A large high-speed machinery supported by bushing can operate continuously, stably, and efficiently. Its internal structure has already achieved high assembly accuracy and met many of its demanding clearance requirements. As for the equipment itself, it must meet the following conditions:
The bending degree of the shaft is within the allowable parameters, which means that a rotor shaft is not allowed to have any bending. Inspection of bending and several reasons for its occurrence. Detection of static and dynamic imbalance.
The friction surface of the shaft, i.e. the shaft diameter, must reach a smooth state with a roughness of less than 0.5 microns and there must be no slip marks. The original parts can meet the requirements, and the parts that have already been run have defects in multiple wear and tear, requiring manual polishing or re grinding on the machine. After treatment, the hardness layer on the surface is relatively reduced and does not affect the smoothness, but it is necessary to reduce the inner diameter of the tile to continuously supplement the wear of the shaft.
The fit between the rotor shaft diameter and the bushing during normal operation reaches a total clearance of 3 to 10, and all contact surfaces have the same clearance. That is to say, the roundness, slope, and taper errors of the shaft and tile themselves must meet the requirement of less than 2 lines. This requirement is quite important and is the key data for installing the tile shaft. There are not many that can fully achieve a snug fit. Reaching 70% is considered good. I almost touched my whole body. It involves measurement skills, global skills, and just the right amount of scraping.
The joint surface of the thrust pad section meets the requirements of full contact and uniform force distribution. The axial force of a TRT gas generator set is quite large, roughly calculated as the product of the cross-sectional area from the high-pressure zone to the low-pressure zone and the pressure difference. If the diameter of the Z large blade is 1200, the pressure difference is 50 kPa, which is 0.05 kg of pressure difference. 60 × 60 × 3.14 × 0.05=565 kg of axial positive pressure. Regardless of whether the positive pressure setting has been adjusted, it should be adjusted during assembly by scraping or adding padding. Use red lead to test the effect.
The limit value of axial displacement at both ends of the rotor shaft is slightly smaller than the movement distance of each stage of the sealing sleeve. After the axial force reaches the unidirectional limit during operation, the various parts of each sealing group are also in a relatively good relative position state. There may be errors in the machining of the dynamic sealing rings at all levels on the rotor and the sealing rings on the stator, not all of which are aligned with the slots. This error will cause the Z-optimal point of the axial seal and the control data of axial displacement to become longer, and the fluctuation and inertia rebound of the airflow will also cause axial displacement of the rotor. The amount of this displacement must be controlled within the limit distance of axial displacement of the seal. Being too large or too small is not conducive to the smooth operation of the rotor. So the axial displacement is controlled within 40 channels. If the limit number is exceeded, the unit will be in a faulty state and shut down. Therefore, in addition to mechanically setting the axis displacement, the fixation of the probe itself is also crucial, otherwise false alarms may occur and the machine will shut down.
The combination of each tile is fixed by the fixing device of the body, without any relative displacement or individual vibration with the body. The back of the tile is fixed on the tile seat using various methods. When there is a significant tilt, displacement, and concentricity error between the shaft and the tile during rough scraping, the back of the tile needs to be scraped first. The contact surface of the curved or spherical surface should not be less than 70%. This data needs to be determined based on the fit between the shaft and the tile to identify the contact between the back of the tile and the tile surface. After the large surface is suitable, fix the tile seat, and there will be displacement of the tile surface or the tile seat. This can easily lead to loose fixation of the tile seat and activity during long-term operation. Pay special attention during assembly.
Components that are connected to rotating parts and have a positional relationship with the sealing must be securely fastened and stable. There is no deformation, damage, or wear. Except for special positions, high-quality spring stop washers must be used. The rotor fins, sealing rings, and their fixing parts, as well as the overall clamping force of the bearing seat, turning gears, coupling devices, measuring components, etc., must be visually inspected and installed securely, without any looseness or conditions for looseness during future operation.
The concentricity error of the mechanical coupling and the opening angle of the wheel inclination shall not exceed 0.05 millimeters. The gap between two pairs of wheels is between 1-3 millimeters. Except for gear couplings or other soft coupling structures. While scraping the tiles, it is necessary to measure the positional relationship between the couplings at any time, taking into account both the degree of fit between the shaft and the tiles and the mutual position between the couplings. If the tile is scraped quite well, but there is a significant deviation in the coupling, it will be much more difficult to move a certain body. Then it is possible to replace or scrape the tiles again. Especially when installing a new unit, special attention should be paid to comprehensive consideration. Unable to handle a single item independently while ignoring adjacent relationships, resulting in significant errors.
