Hot metal detector from Proxitron was installed to detect objects precisely and safely, even if tube diameters were changing. It accurately monitored strip roller path. It offered high repeatability and reliability, while having adjustable measuring rate. |
Monitoring of a strip roller path
Pilger mill in tube rolling mills - hot and cold pipe detection
Hot metal detector from Proxitron was installed to detect objects precisely and safely, even if tube diameters were changing. It accurately monitored strip roller path. It offered high repeatability and reliability, while having adjustable measuring rate.
Challenges
Accuracy of tube length measurement depends upon the ability to detect the beginning and ending of tubes.
A tube rolling mill required length measurement directly at the conveyor track.
Simple commissioning, high repeatability and a integrated error monitoring system were needed.
Furthermore, tubes of different sizes were in production
Solution
Different tube diameters lead in a V-conveyor to a very divergent height position of the pipe. Therefore the tube beginning and end couldn’t be detected with a light barrier.
However, HMD from Proxitron detects objects in a field within the barrier height. This ensures the safe detection of the tubes, even if the tube diameters are changing.
If a tube is detected by the light grid, the counter in the system control is set to zero. By means of an incremental rotary transmitter which runs with the tube, exact length measuring up to +/- 1mm is possible.
The HMD works as a light barrier with 10 single lines in the grid of 8 mm. The invisible infrared radiation between transmitter and receiver scans a height of 75 mm on entering material. A contamination output at the light grid ensures a reliable production even under extremely dusty or dirty conditions.
The intermittent short circuit protection protects both outputs in case of overload. Proxitron HMDs are available with a barrier width from up to 1400 mm.
Products and Accessories
Case Study Number
- TP3
Challenge
- The increasing flexibility of production lines requires a high adaptability of sensors. Continually changing object geometries, different temperatures and very high radiation or surrounding temperatures are no rarity.
- In a pilger mill those rough conditions can be found, among others in the production of seemless steel pipes. The raw steel blocks, each weighing a few tons are heated up first in a round oven at a temperature of 1300 °C.
- After descaling of the surface, the steel block is prepunched in a hole press with a strength from a converted 2000 t. In the next sloping rolling mill the growing pipe rotates between two rollers that are positioned at an angle to each other. The punching is widened to the size of the mandrel diameter.
Previous solution / Competitor product
- N/A
Solution
- The sensor that was installed at this application is the HMD OKA 2038.38 G with tube OL 19.
- The signal of the infrared sensors controls the movement of centering device and abutment. The point of view is restricted by the tube and prevents disturbances by steam in the cooling phase.
- An optimum adaptation to the operating conditions is given due to the adjustable response temperature. The HMD with self-learning response temperature (Auto-Teach function) is suited to continually changing conditions.
- The compact sensor with a stainless steel housing can withstand surrounding temperatures of up to 75° C. The use of a cooling jacket raises this up to 200° C.
- Alternatively sensors with fibre optic cables are available which permit an application at ambient temperatures up to 600° C without cooling.
Customer Benefits
- Maintenance-free
- High temperature stability
- Recognition of hot objects at big distances
- Self adjustment with Auto-Teach or step switch for the response temperature
Product Part number
- OKA 2038.38 G
Brand
- Proxitron
Accessories
- Piros swivel stand HM2
- Tube OL 19
- Pilot light unit (for alignment) DAK 308 + OL 26
- Different cable lengths (e.g. 15 m)
Customer Testimonial
compared to previous solution or competition
Case Studies
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