1. The Olympic Cauldron Car pauses for trackside ceremonies in Boise, Idaho on May 9. A hydraulic drive raises the torch (as it is here) for all to see when the car is stationary and lowers to torch for safety and to keep it from being extinguished by wind when the car is in motion.
An unusual aspect of the cauldron car is a shield of air surrounding the flame. This shield protects the flame from winds by directing a strong current of air upward and dramatically reduces the effects of crosswinds or air rushing by the flame generated by the train’s motion.
Fans mounted below the cauldron push air upward at nearly 150 ft/sec through vents positioned around the circumference of the cauldron. Vinton Wolfe, senior research engineer at Atlanta Gas Light Co., designed and constructed a prototype to test the concept. Using a scaled-down model on a test track, the air shield was able to protect the flame at speeds exceeding 65 mph. This was deemed satisfactory, especially because the 42-in. diameter cauldron on the Cauldron Car would be less likely to be blown out than the smaller flame on the model.
Advance Hydraulics, Milwaukee, was commissioned to design and build the hydraulic system for the Cauldron Car. The basic requirements seemed simple enough: provide a hydraulic system to raise and lower the cauldron from a control panel mounted either on the Cauldron Car itself or from a remote location in an adjacent car. Cycle time to fully raise the cauldron from a lowered position had to be 30 seconds or less. However, addressing details of the design requirements proved the biggest challenge, because much of the Cauldron Car was still being developed, and design parameters were subject to change.
The cylinder for raising and lowering the cauldron required a hollow rod for routing fuel and air lines (for the air shield) to the cauldron. This meant the cylinder would have to be custom designed and built. Because much of the Cauldron Car was still in a concept stage, hand-drawn sketches were all Advance Hydraulics had to work from. Much of the car had not actually been constructed, so design requirements were not finalized. Therefore, Advance Hydraulics had to design the system with generous flow, pressure, and stroke capabilities. Working with a worst-case scenario, they could throttle back flow, pressure, and stroke to match actual requirements. One more minor detail: the project had to be completed and tested in three weeks.
Hydraulic System Design, Operation
Layout of main hydraulic components is shown in the schematic (Fig. 2). Power is delivered to the hydraulic system at 29 gpm at up to 900 psi by a Hydreco fixed-displacement gear pump, which is manufactured by Magna-Pow’r Inc., Franklin Park, Ill. Main directional-control valve A has an open-center configuration that dumps fluid to tank at low pressure when the valve is centered. This configuration serves as an energy-saving alternative to blocking flow from the pump and dumping it to tank over the high-pressure relief valve. Due to space constraints, all directional- and flow-control valves, manufactured by Northman USA Inc., are stack mounted on the power unit.