Four methods for measuring the length of steel pipes
2013-07-18
According to different manufacturing process requirements, there are various length measurement methods for steel pipes. The main ones are as follows:
1. Grating ruler measurement. The basic principle is: two fixed-length grating rulers are set on the outer sides of both ends of the steel pipe, using a rodless cylinder to drive the grating rulers close to both ends of the steel pipe, and utilizing the phenomenon of light interference to measure the length of the steel pipe. The characteristic is high accuracy. However, grating rulers are expensive and difficult to maintain, and they are very sensitive to dust and site vibrations.
2. Camera measurement. Camera measurement uses image processing to measure the length of the steel pipe. The principle is to install a series of photoelectric switches at equal distances on a section of the steel pipe conveyor roller way, with a light source and camera added on another section. When the steel pipe passes through this area, its length can be determined based on the position captured by the camera at a certain photoelectric switch on the screen. The characteristic is that online measurement can be achieved; length data can be obtained as soon as the steel pipe passes through the measuring area without any gaps. The drawback is that if a special light source is not used for illumination, external light will interfere with measurements; after using a special light source, due to high brightness at the end of the pipe after chamfering, strong reflection may lead to reading errors.
3. Encoder measurement. The principle involves installing an encoder at an oil cylinder location, using it to push the steel pipe along the roller way; a series of photoelectric switches are installed at equal distances on another side. When the end of the steel pipe pushed by the oil cylinder touches a photoelectric switch, recorded encoder readings can be converted into oil cylinder travel distance, thus calculating out the length of the steel pipe. The characteristic is that it requires lifting up the steel pipe during measurement. Additionally, there may be some error in photoelectric switch detection which may require thorough measurements.
4. Improved encoder measurement. This method is an indirect measurement approach that measures distances between two end faces of a steel pipe and their respective reference points to indirectly determine its length. A measuring cart is set up at each end of the steel pipe with an initial position at zero and spaced L apart. Then move each editor's length according to their respective travel distances (L2, L3) towards each end of their respective pipes; L - L2 - L3 gives us the length of the steel pipe.
This measuring method overcomes difficulties such as large volume of steel pipes, complex production site environments, and measuring mechanisms being unable to traverse underpipe support frames etc. This method is easy to operate with a measurement accuracy within ±10mm and repeatability ≤5mm.
Shenyang Tengfei Iron Corporation
Shenyang Tengfei Steel Pipe Co., Ltd.
Address: No.6 A 3, No.13 Road, Economic and Technological Development Zone, Shenyang City, Liaoning Province
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