Radian laser tracker on Application in the field of turbine maintenance measurement

The importance of steam turbine maintenance
A steam turbine, also known as a steam turbine engine, is a rotating steam power device. High temperature and high pressure steam passes through a fixed nozzle to form an accelerated airflow and is sprayed onto the blades, causing the rotor equipped with blade rows to rotate while doing external work. Steam turbines are the main equipment in modern power plants and are also used in metallurgical, chemical, and naval power plants.
When a steam turbine is working, its rotor will rotate at high speed to convert the heat energy of the steam into mechanical energy. Due to the large volume and complex internal structure of the steam turbine itself, coupled with its high-speed rotation, the positional relationship between its key components is very important: it is necessary to ensure a compact connection between the components, so that steam thermal energy can be maximized into mechanical energy, improving the overall performance and work efficiency; To maintain a suitable distance between components and avoid friction and collision, high-speed rotation combined with high mass may cause damage to the turbine and even cause serious production accidents.

Therefore, regular inspection and maintenance of steam turbines is a very important task.

Xu Longdao, "Dictionary of Physics," Science Press, September 2007.

Difficulties in Steam Turbine Inspection
As mentioned earlier, the steam turbine itself has the characteristics of large volume, large mass, complex internal structure, and the need for multi component collaborative work. Its maintenance measurement accuracy is extremely high, usually requiring an accuracy of 0.05mm. From this perspective, if it is desired to carry out turbine maintenance and measurement work with high efficiency, it is necessary to have a measurement system with both large size, high precision, and overall data collection and analysis capabilities to assist.
API Solution
The API brand Radian Laser Tracker, equipped with large-scale and high-precision data acquisition capabilities, and corresponding measurement software for data processing and analysis, can solve the problem of turbine maintenance measurement in a one-stop manner.
When using the Radian laser tracker for measurement, the operator holds a laser tracker target ball (SMR) with a built-in prism to touch the target area. The laser tracker host will shoot a laser to lock and track the center of the SMR. When the SMR touches the target area, the 3D coordinates of the target area are accurately collected at a data acquisition rate of 1000Hz, and transmitted to the measurement software for recording and saving.
After collecting several marked points on the workpiece, the corresponding lines, surfaces, and bodies can be formed in the software based on the positions of each point, and the corresponding geometric tolerance data can be calculated. It can also be compared with digital analog to achieve the purpose of measurement and detection.
Application example: maintenance measurement of steam turbine unit equipment in a certain power plant
1. Purpose of testing
After long-term operation, it is necessary to conduct maintenance measurements on the unit, using measurement data as support to evaluate and adjust the positional relationship between key components, ultimately ensuring that the safety and working energy efficiency of the steam turbine reach or exceed the initial design state.
2. Measurement content
Adjust the central axis of the steam turbine rotor and the central axis of the rotor cylinder liner to the coaxial state, and at this time, the steam seal teeth installed on the cylinder liner, the steam seal block, and the steam seal teeth on the rotor will match one by one, achieving optimal energy efficiency during operation.
So the main content of measurement is the cylindrical data of the rotor, cylinder liner, and cylinder liner sealing teeth at each position; Measure the data of each position, analyze and align it in the software, and then make corrections and retests based on the analysis results until the central axis of each position is aligned. The key detection positions involved include: rotor shaft, opening gear, shroud, blade tip, diaphragm, steam seal teeth, etc.
3. Measurement implementation
(1) Laser tracker in place&transfer station deployment
Install a Radian laser tracker at a suitable location around the turbine to be tested. Due to the large volume and complex structure of the turbine, it is necessary to set up several transfer stations in visible positions for the laser tracker's transfer station layout, so that the turbine data can be measured from the required angles for the final overall analysis.
(2) Establishing a coordinate system
Measure all the rotor positions to be measured that have been lifted out of the cylinder and establish the rotor coordinate system; Measure the position of the corresponding depression with the rotor in the half cylinder state and establish the depression coordinate system. Ultimately, all measurement data will be aligned and integrated through two coordinate systems, and the distances between corresponding positions will be analyzed and calculated.
(3) Data collection and analysis
Collect data from each position to be measured on the rotor and cylinder block in sequence and record them in the measurement software. Due to the structural shape of the steam turbine itself, a large number of deep holes, grooves, and hidden point positions will be encountered during measurement, which cannot be directly measured using ordinary tracker targets (SMR). At this point, using the deep hole measurement tool vProbe probe developed with API for the laser tracker, it is easy to collect data on hidden parts.

When measuring, simply align the light port of the vProbe probe with the laser emitted by the tracker, and the probe tip of the probe can be used to touch the deep hole and hidden point position for measurement. The probe length can be selected from various specifications ranging from 50mm-500mm, and the most suitable probe solution can be selected according to actual measurement needs. In addition, the design of vertical and horizontal dual probe positions greatly facilitates the operator's practical measurement operations.

After all data collection is completed, all data can be aligned and analyzed as a whole by transferring stations or creating the same coordinate system.
(4) Adjustment and retesting
According to the collected data, calculate the relationship between the corresponding positions, and then adjust the position of the corresponding parts according to the deviation value shown in the data. After the adjustment is completed, retest until the parts are adjusted to the desired optimal position.
conclusion
Radian laser tracker, with its high precision, large measurement range, and high data acquisition efficiency, can successfully realize high-precision detection of various parts of the steam turbine and cooperate with the software to conduct overall analysis, guide maintenance and assembly, and complete high-quality detection of the steam turbine with the help of vProbe hidden point probe function expansion accessories.
About API
The API brand was founded by Dr. Kam Lau in Rockwell, Maryland, USA in 1987. It is the inventor of laser trackers and holds multiple patents for leading global measurement technologies, making it a leader in the field of precision measurement technology; Since its establishment, API has always been committed to the research and development and production of precision measurement instruments and high-performance sensors in the field of mechanical manufacturing. Its products have been widely applied in advanced manufacturing fields around the world, and are leading in high-precision standards for coordinate measurement and machine tool performance testing.