Methods for Measuring the Length of Spiral Steel Pipe

The raw materials for spiral steel pipes, such as steel coils, welding wire, and flux, undergo strict physicochemical tests and precise measurements of the length of the spiral steel pipes before being put into production. This is crucial for spiral steel pipe vendors. So, what are the applicable methods for measuring the length of spiral steel pipes?

1. Improved length measurement with encoder

This method is an indirect measurement method that determines the length of the steel pipe by measuring the distance between the two ends of the pipe and their respective reference points. A length measurement trolley is placed at each end of the pipe, with the initial position set to zero and a distance of L. Then, the distance L2 and L3 traveled by the encoder to each end of the steel pipe is measured. The length of the pipe is calculated as L - L2 - L3. This method is easy to operate, with a measurement accuracy within ±10mm and a repeatability precision of ≤5mm.

2. Length measurement using a grating ruler:

Two fixed-length grating rulers are installed on the outer sides of the two ends of the pipe. A rodless cylinder drives the grating rulers close to the pipe ends, and the interference of light is used to measure the length of the pipe.

3. Length measurement using an encoder:

An encoder is installed at the hydraulic cylinder. The hydraulic cylinder pushes the steel pipe on the roller track, and a series of photo switches at a uniform distance are installed on the other side. When the end of the pipe pushed by the hydraulic cylinder touches the photoelectric switch, encoder reading is recorded and the stroke of the hydraulic cylinder is calculated, thus determining the length of the steel pipe.

4. Length measurement using a camera:

Length measurement with a camera is achieved through image processing. A series of photoelectric switches are installed at equal intervals on a section of the conveyor roller track, while a light source and camera are installed on another section. When the steel pipe passes through this area, the position of the pipe on the screen can be determined based on the image captured by the camera and the light switch that it passes.