These Lexair 4-way directional control valves were designed specifically for use on automatic bottom dump hopper cars. They are widely used on railcars that haul coal, aggregates of many sorts plus other types of bulk materials. The valves were developed over two decades ago and were rigorously tested for use in temperature extremes. Shock and vibration testing was also performed on them to make certain that they were "railroad tough". Our valves feature a "sliding shoe" design to operate the directional control function of the valve. The "shoe" is shuttled from the door "open" to the door "close" position and back via a piston assembly powered by pneumatic pressure controlled through the solenoids or manual overrides. The valves are subplate mounted for ease of removal when service is needed due to age or working conditions. Please visit the "Technical Information" page to see a cutaway view of a typical valve.
With nearly 15,000 units applied by the beginning of 2007, we have firmly established this product as the market leader for this industry. All operating characteristics needed for a long, trouble free service life are incorporated into this line of valves. The units are equipped with a magnetic detent that latches the valve in the "door closed" position and holds it there even when the air reservoir is exhausted on the railcar. This magnetic latch holds the valve in the closed condition while resisting vibration and mechanical "G" forces when the car is in transit as our detent can hold in excess of "30G's" of mechanical force. We offer additional safety/security features such as our patented (U.S. Patents 7,093,455 and 7,328,661) integral safety check in the "open" side end cap of our products. This device helps prevent inadvertent actuation of the door opening system. The pressure in the reservoir must be 45 PSI or higher before the "open" solenoid or manual override button will be functional. For detailed information on the operation of valves used in this type of service and to see how our patented device works, click here to read an editorial that was printed in the inaugural issue of the "Coal Transporter" the official publication of the National Coal Transportation Association.
We also offer a valve/cover combination that discourages use by unauthorized personnel. The manual override buttons are concealed behind the cover and are inaccessible from any position when the cover is closed and latched. A lock can be added to make certain that no one operates the valve manually unless they have access to the keys taking security to the highest level.