Page 236 - Water Standards
P. 236

—For the bearing cooler, pressure tests shall be done according to the require⁃
                    ments of Item 14 of Article 4   2   2 in this specification.
                   —The oil shall be qualified and the oil level shall meet the design requirements.
                    The deviation shall be no larger than ±10mm  
                 4) The main shaft standby seal shall meet the following requirements:
                   —Before the assembly of the air shroud, an underwater air leakage test shall be
                    done by pumping in the compressed air of 0   05MPa. There shall be no air
                    leakage during the test.
                   —After installation, the radial gap shall meet the design requirements and the de⁃
                    viation shall be no larger than ±20% of the design gap value  
                 5) Installation of the main shaft working seal shall meet the following requirements:
                   —The working seal axial and radial gaps shall meet the design requirements and
                    the allowable error shall be no larger than ±20% of the actual average gap.
                   — The seals shall be able to move up and down freely and they shall contact well
                    with the swivel sealing surface. The pipelines used for water supply and
                    drainage shall be unblocked  
               6  Installation of accessories shall meet the following requirements:
                 1) Start⁃up test and leakage test shall be done for the vacuum breaking valve and air
                   supplement valve. The initial pressure and maximum opening value shall meet the
                   design requirements.
                 2) The installation of the valve seats of the drainage valve or disc valves of spiral case
                   and draft tube shall have a horizontal deviation no larger than 0   2mm/ m. After
                   the disc valve installation, the sealing surface shall be checked to make sure that
                   there is no gap and the valve group can move freely  
           4   2   4  Installation of horizontal shaft turbines shall meet the following requirements:
               1  Before installation, the position, elevation and size of the preformed holes in the
           first⁃stage concrete shall be checked and meet the design requirements  
               2  The equipment installation shall meet the following requirements:
                 1) The deviation of the spiral case verticality shall be no larger than 0   06mm/ m and
                   the deflection shall be less than 0   5mm/ m.
                 2) The allowable error in the levelness of the main shaft shall be no larger than
                   0   02mm/ m. The amount of bounce of the runner end surface shall be no larger
                   than 0   05mm/ m.
                 3) The gap between the runner and the runner chamber shall meet the design require⁃
                   ments and the deviation shall be no larger than 10% of the design gap.
                 4) When the guide vane mechanism has been totally closed, the local gap on the
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