Piling on the pressure in cleaning

28th of December 2015
Piling on the pressure in cleaning
Piling on the pressure in cleaning

Cleaning away substances such as chewing gum, paint, rust and scale can be tricky - even with a state-of-the-art high-pressure cleaning system. And removing any substances from a delicate surface such as a car’s bodywork or the crumbling façade of an old building can also be problematic. ECJ’s Ann Laffeaty looks at some of the most difficult high pressure cleaning tasks.

Cleaning away substances such as chewing gum, paint, rust and scale can be hard work even when using state-of-the-art high pressure cleaning equipment. And tasks such as removing soiling from the delicate surface of a car’s paintwork or from the crumbling façade of an old building can also be problematical.

In fact there are any number of factors that can make high pressure cleaning tasks overly difficult according to product management director at Nilfisk Andrew Caddick. “Considerations such as the accessibility of the area to be cleaned; the type of dirt to be removed and how ingrained it is plus the requirement to respect the delicate nature of the cleaning surface can all add to the level of difficulty,” he said.

He cites tank cleaning as one the most challenging high pressure tasks there are. “Here there is a need to clean in areas that may be inaccessible and that cannot in generally be seen,” he said. “This type of job may also represent a health risk – for example, people have died while cleaning wine barrels from the inside.”

Another particularly difficult task is the cleaning of frying oil from snack production lines and removing melted chocolate from cake-making equipment, says Caddick. “Here the dirt involved tends to be sticky and difficult to remove and it may actually need ‘melting’ rather than blasting away.”

Removing dried concrete from vehicles and construction equipment represents another major challenge, says Caddick. “While it is not particularly difficult to pressure-wash the tough dirt from
these hard surfaces, it can be tiring due to the high water pressures required and the general intense nature of the application,” he said.

Another difficult task involves the cleaning of pig sties, particularly when the pigs have been fed on substances such as molasses and peas. “Here the dirt will be sticky and ingrained and the task may require special processes such as soaking the surfaces or using a detergent to soften the dirt,” he said.

Avoiding damage

“Cleaning surfaces such as monuments, marble walls and delicate stonework can also be a problem since there is a need to avoid damaging the surface. If any residue salts or products are left behind, this could damage the porous stonework later on. Delicate stone surfaces In general require non-abrasive cleaning methods and specialist accessories along with low pressure levels and longer cleaning times.”

He says each application has its own particular challenges. “There may be several possible cleaning methods but the user may not have the necessary information or experience to judge which one will obtain the best results at the lowest running costs,” he said. “This is something that is often underestimated and can lead to over-use of the washer and high cost in use of fuel, labour, water or electricity.”

He says that although hot water is more efficient in some cases than cold, many users will ramp up the heat whether it is required or not in the belief that this will lead to better results. “However our efficiency tests have shown that for some applications, a temperature of 90°C is only four per cent more efficient than 60°C yet will almost double the fuel costs,” he said.

“A major challenge is to know which combination of water flow, pressure, temperature, detergent and accessories will obtain the best result at the lowest cost.”

He says today’s focus on health and safety can add to the difficulty of certain cleaning applications. “For example there is an increasing need to limit cleaning time for the user and to pay more attention to noise and vibration levels and to provide protective clothing.”

He adds that there is a solution for every type of challenge. “For example you could use a softblasting system when cleaning a crumbling building façade, or soft cleaning techniques that involve the continual dripping of water over the surface. This removes some types of dirt without involving the harsh impact of high pressure.”

He says chewing gum can usually be cleaned away using very hot water and pressure levels of around 200 bar. “Here you would probably need to use detergent and perhaps an accessory such as a rotating bar,” he said. “However this type of task is increasingly being solved by using a steam cleaner with brass brush nozzles and special dissolving chemicals.”

Removing graffiti and chewing gum are among the most difficult tasks that Kärcher has had to face according to environmental public relations officer Linda Schrödter. “Paint, varnish and rust are also hard to remove and it can be tough to clean pipes that have become completely blocked as well,” she said.

“It is also difficult to clean away the encrusted grime that collects on historic buildings and monuments. Here special attention needs to be paid to the stone surface particularly when dealing with porous structures such as sandstone that can be prone to flaking.”

She says the cleaning of hard-to-access environments and equipment such as gutters, underbodies, facades and ceilings presents a further challenge. “Nowadays we use rope access
technology to reach hard-to-access places,” she said. “In addition there are compact pressure washers that can be safely used on scaffolding.”

She agrees with Caddick that choosing the correct cleaning agent requires a level of know-how that the average user does not possess. “Choosing the right accessories can also be critical,” she said. “The pressure washer has basic features and there are certain difficult applications that can only be executed efficiently by using the right accessories.

“For example pipe cleaning requires a specific hose and an appropriate nozzle while graffiti, paint or rust can be removed using a wet blasting set. Underbody cleaning is best carried out with a flexible spray lance or underbody spray lance, while facade and ceiling cleaning needs to be tackled with the aid of a telescopic rod. Often we find that users do not know about all the available accessories.”

Kärcher is launching a new range of hot water, high pressure trailers for outdoor use. These have a built-in frost protection device and an eco-efficiency mode that keeps the water temperature at a constant 60°C to save energy.

Saving energy

Cleaning the keels of ships is one the most difficult tasks that Idrobase technical product manager Giovanni Maniero has encountered. “This is because the scales that collect on the outside of ships can be very difficult to remove,” he said. “This type of task requires cleaning systems using very high pressures, typically of between 500 and 800 bar.”

Idrobase offers a range of hot and cold water high pressure washers for various applications in the shipbuilding, food, car wash, agriculture, ground handling, industrial and repair shop sectors.
According to Maniero, chewing gum can be removed from surfaces using a hot water high pressure system at temperatures of 80-90°C. “When it comes to removing paint, rust or scales, a sandblasting system together with a cold water high pressure washer works well,” he said.

“A cold water system and a fan nozzle would also work for cleaning the facade of a crumbling building. But it can be difficult to pressure-wash solar panels because here you need to use systems that will clean both quickly and efficiently while also providing accessibility to high roofs.”

Kärcher’s Linda Schrödter agrees that solar panel cleaning can be a problem. “Solar panels need to be kept thoroughly clean since dirt can reduce electricity production by up to 30 per cent,” she said. The company’s own iSolar system uses rotating brushes attached to a telescopic lance to clean solar panels using non-scratch nylon bristles.

Nilfisk’s Andrew Caddick says he would tackle the same task using a water filtration unit in conjunction with the pressure washer. “High pressure and flow levels must be avoided on solar panels which means that a very soft brush with lower performance is needed to accomplish the task,” he said. “At the same time, water quality is critical since the solar panel must not be left with any stains from poor water or lime.”

Solar panel cleaning is just one of a number of recent applications for high pressure cleaning equipment that are presenting manufacturers with additional challenges.  Another involves the task of sustainable weed-killing, says Schrödter. “The trend is toward eco-friendly weed-killing systems that use hot water, but these require the consistent delivery of water at very high temperatures.”

Europe’s growing number of windmills represents another challenge according to Caddick. “It can be difficult to reach the blades,” he explains. “Even when using a crane to reach the required heights it can be a major challenge to blast away the dirt from the blades.”

Nilfisk is working on several new concepts and on a number of accessory ideas. “Our focus is on providing new solutions for the toughest of industrial applications where higher performance levels are required,” said Caddick.

“We also bring information, experience and test results to the market to help guide the user’s choice in terms of cleaning solution, machinery and accessories. This allows them to focus on the total cost of cleaning while maintaining the best results.”


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