For precise speed control in rolling mills the main drives of the roll stands and the coilers need to be equipped with an encoder. In addition, it is often necessary to provide increased protection for personnel during special operating modes, such as: For this application Johannes Hübner Giessen has been working with Motor OEMs for many decades to provide complete solution ie. Electrical and mechanical components.
Electronic overspeed switch EGS 41 ensures safe rolling mill operations
Pilger mill in tube rolling mills - hot and cold pipe detection
- Safely-Limited Speed (SLS) during maintenance and setup procedures
- Adhering to provisions in the Machinery Directive relating to the protection of persons
- Straightforward implementation with certified EGS 41 (SIL 2 / PL d)
- User-friendly configuration, storage and switch tests
Rolling mill in a hot rolling mill.
Challenges
- For precise speed control in rolling mills the main drives of the roll stands and the coilers need to be equipped with an encoder. In addition, it is often necessary to provide increased protection for personnel during special operating modes, such as:
- Setup procedures with rotating rollers
- Maintenance work under electrical voltage
- The risks of such situations can be significantly reduced by implementing the safety function “Safely-Limited Speed” (SLS). SLS can be realized by using an overspeed switch that operates independent of the encoder and fulfils the special safety requirements (Safety Integrity Level SIL / Performance Level PL).
Electronic overspeed switch EGS 41 mounted on an incremental encoder FGH 6.
Solution
- To meet these requirements Johannes Hübner Giessen supplies the overspeed switch EGS 41, which is certified up to SIL 2 to IEC 61508 and PL d to DIN EN ISO 13849. In addition to two safe switching outputs for speed monitoring of overspeeds and underspeeds it offers integrated standstill functionality as well as an integrated diagnostics switch to monitor safety functions integrated in the device. The programming software included in the scope of supply supports user-friendly parameterization via a USB interface.
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
