Row of glass tubes containing paint of different colors

Glass tubing for a colorful world

Abrasion-resistant glass tubing made of DURAN® replaces steel cylinders in the dosing pumps of paint-mixing machines (dispensers) and makes them more maintenance-friendly and durable.

The magic – and challenge – of paint mixing machines

Colors have a very different effect on people’s psyche and body. In addition, people have their own preferences. That is why there are paint mixing machines in about 8,000 German DIY shops and specialist shops. Controlled by computer, they are able to create interior or exterior paints in one of 40,000 possible shades by coordinated mixing ordinary white with combinations of up to 36 different color pigments. These paint-mixing machines require a lot of maintenance. After just three to five years they usually need to be replaced because a defect means that the customer would have to wait several days instead of a few minutes for their “terracotta wall paint”. However, scrapping the old system too early is not optimal either.

Don’t replace – refurbish

“Refurbishment is far more sustainable,” notes Uwe Michael Schlitt. He is Managing Director of OLDUS GmbH from Bensheim, a specialist service provider that not only maintains and repairs paint dosing systems, but also completely refurbishes them. “The objective is to restore a system’s technology to its delivery condition in order to extend the service life of the machine by at least the previous operating period,” Schlitt continues. During maintenance the machine is dismantled to its basic structure. All assemblies and components are disassembled, cleaned and reassembled into their individual parts. Wear parts are replaced.

But OLDUS does not want to stop here. In the company’s facility, there is a prototype of a system in which the color pigments are fed from bags under airtight seal, instead of filled into open containers. This makes preservatives unnecessary – as also required by the latest EU directives.
Empty paint mixing machine showing clear glass tubes

DURAN® glass cylinders for pumps for mixing paint. Photo: OLDUS GmbH

Man and woman in a paint store looking at sample cards

Customers in DIY shops can choose a paint of their liking with a color fan, which is mixed in the desired quantity in a paint-mixing machine on site.

Long-lasting innovation

Another innovation concerns the 20 to 36 dosing pumps, which are constructed like an oversized medical syringe. Their task is to dispense a precisely measured amount of pigment into the base color. Today’s cylinders are made of steel and are particularly affected by wear, as the pigment particles are highly abrasive and act like sandpaper on the polished metal of the cylinder liners and the Teflon seals of the pump pistons. This issue is becoming even more important in newer machines, as they are designed to work faster.
Uwe Michael Schlitt, Managing Director of OLDUS GmbH
We are replacing the steel cylinders with DURAN® glass tubes from SCHOTT, whose durability clearly exceeds the typical operating time of a paint mixing machine.

The advantages of DURAN® glass tubing

The glass drawn from the melt is much harder than steel, so there is hardly any abrasion. It is also exceptionally smooth on its own, meaning that unlike the steel, it does not have to be elaborately polished. During maintenance work on the machine, paint pigment residue can be easily removed with conventional cleaning agents.

“We are carrying out stress tests here with the support of a well-known paint manufacturer who will install and operate the machine,” explains the Managing Director. The glass must be able to withstand a continuous operating pressure of 2 bar and load peaks of 16 bar.

The cylinders shown above illustrate another obvious advantage of the glass: It is transparent. It is therefore possible to monitor the seals of the pistons and detect even the smallest leaks before they break through. The optical and mechanical surface properties of the glass, which are superior to steel, instantly lead to a higher durability and reliability in this application.

Used materials

DURAN® borosilicate glass tubing offers the ideal combination of high durability, low abrasion, and strong transparency with very tight geometrical tolerances. This results in highly accurate dosing of the paints for a very long lifetime. Strong mechanical and chemical resistance, as well an easy-to-clean surface add to its advantages for the latest paint-mixing machines. DURAN® is a registered trademark of the DWK Life Sciences GmbH.

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Whether you need more information, samples, a quote, or advice for a project, we would be delighted to talk to you.

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