Application Profile

Truck and Bus Wash

Process Systems

Challenge: Automated Drive-Through Truck and Bus Wash Systems

Location: Michigan/Nationwide

A nationwide leader in the manufacture of automated truck and bus wash systems utilizes a variety of hydraulically-operated spinners, oscillators, undercarriage guns and other spray nozzles to wash vehicles.

Air-actuated valves, operated by optical sensors, control all of the various detergent and rinse tools as the vehicle moves through the wash bay. Unfortunately, the customer was experiencing consistent service problems with the two incumbent valve manufacturers whose products would not stand up to the harsh environment.

Flodraulic’s RHM group was brought in to find a solution to this problem and eliminate the costly downtime problems. The answer was Co-Ax Valve, a coaxial designed pressure- balanced externally air-operated valve with no internal piloting which would make it vulnerable to the dirty media inherent to the truck wash environment. Through a prototyping process with the customer, the Co-Ax solution proved itself out and has become the new standard, replacing the two previous valve manufacturers on new and existing applications.

Not only did RHM and Co-Ax solve the break-down problems, the customer discovered that the Co-Ax valve’s 24 VAC solenoid response time was faster than the other two brands. This saves water and caused the Cv air factor to stay more constant in all ports, resulting in reduced spray head fluctuations.


Experts in fluid power, electrical and mechanical technologies.