There’s a wheel barrow in my pipeline!

Rob Welke, from Adelaide, South Australia, took an uncommon cellphone from an irrigator within the late 1990’s. “Rob”, he mentioned, “I think 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 carry equipment for reinstating cement lining throughout delicate metal cement lined (MSCL) pipeline construction within the outdated days.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 occurred through the rehabilitation of the Cobdogla Irrigation Area, near Barmera, South Australia, in 1980’s. It can additionally be suspected that it might simply 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 primary delivered recycled water from a pumping station to a reservoir 10km away.
เกจวัดแรงดัน4นิ้วราคา was that, after a yr in operation, there was about a 10% discount in pumping output. The shopper assured me that he had tested the pumps and they have been OK. Therefore, it just needed to be a ‘wheel barrow’ in the pipe.
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Rob approached this downside much as he had throughout his time in SA Water, the place he had intensive expertise locating isolated partial blockages in deteriorated Cast iron Cement Lined (CICL) water provide pipelines in the course of the 1980’s.
Recording hydraulic gradients
He recorded accurate pressure readings alongside the pipeline at multiple places (at least 10 locations) which had been surveyed to provide accurate elevation info. The sum of the pressure studying plus the elevation at each point (termed the Peizometric Height) gave the hydraulic head at each point. Plotting the hydraulic heads with chainage provides a multiple level hydraulic gradient (HG), very like within the graph below.
Hydraulic Grade (HG) blue line from the friction checks indicated a constant gradient, indicating there was no wheel barrow in the pipe. If there was a wheel barrow in the pipe, the HG can be just like the pink 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 along the finest way, which would be evident by a sudden change in slope of the HG at that time.
So, it was figured that the top loss have to be due to a basic friction build up within the pipeline. To affirm this theory, it was decided to ‘pig’ the pipeline. This involved utilizing the pumps to drive two foam cylinders, about 5cm bigger than the pipe ID and 70cm lengthy, along 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 instant enchancment within the pipeline friction from pigging was nothing in want of superb. The system head loss had been virtually totally restored to original performance, leading to a couple of 10% move improvement from the pump station. So, instead of finding a wheel barrow, a biofilm was discovered answerable for pipe friction build-up.
Pipeline efficiency can be all the time be considered from an vitality efficiency perspective. Below is a graph showing 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 because of biofilm brought on the pumps not solely to function at a higher head, but that a variety of the pumping was compelled into peak electricity tariff. The decreased efficiency pipeline in the end accounted for about 15% additional pumping vitality prices.
Not everybody has a 500NB pipeline!
Well, not everybody has a 500mm pipeline in their irrigation system. So how does that relate to the common irrigator?
A new 500NB
System curve (red line) indicates a biofilm build-up. Black line (broken) exhibits system curve after pigging. Biofilm raised pumping costs by as much as 15% in one yr. Graph: R Welke
PVC pipe has a Hazen & Williams (H&W) friction value of about C=155. When decreased to C=140 (10%) through biofilm build-up, the pipe may have the equal of a wall roughness of zero.13mm. The same roughness in an 80mm pipe represents an H&W C worth of a hundred thirty. That’s a 16% discount in move, or a 32% friction loss improve for the same flow! And that’s just within the first year!
Layflat hose can have excessive energy price
A case in point was observed in an vitality efficiency audit conducted by Tallemenco lately on a turf farm in NSW. A 200m lengthy 3” layflat pipe delivering water to a soft hose growth had a head loss of 26m head in contrast with the producers rating of 14m for a similar move, and with no kinks within the hose! That’s a whopping 85% enhance in head loss. Not shocking considering that this layflat was transporting algae contaminated river water and lay within the hot solar all summer time, breeding these little critters on the pipe inside wall.
Calculated in phrases of energy consumption, the layflat hose was responsible for 46% of complete pumping energy prices via its small diameter with biofilm build-up.
Solution is larger pipe
So, what’s the solution? Move to a bigger diameter hose. A 3½” hose has a new pipe head lack of only 6m/200m at the same flow, however when that deteriorates because of biofilm, headloss might rise to solely about 10m/200m as a substitute 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 $10,700 over 10 years.
Note*: The pump impeller would must be trimmed or a VFD fitted to potentiate the vitality savings. In some circumstances, the pump could need to be modified out for a decrease head pump.
Everyone has a wheel barrow of their pipelines, and it only will get greater with time. You can’t do away with it, but you probably can control its effects, both via vitality environment friendly pipeline design within the first place, or try ‘pigging’ the pipe to do away with that wheel barrow!!
As for the wheel barrow in Rob’s client’s pipeline, the legend lives on. “He and I nonetheless joke concerning the ‘wheel barrow’ within the pipeline when we can’t clarify a pipeline headloss”, mentioned Rob.
Author Rob Welke has been 52 years in pumping & hydraulics, and by no means offered product in his life! He spent 25 yrs working for SA Water (South Australia) within the late 60’s to 90’s the place he conducted in depth pumping and pipeline power efficiency monitoring on its 132,000 kW of pumping and pipelines infrastructure. Rob established Tallemenco Pty Ltd (2003), an Independent Pumping and Hydraulics’ Consultancy primarily based in Adelaide, South Australia, serving shoppers Australia broad.
Rob runs regular “Pumping System Master Class” ONLINE coaching courses Internationally to cross on his wealth of information he discovered from his 52 years auditing pumping and pipeline systems throughout Australia.
Rob could be contacted on ph +61 414 492 256, or e mail . LinkedIn – Robert L Welke

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