Technical Key Points for Turbine Installation

　　 Turbine installation Key technical points for the combined installation of low-pressure cylinders: The combined assembly of the lower outer casing of the low-pressure cylinder includes the following steps: First, position the rear section of the lower outer casing on the motor side and the front section of the lower outer casing on the steam side, adjust their levels, raise their elevations, and accurately locate their centers. Once these requirements are met, separate the front and rear sections by a certain distance, thoroughly clean and inspect the vertical mating surfaces, and ensure that no foreign objects remain before proceeding with the formal assembly. Laser beams, steel wires, dummy shafts, rotors, and other similar tools can serve as reference benchmarks for aligning the assembled cylinders. Currently, the wire-pulling method is widely used: After positioning the rear section of the lower outer casing on the motor side and the front section of the lower outer casing on the steam side and adjusting their levels and elevations accordingly, a longitudinal steel wire can be pulled to adjust the steam seal recesses or bearing oil plugs that have been inserted into these recesses. Furthermore, the dimensions of the recesses and the steel wire in the left, right, and downward directions can be measured to verify compliance with the specified requirements.

　　The installation method for the low-pressure outer upper cylinder assembly of the steam turbine includes: first conducting a trial assembly to check the management level and verify the vertical alignment and gap at the joint surface; only after confirming compliance with design requirements should the formal assembly proceed. The low-pressure inner cylinder assembly involves: positioning and aligning the low-pressure inner cylinder, adjusting the diaphragm, then hoisting the low-pressure rotor into the cylinder for positioning, and finally adjusting the flow passage clearance.

　　The high- and intermediate-pressure cylinders for the steam turbine are delivered as a complete unit and do not require on-site assembly. Turbine The shaft axially and radially positions the rotor and cylinder via a transport ring located at the end of the cylinder block. Before the cylinder is installed, the axial and radial positioning dimensions of the transport ring should be measured, and the manufacturer’s assembly records should be reviewed to verify whether the rotor inside the cylinder has shifted during transportation, ensuring that the flow clearance remains unchanged. For high-pressure or intermediate-pressure cylinders, most Chinese power plants currently adopt a support configuration in which the upper cat-claws rest on the bearing support surface. However, when using the outer casing—whether high-pressure or intermediate-pressure—to position and center the rotor, it is inevitable that the outer casing itself and its cat-claws will be employed for this purpose; thus, only the lower half of the cylinder can be used for positioning and centering. Consequently, the lower part of this type of cylinder is equipped with dedicated support surfaces specifically designed for positioning and centering operations. After the bearings have been preliminarily designed and centered, the lower half of the cylinder can effectively utilize these support surfaces to securely support and connect the cylinder, enabling precise adjustment and final positioning and centering.

　　 Turbine installation The alignment of the shaft system with the wheel centers primarily involves aligning the high-pressure wheel center, the medium-pressure wheel center, the low-pressure wheel center, the low-pressure rotor, and the electric rotor wheel center. When aligning the wheel centers of the shaft system, start by using the low-pressure rotor as the reference point. Next, the adjustment of the wheel positioning center is typically achieved by pressurizing the cylinders and condenser to simulate operating conditions. For each pair of wheels, when re-aligning, it’s essential to leave sufficient clearance and height differences as预留 values. Generally, multiple checks and alignments of the wheel centers are required at different stages.