Extraction Tower

The extraction tower is a type of cylindrical equipment that stands in the vast apparatus areas of petroleum refining, chemical engineering, pharmaceuticals, and other process industries. As the core equipment for achieving separation, purification, and chemical reactions of mixtures, the extraction tower utilizes precision internal trays to facilitate countercurrent contact between gas and liquid, completing key processes such as distillation, absorption, and desorption. Its separation efficiency directly determines the purity, yield of the final product, and the economic benefits of the entire apparatus. The precision of the extraction tower's manufacturing and installation, especially its verticality, internal component levelness, and connection pipe orientation, are crucial for ensuring safe, efficient, and long-term operation.

The Importance of Three-Dimensional Inspection

With increasingly stringent engineering standards and the widespread adoption of digital delivery, implementing three-dimensional precision inspection for extraction towers has become a rigid requirement. Traditional inspection methods such as plumb lines and levels are relatively inefficient, making it difficult to obtain comprehensive and quantifiable spatial data, which does not meet the modern engineering demands for data-driven decision-making. Digital three-dimensional inspection establishes a "digital twin" model for the extraction tower through high-precision spatial coordinate measurement, achieving precise lifecycle management from manufacturing and installation to operation and maintenance. It is an indispensable technical foundation for preventing deformation, guiding installation, verifying quality, and supporting modifications.

Figure 1: API Measurement Service Extraction Tower Measurement Site

API Laser Tracker Three-Dimensional Inspection Solution

The API laser tracker, with its unique advantages of large scale, high precision, and real-time feedback, can meet all the requirements for precise geometric measurement of extraction towers. Its core inspection content includes:

Macro Geometric Tolerance Inspection

√ Tower body straightness and verticality: Measurement of the spatial trajectory of the centerline of the segmented and overall tower body to ensure compliance with design verticality requirements;

√ Cylinder roundness and diameter: Analysis of the roundness of each segment port and typical cross-section, controlling the ellipticity to ensure the installation conditions of internal components.

2. Key internal component installation accuracy inspection

√ Support ring/support beam inspection: Measurement of elevation and levelness, which is the basis for the level of the tower tray or packing bed, directly affecting the uniformity of gas-liquid distribution;

√ Tower tray component inspection: Accurate measurement of the flatness of the tray plate, consistency of weir height, verticality of downcomers, and spacing;

√ Internal component coaxiality: Evaluation of the alignment of the centers of multi-layer internal components with the theoretical axis of the tower body.

3. External interface and auxiliary structure inspection

√ Connection flange: Center coordinates, normal direction of the flange surface (azimuth and inclination angle), flatness, and detection of the distribution circle of bolt holes;

√ Platform ladder and auxiliary tower piping: Spatial position and interference check.

4. Manufacturing and installation process control

√ Segment pre-assembly and circumferential seam alignment: Guiding the on-site assembly of segmented manufacturing of large extraction towers, controlling the misalignment and uniformity of gaps;

√ Foundation and Skirt: Verification of the flatness of the surface of the foundation plate and the positional accuracy of the anchor bolt holes.

Figure 2: API series laser trackers (from left to right: iLT / Radian Plus / Radian Pro / Radian Core / iLTx)

Introduction to the Technical Advantages of API Laser Trackers

Among various measuring tools, the Radian and iLT series laser trackers from the API brand provide precise and efficient solutions for tower detection, thanks to their excellent engineering design and stable measurement performance.

Radian laser tracker is a high-precision 3D/6D measuring instrument with a large measurement range, featuring micron (μm) level accuracy and exceeding 80The measurement radius of the meter, as well as the extremely large measurement angle range, is designed to be compact and small, allowing for installation and operation in any orientation. It can fully meet the requirements for measurement accuracy, efficiency, and range in various stages of extraction tower measurement. Among them, the Radian Plus and Radian Core models also use battery power and wireless communication systems, completely freeing them from the constraints and troubles of various cables, making the entire measurement process easier to control.

Simply set up the Radian laser tracker next to the target to be measured, and you can start the measurement operation; during the measurement, place the Radian laser tracker within the system coordinate system, and the emitted laser will track the SMR (tracker target) in the operator's hand. The operator only needs to hold the target and touch the area where data needs to be collected, and the tracker will automatically collect the three-dimensional measurement data of that data point, send it to the laptop, and record it in the measurement software for subsequent processing and analysis.

