Temperature profiling and analyzing at industrial enameling furnaces

Introduction

Firing is a critical process step at every enameling shop, because it determines the esthetical and functional properties of the fused enamel coating.

In order to continuously achieve good enameling results, it is important to maintain the actual firing conditions at the enameling furnace within strict tolerances.

Regular verification of the actual temperature profile measured on the enamelled object is therefore a common procedure at industrial enameling plants with ISO 9000 quality assurance systems.

Companies with only one enameling furnace and a verification frequency of once per year, will typically outsource these temperature surveys to a specialized company.

Ditmer Trading & Consulting BV has the necessary equipment to measure temperature profile(s) at your enameling plant.

Companies with multiple furnaces and/or a high verification frequency, may consider to perform this test inhouse and purchase a state-of-the-art furnace tracker via our webshop.

Firing curve / temperature profile

Beneath a typical example of a temperature profile at a double hooked U-type continuous enameling furnace for cooker components.

temperature profile of continuous enameling furnace

Important aspects of firing curves are :

  • Top temperature
  • Time at top temperature
  • Time above soaking temperature
  • Temperature differences between top & bottom
  • Temperature increase/decline at preheating & cooling zone

Equipment for measuring actual firing temperature

Traditionally temperature measurement within continuous enameling furnaces was done with a so-called Bozsin box.


These large & heavy insulated boxes contained a full-size working temperature recorder with paper printer, which was connected via one or multiple thermocouples to an object while both being suspended at the furnace conveyor and passing thru the enameling furnace.

Thermal barrier for temperature profiling of industrial enameling furnaces

Over time electronics became smaller & smarter and nowadays furnace temperatures profiles are recorded by means of a data logger which is placed in a much smaller thermal barrier. (see picture above)

Upon completion of the test run this data logger is connected with a laptop or PC and the collected data may be processed & analyzed with advanced software. See our webshop for more details.

Optionally it is even possible to have real time data transmitted from the furnace tracker.

Furnace surveys

As mentioned previously, DTC may perform furnace surveys and measure temperature profiles at your facilities.

Contact us for a cost estimation

Enameling furnace atmosphere

inside view of an gasfired enameling furnaceA clean furnace atmosphere is important for obtaining good enameling results.

Elevated concentrations of CO2 and/or H2O may slow down the emission of gases from the metal substrate thru the enamel layer during the fusion stage and under certain unfavorable circumstances result in enameling defects such as pinholes & fish-scales.

CO2 & H2O may accumulate inside the furnace, if the combustion system is leaking and/or the forced abstraction of combustion gases is not sufficient.

Regular furnace inspections and maintenance are therefore strongly recommended. Continue reading “Enameling furnace atmosphere”