What are the four methods for measuring the length of spiral welded steel pipes

Accurately measuring the length of spiral steel pipes is crucial for manufacturers. Based on years of production experience, four methods for length measurement have been summarized:

1. Improved Encoder Length Measurement: This is an indirect measurement method. The length of the spiral steel pipe is indirectly measured by measuring the distance between each end face of the pipe and its respective reference point. A measuring carriage is set at each end of the spiral steel pipe, initially at zero position, with a spacing of L. The length of the carriage is then measured by moving the measuring carriage a distance (L2, L3) to each end of the pipe. L-L2-L3 equals the length of the spiral steel pipe. This method is easy to operate, with a measurement accuracy within ±10mm and a repeatability of ≤5mm.

2. Optical Grating Ruler Length Measurement: Two fixed-length optical grating rulers are set on the outer sides of each end of the spiral steel pipe. A rodless cylinder moves the rulers close to both ends of the spiral steel pipe, utilizing the interference phenomenon of light to measure the length.

3. Camera-based length measurement of spiral steel pipes: This method utilizes image processing to measure the length of the spiral steel pipe. The principle involves installing a series of photoelectric switches at equal intervals along one section of the spiral steel pipe conveyor rollers, and adding a light source and camera to another section. When the spiral steel pipe passes through this area, its length can be determined by the position of the image captured by the camera at a particular photoelectric switch on the screen.

4. Encoder-based length measurement of spiral steel pipes: This method involves installing an encoder at the hydraulic cylinder. The hydraulic cylinder propels the spiral steel pipe along the rollers. A series of photoelectric switches at equal intervals is installed on the other side. When the end of the spiral steel pipe touches a photoelectric switch, the recorded encoder reading is used to calculate the cylinder's stroke, thus determining the pipe's length.