Underground engineering / Drift mining


Best results with the new pump cleaning-system at PST Spezialtiefbau Süd GmbH

Underwater pumps in the fountain of youth

Lucas Cranach created in 1546 the famous picture of the fountain of youth, that could transform, according to the legend, older women to young girls again by using witcheries. Not capable of any witchery is the pump special-cleaner Inox-Cleaner (Producer: ReiCo GmbH, Ludwigshafen), but very efficient, as Mr. Jürgen Schmitt of PST Spezialtiefbau Süd GmbH approves.


Having it’s roots at Preussag Spezialtiefbau GmbH (with a little transition time at Babcock Borsing AG), the PST Spezialtiefbau GmbH Süd GmbH belongs since 2002 to Wolff & Müller Company in Stuttgart and manages from it’s branch offices in Augsburg, Nürnberg and Frankfurt special unterground engineering projects in whole Germany and abroad. With about 100 employees the company reaches an annual turnover of more than 20 billion Euro.

 

Underground engineering and water drainage

Jürgen Schmitt, construction manager for water drainage in this special underground engineering company is responsible for more than 300 underwater pumps of different sizes (capacities reach from 8 to 125 m³/h) and producers (Grundfos, Lowara, KSB). The pumps‘ job is of highest importance for the quite complex underground engineering projects: they are responsible for water drainage, means the artificial drain of casting pits. This includes not just only the collecting and exhausting of intruding surface water, but often enough also the lowering of the ground water level. If those pumps fail, the casting pit would run full of water in shortest time and the financial damage would be enormous.

So it’s no wonder that Schmitt cares pretty well for „his“ pumps. „If a pump returns after 6 or even more months of permanent usage, it first has to be checked at the pump test facility“. There it’s actual condition of conveyor height and conveyor capability is being compared to the original normal condition. If the pump reaches less than 70%, it is either immediately scrapped (mainly the smaller pumps – where a reconditioning is not worthwile) or disassembled to replace damaged hydraulic parts. If the pump’s efficiency level is higher than 70%, the pump is reconditioned by an intensive cleaning.

 

Pump flushing station
pump check up chart

Why the efficiency level lowers at all is simply explained: the pump soils by deposits of natural iron slime (ochre), lime, rust and tinder. Especially ochre is nonconstructive for the pump’s hydraulic system: in combination with oxygen parts of the ground water’s bivalent iron are oxydated to trivalent iron – iron hydroxide drops out and causes the silting-up of the pump. This has got serious consequences: because of the deposits the pump’s efficiency is continuously lowered and the delivered engery is used ever worse. Just a few percent of loss in effectivity result in a multiple of the original investment costs, calculated all over the pump’s operating time. Soon an apparently normal working underwater pump becomes an energy- and cost-waster. Beside the aspect of costs and environment the cleaning is mainly important to provide the necessary pump-pressure and respectively the wanted conveyor-capability.

 

Pump cleaning with bypass-method

was up to now a long lasting, and for the employees uncomfortable procedure, says Mr. Jürgen Schmitt: „The pump was disassembled what took about 4 to 5 hours. Afterwards the soiled hydraulic parts were cleaned with salt acid – no innocuous job, but definitely an unpleasant and dirty one.

And there is the aspect of costs in addition: 5 hours of employment, each about 45 Euro sum up to 225 Euro per pump, and don’t forget to add the costs for salt acid and it’s disposal afterwards. Some months ago Schmitt heared about the pump special-cleaner Inox-Cleaner in a professional magazine: „We were so impressed, that we decided - just like descibed in the article – to build a system for bypass-cleaning of our pumps. In it the aggregate moves the pump cleaner in a circle so that the pump cleans itself.“ Hereby PST saves on the one hand the time-intensive disassembling of the pump. On the other hand there is the enormous cleaning-effect of Inox-Cleaner: & bdquo;In just only 30 minutes the pump is normally close to it’s original degree of efficiency. We’re really enthusiastic about the much less effort we have to spend!“

This means in daily usage an advantage of degree of efficiency between 10 and 20 percent. Experiences at PST Süd have shown that the good cleaning result also depends on if the aggregate is bulit of cast iron pump or of stainless steel.

So after cleaning Jürgen Schmitt has got the calmative confirmation to have a fully recovered and capable pump for further usage; And there is furhtermore the assurance to apply just as much energy for operation of the pump as necessarily is needed.

Following you see a Grundfos pump before and after flushing with Inox-Cleaner ®

 

Inox-Cleaner is miscellaneous applicable

The hereby with the example of underwater pumps presented advantages of an intensive cleaning are by the way also applyable on other industrial used standard-circlepumps and positive displacement pumps: A clean hydraulic system raises the level of efficiency, supports the availability and optimizes the total costs. ReiCo managing director Werner Häßler: „Good results with the pump cleaner Inox-Cleaner were reached for example by a fabricator of highly viscous media in cement industries and also by a vendor of pump stations. Even results with cleaning of plate heat exchangers were more than just encouraging..”

Conclusion: regularly maintained and checked (with help of a clean hydraulic systems) industrial pumps that operate close to their optimum of efficiency are characterized by convenient lifecycle-costs. By the way: regularly performed maintenance also means that the pump is less stressed and is all in all longer durable. “Who keeps his pump running until barely any pressure can be reached, for example because of ochre or lime, is in danger to damage the bearings or to irreversibly widen the gaps”. It has a lot to commend for an intensely cleaning with the pump cleaner Inox-Cleaner. The fountain of youth for all kind of pumps.