Hot Metal Detector was used for the detection of long product rolling. The sensor’s small spot size is big enough to capture bar fluttering but without sensing crop ends. No water cooling was required as the sensor was provided with a fibre optic cable between the optics and the electronics. Electronics were kept 2m away from the heat zone
Pinch roll rod detection before laying head
Pilger mill in tube rolling mills - hot and cold pipe detection
Dual (Hystersis) Threshold: Customer could now create band to control signal on/off (Son and Soff. Avoid false triggering when temperature dropped for short durations due to presence of steam.
Maintenance free modular design: Three-piece design (Optics, fiber optic cable, electronics) parts can be each purchased separately.
Compact size: Optics are 25mx85mm. Possibility to implement redundancy and shadow mode operations to compare the results.
Flexibility for variable response temperature threshold (400C..10000C) as per site: The object temperature can range from 1000C to 18000C. On special request model can start as low as 250⁰C to 600⁰C
Standard-function, offset-function, alarm-function and jump-detection
2 free adjustable switching outputs
Challenges
The existing solution suffered from various problems
- Oversensing Scanning technology detected hot crops/ tail ends fallen on the track
- Flickering at water box exit: Bar temperature used to drop from 900⁰C to ~600⁰C with existing solution’s fixed triggered threshold.
- Expensive maintenance: Water cooling line had to be ON all times to avoid electronics failure.
- Redundancy not feasible Existing solution had a bulky design therefore it was not feasible to implement dual HMDs.
Solution
HMD optical sensor is ideal for this application. The sensor’s small spot size is big enough to capture bar fluttering but without sensing crop ends. (Optics 20 has 55mm spot size)
No water cooling was required as the sensor was provided with a fibre optic cable between the optics and the electronics. With the FOC system, the sensor can operate at ambient temperatures upto 2900C without any water / air cooling. Electronics were kept 2m away from the heat zone.
All components were housed in protective rugged stainless steel for protection against moisture, steam, shock and vibration. Optical filters protected against spurious radiation.
Variable Response Temperature threshold could be set as per site requirement from 4000C to 10000C.
Note: Other models that start as low as 1000C response temperature are also possible
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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Sample case study title lorem ipsum here
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Sample case study title lorem ipsum here
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