A clean sweep

22nd of December 2016
A clean sweep
A clean sweep

Most customers consider factors such as price, size, ergonomics and ease of use when choosing a sweeper.  But how far should the type of debris that needs to be swept away influence their purchasing decision?

Sweepers are basically an industrial-sized version of a broom, which means their job is to sweep away loose dust and coarse dirt from larger surfaces.  But dirt comes in many different forms. It may consist of leaves, glass fragments, grass, metal shavings, stones, rubble or dust, for example. The ‘dirt’ particles can be either wet or dry and their size will vary enormously.

So, how far does the kind of dirt to be removed affect the customer’s choice of sweeper?
There are two main types of sweeper systems according to Kärcher’s sweeper product manager Marian Anton. “The ‘throw-over sweeping principle’ involves the dirt being transported once completely around the roller brush,” he said. “The waste hopper behind the roller brush is then filled from above and can be used to almost a 100 per cent capacity.” He says this method is particularly suitable for picking up large volumes of items such as leaves.

“There is also the direct sweeping method where the waste is transported into the upstream waste hopper in the same way as when working with a dustpan,” he added. “The filling level with this method is around 50-60 per cent and the speed of the roller brush is significantly lower which leads to less dust dispersion. This is why large industrial sweepers in particularly dusty areas usually work using the direct sweeping principle.”

Types of dirt

Also on the market are vacuum sweepers and municipal machines, says Anton. “These work with two side brushes that feed the dirt into a powerful suction fan which then vacuums up the waste,” he says.

Dirt may be generated by various means such as erosion, natural debris, discarded rubbish or production waste, he goes on. “It can be divided into three types: coarse dirt such as cigarettes, leaves, grass, paper, metal shavings and glass fragments; dry surface dirt such as sand, small stones, mud and car tyre rubber; and wet surface dirt which basically means liquids.”

He explains the mass and size of the dirt plays a role when choosing a machine. “It is therefore advisable to choose a sweeper based on the type and volume of dirt involved,” he said.

Walk-behind sweepers have no suction system and therefore have a lower capacity, explains Anton. “For sweeping up large objects such as cans, coffee cups and leaves you would opt for a sweeper with a coarse dirt flap that uses the throw-over principle,” he said.

Performance differences exist between vacuum sweepers for use in industry; sweepers that use suction and walk-behind sweepers, adds Anton. “Where coarse dirt needs to be removed, a manual sweeper is unlikely to be selected since the waste container will be too small,” he explained. “Higher container emptying - as is possible with ride-on sweepers - is generally better suited to coarse or heavy dirt.”

However, he says sweepers can be adapted to suit different tasks. “For example, a machine that uses the throw-over principle may be used for both fine dust and heavy dirt,” she said. “The dirt is swept up against the direction of travel and then thrown behind into the container using the main sweeper roller. In this way the waste container can be filled almost completely and will need to be emptied less frequently which makes for a time-saving and economical operation.”

She says a fixed roller brush is particularly suitable for use on smooth floors since the contact pressure of the roller to the floor is fixed and wear and tear of the brush will be low. “The floating roller brush on the other hand automatically follows the contours of the floor and is therefore also suitable for uneven floors,” he said.

He adds that different brush materials for the main sweeper roller and side brushes can adapt the machine for different uses. “Each material has its own application and is suitable for either wet or dry use, or for both applications,” he said. “Steel brushes are very aggressive and as a side brush can be used to remove weeds or dried-on dirt. A brush made from natural fibres, by contrast, will have fine, dense bristles and will be ideal for removing dry, fine dust from smooth surfaces. But unlike polypropylene or polyamide brushes these are not water-resistant, not as universally applicable and suffer higher wear and tear on rough surfaces.”

Powerful filter

He says industrial sweepers are often used in dusty environments such as foundries and cement factories. “In these types of locations an efficient and powerful filter system also plays an important role.”

According to Anton there are suitable machines for almost every challenge provided the correct sweeping and filter systems are chosen. “However, sweeping always involves mechanical friction which means sweepers cannot be used for explosive dusts since these pose a high risk,” he said.

