Submersible hydroelectric generator apparatus and method of operating same

A submersible hydroelectric generator apparatus comprising:

• a substantially upright body having an outer chamber and an inner pressure chamber surrounded by and spaced apart from the outer chamber, the inner pressure chamber being in fluid communication with the outer chamber adjacent the lowermost end of the inner pressure chamber, the inner pressure chamber having a pressurizable fluid supply therein, the outer chamber having a charging inlet adjacent the top of the upright body, a discharge outlet located adjacent the bottom of the upright body, and a liquid passageway intermediate the charging inlet and the discharge outlet, the liquid passageway having a turbine mounted therein and a flow regulator in the liquid passageway intermediate the turbine and the discharge outlet, and in which there is provided a closure moveable to and from a first position blocking the discharge outlet thereby preventing evacuation of water from the apparatus and a second position opening the discharge outlet thereby permitting evacuation of water from the apparatus,
• a controller,
• a closure actuator capable of moving the closure to and from the first position to and from the second position in response to a control input from the controller,
• a pressure sensor in the inner pressure chamber in communication with the controller, the pressure sensor being operable to measure the pressure of the pressurizable fluid supply in the inner pressure chamber,
• an auxiliary pressurized fluid supply to supplement the pressurizable fluid supply, and
• a pressure regulator responsive to the controller, the pressure regulator being operable to control the delivery of auxiliary pressurized fluid from the auxiliary pressurized fluid supply to the inner pressure chamber to maintain the pressure of the pressurizable fluid supply in the inner pressure chamber at or above a predetermined pressure level during evacuation of water from the apparatus,
• wherein the flow regulator comprises a sump located in the liquid passageway below the turbine and in which there is provided means to seal the sump, and wherein there is provided means to draw air from the sump thereby creating a vacuum in the sump.