NLK apparatus according to EN 459-2


 Large measuring station type C with two, three or four measuring stations KGW-11218C2, KGW-11218C3, KGW-11218C4

General information

The reactivity of fine lime during slaking is tested by measuring the temperature increase that occurs during its reaction with water as a function of the reaction time. This process is called NLK (wet erasure curve). The equipment and measuring method are based on EN 459-2.

For the reaction process, 150 +/- 0.5 g of undissolved lime is added to the Dewar vessel, which contains 600 +/- 1 g of distilled water at approx. 20° C. As the contents of the Dewar flask must be completely mixed throughout the entire duration of the experiment, this apparatus is equipped with an agitator (speed 350 +/- 1/min).

During the reaction, the heat energy released heats the water. The temperature increase is recorded by a high-quality temperature sensor and can optionally be transferred to software for evaluation.

If you have any questions or would like a quote, please contact us:

Software for recording and analyzing measurement data

The company pdv-software GmbH from Goslar has developed the software solution pdv-nlk3 for the acquisition, storage and mathematical evaluation of the measured values to match our NLK apparatus.

Function overview

  • Recording of values via two temperature sensors/measuring transducers
  • Standard-compliant recording and storage of the wet extinguishing curve (NLK)
  • Evaluation in accordance with DIN EN 459-2 using the characteristic values T0, tmax, Tmax, T’max, tu80, Tu80, t60
  • Display of further characteristic values such as ΔT5, T10, t40 and the R-value (classification of the firing rate according to Schiele, Berens) as well as the maximum conversion rate
  • Representation of the characteristic values in the wet extinguishing curve diagram
  • Saving (as an image file) and printing the recorded measurement curves
  • Print preview with numerous export formats
  • Integrated measurement data management (management and search of measurements and samples)
  • Central master data maintenance
  • Configuration of measurement cycles, drivers, interfaces
  • Integrated device driver for Testo 735 measuring instrument (via USB); other drivers on request
  • Calibration of the sensors via two points
  • Testing the heat loss of the Dewar vessels by determining the water value
  • File-based CSV interfaces for transferring (importing) existing raw data and for forwarding (exporting) intermediate and final results
  • Sample naming and storage in local Windows SQL Server Express Edition database
  • Optional connection to laboratory information systems (LIS/LIMS) possible on request

You can find detailed information about this solution on the Internet at 

If you are interested in pdv-nlk3, please contact us directly:

pdv-software GmbH
Im Schleeke 50, 38642 Goslar
Tel. 05321-57320