Plate and Float Glass
JRG/A Glass Thermometer With Water Cooled P/J Probe

Plate and float glass temperatures during the cooling and annealing processes must be kept extremely uniform or with carefully controlled gradients. The temperature uniformity of the glass across the width of the bath in the float process is also important. These difficult measurements can be undertaken, simply and rapidly, with the Land Precision Glass Thermometer/Probe.

Key Features & Benefits

  • Accurate.
  • Rugged, fast response and reliable.
  • Does not see through the glass – waveband specially selected to 4.8 to 5.2µm.

The JRG/A is a unique temperature survey probe for glass in hot surroundings.
The unit comprises:

  • A miniature radiation thermometer only 43mm/1.7in x 28mm/1.1in dia which measures radiation originating from the surface of the glass.
  • A water cooled probe incorporating an air purge to cool the thermometer and keep the window free from dirt and condensation.

Twin stainless steel tubes carry the cooling water, a small flow of compressed air for the thermometer window and the electrical connections.The thermometer has been designed for ease of handling consistent with strength. Operating lengths up to 4.5m/15 ft are available.

Low Temperature (C): 200 High Temperature (C): 1200
Technical Details
Type: Land Precision Glass Thermometer Type JRG/A, mounted in a water cooled probe Type P/J.
Detector: Thermopile
Optical components: Infrared filter to give an effective waveband of 4.8 to 5.2µm. Zinc sulphide lens and fluorite window.
Lens aperture: 12.5mm/1/2in.
Sighting: The thermometer is focused at 75mm/3in from the front of the lens and the nominal target size at this distance is 25 mm/1 in diameter.
Output: Amplified voltage signal 6000mV at 1200 °C black body. Linear in radiance.
Range: 200 to 1200 °C/300 to 1100 °C
Response time: 1s to 98% of an instantaneous change after setting time of 15s on first being introduced to hot surroundings.
Ambient operating temperature: 0 to 70 °C/32 to 158 °F (inside a furnace)
Absolute accuracy: 0.75%K + 1 °C
Repeatability: 1 °C
Ancillary services: Water – flow required depends on the length of probe and temperature of hot zone.
Air – a flow of filtered low pressure air equivalent to 1 litre/min/2ft3/h.
Connections: Electrical – self locating demountable connector.
Water – snap on connectors.
Air – snap on connectors.
Dimensions: 43mm/1.7in x 28mm/1.1in dia.
Weight (Probe and JRG/A): Approx 4.5kg/10lb plus 1.8 kg/4lb per 300mm/1ft of operating length.
Download Datasheet
JRG Probe

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