Thermal imaging of enameling furnaces

The performance of industrial enameling furnaces may gradually decline over time.

This may result in higher energy consumption (read increased enameling cost) and reduced quality of the coated surface.

In extreme cases the enameling furnace may even unexpectedly break down, because insulation has been damaged and/or worn out.

Therefore we suggest regular inspections & thermal imaging to identify major heat bridges and other spots with possible insulation issues.

Thermal imaging of industrial enameling furnace roof at hotzone near 180 degree turn
Thermal imaging of industrial enameling furnace roof
Thermograph inspection of enameling furnace door
Heat bridges at clean out door

Other second-hand enameling furnace for sale

One of our relations has a low thermal mass continuous enameling furnace for sale.

The main characteristics of this furnace are as follows :

– original manufacturer New Furnace
– double hooked U-type
– hotzone length 5 meters
– effective product sizes 1250 mm height and 550 mm width
– gas fired with 4 radiant tubes & metal flue
– capacity circa 2500 kg gr/h

Please contact us, if you are potentially interested in this second-hand enameling furnace.

Second hand New Furnace

Expired: Second-hand enameling furnace

One of our relations has a low thermal mass continuous enameling furnace for sale.

The main characteristics of this furnace are as follows :

– original manufacturer Ferro (Holland) BV
– double hooked U-type
– hotzone length 5.3 meters
– effective product sizes 900 mm height and 600 mm wide
– gas fired with 5 radiant tubes & metal flue
– capacity circa 900 kg gr/h

Please contact us, if you are potentially interested in this second-hand enameling furnace.

Second hand enameling furnace

Enameling furnaces

Enameling furnaces

Curing or firing a porcelain (vitreous) enameling coating is done in high temperature enameling furnaces.

In the early days these enameling furnaces were made of refractory bricks, due to the required firing temperature between 800 and 850 degrees Celsius.

However, such bricks are sensitive for thermal shocks and need to be heated up & cooled down very slowly.

Therefore modern enameling furnaces are nowadays made of Low Thermal Mass insulation materials, like stone wool, vermiculite & ceramic fibers. Continue reading “Enameling furnaces”

Temperature profiling and analyzing at industrial enameling furnaces


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”