Rob Welke, from Adelaide, South Australia, took an uncommon phone from an irrigator within the late 1990’s. “Rob”, he mentioned, “I suppose there’s a wheel barrow in my pipeline. Can you find it?”
Robert L Welke, Director, Training Manager and Pumping/Hydraulics Consultant
Wheel barrows were used to carry package for reinstating cement lining throughout mild metal cement lined (MSCL) pipeline development 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 through the rehabilitation of the Cobdogla Irrigation Area, near Barmera, South Australia, in 1980’s. It can also be suspected that it may simply have been a believable excuse for unaccounted friction losses in a model new 1000mm trunk main!
Rob agreed to help his client out. เกจวัดแรงดันไนโตรเจนราคา . PVC rising major delivered recycled water from a pumping station to a reservoir 10km away.
The problem was that, after a year in operation, there was about a 10% reduction in pumping output. The consumer assured me that he had examined the pumps and so they have been OK. Therefore, it just needed to be a ‘wheel barrow’ in the pipe.
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Rob approached this drawback much as he had during his time in SA Water, the place 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 number of places (at least 10 locations) which had been surveyed to provide accurate elevation info. The sum of the strain reading plus the elevation at each point (termed the Peizometric Height) gave the hydraulic head at every level. Plotting the hydraulic heads with chainage gives a a number of point 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 factors 3 and four km. Graph: R Welke
Given that the HG was pretty straight, there was clearly no blockage alongside the best 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 should be because of a common friction build up in the pipeline. To confirm this principle, it was decided to ‘pig’ the pipeline. This concerned utilizing the pumps to drive two foam cylinders, about 5cm bigger 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 performance was improved 10% on account of ‘pigging’. Photo: R Welke
The prompt enchancment in the pipeline friction from pigging was nothing in want of wonderful. The system head loss had been virtually totally restored to original performance, resulting in a couple of 10% circulate improvement from the pump station. So, instead of finding a wheel barrow, a biofilm was found answerable for pipe friction build-up.
Pipeline ENERGY EFFICIENCY
Pipeline efficiency can be all the time be viewed from an energy effectivity perspective. Below is a graph displaying 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 operate at the next head, however that some of the pumping was compelled into peak electrical energy tariff. The reduced efficiency pipeline finally accounted for about 15% additional pumping vitality costs.
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) signifies a biofilm build-up. Black line (broken) reveals system curve after pigging. Biofilm raised pumping costs by as much as 15% in one 12 months. 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 may have the equal of a wall roughness of 0.13mm. The similar roughness in an 80mm pipe represents an H&W C worth of a hundred thirty. That’s a 16% discount in flow, or a 32% friction loss increase for a similar flow! And that’s just within the first year!
Layflat hose can have excessive power value
A living proof was observed in an vitality effectivity audit performed by Tallemenco recently on a turf farm in NSW. A 200m lengthy 3” layflat pipe delivering water to a delicate hose increase had a head loss of 26m head in contrast with the manufacturers rating of 14m for the same circulate, and with no kinks within the hose! That’s a whopping 85% improve in head loss. Not shocking contemplating that this layflat was transporting algae contaminated river water and lay in the hot solar all summer season, breeding these little critters on the pipe inside wall.
Calculated when it comes to vitality consumption, the layflat hose was responsible for 46% of complete pumping power costs by way of 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 model new pipe head lack of solely 6m/200m at the similar flow, but when that deteriorates because of biofilm, headloss might rise to solely about 10m/200m as an alternative of 26m/200m, kinks and fittings excluded. That’s a potential 28% saving on pumping energy costs*. In phrases 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 need to be trimmed or a VFD fitted to potentiate the vitality savings. In some cases, the pump may have to be changed out for a lower head pump.
Everyone has a wheel barrow of their pipelines, and it only gets greater with time. You can’t eliminate it, but you can management its results, both through power environment friendly pipeline design within the first place, or attempt ‘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 still joke in regards to the ‘wheel barrow’ within the pipeline after we can’t explain a pipeline headloss”, mentioned Rob.
Author Rob Welke has been 52 years in pumping & hydraulics, and by no means sold 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 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 based mostly in Adelaide, South Australia, serving shoppers Australia broad.
Rob runs regular “Pumping System Master Class” ONLINE coaching programs Internationally to cross on his wealth of knowledge he discovered from his 52 years auditing pumping and pipeline methods all through Australia.
Rob could be contacted on ph +61 414 492 256, www.talle.biz or email r.welke@talle.biz . LinkedIn – Robert L Welke
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