Duff Norton is still very much in business and supplies jacking mechanisms and rotary unions for any number of applications both in industry as well as construction. Although it looks as though they no longer make steam or even hydraulic driven jacks.
Duff Norton jacks are basically a jack screw mechanism used to raise and lower something in a controlled manner.
We use numerous Duff Norton jacks here in the aluminum rolling mill to raise and lower just about anything you can think of, including jacking up the boss, but that's another story.
Duff Norton catalog