Developed by Dan Turner, President of Turner Hydraulics, Inc. of Carlisle, PA., this can save time, energy and money. The unique cylinder design makes changes to the internal parts of off-the-shelf cylinders and can double their productivity with no more moving parts than the rod and piston.
On this website there are two video demonstrations. One is a dump truck with a two-speed cylinder installed. The other is a working comparison between a conventional cylinder and a two-speed cylinder. Both use the same power unit and control valve. The only difference is the cylinders. The cycle time is about 15 seconds for the two-speed cylinder and 40 seconds for the conventional cylinder. Both are retracting with gravity only. There is no oil flowing through the rod port.