The particles, moisture, oxidation degree, acidity, and viscosity of the oil in the lubrication hydraulic station meet the requirements of new oil. There are continuous and intact filtration and purification facilities, complete oil cooling system, and oil supply temperature not exceeding 40 degrees. The water pressure is lower than the oil pressure. The fuel supply pressure meets the parameter requirements. The lubrication status is crucial for the operating cycle of the equipment. During normal operation, the lubricating oil should be circulated and purified, and the appearance quality of the oil should be regularly checked. After each shutdown, the fault switching of the oil pump should be tested, and the return oil circuit of the high-level oil tank should be tested to ensure smooth operation. In addition to requiring acid treatment and carbon tetrachloride cleaning of the oil pipeline during the installation of the new machine, it is necessary to replace the new oil after the first few days of operation, clean the oil tank, check for leaks, and check the cooling effect of the oil pipeline. Then, the new oil is purified and stored as a backup after passing the test. For equipment that has been in operation for a long time, maintenance workers can regularly inspect the appearance of the oil quality.
The cooling system of the body itself is complete, with no scale or leakage in the inner tank, and the temperature difference between inlet and outlet is basically stable. In addition to independent cooling of lubricating oil, some models also have cooling for the unit or medium, such as oxygen producing air compressors. The structure of the cooler is closely related to the normal operation of the equipment, because the temperature changes during its startup and shutdown state directly affect the deformation and sealing of the entire machine. Therefore, during maintenance, the water system should be considered simultaneously. Like large high-pressure water pumps, thrust disc return water pipelines? To check and unblock.
The connected pipelines and facilities have no pulling force on the host, and the host is free and independent, unaffected by external physical forces. All pipelines and facilities connected to the machine body must have activity elimination displacement settings, such as pipeline expansion joints, pipeline bending structures, etc., to prevent deformation, vibration, and displacement of facilities outside the machine body from affecting the equipment host.
All servo mechanisms, operating structures, safety facilities, and interlocking settings are intact, flexible, and effective. The feedback record is complete. No distortion. A significant portion of equipment malfunctions or accidents are caused by the presence of ancillary facilities. So it is important to pay attention to the causes of small problems, promptly fix them, correct them, and adjust them to the best state in a timely manner. For example, in the gear shifting operation of our car, if it is not in place, the clutch will start to loosen, and the gears will not be fully engaged. Over time, it will cause gear shifting and damage to the equipment.
The supporting mechanism is fully stressed and in a free state. The support of equipment foundation mostly consists of a few points, or more than ten points. After running for a period of time, the force situation at each point is different, and the supporting structure during installation is different. Some have hard contact, some have elastic contact, while some have hand force and some do not. The body will vibrate, and the vibration will cause the bolts to loosen. After loosening, they will be tightened. The consequence is that some supporting points are under pressure, some are under tension, and the body itself is in an unfree state. This development will lead to intensified equipment vibration and damage. So before shutting down for maintenance, it is important to pay attention to the vibration of each foot and conduct tests. For those with significant vibration, they should be treated separately with nine pads. The way to handle it is to first determine the bolt with a large Z vibration, select a quarter, loosen it separately after stopping the machine, test the rebound amount with a meter, and then try to add a pad with the same thickness as the rebound amount below, and then tighten it. Regularly check the Z-axis vibration point. We can't just tighten things up for a moment. The bottom is empty, no matter how tight it is, it won't matter, it will actually damage the equipment.
All temperature measurement points, pressure measurement points, and displacement measurement points are in place accurately and reasonably. The transmission and transmission system is intact, and the displayed numbers are compared and verified by multiple parties, accurate and error free, with good shielding and flexible feedback. The operator observes the changes in various data, and every time the machine is shut down, the electrical instruments and operators must conduct a detailed inspection to identify and confirm the data.
The equipment operation requirements to be achieved after maintenance: after full load operation, there should be no more than 5 channels with a large amplitude of 3000 rpm per minute, and no more than 8 channels with a maximum amplitude of 1500 rpm per minute. The temperature at the top of the bearing shall not exceed 70 degrees, the oil temperature shall be within 40 degrees, and the axial displacement and current (axial flow blower) shall be within the rated range. The temperature data of the steam turbine unit may vary.
2024 June 2nd Week Marginal Product Recommendation:
Margianl LCB Plastic Clip Linear Bushings：
Made of high anti-wear material EPB13;
2.Maintenance-free, self lubricating;
3. Chemical resistant;
4. Dust resistant and quit running;
5. Installation by force fitting;
6. The E10 inner tolerance ensues only after the press fit.
https://www.marginalbushings.com/plastic-sliding-bushings/margianl-lcb-plastic-clip-linear-bushings.html
