cast iron Cement Lined (CICL) water provide pipelines through the 1980’s.
Recording hydraulic gradients
He recorded correct stress readings alongside the pipeline at a number of locations (at least 10 locations) which had been surveyed to provide correct elevation information. The sum of the strain reading plus the elevation at every level (termed the Peizometric Height) gave the hydraulic head at each point. Plotting the hydraulic heads with chainage gives a a number of level hydraulic gradient (HG), very like in the graph beneath.
Hydraulic Grade (HG) blue line from the friction exams indicated a constant gradient, indicating there was no wheel barrow within the pipe. If there was a wheel barrow within the pipe, the HG would be like the purple line, with the wheel barrow between factors three and four km. Graph: R Welke
Given that the HG was fairly straight, there was clearly no blockage along the way in which, which might be evident by a sudden change in slope of the HG at that point.
So, it was figured that the top loss should be because of a common friction construct up in the pipeline. To verify this principle, it was decided to ‘pig’ the pipeline. This involved utilizing the pumps to force two foam cylinders, about 5cm bigger than the pipe ID and 70cm lengthy, alongside the pipe from the pump end, exiting into the reservoir.
Two foam pigs emerge from the pipeline. The pipeline performance was improved 10% on account of ‘pigging’. Photo: R Welke
The prompt improvement within the pipeline friction from pigging was nothing wanting wonderful. The system head loss had been nearly completely restored to unique performance, resulting in a couple of 10% move improvement from the pump station. So, instead of discovering a wheel barrow, a biofilm was discovered liable for pipe friction build-up.
Pipeline efficiency could be at all times be viewed from an energy effectivity perspective. Below is a graph exhibiting the biofilm affected (red line) and restored (black line) system curves for the client’s pipeline, before and after pigging.
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The improve in system head because of biofilm caused the pumps not solely to function at a better head, but that a variety of the pumping was compelled into peak electrical energy tariff. The reduced efficiency pipeline finally accounted for about 15% extra pumping power costs.
Not everybody has a 500NB pipeline!
Well, not everyone has a 500mm pipeline in their irrigation system. So how does that relate to the average irrigator?
A new 500NB
System curve (red line) signifies a biofilm build-up. Black line (broken) exhibits system curve after pigging. Biofilm raised pumping prices by up to 15% in one year. Graph: R Welke
PVC pipe has a Hazen & Williams (H&W) friction value of about C=155. When reduced to C=140 (10%) via biofilm build-up, the pipe could have the equivalent of a wall roughness of zero.13mm. The similar roughness in an 80mm pipe represents an H&W C worth of one hundred thirty. That’s a 16% discount in circulate, or a 32% friction loss improve for the same flow! And that’s simply in the first year!
Layflat hose can have high power value
A working example was observed in an power efficiency audit performed by Tallemenco lately on a turf farm in NSW. A 200m lengthy 3” layflat pipe delivering water to a gentle hose increase had a head loss of 26m head in contrast with the producers score of 14m for a similar flow, and with no kinks in the hose! That’s a whopping 85% improve in head loss. Not shocking considering that this layflat was transporting algae contaminated river water and lay within the hot solar all summer, breeding those little critters on the pipe inside wall.
Calculated by way of energy consumption, the layflat hose was liable for 46% of whole pumping vitality costs by way of its small diameter with biofilm build-up.
Solution is larger pipe
So, what’s the solution? Move to a larger diameter hose. A 3½” hose has a new pipe head lack of solely 6m/200m on the identical flow, however when that deteriorates due to biofilm, headloss may rise to solely about 10m/200m as a substitute of 26m/200m, kinks and fittings excluded. That’s a possible 28% saving on pumping power costs*. In terms of absolute power consumption, if pumping 50ML/yr at 30c/kWh, that’s a saving of $950pa, or $10,seven hundred over 10 years.
Note*: The pump impeller would must be trimmed or a VFD fitted to potentiate the vitality financial savings. In some instances, the pump could have to be modified out for a lower head pump.
Everyone has a wheel barrow in their pipelines, and it solely will get bigger with time. You can’t do away with it, however you can control its results, both via energy environment friendly pipeline design within the first place, or try ‘pigging’ the pipe to eliminate that wheel barrow!!
As for the wheel barrow in Rob’s client’s pipeline, the legend lives on. “He and I still joke concerning the ‘wheel barrow’ within the pipeline after we can’t explain a pipeline headloss”, stated Rob.
Author Rob Welke has been fifty two years in pumping & hydraulics, and never sold product in his life! He spent 25 yrs working for SA Water (South Australia) in the late 60’s to 90’s the place he conducted in depth pumping and pipeline energy effectivity monitoring on its 132,000 kW of pumping and pipelines infrastructure. Rob established Tallemenco Pty Ltd (2003), an Independent Pumping and Hydraulics’ Consultancy based in Adelaide, South Australia, serving purchasers Australia broad.
หลักการทำงานของเกจ์วัดแก๊ส runs regular “Pumping System Master Class” ONLINE coaching programs Internationally to move on his wealth of knowledge he discovered from his fifty two years auditing pumping and pipeline techniques throughout Australia.
Rob can be contacted on ph +61 414 492 256, or e mail . LinkedIn – Robert L Welke

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