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REFLEX GLASS LEVEL GAUGES

Product description

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Sizes: Single glass: from size 1 to size 9; Multiple glasses: from 2 X size 4 up to 7 x size 9
Ratings: ASME Class 600 to 2500, PN 16 to 400
Visible length: Single glass: from 95 mm to 320 mm; Multiple glasses: from 380 mm to 2480 mm.
Materials: Carbon steel, Stainless steel, Monel, Hastelloy, Incoloy, Carpenter, Nickel, Titanium, Zirconium, Tantalum, Ebonite, PVC, Polypropropilene, PTFE etc.other special materials
Connections: End tubes, stuffing boxes, screwed nipples

 Reflex glass level gauge

 

Features:

  • In the reflex glass level gauge, the liquid level is distinguished by the different brightness of the reflex glass in water or in steam space
  • "Right-handed" or "Left-handed" according to the position of the shut-off valve compared with the gauge body
  • The nominal passage diameter in the gauge is 10 mm
  • BR25 type have a "large chamber" with 40 mm inside diameter
  • BR26 and BR27 are manufactured for AMSE 600 rating
  • Other sizes and Standards are available on request
  • Applicable optionals and bolting torque

 

Application:

  • Can be used in most of application
  • Offer great advantages such as low initial cost, low operating cost, easy level reading
  • Cannot be used when the separation level between two liquids has to be read (interface)
  • Cannot be used when besides the level indication, the observation of the liquid colour is required
  • Cannot be used when the process fluid is high pressure water steam
  • Cannot be used when the process fluid can corrode the glass

 

Qualifications and Standards:

  • ISO 9001:2008
  • PED 97/23/EC
  • ATEX 94/9/EC

Working principle

Light path with gas or steam inside

Light path with liquid inside

Reflex glass level gauges working principle is based on the light refraction and reflection laws.
Reflex glass level gauges use glasses having the face fitted towards the chamber shaped to have prismatic grooves with section angle of 90°. When in operation, the chamber is filled with liquid in the lower zone and gases or vapors in the upper zone; the liquid level is distinguished by different brightness of the glass in the liquid and in the gas/vapor zone. The reflex level gauges do not need a specific illumination: the day environmental light is enough. Only during the night an artificial light must be provided.
The different brightness in the two zones is obtained as explained below:

LIQUID ZONE
This zone appears quite dark when the gauge is in operation and lighted as above said.
Given the construction, most of the environmental light rays incident on the external face of the glass are quite perpendicular to said face and, therefore, not deviated by the glass. These rays reach the glass/liquid interface with an inclination of approx. 45°. The critical angle glass/liquid is always superior to 45°. Therefore the rays incident within the critical angle (practically the totality) are refracted within the liquid and, since the internal walls of the gauge chamber are not reflecting, the rays cannot be seen from the outside. In fact the zone will appear dark, nearly black, to the observer.

Reflex Level gaugeGAS/VAPOR ZONE
This zone appears almost silver bright to the observer.
As for the liquid zone, the light rays reach the glass/gas-vapor interface with an angle around 45°. Since this angle is greater than glass/gas-vapor critical angle, the rays are not refracted , but totally reflected making 90° turn, thus reaching the nearest glass/gas-vapor interface again with angle of 45°. For same reason they will be reflected and turned by 90° towards the observer, to whom the zone will appear silver bright.

NOTES:
Reflex glass level gauges can be used in most of the cases and offer great advantages in terms of: low initial cost, low operating cost, easy level reading.
Reflex glass level gauges cannot be used in certain cases (where Transparent Glass Level Gauges must be used) as for example:

  • when the separation level between two liquids has to be read (interface),
  • when, besides the level indication, observation of the liquid color is required,
  • when the process fluid is high pressure water/steam (since in this case the glass must be protected from the chemical attack of the boiler basic water by using mica shields),
  • when the process fluid is such that can corrode the glass (e.g. high temperature alkaline solutions or hydrofluoric acid) since mica shields or Polytrifluorochloroethylene shields must be used to protect the

 

 

A world leader in Valves

Since 1905 Cesare Bonetti S.p.A. has been manufacturing high performance valves and liquid level indicators, both as standard or as custom designed products to meet the exact requirements of any fluid  pressure and temperature handling application. Thanks to our reputation and experience, our trademarks BONETTI, BONT, CMI and WVE are  recognized worldwide as a guarantee in terms of quality reliability and service to our Customers.