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Changes in sweeper technology25th of November 2011
In recent years, indoor and outdoor sweeper technology has advanced considerably, making it easier for the customers to find the right solution for their sweeping requirements. Once the need for sweeping has been established, the choice for the most suitable equipment is driven by a number of criteria that relate to air quality, safety, cost of operation, versatility and sustainability. Latest trends and developments have created new applications and benefits - explains Tennant in this article written exclusively for ECJ.
Mechanical sweeping was the first technology chosen for large area cleaning. Later there was migration to scrubbing as hygiene standards increased. There are still numerous applications where water can’t be used for hard surface cleaning, eg, in cement factories or when high-voltage is used in the production process (aluminium production), sweeping is generally used to clean premises. It is also commonly used in warehouses, parking areas and a variety of applications where the material or waste of the production process is dry and not compacted on the floor.
Why choose sweeping for indoor hard floor cleaning? Or alternatively, why choose dry sweeping before scrubbing – which is actually wet sweeping? Depending on the amount of debris, there are three alternative technologies that can be used to remove debris: a cylindrical scrubber dryer, a scrubber dryer with a pre-sweep option or a dedicated sweeper can be used. Where the type of soil requires scrubbing (eg, oily soil), the sweeping operation removes the debris off the floor before scrubbing. If the debris were left on the floor it would get caught in the squeegee and the result might not be up to standard, leaving streaked or unsafe floors.
So, sweeping either prepares the floor for another type of maintenance or delivers the required finished result. Indeed, depending on the industry segment, sweeping can result in an acceptable level of clean that will not require any scrubbing afterwards, especially when the debris being removed is similar to ordinary dust, sawdust, sand and other dry debris.
In certain industries, such as the food production or handling sector, healthcare and retail, cleaning standards are being raised and certain levels of hygiene have to be attained. In those cases, sweeping alone will not be enough.
Sweeping – removing debris from the floor - is typically done with walk-behind or ride-on sweepers with optional side brushes. These have long bristles that extend outside of the machine frame and allow for excellent edge and corner cleaning. The rotating side brush moves the debris in front of the machine and by its forward motion the debris comes into contact with the main broom that rotates against the travel direction. This main brush acts as hundreds of brooms that throw the debris directly into the hopper, either by direct throw (for the larger sweepers) or by overthrow (smaller sweepers). Once the debris is in the hopper, the dust has to be contained in the machine. All sweeper manufacturers use some sort of filtration system.
The latest development however, is a cyclonic dust control system on indoor sweepers. This three-stage filtration system uses a first-stage filter for removing large debris, a cyclonic pre-filter for smaller particulates and finally removes the remaining dust (as small as 0.5 micron) from the airflow in the third stage of the filtration. Although some manufacturers use water on the side brooms for indoor sweeping, that might cause concern for slip-and-fall accidents.
On outdoor sweepers (mechanical or air sweepers) however, this is less of a worry. There, the latest innovation offers improved dust containment through atomisation of water, reducing the amount of water used and the number of refills per working shift.
When a customer is faced with the decision to select a dedicated sweeper, the choice is obviously determined by the particular sweeping needs and largely influenced by different aspects that matter to the customer’s specific situation.
Indoor air quality can be largely improved by the sweeping operation. Based on customer requirements, manufacturers today spend a lot of R&D effort on the development of dust filtration technologies that maximise dust control while sweeping. The latest development in this area as described above is a three-stage filtration system that provides a longer, more effective air filtration, assisting in containing dust that would otherwise get into the environment.
In the outdoor or street sweepers segment, we see a similar focus on air filtration and dust containment. Of course the element of air quality is important in city centres as well. In this respect, another development in street sweepers is the move towards electrical vehicles. The use of battery-driven machines that can run for a full shift without recharging is important as it enables municipalities to comply with the ever more stringent standards for carbon emissions they are faced with. It helps to make the city a healthier place to live, work and play in.
The safety aspect is largely related to the operator comfort. Here, several innovations and developments have increased safety of the sweeping operation. Noise levels of sweepers have become lower in recent years, thus reducing the impact not only on the operator’s well-being but also on the working environment, allowing for sweeping 24/7 and even when people are present.
Optional cabins can also protect the operator from noise and dust, or falling objects from the environment. These cabins nowadays come with climate control, air filtration, tilted steering and adjustable seats that improve the operator experience considerably.
In terms of handling, the trend is towards replacing mechanical controls with electronic ones and even one-button operation for ease of use and productivity.
Developments in outdoor sweepers show a similar focus on ease of use, noise reduction and easy maintenance. Electric street sweepers combine these with zero exhaust emissions for unobtrusive use in city centres.
Total cost of ownership
There are several ways in which recent developments in sweeper technologies assist customers in reducing the total cost of ownership of their sweeping solution. In itself, sweeping is less expensive than scrubbing: there are no water refill cycles that take time, there is no introduction of a cleaning medium (water, detergent) and there is no need to dispose of potentially harmful waste water, since there is only dry waste.
With easy-access maintenance points and no-tool brush changes, sweepers are increasingly easier to service, resulting in higher productivity. Less downtime is also achieved by the optional bumpers and protection guards that withstand the most demanding environments for long machine life. A multi-phase filtration system captures more dust before it reaches the final-stage canister filter, lowering the need for replacement.
With tight budgets for municipalities there is pressure on cost in use and service. With the latest electric street sweeper they purchase the ‘fuel’ upfront (ie, the battery) knowing that the machine is easily accessible and requires much less maintenance. There is also considerably less maintenance on electric utility vehicles - similar to electric cars - since there is no need for oil change, engine filter change, etc.
These days, most sweepers can be tailored to meet the customer requirements. They can get exactly what they need for their particular application. Machines can be equipped with an optional side brush for a wider sweeping path or with an extra suction wand for reaching hard to sweep places. Indoors, they can be used on hard floors, but also on carpets. Compact sweepers can be used in a wide variety of places and even move through doorways and narrow aisles.
Picking up small to big debris make sweepers suited for varying environments and applications.
Lastly, the cabin prepares sweepers for use in any type of weather conditions, for example when cleaning car parks.
On outdoor sweepers we see an increase in use of add-on equipment such as a snow plough or separate scrub option to reach under benches, as well as other tools to expand the use of the machine.
The sustainability aspect plays an increasing role in today’s cleaning operation. Battery-operated sweepers – both indoor and outdoor - do away with exhaust fumes. By pre-sweeping or using dust containment techniques, less water is used in the cleaning process. In a facility where the soil doesn’t require scrubbing with water, sweeping will only result in dry waste. A medium scrubber dryer will easily require the disposal of around 100 litres of waste water after a shift.
In general, every increase in hygiene requirements will result in more waste.
If some of the cleaning can be done by sweeping, at least the disposal cost will be reduced considerably.
Obviously, recently introduced electric street sweepers can be the sustainable choice for urban and other outdoor hygiene as they generate zero exhaust emissions and use less water for dust control.
All in all, the sweeper segment remains an important one in the cleaning industry. There are benefits to be gained from choosing a sweeper depending on the application, the floor type and the volume and type of debris. Many manufacturers continue to focus on innovating technologies that maximise productivity, increase safety and reduce costs, all with the sustainability aspect in mind.