Large quantities of leaves present a particular challenge since the waste hopper will quickly become full, he adds. “In this instance, a mid-range machine will be suitable since it has a high filling level.”

Range of factors

Customers consider a range of criteria when choosing a sweeper, says Anton.  “They look at factors such as cleaning results, dust-free work, ergonomics, robust design and the efficiency of set-up requirements,” he explains. “They also consider the size of the area that needs to be swept as well as the type of debris.”

However, not every customer knows in advance what type of debris they are likely to want to remove according to group product manager of Nilfisk-Advance Thomas Tykskov. “Although many customers will know what they want swept away, others who have problems with dust for example may not realise the problems that can be avoided by choosing a sweeper with good dust control,” he said.

“Considering the type of rubbish to be swept away should be one of the first requirements when choosing a sweeper since different machines are designed to sweep up different types and amounts of debris.”

He says a sweeper with good dust control is vital for removing fine dust, especially if the machine is to be used indoors. “For removing items such as rubble, leaves and twigs you would find an outdoor road sweeper to be the best option since it will have a greater hopper capacity and the ability to collect larger debris,” said Tykskov.

A sweeper can be used to clean away almost anything, he says. “Items such as nails, small wooden pieces, gravel, cigarette butts, paper, small metal waste and animal food are just some of the examples,” he said.

The removal of light debris from a smooth-surfaced floor can be among the most difficult challenges for a sweeper, according to Tykskov. “This type of soiling can easily can be pushed away from the broom chamber by the front flap,” he said. “However, a sweeper with dust control will have rubber skirts around the main broom chamber to provide a vacuum and this will ensure that no dust is allowed to escape the broom chamber.”

Besides debris type, other considerations for a customer when choosing a sweeper should include productivity level, performance, total cost of ownership, safety, ease of maintenance and dust control, he said.

“The choice of power source is also important since this will have an impact on running time and noise levels which should be a particular consideration in indoor, noise-sensitive areas,” he said.
Hako’s municipal technology product manager Dr Olaf Heinemann believes the type of debris that needs to be swept away should be the chief consideration when choosing a sweeper.

Choice of power source

“The type of dirt will vary depending on the season and geographical location,” he points out. “In northern countries for example, a typical spring clean-up will involve the heavy-duty sweeping of sand and grit from winter maintenance along with the removal of partially-composted leaves from the previous autumn. During the summer months, light-duty debris such as general dirt and dry sand will need to be swept away while leaves will be the major challenge in the autumn.”

There are major differences between the sweeping challenges in rural and urban areas too, according to Heinemann. “Nature causes most of the debris in rural areas whereas the rubbish in cities is mainly caused by pedestrians dropping litter,” he said.

According to Heinemann a sweeper needs to have a large roller-guided suction nozzle plus a highly efficient, low-noise blower for removing outdoor rubble, dust, leaves and twigs. “Moreover, the sweeper should be PM 10 certified,” he said. “And for applications involving a great deal of dust, the machines should be equipped with efficient and sustainable dust control systems that reduce the emissions of particulate matter in accordance with the EUnited PM 10 standard.”

Particular challenges for sweepers include the removal of industrial waste, wood chips, compost and the clean-up of recycling areas, he said.

“Another major challenge for outdoor sweepers is collecting wet dirt in puddles and dry leaves,” he said. “The volume and stickiness of the collected material can be a problem here since the sweeper’s collection system may become blocked with clumps of debris.”

Highest efficiency

According to Heinemann, many customers mainly consider the purchase price when choosing a sweeper. “However, they should choose the machine that best meets their requirements while providing the highest possible operational effectiveness and ease of use,” he said.

And he adds that productivity and technology will both become more important when the next generation of sweepers is developed. “We see a clear trend for multifunctional sweepers that use innovative quick-change systems,” he said.

“We will therefore continue to refine and optimise this concept, offering systems that allow the operator to quickly change from one attachment to another. In years to come we will also refine our intelligent interfaces that provide communication between the attachment device and the carrier vehicle.”


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