Once the data collection for all test locations is completed, the operator can set, analyze, and compare this data with the nominal values in the measurement software, thereby obtaining the error of the actual values and achieving the detection effect.

Figure 3: Radian (left) and iLT (right) laser trackers

The newly launched iLT laser tracker further reduces the overall size of the laser tracker by 50% (compared to the Radian series) while achieving completely wireless measurement. The entire machine weighs only 4.9 kg, maximizing its portability and fully meeting the needs for applications in outdoor, field, confined spaces, and multi-machine integration environments.

Measurement Operation Process

1. On-site plan formulation and base station setup

Based on the dimensions of the extraction tower and the key detection points, plan the positioning of the tracking instrument, usually selecting a location that has a clear line of sight to most of the detection area and a stable foundation. Due to the high integration and portability of the API laser tracker, it can be flexibly deployed.

2. Establish a global unified coordinate system

On the foundation or skirt of the extraction tower, measure at least three reference points with known design coordinates (or establish temporary references), and perform optimal fitting alignment of the coordinate system using supporting software (such as SpatialAnalyzer, Polyworks, Metrolog, Verisurf, MeasurePro, etc.) to establish the absolute reference for detection.

Figure 4: Measurement site of the extraction tower

3. Accurate measurement of key features and real-time adjustment guidance

The operator only needs to touch the measurement position with the tracking instrument's target ball, which has a built-in prism (please refer to Figure 4), to record the spatial coordinates of the measurement position and transmit them to the measurement software on the laptop for subsequent analysis. In addition to using traditional target balls for measurement, API laser tracker measurement accessories can also be selected according to actual measurement needs to detect relevant data. (For example: using the vProbe probe for hidden point measurement; using iScan3D for rapid point cloud acquisition; using ActiveTarget for automated data collection; using STS six-dimensional sensors for precise measurement of 6DoF data, etc., please refer to Figures 5 and 6.)

Figure 5: API Laser Tracker Measurement Accessories (from left to right: iScan3D / ActiveTarget / STS / vProbe)

Figure 6: Introduction to the Functions of Tracker Measurement Accessories

4. Measurement Data Analysis

By using the measured point cloud data, corresponding lines, surfaces, and volumes can be constructed, and measurement data analysis can be conducted in conjunction with detection requirements.

Figure 7: Measurement Site of the Extraction Tower

Figure 8: Measurement Site of the Extraction Tower

Measurement Site

The content of the field operation in this measurement case is the spatial trajectory measurement of the segmented centerline of the extraction tower.

During the measurement, the operator first sets up the API laser tracker at one end of the extraction tower, then collects spatial points on the inner wall of the tower body, and fits them into corresponding circles based on different positions to calculate the center positions of the circles; once multiple center positions are calculated, the straightness of the centerline can be evaluated based on the corresponding XYZ values, thus achieving the detection purpose.

Figure 9: Measurement Data and Analysis

Figure 10: Measurement Data and Analysis

Summary

The API laser tracker solution enhances the detection experience in the manufacturing and installation processes of extraction towers to a whole new level, thanks to its exceptional measurement accuracy, strong environmental adaptability, intelligent human-machine interaction, and efficient real-time feedback capabilities.

It is not only a "diagnostic tool" for identifying problems but also a "navigator" for guiding precise construction. The API laser tracker ensures the level placement of each tower tray, the precise alignment of every flange, and the vertical standing of the entire extraction tower. This significantly shortens construction time, eliminates potential operational risks, and provides solid measurement assurance for the safe, efficient, and long-term operation of large industrial installations.

Figure 11: API Headquarters Building

About API

The API brand was founded by Dr. Kam Lau in 1987 in Rockville, Maryland, USA. He is the inventor of the laser tracker and holds multiple patents for globally leading measurement technologies, making him a leader in the field of precision measurement technology. Since its establishment, API has been dedicated to the research and production of precision measuring instruments and high-performance sensors in the mechanical manufacturing sector. Its products are widely used in advanced manufacturing fields around the world and are at the forefront of high-precision standards in coordinate measurement and machine tool performance testing.