Rob Welke, from Adelaide, South Australia, took an uncommon cellphone from an irrigator in 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 had been used to carry kit for reinstating cement lining during gentle steel cement lined (MSCL) pipeline development within the outdated days.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 occurred through the rehabilitation of the Cobdogla Irrigation Area, close to Barmera, South Australia, in 1980’s. It is also suspected that it could simply have been a plausible excuse for unaccounted friction losses in a model new 1000mm trunk main!
ราคาเกจวัดแรงดันน้ำ agreed to assist his shopper out. A 500mm dia. PVC rising main delivered recycled water from a pumping station to a reservoir 10km away.
The problem was that, after a year in operation, there was a couple of 10% reduction in pumping output. The consumer assured me that he had examined the pumps and they had been OK. Therefore, it just had to be a ‘wheel barrow’ within the pipe.
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Rob approached this downside a lot as he had during his time in SA Water, the place he had intensive expertise locating isolated partial blockages in deteriorated Cast iron Cement Lined (CICL) water supply pipelines in the course of the 1980’s.
Recording hydraulic gradients
He recorded accurate strain readings along the pipeline at multiple locations (at least 10 locations) which had been surveyed to provide correct elevation data. The sum of the pressure reading plus the elevation at each point (termed the Peizometric Height) gave the hydraulic head at every level. Plotting the hydraulic heads with chainage offers a a number of point hydraulic gradient (HG), much like within the graph beneath.
Hydraulic Grade (HG) blue line from the friction exams indicated a consistent gradient, indicating there was no wheel barrow in the pipe. If there was a wheel barrow within the pipe, the HG can be like the purple 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 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 because of a common friction construct up within the pipeline. To affirm this concept, it was determined to ‘pig’ the pipeline. This involved using the pumps to force two foam cylinders, about 5cm larger than the pipe ID and 70cm long, alongside the pipe from the pump finish, exiting into the reservoir.
Two foam pigs emerge from the pipeline. The pipeline efficiency was improved 10% because of ‘pigging’. Photo: R Welke
The instant enchancment within the pipeline friction from pigging was nothing in need of wonderful. The system head loss had been nearly totally restored to original efficiency, leading to a couple of 10% circulate enchancment from the pump station. So, as a substitute of discovering a wheel barrow, a biofilm was found liable for pipe friction build-up.
Pipeline ENERGY EFFICIENCY
Pipeline performance can be always be considered from an power 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 increase in system head due to biofilm brought on the pumps not solely to function at the next head, but that a few of the pumping was pressured into peak electrical energy tariff. The lowered performance pipeline finally accounted for about 15% extra pumping vitality 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 12 months. 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 equal of a wall roughness of 0.13mm. The identical roughness in an 80mm pipe represents an H&W C value of a hundred thirty. That’s a 16% reduction in move, or a 32% friction loss improve for the same flow! And that’s simply in the first year!
Layflat hose can have excessive vitality price
A living proof was observed in an power efficiency audit performed by Tallemenco just lately on a turf farm in NSW. A 200m long 3” layflat pipe delivering water to a delicate 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 in the hose! That’s a whopping 85% improve in head loss. Not surprising contemplating that this layflat was transporting algae contaminated river water and lay within the scorching solar all summer, breeding these little critters on the pipe inside wall.
Calculated in phrases of energy consumption, the layflat hose was liable for 46% of complete pumping energy costs via its small diameter with biofilm build-up.
Solution is bigger pipe
So, what’s the solution? Move to a larger diameter hose. A 3½” hose has a new pipe head loss of solely 6m/200m at the same move, however when that deteriorates because of biofilm, headloss could rise to only about 10m/200m instead of 26m/200m, kinks and fittings excluded. That’s a potential 28% saving on pumping energy costs*. In terms of absolute vitality 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 savings. In some cases, the pump could should be changed 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, however you can control its effects, both by way of power environment friendly 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 nonetheless joke concerning the ‘wheel barrow’ within the pipeline when we can’t explain a pipeline headloss”, stated 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) in the late 60’s to 90’s the place he carried out in depth pumping and pipeline power effectivity 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 clients Australia wide.
Rob runs regular “Pumping System Master Class” ONLINE training programs Internationally to move on his wealth of knowledge he discovered from his 52 years auditing pumping and pipeline systems throughout Australia.
Rob could be contacted on ph +61 414 492 256, www.talle.biz or e mail r.welke@talle.biz . LinkedIn – Robert L Welke
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