Overview

Basic Specification (typical)

Measuring object	Length accuracy	Positioning travel	Positioning speed
Hot or cold slabs, blooms, billets or sections	< ± 0.03%	800 mm / 31 inch	256 mm/s / 10 inch/s

Operating Principle

The length is measured using the principle of dual beam laser Doppler velocimetry which ensures highly accurate measurement without contact. However for this technique to function, the material must pass at the reference distance ±100 mm. The Doppler gauge is mounted on a servo operated positioning mechanism that automatically tracks the slab position using a separate laser distance sensor. This ensures the Doppler gauge is at the correct distance for optimum measurement.

Applications

• Speed measurement on slab continuous casters
• Length measurement on slab continuous casters for cut-to-length control
• Hot rolled section length control at hot saws
• Run-out length of hot rolled sections
• Slab length prior to reheat furnace

Functions

Accurate length measurement

The correct positioning of the doppler will ensure an accurate length measurement.

Automatical positioning of the doppler

The doppler will automatically be positioned to the optimum distance from the measuring object. This is done by reading the actual distance by a separate laser sensor.

Air cooling

The system is cooled by an air blower.

Outputs

Several different output interfaces are available such as RS232, RS422, Ethernet, Quadrature Pulse.

Mounting stand

The mounting stand for the doppler housing is adopted to each installation.

Hot to cold conversion

A pyrometer will provide the actual measuring object temperature at the point of measurement enabling a hot to cold correction.

Benefits

Proven technology

Doppler gauges were introduced to the metals industry more than 30 years ago and are proven technology with thousands of installations worldwide. Measuring length or speed with Doppler ensures the best accuracy and reliable measurement for all types of applications.

Complete solution

The LengthProfiler system allows applications that would have once been difficult or impossible to accomplish reliably to be done with ease. LIMAB provide a complete turn-key solution including all hardware and software.

Replace water-cooled contact rollers on casters

With accuracy better than ± 0.03%, irrespective of the material grade, temperature, surface condition the LengthProfiler is ideal for replacing traditional water-cooled contact rollers found on continuous casters. The measurement is more accurate, reliable and due to non-contact technology much less costly to maintain.

Eliminate the need for multiple hot metal detectors or photocells

Traditionally sections lengths are measured with banks of HMD’s or photocells together with a tachometer driven by a contact roller. In the harsh steel mill environment, the position and alignment of the photocells are difficult to maintain resulting in poor reliability and accuracy. The LenghtProfiler eliminates all these problems.

Side mounting

Measuring hot slabs from the side is the most accurate method as the heat shimmer in the surrounding air is much reduced when compared with mounting above the slab. Furthermore the ambient temperature and heat transfer is much lower, this reduces the installation cost and makes the operation more reliable.

Specifications

Specification mm (inch)

Speed range	0… ±19,000 m/min for 1.5 m stand off
Accuracy	Better than ±0.03%
Repeatability	±0.02%
Measuring object	All metals up to 1200 +C°
Stand off distance	1.0, 1.5, 2.0, 2.5 or 3.0 m
Laser class	Laser Class 3B according to EN 60825-1:2014 and 21 CFR 1040.10 and 1040.11 except for deviations pursuant to Laser Notice No. 50, dated June 24, 2007.
Outputs	RS232, RS422, Ethernet, Quadrature Pulse
Servo travel	800 mm
Servo speed	256 mm/sec
Distance laser type	LIMAB XLR30
PLC type	Siemens
Cooling	Air blower & filter assembly
Cooling air volume	2000 m³ / h
Dimensions of housing (typical)	1800 x 600 x 300 mm
Adjustable mounting stand	Provided to suit application