High Temperature Observation of Glass Melting Process

HTO - SCHEME OF SYSTEM SETUP

We offer HTO Measurement and HTO Equipment. Both options are described below:

HTO Measurement

The glass melting process, as well as phenomena within the melt, can be continuously observed, recorded and evaluated using an HTO furnace equipped with a special silica observation crucible. This equipment is further coupled with Imaage Analysis to provide easy manipulation of recorded data.

The examples of the most frequent applications:

Batch Melt Test - Fining Study

The objective of a melt test is to evaluate the fining characteristics of differing batch compositions. The area of the recorded images occupied by inhomogeneities (bubbles), bubble size distribution, bubble number, as well as bubble growth rates vs. melting time, are evaluated to provide comparison between individual batches.

The records of the melting course are provided in the form of video files, which can be replayed on a personal computer.

TIME RELATED FINING STATUS OF 4 INDIVIDUAL BATCH TESTS

Data Measurements for Mathematical Models - Bubble Growth/Shrinkage Rate

Bubble growth rate measurements are based on direct observation and recording of bubble sizes depending on time. It is possible to keep bubbles suspended in the melt for hours by the developed "shuttle" method.

The temperature dependence of the bubble growth rate as a function of the stationary concentration of the refining gases can be used as input data to the Trace program in the GS Glass Furnace Model to calculate fining studies.

Refractory Test

A refractory sample is inserted into glass melt at high temperature to visualize and record the bubble release as a function of time. Testing a selected refractory generally takes 2 to 5 dates, depending on the testing temperature and composition of glass sample.

Evaluation by Image Analyzer quantifies the bubble amount in relation to time. The records from the test are provided in the form of video files, which can be replayed on a standard office computer.

BUBBLE EVOLUTION FROM REFRACTORY IN CONTACT WITH TV GLASS

Fining at Reduced Pressure

BUBBLE BEHAVIOR IN MOLTEN GLASS AT REDUCED PRESSURE (300 mbar)

HTO Equipment

In addition to testing in our laboratories, GS can also supply HTO equipment on a turn-key basis which includes installation and training at the customer´s site:

The HTO furnace delivery can be provided in two versions, both coupled with the Image Analysis HW & SW:

Open air furnace

Vacuum/gas controlled furnace

Maximum continuous operation temperature for both HTO furnace versions is 1600°C. A side observation window facilitates viewing. Silica observation crucibles are inserted by means of a crucible holder from the top while general crucibles from the bottom are inserted by means of an electric elevator.

Minimum operation pressure of the vacuum version is ~ 5 mbar (depending upon the temperature). The required atmosphere of the nonflammable gases can be continuously introduced into the furnace chamber.