There’s a wheel barrow in my pipeline!

Rob Welke, from Adelaide, South Australia, took an uncommon phone from an irrigator in the late 1990’s. “Rob”, he mentioned, “I suppose there’s a wheel barrow in my pipeline. Can you locate it?”
Robert L Welke, Director, Training Manager and Pumping/Hydraulics Consultant
Wheel barrows were used to hold kit for reinstating cement lining throughout gentle steel cement lined (MSCL) pipeline building in the outdated days. It’s not the primary time Rob had heard of a wheel barrow being left in a large pipeline. Legend has it that it happened through the rehabilitation of the Cobdogla Irrigation Area, near Barmera, South Australia, in 1980’s. It can additionally be suspected that it could just have been a believable excuse for unaccounted friction losses in a model new 1000mm trunk main!
Rob agreed to assist his consumer out. A 500mm dia. เกจวัดco2 rising primary delivered recycled water from a pumping station to a reservoir 10km away.
The drawback was that, after a yr in operation, there was a few 10% discount in pumping output. The consumer assured me that he had tested the pumps and so they had been OK. Therefore, it simply needed to be a ‘wheel barrow’ within the pipe.
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Rob approached this problem much as he had throughout his time in SA Water, where he had in depth expertise locating isolated partial blockages in deteriorated Cast iron Cement Lined (CICL) water supply pipelines during the 1980’s.
Recording hydraulic gradients
He recorded correct strain readings alongside the pipeline at a quantity of places (at least 10 locations) which had been surveyed to supply correct elevation information. The sum of the pressure studying plus the elevation at every level (termed the Peizometric Height) gave the hydraulic head at every level. Plotting the hydraulic heads with chainage gives a a quantity of level hydraulic gradient (HG), much like in the graph below.
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 in the pipe, the HG would be like the red line, with the wheel barrow between points three and 4 km. Graph: R Welke
Given that the HG was fairly straight, there was clearly no blockage alongside the way, which would be evident by a sudden change in slope of the HG at that point.
So, it was figured that the pinnacle loss must be as a end result of a general friction build up within the pipeline. To verify this concept, it was decided to ‘pig’ the pipeline. ราคาเกจวัดแรงดันน้ำ involved utilizing the pumps to force two foam cylinders, about 5cm larger 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 efficiency was improved 10% on account of ‘pigging’. Photo: R Welke
The instant improvement in the pipeline friction from pigging was nothing in want of superb. The system head loss had been almost totally restored to authentic efficiency, resulting in a couple of 10% move improvement from the pump station. So, as a substitute of discovering a wheel barrow, a biofilm was found liable for pipe friction build-up.
Pipeline efficiency could be all the time be considered from an vitality efficiency perspective. Below is a graph displaying 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 enhance in system head due to biofilm caused the pumps not solely to function at a better head, but that some of the pumping was pressured into peak electricity tariff. The lowered efficiency pipeline in the end accounted for about 15% extra pumping vitality costs.
Not everyone has a 500NB pipeline!
Well, not everybody has a 500mm pipeline of their irrigation system. So how does that relate to the average irrigator?
A new 500NB
System curve (red line) indicates a biofilm build-up. Black line (broken) exhibits system curve after pigging. Biofilm raised pumping prices by as much as 15% in a single year. Graph: R Welke
PVC pipe has a Hazen & Williams (H&W) friction worth of about C=155. When lowered to C=140 (10%) by way of biofilm build-up, the pipe will have the equal of a wall roughness of 0.13mm. The similar roughness in an 80mm pipe represents an H&W C value of one hundred thirty. That’s a 16% discount in circulate, or a 32% friction loss enhance for a similar flow! And that’s simply in the first year!
Layflat hose can have high power cost
A case in point was noticed in an energy effectivity audit performed by Tallemenco recently on a turf farm in NSW. A 200m lengthy 3” layflat pipe delivering water to a gentle hose boom had a head lack of 26m head in contrast with the manufacturers ranking of 14m for the same move, and with no kinks within the hose! That’s a whopping 85% enhance in head loss. Not surprising considering that this layflat was transporting algae contaminated river water and lay within the hot sun all summer, breeding these little critters on the pipe inside wall.
Calculated in terms of energy consumption, the layflat hose was responsible for 46% of whole pumping vitality prices via its small diameter with biofilm build-up.
Solution is bigger pipe
So, what’s the solution? Move to a bigger diameter hose. A 3½” hose has a brand new pipe head lack of only 6m/200m on the similar move, however when that deteriorates due to biofilm, headloss might rise to solely about 10m/200m as a substitute of 26m/200m, kinks and fittings excluded. That’s a possible 28% saving on pumping vitality costs*. In phrases 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 should be modified out for a lower head pump.
Everyone has a wheel barrow in their pipelines, and it only gets larger with time. You can’t get rid of it, however you can management its effects, either by way of energy environment friendly pipeline design in the first place, or attempt ‘pigging’ the pipe to get rid of that wheel barrow!!
As for the wheel barrow in Rob’s client’s pipeline, the legend lives on. “He and I nonetheless joke about the ‘wheel barrow’ in the pipeline after we can’t clarify a pipeline headloss”, mentioned Rob.
Author Rob Welke has been fifty two years in pumping & hydraulics, and by no means bought product in his life! He spent 25 yrs working for SA Water (South Australia) within the late 60’s to 90’s where he carried out extensive pumping and pipeline vitality 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 mostly in Adelaide, South Australia, serving clients Australia broad.
Rob runs regular “Pumping System Master Class” ONLINE coaching programs Internationally to cross on his wealth of knowledge he realized from his fifty two years auditing pumping and pipeline methods all through Australia.
Rob could be contacted on ph +61 414 492 256, or e mail . LinkedIn – Robert L Welke

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