Page 241 - Water Standards
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shall be no larger than 0   25mm and the total length shall
                     be no larger than 25% of the guide vane height.
                7  Installation of the main shaft and runner shall meet the follow⁃
           ing requirements:
                  1) The allowable installation error of the main shaft and
                      runner shall meet the requirements of Table 4   2   5-4.
                  2) The main shaft levelness deviation shall be no larger than
                     0   04mm/ m  
                       Table 4   2   5-4  Allowable installation error of
                                main shaft and runner
             No            Item                   Allowable error
                   Composite joint between runner
             1                             No gap
                 and main shaft flange
                    Gap  between  runner  and
             2                             ±20% of the actual average gap
                 runner chamber
                                            Meet requirements of Article 4   2   3 in
             3     Main shaft sealing gap
                                         this specification
           4   2   6  Installation of impulse turbines shall meet the following requirements:
               1  The deviation of the distance between the penstock inlet center line and the turbine
           coordinate lines shall be no larger than ±0   2%  
               2  Casing installation shall meet the following requirements:
                 1) Compound casings with split segments shall meet the requirements of Item 10 of
                   Article 4   2   2 in this specification. Composite surfaces which have no sealing or
                   cushion shall be coated with sealant.
                 2) When installing the casing, the distance deviation to the turbine X and Y datum
                   lines shall be no larger than 1mm and the elevation deviation no larger than ±
                   2mm. The horizontal deviation of the casing upper flange surface shall be no
                   larger than 0   04mm/ m. For vertical shaft turbine⁃generator units, the elevation
                   of each nozzle flange which is welded to the casing shall be the same, and the de⁃
                   viation shall be no larger than 1   0mm. Each flange  s verticality deviation shall be
                   no larger than 0   30mm/ m and the distance between each flange and the turbine
                   coordinate datum line shall meet the design requirements.
               3  Bearing assembly shall meet the following requirements:
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