Customers will appreciate the end-result of the high-pressure prewash, detergent application, water rinse and final wax delivered by these machine, but are likely to be completely unaware of the technology behind it. As Rüdiger Hirschmann, team manager for gantry development at WashTec explains, gantry car washes combine a wide variety of functions in the tightest of spaces, with pneumatic systems being used to control chemical-dispensing pumps as well as aligning the washing equipment with the car.
As many as 80 functions on these machines are controlled using pneumatic valves. These valves need to be robust, since they are exposed to jet streams and chemicals in the washing system, and plastic valves have thus proved the only option for WashTec. However, what was initially available on the market was relatively limited. Back in 2010, Aventics (the company was known as Bosch Rexroth at the time) won over WashTec with an offer to involve its customer in the development of a whole new valve generation, the AV03.
The AV03 proved something of an innovation in valve technology. The diagonal design of the valve decreases the dimensions by nearly 50 percent. As a result, individual valves are made as small as a business card. The use of high-performance plastics in their construction results in significant weight reduction, which enables them to be mounted directly on the actuator (in this case, a pneumatic cylinder). Lower hose volumes ensure a substantial reduction in the quantity of compressed air required for pressurisation, while ventilation is optimised.
The new generation of valves offers full IP65 protection; as Hirschmann explains, even the ‘weak’ points experienced with other products where water can ingress through the LED display after just a few weeks in operation, have been eliminated from the AV03.
Despite the relatively large size of gantry washing facilities, WashTec relies on the miniaturisation of components to keep the design as tight as possible. The compact dimensions of the valves contribute to this goal. The two cabinets used to house the control system and media supply are around two metres in height, so that operators and service technicians can see and replace all components without having to use any special access arrangements. This easy access is aided by LEDs on the valve heads, which give the service technicians fast and convenient indication of valve status.
WashTec offers its gantry wash systems in various equipment variants. To reduce complexity, the company has plumped for a modular design, and this also applies to the pneumatic systems as well. The team at WashTec has developed twelve different pneumatic valve combinations with the most frequently ordered functional variants and added these to its SAP system in order to streamline procurement.
Depending on the AV03 valve terminal plug connection, users can increase the number of valves from a minimum of two up to 36 in increments of two for a multi-pole connection, as Rüdiger Hirschmann explains:
“We equip the valve systems to ensure that they are almost always fully loaded. Each valve block at WashTec is constructed using two rules based on logical principles: the ‘ranking rule’ states that valves for emergency-off functions are always positioned at the front, followed by anti-frost functions. As soon as temperatures drop below four degrees, the system needs to be automatically drained to avoid frost damage. The subsequent functions are arranged in order of frequency according to the correspondence rule. Frequently used functions are situated at the start; more ‘exotic’ functions are integrated at the end of the valve system.”
Valve efficiency is particularly advantageous for WashTec’s gantry car wash machines. The AV03 coils control very high-volume flows with a low power input. As a result, additional relays are not required, substantially reducing system costs. When using a multi-pole connection, up to 36 valves can be combined on one valve system. WashTec connects all its valve systems via a D-SUB 25 plug, which reduces the effort required for assembly.
In addition to the multi-pole connection, the new AES valve electronics also support connection via all standard fieldbus and Ethernet protocols. The valve design is based on the ‘poka-yoke’ principle, which ensures correct installation. During assembly, the valve is slid into a hook in the base plate and is secured in place by a metal screw from above. This also simplifies service, particularly as the electronics boards can be replaced separately.
Summarising his experience of the new Aventics valve generation, Rüdiger Hirschmann says the AV03 development has been pivotal to the success of WashTec’s machines, thanks to the valve’s extremely long service life, function-specific design and outstanding product quality.
WashTec has more than 20,000 gantry car washes installed worldwide. In addition to the gantries, its portfolio also includes conveyor tunnels, self-service jet wash equipment, commercial vehicle wash systems, water recovery systems, as well as complementary cleaning and care chemicals. In 1962, the company’s founders submitted a patent application for the world’s first automatic wash system for automobiles.
A customer’s choice of machine depends on the expected number of monthly washes. Selection begins with models for locations with little space and a low washing potential. The SoftCare Pro Classic pays off after 400 washes a month and the SoftCare² Pro is a particularly profitable system for operators exceeding 600 washes a month.
The fastest gantry wash system, SoftCare² Juno for top locations with over 1,200 customers monthly, washes and dries up to 18 cars per hour. And all of WashTec’s gantry wash systems have one common feature: robust, maintenance-friendly technology to ensure maximum availability.