The MTDC Portable Vehicle Washer

The center has designed and fabricated a portable vehicle washer to meet the project's goals (figure 2). Operators use two high-pressure wands to wash the vehicle's sides, wheels, and wheel wells. A high-pressure, high-volume nozzle system washes the vehicle's underbody. An industrial rubber mat with foam-filled barriers on all sides confines the wash water. The used wash water is pumped from the mat to two 175-gallon settling tanks. Large particulate matter sinks to the bottom of the tanks. The effluent from the settling tanks is pumped through two filters. The filters have felt bags that can remove particulate as small as 3 microns. After the water has passed through the filters, it is dumped into a 550-gallon holding tank where a pump with high pressure (about 800 pounds per square inch) and high volume (about 20 gallons per minute) pushes the water through the wands and under-body washers. Figure 3 shows the flow of water. The washer does not use hot water nor does it use any soaps, chemicals, or detergents. The components are mounted on a twin-axle, 8- by 18-foot trailer that can be towed by a ¾-ton pickup truck (when the water tanks are empty).

Figure 2—The MTDC portable vehicle washer being used in the field.

The pumps, generator, tanks, and filter housings are permanently mounted on the trailer. The trailer also carries the mat, hoses, and miscellaneous equipment.

Figure 3—The flow of water through the vehicle washer system.

Wands and Underbody Washers

The MTDC portable vehicle washer uses two hand wands and two underbody washers. The two hand wands operate at a pressure of 800 pounds per square inch. Each wand sprays about 8 gallons of water per minute (figure 4). The wand has a rotating, single-stream nozzle that does a better job of cleaning than standard fan nozzles.

Figure 4—The hand-operated, high-pressure wands are
used to clean mud, dirt, spores, and weed seeds from a
vehicle's wheel wells, tires, sides, and bumpers.

The underbody washer (figure 5) is one of the few components of the vehicle-washing system that is not commercially available. The underbody washers are made of 1-inch pipe, welded to form a U shape. Six high-pressure fan nozzles attached to each underbody washer provide complete coverage under the vehicle. The six nozzles operate at about 800 pounds per square inch of pressure and use a total of 18 gallons of water per minute.

Figure 5—The underbody washer uses high pressure
and a large volume of water to wash mud, dirt, and
debris from underneath the vehicle. Nozzles are mounted
so that they provide complete coverage under the
vehicle. The ramp protects the hose that supplies water
to the underbody washer. One underbody washer
cleans vehicles as they drive onto the mat and
another cleans them as they drive off.

During a typical washing operation, a vehicle drives slowly onto the mat and over the first underbody washer. Once the vehicle has been driven completely over the underbody washer, operators close a valve on the wash system's trailer, stopping the flow of water to the underbody washer. Operators wash the vehicle with the two high-pressure wands, removing all mud and dirt on the sides, wheels, wheel wells, and bumpers. Operators turn on the valve to the second underbody washer, which cleans the underbody again as the vehicle drives off the mat.