| 摘要 |
A control apparatus responsive to the difference between liquid levels, and a method of controlling a liquid flow regulator by use of the apparatus is disclosed. The control apparatus may comprise a transducer responsive to the back-pressure maintained in a bubbler system including a pair of interconnected gas bubblers, one positioned upstream and one downstream of a flow restriction, such as a trash screen protecting the inlet to a hydroelectric turbine. The mouth of the downstream bubbler is positioned at a pre-selected elevation below that of the mouth of the upstream bubbler so that the pressure head of water at the mouth of the upstream bubbler sets the system back-pressure. When the downstream water level drops sufficiently below that of the upstream water level, the reduced water pressure head at the mouth of the downstream bubbler sets the system back-pressure. A flow regulator, such as a turbine wicket gate, is operated in response to the control apparatus.
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