Wheel washing system
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A wheel washing system is a device for cleaning the tires of trucks when they are leaving a site, to control and eliminate the pollution of public roads. The installation can be made in or above the ground for either temporary or permanent applications. There are two types of wheel washing systems: roller and drive-through systems.
At a roller unit, the truck places each set of wheels on the rollers as it leaves the plant. At this point the washing process is automatically triggered. While the wheels of each axle are rotated automatically, water is sprayed out from strategically placed nozzles to clean the tires, wheel wells and mud flaps.
The advantage of drive-through systems is that the vehicle does not have to stop for cleaning. As the vehicle passes the magnetic-sensor or photo-sensor at the entrance, the washing process is triggered. During the slow passage (5 mph speed) through the wash platform, the vehicle's tires, wheel wells and mud flaps are cleaned by water sprayed from many strategically placed nozzles (spray bar). The nozzles are mounted angle-iron grids which open the tire treads and flushing the mud for a high cleaning performance. The washing platform is usually of galvanized steel. The first modern systems were introduced as the MobyDick “Quick” series at a German construction industry trade exhibition. The Quick system was a significant design improvement from the modified high pressure truck wash systems that were used as wheel and tire wash systems before. Today all modern drive through systems are based on the engineering and design development of the Quick series.
A key aspect of the philosophy of wheel and tire cleaning is the use of high volume water flow at low pressure. The high volume flow of water flow serves to clean the tires and effectively remove the wash sludge slurry from the wash platform into the recycling and solids collection tanks. Mist and overspray from high pressure systems would not be an effective method of cleaning and removing the wash sludge into the recycling and solids collections tanks. Other disadvantages of high pressure cleaning are wasted water, energy and obstruction of driver visibility.
Once the wash sludge arrives to a recycling tank the solids typically sink by gravity to the bottom. To accelerate the sedimentation of the solids, flocculants are used. Periodically the settled solids at the bottom of the recycling tank are removed from the tank with an automatic scraper conveyor system or by other means such as a wheel loader, an excavator with bucket or a vacuum truck. After the solids settlement process the wash water is ready for the next washing cycle. The goal of the sedimentation process is to deliver clean and optically clear water for every wash.