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 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 had been used to hold kit for reinstating cement lining throughout gentle metal cement lined (MSCL) pipeline building within the old days. It’s not the primary time Rob had heard of a wheel barrow being left in a big pipeline. Legend has it that it occurred through the rehabilitation of the Cobdogla Irrigation Area, close to Barmera, South Australia, in 1980’s. It can also be suspected that it might simply have been a believable 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 problem was that, after a 12 months in operation, there was about a 10% reduction in pumping output. The shopper assured me that he had examined the pumps they usually were OK. Therefore, it just needed to be a ‘wheel barrow’ in the pipe.
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Rob approached this drawback a lot as he had throughout his time in SA Water, the place he had in depth experience finding isolated partial blockages in deteriorated Cast iron Cement Lined (CICL) water provide pipelines during the 1980’s.
Recording hydraulic gradients
He recorded correct pressure readings alongside the pipeline at multiple areas (at least 10 locations) which had been surveyed to provide accurate elevation data. The sum of the pressure studying plus the elevation at each level (termed the Peizometric Height) gave the hydraulic head at each point. Plotting เกจวัดแรงดันน้ำดิจิตอล with chainage provides a multiple level hydraulic gradient (HG), much like within the graph beneath.
Hydraulic Grade (HG) blue line from the friction checks indicated a consistent gradient, indicating there was no wheel barrow in the pipe. If there was a wheel barrow in the pipe, the HG could be like the pink line, with the wheel barrow between factors 3 and four km. Graph: R Welke
Given that the HG was fairly straight, there was clearly no blockage along the way, which might be evident by a sudden change in slope of the HG at that point.
So, it was figured that the pinnacle loss have to be as a result of a basic friction build up within the pipeline. To affirm this principle, it was determined 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% because of ‘pigging’. Photo: R Welke
The immediate enchancment in the pipeline friction from pigging was nothing short of superb. The system head loss had been nearly completely restored to authentic efficiency, leading to a couple of 10% flow enchancment from the pump station. So, as a substitute of finding a wheel barrow, a biofilm was discovered answerable for pipe friction build-up.
Pipeline efficiency could be at all times be seen from an power efficiency perspective. Below is a graph exhibiting the biofilm affected (red line) and restored (black line) system curves for the client’s pipeline, earlier than and after pigging.
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The improve in system head due to biofilm triggered the pumps not only to function at a better head, but that a number of the pumping was forced into peak electrical energy tariff. The decreased efficiency pipeline in the end accounted for about 15% extra pumping power 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 typical irrigator?
nuova fima pressure gauge ราคา (red line) indicates a biofilm build-up. Black line (broken) exhibits system curve after pigging. Biofilm raised pumping costs by up to 15% in a single yr. Graph: R Welke
PVC pipe has a Hazen & Williams (H&W) friction worth of about C=155. When decreased to C=140 (10%) by way of biofilm build-up, the pipe could have the equivalent of a wall roughness of zero.13mm. The same roughness in an 80mm pipe represents an H&W C value of 130. That’s a 16% reduction in move, or a 32% friction loss enhance for a similar flow! And that’s just within the first year!
Layflat hose can have high vitality price
A working example was noticed in an energy efficiency audit carried out by Tallemenco lately on a turf farm in NSW. A 200m long 3” layflat pipe delivering water to a gentle hose increase had a head lack of 26m head compared with the manufacturers rating of 14m for a similar move, and with no kinks in the hose! That’s a whopping 85% enhance in head loss. Not surprising contemplating that this layflat was transporting algae contaminated river water and lay within the hot solar all summer, breeding these little critters on the pipe inside wall.
Calculated by means of energy consumption, the layflat hose was answerable for 46% of complete 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 brand new pipe head loss of solely 6m/200m at the identical move, but when that deteriorates due to biofilm, headloss might rise to solely about 10m/200m instead of 26m/200m, kinks and fittings excluded. That’s a potential 28% saving on pumping energy costs*. In phrases of absolute energy 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 power savings. In some cases, the pump may need to be modified out for a decrease head pump.
Everyone has a wheel barrow in their pipelines, and it solely gets bigger with time. You can’t get rid of it, but you’ll be able to control its effects, both through energy efficient pipeline design in the first place, or try ‘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 still joke in regards to the ‘wheel barrow’ in the pipeline after we can’t clarify a pipeline headloss”, mentioned Rob.
Author Rob Welke has been 52 years in pumping & hydraulics, and never bought product in his life! He spent 25 yrs working for SA Water (South Australia) in the late 60’s to 90’s where he conducted extensive 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 shoppers Australia broad.
Rob runs common “Pumping System Master Class” ONLINE coaching courses Internationally to cross on his wealth of information he learned from his 52 years auditing pumping and pipeline techniques throughout Australia.
Rob could be contacted on ph +61 414 492 256, or e-mail . LinkedIn – Robert L Welke

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