Bi Color Level Gauge for Boilers
The observation windows of the bi color level gauge are arranged in two straight lines along the length of the gauge body. By adopting a staggered combination of observation holes, the central blind area is effectively eliminated, ensuring continuous and clear level visibility.
Red and green light emitted by the built-in light-emitting diodes are separately directed toward the observation window. In the vapor phase section of the gauge body, the red light travels directly toward the viewing direction, while the green light is refracted toward the chamber wall and absorbed.
In the liquid phase section, due to the refraction effect of the liquid, the green light is directed straight toward the observation window, while the red light is deflected toward the wall and absorbed. As a result, when viewed from the front, the vapor phase appears red and the liquid phase appears green, providing a clear and intuitive bi-color level indication.
Key Features
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Direct visual indication of the actual liquid level, allowing real-time observation without electrical power or signal conversion.
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Equipped with an automatic quick shut-off mechanism that isolates vapor and liquid flow in case of leakage or glass damage, enhancing operational safety.
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Well-engineered mechanical structure with standard connections, enabling simple installation, convenient maintenance, and reliable long-term operation.
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Durable construction with minimal moving parts, resulting in low maintenance requirements and reduced operating costs.
Specifications
| Model | B49H-10/2-W | B69H-16/2-W | B69H-25/2-W | B69H-32/2-W |
| Nominal Pressure | 10MPa | 16MPa | 25MPa | 32MPa |
| Working Pressure | ≤6.4MPa | 11.5MPa | 15.5MPa | 21.5MPa |
| Process Connection | DN20 PN10 | Welding Ø28×4mm | ||
| Working Temperature | Saturated steam temperature | |||
| C to C（mm） | 440、600、670 | 600、670、685、1026、1130、1270 | ||
| Visible Length（mm） | 250、300、420 | 300、420、430、460、480、550、670 | ||
| Lights | LED | |||
| Customization for other special requests. | ||||
What is a bi color level gauge and how does it work?
A bi color level gauge, also called a sight glass level indicator, is a visual instrument for monitoring liquid levels in tanks and vessels. It uses dual-color optical technology to distinguish liquid (green) and vapor (red) phases, providing instant, real-time level observation without electrical power. This makes it ideal for chemical, boiler, and industrial process applications.
What types of bi color level gauges are available?
Bi color level gauges are available in transparent, reflex, and mirror-type configurations. Transparent gauges are best for clear liquids, reflex types improve visibility in steam or high-temperature systems, and mirror-type gauges enhance readability in low-light or medium-pressure vessels.
Which industries commonly use bi color level gauges?
Bi color level gauges are widely used in chemical, petrochemical, boiler, water treatment, food, pharmaceutical, and oil & gas industries. They are especially suitable for high-temperature, high-pressure, or steam conditions where reliable liquid level monitoring is critical for process safety and efficiency.
How should a bi color level gauge be installed and maintained?
The gauge should be installed via standard flanges or threaded connections to the vessel. Before operation, pressure testing is required. During use, valves should be opened gradually, and the gauge should be checked regularly for leaks. Contaminated glass can be safely cleaned after draining the medium and relieving pressure, ensuring long-term reliable performance.
How does the safety mechanism of a bi color level gauge work?
Most bi color level gauges feature a built-in safety steel ball. If the glass plate breaks or vapor/liquid pressure exceeds the rated threshold, the steel ball automatically seals the flow path. This prevents media leakage, protects personnel, and ensures safe operation in chemical, boiler, and industrial vessels.
How does a bi color level gauge perform under extreme temperature and pressure conditions?
Bi color level gauges are designed for high-temperature and high-pressure industrial applications. The dual-color optical system ensures clear visual differentiation between liquid and vapor phases, even under steam or superheated conditions. High-strength borosilicate or quartz glass and corrosion-resistant metal housings provide mechanical stability, while the built-in safety steel ball prevents media leakage if the glass is damaged, ensuring reliable and safe operation in demanding chemical, boiler, or industrial processes.
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