One of southern Germany’s leading providers of automated car washes is relying on Qdos pumps from Watson-Marlow Fluid Technology Group (WMFTG) to dose an expensive pre-cleaning chemical. Among the purchase decision factors in favour of the Qdos over diaphragm pumps were dosing accuracy, ease-of-operation and ease-of-maintenance.

“With a total length of over 61m, the facility in Stuttgart-Vaihingen is our new flagship car wash,” states Benjamin Schlechta, General Manager of WaschWelt Süd GmbH & Co KG.

In total, 10 car wash facilities under the WaschWelt brand name, which translates as ‘WashWorld’ in English, offer a wide range of different wash programmes of the highest standard. There are several cleaning ‘arcs’ in the plant at Stuttgart-Vaihingen, which vehicles pass one by one. The first one is the pre-cleaning/soaking arc, which is served by two Qdos dosing pumps to prepare the vehicle for subsequent high-pressure cleaning. One Qdos pump meters the pre-cleaner from a large barrel to the arc, while the second meters to a lance that is operated by an employee to take special care of the wheel rims.

WaschWelt’s pre-cleaner is designed for tough dirt removal, particularly around the wheel rims of cars and trucks. The substance (high alkaline, phosphate-free) offers a high concentration of surfactants and special additives that spontaneously dissolve even the most stubborn marks, including insects, bird droppings and general environmental dirt.

Perfect precision

“The best possible pumping accuracy is paramount,” explains Mr Schlechta. “This is because the pre-cleaner is relatively expensive and only lasts for a few days, so we want to avoid overdosing as much as possible.”

Precision is also required because the best cleaning result is achieved through correct dosing. In the worst cases, it is possible for door seals and chrome trim to be damaged by overdosing, making it important to observe optimum pH values.

The car wash uses Qdos dosing pumps to help ensure the delivery of these desirables.

“From the beginning we were convinced by the accuracy and reliability of the new pumps,” says Mr Schlechta. “We can now use the pre-cleaner much more efficiently and make substantial savings. What’s more, the Qdos pumps are clearly superior to diaphragm pumps in terms of operation and safety.”

Christian Paschen, Commercial Manager at WMFTG in Germany, adds: “Peristaltic pumps like Qdos lend themselves very well to the dosing of highly concentrated chemicals due to their high accuracy. However, Qdos not only offers reliable accuracy to within ±1%, but intuitive ease-of-use: flow volumes can be entered in millilitres via the numeric display.”

Peristaltic versus diaphragm pumps

Another advantage of peristaltic pumps in contrast to diaphragm pumps is that they have no seals or non-return valves, and therefore require only minimal maintenance. The only wear part of the whole unit is the pump head, which can be replaced on site within minutes. Furthermore, the flow direction on the pump can be reversed easily for this purpose, allowing the fluid to be fed back into the storage vessel from the pipe system.

“Changing the pump head is therefore significantly safer,” adds Mr Schlechta. “Moreover, conversely to other pump types, peristaltic pumps are safe to run dry, are self-priming and can easily process even gaseous fluids. As a result, we no longer need to bleed the barrel when changing it, which saves us time.”

With a vehicle entering the Stuttgart-Vaihingen facility every minute on average, time is extremely precious. Indeed, it soon became clear to WaschWelt that the company’s other facilities would benefit by upgrading to Qdos pumps.

“At our other car washes – ones with proportionally high throughput of highly concentrated pre-cleaner – it will be worth adopting peristaltic pumps very soon, based solely on their precision dosing and low maintenance requirements,” concludes Mr Schlechta.