Gauge Glass

Gauge Glass



For viewing the internals of vessels, silos, reactors etc.; mainly used as fluid level indicator.


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Used for viewing the intervals of vessels, silos, reactors etc; mainly used for liquid level gauges.
The base frame of rectangular sight glass fittings is welded onto or into the vessel wall. Then the sight glass plate together with two seals is firmly bolted down by the cover frame and a set of fastening bolts.

  • Borosilicate Glass DIN 7081, Temperature up to 243°C
  • Optionally with clear or reflex surface

Reflex gauges have a single piece of glass, mounted on one side of the chamber. This piece of glass is flat on the outside, and has a series of prisms on the inside, facing the process fluid. When light strikes the portion of the glass covered by a liquid, the light is reflected from the back of the chamber. This area appears “black”. When light strikes the glass where no liquid is present, the prisms reflect the light directly out of the gauge. This area appears “silvery”. Reflex gauges provide an excellent way to measure clear, or difficult to see fluids. The “silvery” / “black” interface is easy to see from several feet away.
Transparent gauges have two pieces of glass on opposite sides of the chamber. Light enters the gauge from one side, and the level is viewed from the other. Transparent gauges are useful when the actual liquid characteristics need to be seen. They are also commonly used for liquid-liquid interfaces. Mica shields can be used in transparent gauges to protect the glass in steam environments, although visability may be affected.