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Installation Quality of The Upper And Lower Draft Cones of The Hydro Generator

September 9, 2020

Installation quality of the upper and lower draft cones of the hydro-generator

The allowable deviation between the center of the upper nozzle of the draft tube of the hydro-generator and the center of the unit is 1.5mm. The allowable deviation of the plane elevation of the upper nozzle flange of the draft cone is ±2mm. The permissible deviation of the plane non-parallelism of the flange of the upper nozzle of the elbow is 0.10mm/m.

1. Installation of turbine generator volute seat ring
1.1 The volute seat ring should be cleaned and cleaned before installation.
1.2 Install the volute jack, adjust the elevation and level.
1.3 Lift the volute seat ring into the pit and put it on the jack. The X and Y lines on the seat ring should be consistent with the reference line.
1.4. Adjust the center and elevation of the volute seat ring.
1.5. In order to prevent the displacement and deformation of the volute seat ring, further strengthen the support for the volute seat ring 1.6. After the above work is completed, the installation dimensions should be checked again and a record should be made.
1.7 Installation quality requirements of volute seat ring:
The allowable deviation between the X and Y marks on the seat ring and the X and Y baseline of the unit is 1.5mm.
The allowable deviation of seat ring elevation is ±2mm.
The allowable deviation of the upper plane of the seat ring is 0.05mm/m. (Radial measurement
The radius difference between the upper and lower inner circles of the seat ring shall not exceed 0.100mm.

2. Hydro-turbine generator volute water pressure test
2.1 According to the volute water pressure test tool drawing, assemble the parts of the water pressure test so that the parts are in place.
2.2 Perform a hydraulic test on the volute according to the technical requirements in the volute hydraulic test diagram, and record the test results.
2.3. After the hydraulic test meets the requirements. The water pressure is reduced to 4.0MPa according to the technical requirements in the volute water pressure test.
2.4. Re-check the installation dimensions of the seat ring to make it meet the quality requirements in 3.3.8.
2.5. All tie rods and jacks used for support adjustment must be spot welded firmly to prevent deformation and displacement of the volute when concrete is poured.

3 Installation of the lining of the turbine generator pit
3.1 Adjust the center of the pit lining according to the inner circle of the seat ring, and adjust the elevation according to the plane of the seat ring.
Quasi-X-Y line, then weld according to the drawing requirements, and fix the machine pit lining on the seat ring by welding. Equipped with cutting, welding, servomotor seat, lock foundation plate machine pit access door, etc.
3.2 Installation quality requirements
The allowable deviation of the coaxiality of the center of the seat ring is Φ5mm.
The allowable deviation of the upper opening diameter of the pit lining is ±5mm.
4 Installation of Hydrogenerator Servo Base
4.1 After passing the adjustment, the servomotor base must be firmly fixed and welded to the lining of the machine pit. Check the verticality of the flange surface, the center elevation, and the distance to the center line of the unit once.
4.2 Installation quality requirements
The verticality of the flange surface of the servomotor seat is 0.3mm/m.
The allowable deviation of the center and elevation of the servomotor seat is ±1mm.
The allowable deviation between the flange surface and center line of the servomotor base and the unit coordinate reference line is ±3mm.

5 Installation of the water pipe on the volute of the turbine generator
5.1 All water, gas and instrument system pipelines in the pipeline should be unblocked, and there should be no impurities.
5.2 When preparing the pipeline, the ovality of the pipe section shall not exceed 10% of the pipe diameter; the local concavity and convexity of the pipe incision shall not be greater than 3mm.
5.3 The position of each flange on the pit lining is determined by the position of each pipe in the top cover.

6 Concrete pouring in the installation of water turbine generator
6.1 The pressure is maintained and the concrete is poured. During pouring, close monitoring of the level and roundness of the seat ring should be performed.
6.2 When pouring concrete, there should be measures to prevent deformation of the seat ring. Control the rising speed of concrete pouring and the pouring height of each layer, monitor the deformation of the seat ring during construction, and adjust the concrete pouring sequence at any time according to the actual situation.
6.3 The pressure of the volute can not be released until the concrete maintenance period is over.