Level indicators for containers or tanks
Level indicators are classic direct water level indicators that display the level in containers or tanks. All the level indicators listed here, such as glass tube indicators, reflective indicators, or transparent indicators, are based on the principle of communicating tubes, also known as the hydrostatic paradox or Pascal's paradox.
Reflection indicators are classic level indicators and allow for the quick viewing of the level without any additional technical aids. An unlit level indication on a container, tank, or steam boiler is possible through a reflection indicator.
Level indicator with rear holes
Level indicator with weld-on spigot on the front side
Level indicator with rear welding ends
Valve liquid level indicator for working pressures up to max. 25 barg
Valve liquid level indicator for working pressures up to 10 barg
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Functionality and Selection for Industrial Applications
This design is traditionally executed with a reflective sight glass according to DIN 7081 (manufacturer Maxos®). The side of the glass exposed to the medium has a prismatic surface treatment (pressed grooves). The viewing side is normal and smooth. The level indication in the reflection indicator is displayed by the principle of light refraction. This means that the area filled with liquid absorbs light rays, while the gas/air filled area reflects them. This light refraction makes the area filled with liquid appear darker, while the unfilled area appears brighter. The difference compared to a transparent indicator equipped with smooth glasses lies in the design equipped on one side with reflective glass.
The reflective sight glass indicators are cost-effective indicators for steam use up to a maximum of 35 bar. For other applications with liquid media at tanks or silos, they are also suitable up to 100 bar. A very common reflective level indicator is, for example, the ACI level indicator type 425. This is equipped with matching shut-off valves in the delivery state to simplify maintenance of the device. Our sight glass type 425 is designed for installation as a level indicator outside of a container. The connection of the indicators with the container is made via flange connections. The housing itself has venting and draining openings or drain valves in this design to enable safe and controlled emptying and filling of the level indicator. During maintenance, the sight glass can be easily disconnected from the overall system via the shut-off valves, allowing the housing of the level indicator to be safely opened or dismantled for repairs and cleaning.
However, the area of application of a level indicator is restricted in application areas where the color of the medium must be determined, a separating layer in the medium is recognized, or a high-pressure steam measurement is required. For these areas of application, a transparent indicator is recommended.
In a transparent level indicator, two transparent sight glasses are constructed on opposite sides by design. This allows a lighting device mounted on the back to shine through both sight glasses and visibly display the level. The transparent level indicators can be equipped with additional mica protective screens, unlike the reflective indicators. Mica has the advantage of being resistant to almost all media such as bases, caustics, or acids. The mica protective screen protects the transparent glasses of the level indicator from high pressures, temperatures, and the associated erosion of the surface, thereby increasing the service life and maintenance intervals of your sight glass fitting.
For our level indicators, we use the same high-quality Maxos borosilicate glass sight glasses according to DIN 7081 as in our proven level indicator type 330. These glass plates are available in "reflective" and "transparent" variants. While in the "transparent" variant there is the option to attach a protective screen made of mica or FEP, in reflective sight glasses, the level of the liquid being viewed is clearly visible without aids due to the prisms mounted on the media side.
Glass tube indicators are the most economical indicators for level measurement. They consist essentially of just two valves with external thread or flange connections and a glass tube (usually made of borosilicate glass). The simple mounting of the glass tube via compression fittings enables quick replacement of the glass tube.
For the media side sealing, we choose the sealing material from our extensive range of flat sealing materials that is suitable for your process. We offer proven aramid fiber seals such as KlingerSIL C4400, graphite materials like Frenzelit novaphit VS, SSTC or MST with XP technology with and without metal insert, Garlock Gylon, or pure and expanded PTFE. We also have soft materials like EPDM or NBR in stock for you.
We are happy to provide you with individual and tailored advice so that we can deliver exactly the fitting that suits your application. Contact us for a suitable offer or if you need more information about the sight glass level indicator.