Page 223 - Water Standards
P. 223

3) The stroke switch shall move sensitively and reliably.
                 4) For screw headstock gear with load control and height indicating devices, special
                   tests shall be done to check the sending and receiving of the sensor signal in order
                   to ensure that the mechanism can move sensitively and indicate correctly, safely
                   and reliably.
                 5) For headstock gear with dual lifting points, synchronous lifting up and lowering
                   down shall have no blockage.
                 6) The operation of the electric motor shall be steady and the transmission belt shall
                   have no slippage phenomenon  
           4   1   16  Installation of the embedded penstock shall meet the following requirements:
               1  The penstock supporters shall have enough strength and stability to ensure the pen⁃
           stock has no displacement and deformation during installation  
               2  The allowable installation error of the embedded penstock centerline shall meet the
           requirements of Table 4   1   16-1. The mileage deviation of starting segment shall be no larger
           than ±5mm and no larger than ±10mm for the elbow starting point. The perpendicularity de⁃
           viation of the starting segment orifice shall be no larger than ±3mm  
                  Table 4   1   16-1  Allowable installation error of embedded
                                 penstock centerline         Unit: mm

                                      Orifice centerline allowable
                                      error of the elbow starting
                          Allowable error                 Orifice centerline
                                       points and the segments
             Penstock inner  of the orifice               allowable error of
                                     connected with spiral cases,
              diameter D  center of starting               penstocks in
                                      expansion joints, butterfly
                            segment                         other parts
                                       valves, spherical valves
                                        and bifurcated pipes
               D≤2000                         6               15
             2000<D≤5000      5               10              20
               D>5000                         12              25
               3  After the penstock installation, the non⁃circularity of orifice, which means the maxi⁃
           mum difference in length between two diameters perpendicular to each other, shall be no larger
           than 5D/ 1000. At least two pairs of diameters shall be measured  
               4  The value of the allowable misalignment error of the circular seams shall meet the re⁃
           quirements of Table 4   1   16-2  


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