Sweepers get streetwise
As towns and cities have been redeveloped over recent years, street sweepers have learnt to fit in well with the modern urban landscape. Peter Crewe explainsThe traditional image of a street cleaning machine is of a strange vehicle trundling along, followed by a queue of frustrated drivers. These lorry-based machines were functional and, in spite of their inconvenience, performed a valuable service in maintaining a clean urban environment. This was particularly true when most urban development took place on the outskirts of towns.
Lorry-based sweepers were built by mounting a self-contained sweeper body on to a conventional truck chassis. The vehicle was propelled by one engine, with the sweeper's fan, brushes and tipping gear being powered by another.
Technological advances have seen truck-based road sweepers become more efficient and less cumbersome, but changes in our urban environment have overtaken them. Now we need smaller, cleaner and friendlier machines - step forward the compact urban sweeper. In recent years, town and city centres have been redeveloped with the introduction of pedestrianised shopping centres and open spaces. These impose a different set of requirements upon cleaning equipment.
A need for nimble movers
In the past, the sweeper concentrated on sweeping roads with kerbs and gullies. Litter picking was done manually. Now, we need a machine that can move easily between the roadway and the shopping and leisure areas of our cities. This is where the compact street sweeper excels.
Compact sweepers are characterised by their ability to fit into the modern urban landscape. Small in stature, they are highly manoeuvrable and able to work in confined spaces. They utilise the latest cleaner diesel engines that are low on emissions and quiet, and they significantly exceed the cleaning efficiency of their predecessors.
As you would expect, they look completely different to their truck-mounted predecessors. Nowhere is this more obvious than the driver's cab. Contrast the modern glasshouse cabin of the purpose-built compact sweeper with that of the truck. Modern technology has given the driver a panoramic view of his work area, with obvious benefits in terms of safety and efficiency. Being lower to the ground means he is able to guide the sweeper more precisely and see the results of the cleaning. Obstacles and people are seen more easily, which gives added protection to both.
Size is the other big difference. Modern compact street sweepers are exactly that - compact. Within an overall length of less than 4m, they pack in a lot of technology - and cleaning capacity. Hoppers that can carry up to 2 tonnes of waste mean the machines can work long hours before needing to be
emptied. Swinging and extending brushes give them cleaning widths of nearly 2m, although the machines themselves are only just over 1m wide.
A sweeper or a washer?
There are two methods of street cleaning - sweeping and washing. Sweeping uses two rotating brushes that sweep litter into the path of the machine's suction system. This type of machine is excellent at collecting litter and loose dry waste, but fast food outlets, bars and clubs produce greasy and sticky deposits that sweeping will not remove. This is where a street washer comes in.
Street washing using a modern compact vacuum scrubber is a relatively new development. Almost identical to a compact street sweeper, a compact street washer utilises two cleaning principles: scrubbing and suction. These machines are the best way of cleaning soiled urban surfaces, particularly those near fast food outlets.
Euromec's Aquazura typifies such a vacuum street washer. This machine has front-mounted brushes that scrub the pavement using water that is added as the machine travels along. The brushes push the wastewater and rubbish into the path of the machine, which then collects it using its suction system. The pavement is left clean and dry, and the wastewater containing the unpleasant residue is collected and not left to run down the drains.
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