Extreme operating conditions bring a varied range of challenges for rail operators when keeping their components and systems in operation. The selection of components designed to deliver in difficult conditions can maximize productivity. Dave Walker, Parker Hannifin’s Market Development Manager for the rail industry, outlines some key considerations when selecting pneumatic solutions for extreme environments.
Railway vehicles are expected to constantly operate and be reliable whilst achieving the high demands for minimal life cycle costs, often in some of the most challenging conditions. It is crucial that these vehicles withstand extreme temperatures, attacks from aggressive contaminants plus endure severe shock and vibration. It is a fundamental design prerequisite to ensure the engineering technology selected is robust, dependable and delivers long lasting reliability.
With extremes of weather come extreme challenges, from ice forming on rail vehicles to equipment contamination from dirt; all contributing to unnecessary friction and increasing the power required to deliver motion control. The correct selection of pneumatic equipment by vehicle manufacturers can significantly improve performance.
1 Sealing technology specified to extreme temperatures
The specification of products designed specifically for use in extreme environments is key, particularly as they feature seal technology that can withstand extremes of temperature whilst retaining operational performance.
The ability for seal materials to recover and maintain material characteristics, providing effective sealing over the wide temperature range, along with all elements in the construction of the product to achieve ultimate performance should be a key consideration during the product design process.
An excellent example of this is the Parker Xtreme range of body ported valves; a standard product range which can still deliver results in temperatures from +60°C down as low as -40°C. These hard-wearing valves have also successfully passed in-service “winterisation” tests; which demonstrated the valve’s effective operation when rapid temperature changes were applied to simulate thermal shocks from entering and leaving tunnels in cold environments.
The valve design of the Xtreme range features an over-moulded single piece spool, resulting in fewer moving parts and, with a short spool movement, provides outstanding extreme temperature performance with high reliability.
Complementing the Viking Xtreme valves, Parker offers the P1D-Xtreme range of cylinders which, along with adhering to ISO15552, demonstrate proven capability from -40°C up to +150°C. Combining the most sought after features of seal technology, these low temperature pneumatic cylinders deliver high reliability, low leakage and long service life. The seals are specifically engineered for low temperatures and designed for optimal performance when operating at -40°C to +80°C as the material retains its elastic properties even at extreme low temperatures.
Available as standard production units, these extreme cylinders and valves are suitable for various applications and are readily available for maintenance or for direct replacement of existing components. With the population of skilled maintenance technicians declining, those remaining need componentry that is easy to understand and easily available. Having straightforward and modular solenoid valves and air cylindershelps to make replacements an easy plug-in process.
2 Operating performance matched to extreme environment requirements
Temperature may be one of the most recognized and talked about issues when considering extreme operating conditions. However there are other factorsin the operating environment which can have devastating effects on performance and reliability and, if not considered and acted upon,can severely compromise Life Cycle Cost.
Spikes in power supply
Solenoids such as Parker’s Xtreme valves have wide voltage tolerance to provide continued reliable performance across typically +/- 30% of nominal voltage, this negates the need (and costs) for protected power supplies
Attacks from the environment
Valve bodies need to be anodized and have passed aggressive salt spray testing.Parker’s Viking valves are made entirely of anodized aluminium, for good corrosion resistance. The smooth design, with no dirt-collecting pockets, makes the valve suitable for most environments. The valve has stainless steel fixing screws for the end covers, to withstand aggressive environments
Shock and vibration due to vehicle dynamic movements
Parker’s Viking Xtreme valves are tested and approved to meet the required standards for shock and vibration: IEC6173: 1999 Cat 1 Class B
3 Specify components and systems approved for use in the rail industry
There are many components available in the global marketplace, however, it is important to ensure they are suitable for the rigors of the rail industry as opposed to general industrial use and have been subjected to approval to the required industry standards.
Of course pneumatic product performance in extreme environmental conditions is also dependent on the quality of air being supplied, it should come as no surprise then that Parker also supplies class leading air filtration, and complete filtration and dryer packages for the rail industry, with the capability to provide air to NF F11-100 Air Quality Standards.
In conclusion, the selection of the most appropriate pneumatic components contributes to a reduction in required maintenance activity and enhances life cycle costs of both equipment and vehicles. When considering the best solution,utilising a complete system approach, from air treatment through to components designed for extreme environments, promotes a long and reliable performance from each of the system elements. Choosing from the Parker range offers the additional significant benefits of availability of standard component ranges that can be integrated into existing systems and, of course, the peace of mind that comes from partnering with a reputable company with a proven track record.
Parker Hannifin is a global manufacturer offering an extensive range of robust and durable pneumatic, fluidic and electromechanical motion control solutions. With proven expertise, and experience of over 40 years’ supplying solutions into the railway industry, Parker provides customers a wealth of product and application knowledge.
