Container Glass
The measurement of temperature at critical locations in the production process is essential for the full understanding and efficient control of container glass manufacture and processing. Illustrated below are some of the locations for these measurements and our recommendations for the best choice of instrument. If your specific area of interest is not covered here, our engineers will be pleased to discuss your requirements with you.
Document download: container_glass_18-05-2011.pdf
1. Regenerator
Accurate and reliable temperature measurement of the crown and packing is essential for this important and vulnerable area of the tank. Thermocouples, despite their lower initial cost, can rapidly deteriorate. Infrared thermometers provide a long-term, cost effective and more reliable measurement.
2. Bridge Wall
This measurement is often taken using outdated Disappearing Filament Pyrometers, which although widely used in the glass industry, are prone to operator variations and hence poor reproducibility of results. Both portable and on-line radiation thermometers improve measurement quality.
Land Instruments recommends:
3. Port Arch
Measurement of the port arches, especially in cross-fired furnaces, can provide important information on basic firing conditions, giving early indication of an incorrrect or unbalanced firing situation.
Land Instruments recommends:
4. Tank Roof
Thermocouples have been used for many years for this critical measurement. However, at the high temperatures at which they operate, deterioration can be rapid and often undetectable due to contamination of the element and migration of elementary materials from one wire to the other. LAND Fibroptic thermometers overcome these problems without the need for water cooling. This location can also be used for bulk glass temperature as an alternative to mounting thermometers underneath the tank in the Glass Bath Sighting System.
5. Tank Outer Surface
The condition and safety of the furnace refractories are vitally important, especially as the end of a campaign approaches. A LAND thermal imager or a portable thermometer from the Cyclops range can be used to make routine checks on key areas of the tank to minimize the possibility of glass break-out or refractory failure.
Land Instruments recommends:
6 and 8 *4 - Bulk Glass
Where electric boosting is used, thermocouple measurement of the glass itself can be dramatically upset by electrical interference. Fibroptic thermometers used with the well proven Glass Bath Sighting System supplied by tank manufacturers, provide stable and reliable measurement. * See also Tank Roof.
Land Instruments recommends:
7. Working End/Refiner
The temperature of glass emerging from the Refiner or Distributor can be critical. As in many other areas of the process, thermocouples can be easily damaged and have a limited useful life. They can also introduce "seeding". Radiation thermometers are non-intrusive and can give many years of trouble free operation.
Land Instruments recommends:
9. Glass Forehearth
Delivering the glass, in an homogeneous condition and at a precise temperature makes accurate and consistent temperature control in the forehearth vital. The silicon cell detector used in so many radiation thermometers in the glass industry is at the heart of the Fibroptic Model FG thermometer, custom designed for this application. Water cooling is not required and installation is simple.
Land Instruments recommends:
10. Gob
It is vital to obtain an accurate measurement of gob temperature to maintain the relationship between glass viscosity and gob weight. Both portable thermometers such as the Cyclops 100 and on-line thermometers such as System 4 M1 Fibroptic are available, and have been proven over many years to improve the reliability of the measurement and therefore product quality.
Land Instruments recommends:
11. Mould
LAND pioneered the use of the fibre optics thermometer to measure mould temperatures, and the new GMT thermometer is the best tool to aid rapid setting of cooling levels after a job change. Other fully portable thermometers may also be suitable for mould temperature measurement.
Land Instruments recommends:
12 and 13. Lehr
A low temperature thermometer at loading point views the conveyor chains to ensure that they are heated sufficiently to prevent cracking or build up of stress in the glass.Defects in finished product may only become evident when it leaves the annealing lehr. LAND provide two high speed process imagers capable of thermally mapping the surface of the hot product - LSP linescanning and FTI-E thermal imaging systems.
