Straight seam steel pipe length measurement method

1.Measure the length of the grating ruler
The basic principle is to install two fixed-length grating rulers on the outside of both ends of a straight-seam steel pipe. The grating ruler is driven by a rod near both ends of the steel pipe. The length of the straight-seam steel pipe is measured by the interference phenomenon of light.

It has the characteristics of high precision. However, scales are expensive, difficult to maintain, and therefore sensitive to the effects of dust and on-site vibration.

2. Camera length measurement
Camera length measurement is achieved through image processing to measure the length of steel pipes. The principle is to install a series of equidistant photoelectric switches on one section of the straight-seam steel pipe conveyor roller, and add a light source and camera to another section. When the steel pipe passes through this area, the length of the steel pipe can be determined based on the photoelectric switch based on the position of the image captured by the camera on the screen.
Its characteristic is that when the steel pipe passes through the measurement area without gaps, online measurement can be achieved and length data can be obtained.
3. Encoder length measurement
The principle is to install an encoder on the cylinder, use the cylinder to drive the steel pipe to move on the drum, and install a series of equidistant photoelectric switches on the other side. When the steel pipe is touched by the photoelectric switch at the end of the cylinder, the cylinder's stroke can be converted from the recorded encoder readings to calculate the length of the steel pipe.
Its characteristic is that the steel pipe needs to be lifted when measuring the length. In addition, there are some errors in photoelectric switch detection, which may require adequate measurement.

4. Improved encoder length measurement
This method is an indirect measurement method. By measuring the distance between the two ends of the steel pipe and their respective reference points, the length of the steel pipe can be measured indirectly. Set up a length measuring vehicle at both ends of the steel pipe, with the initial position being zero and the distance being L. Then move the length of the editor to the walking distance (L2, L3) of one end of each steel pipe, which is the length of the steel pipe.






     This measurement method overcomes the difficulties of large steel pipe volume, complex production site environment, and the measurement mechanism cannot span the lower support of the steel pipe. It is easy to operate, has a measurement accuracy of less than ±10 mm, and a repeatability accuracy of ≤5mm.