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FG - Glass Forehearth

FG - Glass Forehearth
A simple fibre-optic, two-wire, loop powered thermometer with 4 to 20mA output. Specifically designed to improve process control in the glass industry. 
  • Overview +

    The Glass Forehearth (FG) is a application dedicated fibre-optic, two-wire, loop powered thermometer with 4 to 20mA output. Offering accurate, high resolution and reliable temperature measurements up to 1650°C (3000°F), the FG thermometer enables precise control of process temperatures in the glass industry.

    FG is a cost-effective alternative to tri-level thermocouples for some zones measuring bulk glass temperature independent of glass level. FG’s highly stable temperature measurement is available in five temperature spans for maximum cross-application flexibility withstanding the existing harsh environmental conditions.

    Containing AMETEK Land’s market-leading infrared measurement within an advanced optic head, FG is easily installed in the furnace and linked by multi-core fibre-optic light guide to a remotely located signal processor unit. 

    FG’s flexible design means it not only can monitor and control glass or refractory temperature in the forehearth, but also in the regenerator, tank and refinery, as well as other spot measurements required for glass production.

    FG offers long-term, drift-free operation with no on-line calibration requirement. The signal processor unit is located away from the high temperatures at the optic head, linked by a multi core fibreoptic light guide.

    The two-wire 4-20mA current loop system makes the FG simple to install. A versatile adjustable mounting assembly, complete with quick release adapter and air purge, provides ease of installation and removal for inspection purposes.

    In addition to monitoring and controlling glass or refractory temperatures, FG can monitor and safeguard vulnerable refractory materials such as the crown, detect possible firing imbalance at the port arch, and give improved control of bulk glass temperatures.

    FG is AMETEK Land’s dedicated, cost-effective solution for temperature measurement in glass production.


  • Specifications +

    Measurement Ranges     
    Model  Temperature Range Light Guide  Alternative Light Guides Available 
    FG 9.8/13C  980 to 1300 °C  6.1m/20ft
    10m/33ft , 20m/66ft
    FG 850/1150C
    850 to 1150°C
    FG 9/16C
    900 to 1600°C
    10m/33ft , 30m/98ft
    FG 10/14C  1000 to 1400 °C  6.1m/20ft
    10m/33ft , 15m/49ft , 20m/66ft
    FG 12/16.5C  1200 to 1650 °C  6.1m/20ft
    10m/33ft , 15m/49ft , 20m/66ft
    FG 18/24F 
    1800 to 2400 °F  6.1m/20ft
    FG 22/30F  2200 to 3000 °F  6.1m/20ft

       Interchangeability  ±2 °C / 4 °F 
       Resolution 0.1 °C 
       Linearisation Conformity <0.5° 
       Temperature Coefficient <0.04 °C / °C - mid span 
    <0.07 °C / °C - extremities 
       Absolute 5 °C 
    General Specifications
       Output 4 to 20 mA (linear) 
       Response Time 0.5 s (to 98%) 
       Spectral Response 0.7 to 1.0 µm 
       Emissivity 0.10 to 1.00 adjustable
    (factory set to 1.00) 
       Field of View 100:1 + 10 mm/0.4 in 
       Processor 160 x 75 x 55 mm / 6.3 x 2.9 x 2.2 in 
       Optic Head 106.5 x ∅ 18.5 mm / 4.2 x ∅ 0.7 in 
    Ambient Temperature Limits
       Optic Head 200 °C / 400 °F 
       Light Guide 175 °C / 350 °F 
       Processor 10 to 60 °C / 50 to 140 °F 
       Power Requirement 24V d.c. (nominal)
    18 to 40V d.c. 
       Over Voltage Protection 250V a.c. 
  • Documentation +

  • Related Applications +

    • Forehearth
      Forehearth (Container / Fibreglass / Rockwool / Speciality / Tableware)

      Temperature control here is vital to glass condition. The fibre-optic Model FG radiation thermometer is specifically designed for this measurement, while the Cyclops 100L and Lancom 4 are also recommended.

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    • Regenerators

      Accurate, reliable temperature measurements are essential for this important area of the tank. The solutions recommended by AMETEK Land are the Model FG, SPOT M100 and Lancom 4.

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    • Canal

      The canal links the melt tank exit to the tin bath. We recommend the Model FG or SPOT M100 thermometer for bulk temperature measurement of the glass here.

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    • Distributors and Feeders
      Distributors and Feeders

      Measurements are essential to help control the flow of molten glass into uniform gobs. The Model FG and Cyclops 100L provide the thermal monitoring required for process and quality control.

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    • Melt Tank - Bulk Glass
      Melt Tank - Bulk Glass

      Measuring the temperature of the melted glass in the tank provides measurements for process control and efficiency. Our recommended solutions are the NIR-B Glass, Cyclops 100L, Model FG and SPOT M100.

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    • Melt Tank – Inside Refractory
      Melt Tank – Inside Refractory

      Optimum process control, energy efficiency and tank condition can be controlled through refractory wall measurements. The NIR-B Glass, Cyclops 100L, Model FG and SPOT M100 are recommended.

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