Pump turbine for pumped storage system - has water under pressure injected into stage for starting as pump

摘要

The machine has a pump inlet (1) and a first stage with impeller blades (2) and guide vanes (3) on the outlet. This is followed by two further stages (5,6;8,9) the last of which discharges into a volute (11) from which the outflow (12) is taken. A bypass (20) has an inlet valve (24) with a connection (22) downstream of the main stop valve (13). The bypass takes water under pressure to a header (17) round the first stage. A ring of nozzles (16) injects the water into the annular gap (16) between the first stage impeller blades (2) and the guide vanes (3). This reduces the idling load as the pump comes up to full speed.