How does a terry turbine work?

Terry was the name of a steam turbine manufacturer. The company was bought by Dresser-Rand some years ago. I don't think they sell this model now, only spare parts.

The basic design is that of an impulse turbine (as opposed to a reaction turbine). The unique feature with Terry is the nozzles feed steam radially inward to a single rotating wheel with blading on the circumference. The blades are semi-circular so the flow path is spiral between the blades and the stationary nozzles. They are arranged in sets of an inlet nozzle with 4 or 5 reversing nozzles before the spent steam is exhausted. The number of nozzle sets depends on the steam rate.