With the wider and wider application of steam turbines, relevant people pay more and more attention to steam turbines. After the steam turbine has been used for a certain period of time, some failures cannot be avoided, so how to repair the steam turbine correctly? Next, this article will introduce the repair methods of the main components of the steam turbine, as follows:

1. Troubleshooting of steam turbines

There are many reasons for the vibration of the steam turbine. From the analysis of the overall operation of the unit, the reasons for the sensation are generally the same, that is, almost all of them are caused by a fault. The diagnosis of steam turbine failure should start from the specific characteristics of the failure. Find out the characteristics of the fault itself, and then analyze and summarize the types of faults according to these characteristics. The methods for diagnosing steam turbine faults are as follows:

(1) Investigation of oscillation characteristics and collection of specific relevant information. Generally, the analysis of oscillation characteristics includes the following contents: analyzing the trend of oscillation, finding out the relationship between rotational speed and oscillation, analyzing the frequency of oscillation, and analyzing the phase and amplitude of oscillation. The relevant information to be collected includes: the maintenance of the steam turbine, the operation information of the peer units, the analysis records of the daily operation, and the information of the unit organization.

(2) After investigating the oscillation characteristics and collecting relevant information, the mechanism of the fault should be carefully analyzed. Patch for reference.

(3) It is clear that the purpose of the steam turbine diagnosis is to eliminate frequent faults, so try to make the diagnosis method as simple and efficient as possible.

2. Repair of the main components of the steam turbine

2.1 Overhauling the steam turbine cylinder

The cylinder is one of the important components of the steam turbine, and it is divided into two cylinders. The internal components of the cylinder are mainly static blade cascades, rotors, baffles, etc. The inner vacuum layer can effectively block the entry of air, thereby improving the reliability and safety of the steam turbine. For the maintenance of the cylinder, the following procedures should be followed:

(1) Withdrawal of the table. Removing the watch includes two aspects of work: remove all the connecting screws on the decoration board bracket, but make sure that the bead, bracket and bolt are not damaged, all the decoration boards can be lifted, and the decoration should be effectively maintained at the same time. Spray paint on the board. In addition, the serial number of the device on the costume board must be marked, and all the removed parts must be placed at a fixed point for better installation.

(2) It is not possible to disassemble the thermal insulation layer of the steam turbine at any time. It can only be carried out after the temperature of the upper cylinder of the cylinder is lowered to 120 °C. At the same time, be careful to avoid cotton yarn, wood chips, etc. falling into the thermal insulation layer. cause burning.

(3) Remove all tripod bolts on the speed regulating valve, take out the positioning pin, remove the tripod, and then remove the flange bolts on the front, rear, left, and right sides of the cylinder, and ensure that the bolts will not creep, twist, buckle, etc. during the operation. glitches, etc.

(4) When installing the guide rod, make sure that the guide rod is lubricated. In order to achieve this purpose, it is possible to apply turbine oil to the guide rod, and then perform a diagonal installation. It is also necessary to check the deformation status of the cylinder and the joint surface of the cylinder in time, and measure the horizontal bisector of the longitudinal horizontal cylinder in time. Fifth, after checking the maintenance of each important component, assemble the body part of the steam turbine, check whether the records in the operation process are in good condition, block the vagueness of each cooperation surface of the cylinder, and make a record, and then stick a seal.

2.2 Overhaul steam turbine rotor

As the transmission part of the steam turbine, the rotor plays an important role in the operation of the steam turbine. The principle of its effect is that through the utilization of the high-temperature and high-pressure kinetic energy of the nozzle, the conversion of the reverse mechanical energy of the steam turbine is achieved. Repairs to the rotor include:

(1) Mark the orientation of the rotor, place a spirit level in the middle of the journal, and record the level of the lower shaft carefully. Compare the interval difference between this record and the last record to ensure that the measured journal lift is within the specified range.

(2) Use the dial indicator flexibly to measure the sway of the rotor during operation, and strictly check the accuracy of the dial indicator before measurement. And before the measurement, it is necessary to check the measurement readings, and then compare the measured readings with the previously recorded readings to check whether the two readings are the same. Once there is an error in the two readings, the error in the measurement process needs to be found and the measurement must be re-measured.

(3) Measure the dynamic blade clearance of the steam turbine. The measuring parts are at the two ends of the joint surface of the cylinder, the measuring tool is a wedge-type feeler gauge, and the measuring task is to measure the gap between the stator vane outlet and the moving vane outlet. After the measurement, pay attention to make specific records.

(4) Remove the turbine coupling bolts and lift the rotor out. To achieve this purpose, it is necessary to first remove the outer casing of the coupling and the bolts that are fastened, then remove the square head bolts that lower the coupling end, and disengage the coupling stops at the turbine end and the generator end. In this process, attention should be paid not only to control the distance between the two ports of the steam turbine and the generator, but also to check the bolts of the coupling to avoid cracks. The final step is cleaning of moving blades, refurbishment and inspection of blades and impellers, and inspection of thrust discs and journals.

(5) Overhaul the diaphragm sleeve, nozzle and diaphragm of the steam turbine. For the nozzle installed at the inlet of the baffle and the steam entering the cylinder, it is more troublesome to repair, especially because the baffle and the baffle are sleeved on the support inside the cylinder, the repair process is as follows, first install the nozzle, The clapboard and the guide vane ring are removed, and secondly, when the clapboard is removed, the pressure plate bolts are first removed, and finally the hoisting equipment is used to lift out the sleeves and the clapboard. During the process, it is necessary to ensure the smooth and safe lifting operation. Remove the guide vane ring, pressure plate and screws, lift the guide vane ring, remove the nozzle, remove the bolt, and finally complete the lifting of the nozzle group. Check the turbine diaphragm stator blade, diaphragm and diaphragm sleeve screws. Before viewing, the partition should be cleaned and disassembled, and then the surface should be dried with compressed air. During the cleaning operation, it is necessary to pay attention to maintaining the stationary vanes and other related parts from harm, and investigate whether there are cracks in the instant noodles and whether the parts are loose.