DNS Distribution have launched a new portable low-pressure building cleaning system called Doris. They say it offers substantial time and cost savings when removing graffiti and dirt from stone, brickwork and other building fabrics.

Made in the UK by DNS\'s associate company LPP, the Doris surface restoration system operates at much lower air volumes that conventional blasting systems and without the need for a pressure pot, so it requires less energy to run, costs less to run and produces less dust and noise.

The key to the system is that it draws the cleaning medium down the line by a vacuum rather than forcing it out with compressed air. While traditional sand blasting equipment might require air volumes of up to 10m3 a minute, the Doris will operate at between two and 3.25m3 a minute. With a typical compressor, this can yield a saving of 30-35 gallons of diesel a day.

The Doris gun weighs only 7kg and, without a pressure pot, makes the whole system lightweight. And the system is not subject to a statutory requirement for annual pressure testing, so downtime is minimized.

Because the cleaning medium is drawn down the line under a vacuum, there are few safety risks. Should the line rupture, the vacuum is simply lost and there is no threat from escaping compressed air and abrasive materials.

Another key feature of the new design is its speed of operation. It has only three essential connections - for the compressor, cleaning medium and water. It can be set up in as little as five minutes.

And all the controls are at the user end, so there is no need to stop work and return to the compressor when adjustments need to be made.

The Doris system can be used with all commonly used cleaning media such as Alublast, calcium silicate, kiln dried sand and glass grit. It also features an in-built water spray that can be used as a low pressure cleaner to wash down recently treated surfaces and to suppress the production of dust while masonry is being cleaned.

In addition to graffiti removal, the system can be used to remove traffic and industrial grime from masonry, to eradicate organic growth such as moss and algae, and to remove nuisance materials such as bird droppings, oil patches and chewing gum.

Tests by the manufacturers have also shown that the Doris system provides an efficient means of raking out damaged mortar, preparing one square metre of wall for repointing in approximately three minutes.

For more information call Steve Holden on 01254 690111.