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Pre-installation Of water Guiding Mechanism Of Hydroelectric Generator And Installation Of Main Shaft And Runner

September 14, 2020

Pre-installation of water guiding mechanism of hydroelectric generator and installation of main shaft and runner

1 Pre-installation of water guide
1.1 Lift out the parts (except the bottom ring and guide vanes) of the volute pressure holding tool, and recheck the seat ring according to 3.3.8.
1.2 Re-check the bottom ring and the lower fixed leak-proof ring and guide vanes installed on the bottom ring, and then hoist the top cover and the top cover
Fix the o-ring. Check the coaxiality of the upper and lower anti-leak rings, and determine the centerline of the upper anti-leak ring as the unit reference centerline.
1.3 The tail water cone is fixed on the bottom ring. The flange at the joint between the draft tube and the elbow is tightened after the main shaft is cranked.
1.4 Detect the bottom ring. It is required to check the coaxiality and coaxiality of the lower leak-proof ring on the bottom ring.
1.5 The allowable deviation of the coaxiality between the bottom ring and the top cover non-leak ring is ±0.10mm.
1.6 The roundness deviation of the bottom ring and the top cover non-leak ring is ±0.10mm.
1.7 The pre-installed number of guide vanes is 23.
1.8 After adjusting the top cover and bottom ring, generally tighten half of the bolts. Check that the clearance at the end of the guide vane and the vertical clearance are within the design range.
1.9 After the pre-installation meets the requirements, the top cover is lifted out, the bottom ring does not need to be lifted out of the machine pit, and the positioning hole is drilled with the seat ring.
2. Installation of spindle and runner
2.1 Before connecting the main shaft and the runner, the flange surface and bolt holes must be cleaned up, and there must be no dirt and burrs.
If the manufacturer has connected the pump plate to the runner, in principle, it is not necessary to disassemble and assemble during installation, but should be checked, and all debris in the upper crown of the runner should be removed.
2.2 The connection between the main shaft and the runner should be symmetrically tightened with bolts, as far as possible to complete at one time. Through a flame heating device
For pre-tightening bolts, the expansion and contraction length of the bolts is 0.51~0.56mm.
2.3 Since the main shaft and the runner are connected by friction transmission torque, the torque is transmitted from the runner to the turbine shaft through the friction surface (flange joint surface), and then to the generator shaft. Coupling bolts are only subjected to tensile force. For the HL(E)-LJ-215 hydraulic turbine installation rules, the force has nothing to do with torque. No matter the torque is zero or maximum, as long as the appropriate tensile stress is maintained Ensure that the two friction surfaces do not slip under the maximum torque. It is very important to thoroughly clean the friction surface. Before connecting the turbine shaft and the runner, the following steps must be followed.
2.3.1 In order to facilitate the removal of oil stains, the machining tool marks on the friction surface must be cleaned. The flange screw holes should also be polished with fine oil stone.
2.3.2 Rinse the friction surface with thinner and thoroughly remove burrs and flashes. Lubricate the lower end surface of the nut and all threads, while avoiding the friction surface being damaged by the lubricant.
The threads of the stud are coated with a molybdenum disulfide lubricant.
Before the stud is put into the screw hole and the nut is screwed on the stud, the thread of the nut and the thread of the runner threaded hole are coated with a thicker layer of molybdenum disulfide lubricant.
2.3.2 Before screwing the nut to the flange, apply a thin molybdenum disulfide lubricant to the lower end of the nut.
2.3.3 Measure the length C1 of each stud with the "measuring instrument for measuring bolt elongation", and record all the measured values in the table.
2.3.4 Tighten each bolt as shown in the figure below, tighten each bolt column with the handle, and then measure the length C2 of each stud and record it in the table. (C2 elongation is not less than 0.10mm)
2.3.5 Mark the corresponding position of each nut on the nut and on the plane with ink Ⅰ
2.3.6 Calculate the angle of cold tightening α1
α1=K(C2-C1) where K=360°/4 (where 4 is the pitch of M68×4) α1=90°(C2-C1)
2.3.7 Use "angle template" to mark the cosine angle α from point I on the upper plane of the nut
tot-α1 α2
And mark on the flange
2.3.8 Bolts at the connection between the turbine shaft and the runner
tot=360°/4×0.56=50.4°; total elongation of bolt △l=0.56mm
α2=50.4°-90°(C2-C1) 5.3.8. α1, α2
Record in the table. After the measurement, before heating, loosen the nut so that there is a certain gap between the nut and the flange (not less than 0.2mm)
2.3.9 Use the "coupling bolt heating device" to heat the stud, turn the nut to the α diameter direction and tighten it symmetrically, and tighten the other studs in the same way.
2.3.10 After the stud has cooled to room temperature, measure the length C3 of the stud and record it in the table, and calculate the elongation △l=C3-C1
Error range: The elongation of each bolt is required to be within the range of △l (0.51~0.56mm). If the elongation of the stud does not meet the requirements, the nut angle must be corrected.
2.4 After the runner is connected to the main shaft, apply sealant in turn (tighten Loctite glue) to prevent loosening. 2.5 Installation quality requirements:
1 The bolts must have sufficient tightness, and the measured elongation value is (0.51~0.56mm).
2 The joint surface of the main shaft and the connecting flange of the runner must be tight, and it cannot pass through inspection with a 0.02 mm feeler gauge.
2.6 When the runner is hoisted in and installed, it should be placed at a position about 17 mm lower than the design elevation. When hoisted, it should be placed slowly and gently.
2.7 Adjust the verticality of the spindle.
2.8 Installation quality requirements:
2.8.1 The allowable deviation of coaxiality and roundness opposite to the stop ring on the top cover is ±0.10mm. 2.8.2 The allowable deviation of coaxiality and roundness opposite to the lower leak-proof ring of the bottom ring is ±0.10mm. 2.8.3 The verticality of the spindle is not more than 0.02mm/m.
Note: The coaxiality and roundness of each part of the runner shall be checked with the main shaft as the center.