Control system and nozzle for impulse turbines

A fluid impulse turbine system (10) comprising:

• (a) a rotatably mounted turbine wheel means (12) rotated in response to a driving force from a jet driving fluid,
• (b) speed sensing means (40) connected to sense the speed of said turbine wheel means (12),
• (c) nozzle means (14) spaced from said turbine wheel means (12) and operative to selectively direct a jet of driving fluid from a nozzle opening (26) against said turbine wheel means (12), said nozzle means (14) including:
• (1) a neck section (20,46)
• (2) a diverging section (24) extending between said neck section (20,46) and said nozzle opening (26), said diverging section (24) tapering outwardly to said nozzle opening (26) from a juncture (22,48) with said neck section (20,46), and
• (d) fluid diverter means (30, 38, 74) mounted upon said nozzle means (14) and selectively operable to divert a flow of fluid from said neck section (20,46) outwardly at an angle to the common central axis of said neck section (20,46) and diverging section (24) to reduce the driving force applied by the jet of driving fluid from said nozzle opening (26) on the turbine wheel means (12), said fluid diverter means (30, 38, 74) acting to divert the flow of fluid from said neck section (20,46) at a location substantially aligned with the juncture (22,48) between said neck section (20,46) and said diverging section (24) by providing a flow of control fluid transverse to the flow of fluid from said neck section (20,46),
• (e) said speed sensing means (40) operating to cause said fluid diverter means (30, 38, 74) to divert the flow of fluid from said neck section (20, 46) outwardly when the speed of said turbine wheel means (12) exceeds a desired speed.