Car Wash - Automatic Car Wash

Automatic Car Wash

The first conveyorized automatic car washes appeared in the late 1930s. Conveyorized automatic car washes consist of tunnel-like buildings into which customers (or attendants) drive. Some car washes have their customers pay through a computerized POS, or point of sale unit, also known as an "automatic cashier", which may take the place of a human cashier. The mechanism inputs the wash PLU into a master computer or a tunnel controller automatically. When the sale is automated, after paying the car is put into a line-up called the stack or queue. The stack moves sequentially, so the wash knows what each car purchased. After pulling up to the tunnel entrance, an attendant usually guides the customer onto the conveyor. At some washes, the system will send the correct number of rollers automatically, based on tire sensors. The tire sensor lets the wash know where the wheels are and how far apart they are. On other systems the employee may guide the customer on and press a 'Send Car' button on the tunnel controller, to manually send the rollers which push the car through.

When the customer is on the conveyor, the attendant (or signage) will instruct the customer to put the vehicle into neutral, release all brakes, and refrain from steering. Failure to do so can cause an accident on the conveyor. The rollers come up behind the tires, pushing the car through a detector, which measures vehicle length, allowing the controller to tailor the wash to each individual vehicle. The equipment frame, or arches, vary in number and type. A good car wash makes use of many different pieces of equipment and stages of chemical application to thoroughly clean the vehicle.

The carwash will typically start cleaning with pre-soaks applied through special arches. They may apply a lower pH (mild acid) followed by a higher pH (mild alkali), or the order may be reversed depending on chemical suppliers and formula used. Chemical formulas and concentrations will also vary based upon seasonal dirt and film on vehicles, as well as exterior temperature, and other factors. Chemical dilution and application works in combination with removal systems based on either high pressure water, friction, or a combination of both. Chemical substances, while they are industrial strength, are not used in harmful concentrations since car washes are designed not to harm a vehicle's components or finish.

The customer next encounters tire and wheel nozzles, which the industry calls CTAs (Chemical Tire Applicators). These will apply specialized formulations, which remove brake dust and build up from the surface of the wheels and tires. The next arch will often be wraparounds, usually made of a soft cloth, or closed cell foam material. These wraparounds should rub the front bumper and, after washing the sides, will follow across the rear of the vehicle cleaning the rear including the license plate area. Past the first wraps or entrance wraps may be a tire brush that will scrub the tires and wheels. This low piece is often located beneath a mitter (the hanging ribbon-like curtains of cloth that move front to back or side to side) or top wheels. There may also be rocker panel washers which are shorter in size (ranging in size from 18 inches up to 63 inches tall) that clean the lower parts of the vehicle. Most rocker brushes house the motor below the brush hub so they don't inhibit cloth movement and allow the brush to be mounted under a support frame or below a mitter. Some car washes have multiple mitters, or a combination of mitters and top brushes.

After the mitter or top brush(es) the car may pass through a second set of wraparounds. This may also be where high pressure water streams are used to clean difficult to reach parts of the vehicle. The car generally passes over an under carriage wash and/or has high pressure nozzles pointed at it from various positions. Next may be a tire spinner, high pressure nozzles angled specifically to clean wheels and tires. After the several wash stations the vehicle may go through triple foamers, usually red, blue, and yellow, although colors can be customized with higher end chemical suppliers. The triple foam process includes special cleaners as well as some protective paint sealant.

Some washes have multiple rinse stages, usually offering a protectant as an option.

Protectants vary by manufacturer. Near the rinse is where a tire shining machine is often installed, which is designed to apply silicone tire dressing to the tires. This application makes the tires look good (new, and glossy) and preserves the rubber. Next the vehicle is treated with a drying agent and a final rinse. Many carwashes utilize a "spot free" rinse of soft water, that has been filtered of the salts normally present, and sent through semi permeable membranes to produce highly purified water that will not leave spots. After using spot free water, the vehicle is finished with forced air drying, in some cases utilizing heat to produce a very dry car.

Older automatic washes - a majority of which were built prior to 1980 - used to use brushes with soft nylon bristles, which tended to leave a nylon deposit in the shape of a bristle, called brushmarks, on the vehicle's paint. Many newer washes in the US are either cloth (which is not harmful to a car's finish, as long as it is flushed with plenty of water to remove the grit from previous washes) or a closed cell foam brush, which does not hold dirt or water, thus is far less likely to harm any painted finish. Closed cell foam brushes can, in fact, provide a gentle polishing effect that will shine the vehicle's surface during a wash.

In order to avoid marking paintwork, "touchless" (aka "touchfree" or "no-touch") car washes were developed. A touchless car wash uses high water pressure to clean the vehicle instead of brushes, minimizing the chance of surface damage to the vehicle. There are five primary factors to cleaning a vehicle successfully using a touchless system. These five factors are water quality, water temperature, chemistry, time, and water pressure generated by the equipment. If these factors are all set properly, vehicles will come out clean and shiny without the chance of vehicle damage caused by brushes.

At "full-service" car washes, the exterior of the car is washed mechanically with conveyorized equipment, or in some cases by hand, with attendants available to dry the car manually, and to clean the interior (normally consisting of cleaning the windows, wiping the front and side dashes, and vacuuming the carpet and upholstery). Many full service car washes also provide "detailing" services, which may include polishing and waxing the car's exterior by hand or machine, shampooing and steaming interiors, and other services to provide thorough cleaning and protection to the car.