According to the requirements of different manufacturers, the length of steel pipe measurement methods, mainly in the following categories:
1, grating length measurement
The basic principle is: the steel pipe at both ends of the outer side were set up two fixed-length grating, the use of rodless cylinder driven grating near the ends of the pipe, the use of light interference to achieve the length of the measurement of steel pipe.
Characterized by high accuracy. But the grating is expensive and difficult to maintain, the dust and the impact of vibration is very sensitive.
2, the camera length measurement.
Camera length measurement is the use of image processing to achieve the length of steel pipe measurement, the principle is in the steel conveyor roller on a section of the installation of equidistant range of photoelectric switch, in another section plus light source and camera. When the steel pipe through this area, you can according to a photoelectric switch through the camera to capture the image on the screen position to determine the length of the pipe.
Features can be achieved on-line measurement, the length of the pipe through the length of the area can be obtained when the length of data, no interval. Inadequate is: If you do not use special light source, the steel pipe will be subject to external light interference, and the use of special light source after the steel pipe in the inverted edge of the tube after the high brightness and reflection of the light is very strong, likely to cause reading error.
3, the encoder length measurement
The principle is to install the encoder at the cylinder, the use of cylinder to promote the movement of the steel pipe in the roller, on the other side of the installation of a series of equidistant photoelectric switch, when the pipe is pushed by the cylinder tube to the photoelectric switch, from the recorded encoder reading , Calculate the stroke of the cylinder, so you can calculate the length of the pipe.
The characteristic is that the pipe needs to rise when the length is measured. In addition, the photoelectric switch detection there are some errors, may need to be fully measured.
4, improved encoder length measurement
This method is an indirect measurement method, by measuring the two ends of the steel pipe and the distance between the respective reference points, indirectly measured the length of steel pipe. In the steel pipe at both ends of the set of a trolley car, the initial position of zero, the spacing of L. And then move the editor length to the respective pipe end of the walking distance (L2, L3), L-L2-L3, is the length of the steel pipe.
This measurement method to overcome the huge volume of steel, the production site environment is complex, the measurement mechanism can not cross the lower part of the steel pipe support and other difficulties. This method is easy to operate, measuring accuracy within ± 10mm, repeat the accuracy of ≤ 5mm.
Source: China Steel Pipe Manufacturer – Yaang Pipe Industry Co., Limited (www.yaang.com)