The liquid column is contained between the two gauge-glasses. When necessary an illuminator is mounted on rear-side of the gauge; its light rays are deflected by a louvered screen upwards into the liquid column. Light rays which impinge on the surface of the liquid meniscus are reflected back to the eye of the observer who sees in the gauge the illuminated surface of the liquid. The clearest indication is attained when the angle between the direction of observation and the liquid surface is approximately the same as that between the light source and the liquid surface. Explosion-proof illuminators safety class IP 65, Type EVA E Ex dII Ct5 Voltage 230 V, 50 Hz. Type approved according to ATEX.
Coloured media are easily observed. With water-clear media or steam, error-free observation is only possible when the transparent gauge is used along with an illuminator. The liquid level is made visible through the reflection of the light-source in the surface of the liquid.
If the observation point is remote from the gauge, the liquid level may also be transmitted via closed-circuit TV to a monitoring console. In this case a TV camera must be directed to the visual surface of the gauge at an angle from below and at a distance of about 2 meters.
Depending on gauge type and design in steam or process applications there are various materials available for sealing gaskets and cushion gaskets.
Applications
Steam:
Up to 120 bar saturated steam
The gauge glasses must be protected against the attack of the boiler water by means of mica shields fitted on the side of the glass facing the liquid chamber. An illuminator is invariable required.
Other media:
Up to 340 bar at cold hydraulic pressures (120 °C).
An illuminator is required for waterclear media, with coloured media this may be dispensed with.
Indication
The indication with coloured liquids appears as a dark column of liquid corresponding to the colour of the medium.
Note: Only KLINGER original parts guarantee a trouble free operation of the gauge glasses. Therefore it is recommended to use only original spare parts for gauge glasses, mica shields, sealing gaskets and cushion gaskets.
