Transparent level gauges are always fitted with two plate transparent glasses between which the fluid is contained. The fluid level is indicated as the result of the different transparency of the two media and in some cases (for water steam), by conveying upwards on to the surface of separation (between liquid and gaseous substances) a source of light located at the back of the gauge, the rays of which are totally reflected down to the observer.
To avoid leakage in case of glass breakage, safety ball-check device can be provided in cross-fittings or shut-off valves. This kind of indicator is suitable for water/steam. To protect glass surfaces from corrosive action of the process fluid, Transparent Level Gauges can be fitted with Mica shields or Polytrifluorochloroethilene shields. This kind of indicator is suitable for liquids colorless and very fluid.
1. They do not need electrical power to operate. This can be a great advantage in the case of a power outage.
2. Simple to install – no calibration is necessary.
3. Can be used as a reference to check, or calibrate, other level technologies.
4. Pressure rating from vacuum to 4Mpa.
5. Temperature rating from -20℃ to 450℃
7. Not affected by the chemical or electrical properties of the process liquid.
8. Specific gravity, dielectric, conductivity, surface turbulence, vapor, foam, etc. no longer needs to be considered.
The classification and scope of use of glass level gauges are as follows:
1. Heat-tracing glass plate level gauge: mainly used for the occasions where the measured medium needs heat preservation;
2. Frost-proof glass plate level gauge: mainly used for occasions where the operating temperature of the medium under test is -196~0℃ and the glass is prone to frosting;
3.Glass plate level gauge without blind area: mainly used in situations where continuous observation is required and blind areas are not allowed in the visual range;
4. Two-color glass plate level gauge: mainly used for occasions where the medium is colorless and transparent liquid and liquid level is not easily observed;
5.Uv - proof glass plate level gauge:mainly used for the occasions where the measured medium is afraid of ultraviolet light;
6. Wide liquid chamber glass plate level gauge: mainly used for occasions where the viscosity of the measured medium is relatively large or the volume of the instrument is relatively large;
7. Illuminating glass plate level gauge: mainly used for night observation.