Shuttlewagon Inc., Grandview, Kansas, designs and manufactures mobile railcar movers for industries including aggregate, mining, and refining. The company makes safe, reliable, and efficient operation top priorities for the nine models of railcar movers they offer, each with engine configurations suited for specific application needs.
Shuttlewagon’s new Navigator Series includes the NVX8040, which has the highest capacity of any mobile railcar mover in the world. Regardless of the model, they are all designed for maximum power, controllability, and ease of operation.
Typical operating conditions for this equipment are harsh — marked by temperature extremes, dirty environments, and periodic shock loading — so mobile railcar movers need pumps that withstand temperature extremes, as well as corrosive and dirty environments, without losing power or efficiency.
Pumps provide power
The pumps on the mobile railcar are driven by a power takeoff from the vehicle’s transmission. The hydraulic system runs several functions, and depending on the application, two or three pumps operate in tandem in the same drive. Functions typically powered by the tandem pumps include steering, moving the rail gears and couplers, powering the hydraulic cooling fan, and powering the intake charge air and transmission cooler. The pumps may also power a rotary broom or other optional equipment on the railcar mover.
Pressurized fluid from the pumps flows to custom manifold cartridges, which provide proportional control to maximize economy and fuel savings while providing precise control of the available power for each pump circuit. Each system is controlled differently:
ÂSteering cylinders and two broom motors use load sensing to conserve energy while delivering maximum power required by the load.
ÂRail gear pressure is proportionally controlled to adjust to adjust speed in response to changing track conditions.
ÂSpeed of a hydraulic cooling fan motor is proportionally controlled for varying heat loads and ambient conditions using load sensing. The fan motor also provides a reversed-flow feature to blow out any debris that might get accumulate in the heat exchangers.
This combination of load sense and proportional control provides the best-in-class performance to meet the different pressure and flow requirements of each circuit — overall, improving fuel savings, reducing costs, and improving the longevity of the hydraulic components
X20 pumps now feature enhanced pressure controls
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The open-circuit piston pumps in Eaton’s X20 portfolio now have inverse proportional pressure control and remote pressure control options for improved system efficiency in all types of on- and off-highway equipment. The inverse proportional pressure control (IPPC) allows the speed of a hydraulic cooling fan motor to be controlled independent of engine speed and load. When coupled with an X20 pump, the IPPC provides accurate and efficient control of fan power. Inputs from individual temperature sensors or the vehicle’s CAN bus are used to manage total vehicle cooling and enable engine after-treatment requirements to be well-matched.
The remote pressure control is important for applications where frequent pressure adjustment is required due to varying loads. This control works in conjunction with a remote relief valve placed outside the system that can be manually or electronically adjusted when the system needs a change in working pressure. If dual-pressure settings are required for two different work circuits, two parallel relief valves can be used in combination with a two-way valve. Common applications requiring this functionality include mobile crushers and screens, and forestry recycling chippers.
“With these new control options, equipment manufacturers can now rely on X20 piston pumps to improve efficiency within fan drive systems and applications needing frequent pressure adjustments,” said Sonya Anderson, Eaton’s mobile open circuit piston pump product manager. X20 piston pumps come in three frame sizes (220, 420, and 620) encompassing seven displacements from 28 to 98 cc/rev. A rear-port option for all displacements makes the pump compatible with a wider range of configurations.
For more information on Eaton’s X20 series pumps, including descriptive videos, click here.
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Hydraulics Behind Improvements
Shuttlewagon had been using a load-sense piston pump in the NVX8040, but the pump’s manufacturer phased it out of production. So hydraulic system designers at Shuttlewagon had to find a powerful, reliable, load-sense pump to replace the one no longer available. Engineered Sales, Inc., North Kansas City, Mo. — an Eaton Hydraulics distributor, and part of the Applied Fluid Power Network — recommended Eaton’s X20, 420 Series pump. The displacement and power output of the 420 Series are equivalent to those of the original pump, but in a more compact size and at no additional cost.
From its X20 open-circuit piston pump portfolio, Eaton delivered the 420 series pumps to maximize power density and work within the tough environment. The pumps deliver 10 to 30 gpm and pressure to 3000 psi, depending on the load.
