Level Ultrasonic Sensor: Working Principle, Types & Industrial Applications
Level Ultrasonic Sensor Overview A level ultrasonic sensor is a non-contact device used to measure liquid or solid levels...
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Quartz Tube Bi-Colour Level Gauges
Quartz tube bi-colour level gauges are reliable and highly visible liquid level measurement instruments designed for continuous level indication in industrial process applications. By utilizing a quartz glass tube combined with a bi-colour indication system, these level gauges clearly display vapor and liquid phases, ensuring safe and accurate monitoring under high temperature and high-pressure conditions.
The bi-colour quartz tube level gauge displays red for vapor phase and green for liquid phase, allowing operators to instantly distinguish fluid states even in harsh environments. With excellent corrosion resistance, pressure resistance, and long service life, quartz tube bi-colour level gauges are widely used in petrochemical, power generation, chemical processing, and other safety-critical industries.
Level Measuring Instruments Description
Bi-Colour Quartz Glass Tube Level Gauges-Features
Clear bi-colour level indication: red vapor phase, green liquid phase
High-strength quartz glass tube with excellent thermal stability
Suitable for high pressure and high temperature applications
Multiple material options for corrosive and non-corrosive media
Long center-to-center distance options, customizable up to 2000 mm
Simple structure with low maintenance requirements
Optional electric heating and self-limiting temperature heating
Compatible with industrial standard flanges and connections
These features make quartz tube bi-colour level gauges an ideal solution for continuous and reliable liquid level indication.
Quartz Tube Bi-Colour Level Gauges-Applications
Quartz tube bi-colour level gauges are widely applied in:
Boilers and steam drums
Petrochemical and chemical processing plants
Power generation systems
Oil & gas production facilities
Industrial storage tanks and vessels
Process control systems requiring visual level monitoring
Safety-critical level indication applications
The high visibility and durability of bi-colour quartz tube level gauges make them suitable for both indoor and outdoor industrial environments.
quartz tube bi-colour level gauges-Working Principle
The working principle of quartz tube bi-colour level gauges is based on optical refraction and reflection. A light source projects light through the quartz glass tube:
In the liquid phase, light is refracted and reflected to appear green
In the vapor phase, light reflection changes and appears red
This optical contrast allows operators to accurately identify liquid levels in real time, even from a long distance. The quartz tube ensures stable performance under extreme temperatures and pressures.
Quartz Tube Bi-Colour Level Gauge-Structure
The quartz tube bi-colour level gauge mainly consists of:
High-strength quartz glass tube
Gauge body (carbon steel or stainless steel)
Upper and lower process flanges
Drain valve and vent valve
Steel ball self-closing safety device
Optional electric or steam heating interface
The robust structure ensures safe operation and reliable sealing during long-term industrial use.
Level Measuring Instruments Parameter
| Parameter | Specification |
| Bi Color quartz tube Level Gauge-Type | INBC113 |
| Center-Center Distance | 300, 500, 800, 1100, 1400, 1700, 2000 mm (custom made) |
| Indicate Mode | Single color, bi-color (red vapor phase, green liquid) |
| Material | Carbon steel, 304, 316L, 1Cr18Ni9Ti, 0Cr18Ni9, 304 + PTFE lining |
| Nominal Pressure | PN6–PN100 (×0.1 MPa); 304 + PTFE ≤ PN40; PP ≤ 100℃ |
| Working Temperature | Carbon steel ≤ 350℃; Stainless steel ≤ 450℃; 304 + PTFE ≤ 200℃; PP ≤ 100℃ |
| Drain Valve | Drain needle valve (customizable) |
| Vent Valve | Vent needle valve (customizable) |
| Process Flange | DN20 / RF HG/T 20592-09 |
| Heat Steam Interface | ZG1/2″ male screw thread |
| Heat Steam Pressure | ≤ 1.0 MPa |
| Electric Heating | Self-limiting temperature heating (optional) |
| Steel Ball Self-Closing Pressure | ≥ 0.3 MPa |
| Power Supply | 24V DC, 36V AC |
| Environment Temperature | −50 ~ +80℃ |
Instrava OEM/ODM
Reliable Instruments. Solutions That Fit Your Application.
Instrava is focused on delivering reliable industrial solutions through carefully curated products, application-driven optimization, and flexible customization. We select proven instruments from trusted manufacturers to ensure consistent quality, optimize solutions based on real working conditions to solve practical challenges, and provide tailored configurations to meet specific application needs.
By combining selection expertise with application understanding, Instrava helps customers reduce risk, improve efficiency, and achieve dependable results in complex industrial environments.
What are quartz tube bi-colour level gauges used for?
Quartz tube bi-colour level gauges are used for continuous visual liquid level monitoring in industrial vessels, boilers, and tanks. They provide clear red and green colour indication to distinguish vapor and liquid phases, making them suitable for high-temperature and high-pressure process control applications.
How does a bi-colour quartz tube level gauge indicate liquid level?
A bi-colour quartz tube level gauge works based on optical refraction and reflection. The liquid phase reflects light as green, while the vapor phase appears red, allowing operators to clearly identify liquid levels even under harsh operating conditions.
What is the maximum working temperature of quartz tube bi-colour level gauges?
The maximum working temperature depends on the material selection. Carbon steel models can operate up to 350℃, stainless steel models up to 450℃, and PTFE-lined versions up to 200℃. This makes quartz tube bi-colour level gauges suitable for high-temperature industrial environments.
Are quartz tube bi-colour level gauges suitable for high-pressure applications?
Yes. Quartz tube bi-colour level gauges support nominal pressure ratings from PN6 to PN100, making them suitable for a wide range of high-pressure industrial applications, including boilers, petrochemical systems, and power plants.
Can quartz tube bi-colour level gauges be customized?
Quartz tube bi-colour level gauges can be customized in terms of center-to-center distance, materials, pressure rating, heating method, valve configuration, and flange standards to meet specific process requirements and operating conditions.
What safety features are included in quartz tube bi-colour level gauges?
Most quartz tube bi-colour level gauges are equipped with steel ball self-closing safety devices, drain and vent valves, and optional heating systems. These features enhance operational safety and reliability in safety-critical and process control applications.
Why Choose Instrava
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Focused on Industrial Applications
We specialize in industrial analysis and detection, with a clear understanding of real-world operating environments and requirements.
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Every instrument is evaluated based on performance, stability, and application suitability—not just specifications or pricing.
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We work with trusted manufacturers to ensure stable supply, consistent quality, and dependable delivery.
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Our recommendations are grounded in application understanding, helping customers avoid common issues and achieve reliable results.
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