Product
Red Line Gauge Glass Tube
Red Line Gauge Glass Tube is a borosilicate glass level indicator with a red center line for enhanced liquid level visibility.
Technical Specifications
| Product Type | Gauge glass tube |
|---|---|
| material | Borosilicate glass |
| Wall thickness | standard and heavy thickness |
| Application | Liquid level measurement |
- High thermal shock resistance with borosilicate glass construction
- Standard and custom sizes available
- Compatible with level gauge fittings and accessories available upon request
Gauge Glass Tubes
Product Description
Red Line Gauge Glass Tube is a transparent tubular glass designed for direct liquid level observation in mechanical level gauges. A red line and a white line are embedded along the length of the glass tube, creating an optical contrast effect that makes the liquid boundary easier to identify during operation.
The tube is manufactured from high-quality borosilicate glass, which provides excellent chemical resistance, low thermal expansion, and improved resistance to thermal shock compared with ordinary soda-lime glass. The typical thermal expansion coefficient of borosilicate glass is approximately 3.3 × 10⁻⁶/K at 20 – 300°C, allowing it to withstand rapid temperature changes in industrial environments.
During operation, the red line acts as a visual reference. When liquid covers the tube area, the optical refraction changes and the red line appears differently through the liquid and gas sections, helping operators quickly distinguish the liquid level.
Red Line Gauge Glass Tube is commonly installed in boilers, pressure vessels, storage tanks, water treatment equipment, and industrial level indicators requiring reliable visual monitoring.
Key Features and Advantages
Enhanced Level Visibility
The red center line improves visual contrast between liquid and vapor phases, allowing faster and easier liquid level reading compared with ordinary transparent glass tubes.
High Temperature Performance
Made from borosilicate glass with a maximum recommended continuous working temperature commonly around 280°C, with short-term service capability up to approximately 500°C depending on design and application conditions.
Excellent Chemical Resistance
Borosilicate glass provides good resistance to water, steam, and many industrial chemicals, making it suitable for various process applications.
Low Thermal Expansion
With a thermal expansion coefficient of approximately 3.3 × 10⁻⁶/K, the glass offers improved resistance to thermal stress caused by temperature fluctuations.
Custom Manufacturing Capability
Available in different outer diameters, wall thicknesses, lengths, and end finishes according to equipment requirements.
Technical Specifications
| Parameter | Specification |
| Material | Borosilicate Glass |
| Main Composition | SiO₂ + B₂O₃ based glass system |
| Thermal Expansion Coefficient | Approx. ≤3.3 × 10⁻⁶/K (20–300°C) |
| Density | Approx. 2.23 g/cm³ |
| Softening Point | Approx. 820°C |
| Maximum Working Temperature | Up to 280°C (continuous service) |
| Short-Term Temperature Resistance | Up to 500°C (application dependent) |
| Thermal Shock Resistance | Approx. 180K |
| Hardness | Approx. 5.5 Mohs |
| End Finish | Cut, Ground, or Fire Polished |
Sizes
Red Line Gauge Glass Tubes are available in standard and customized dimensions.
Common specifications include:
Outer Diameter: 12.7 mm (1/2″), 15.9 mm (5/8″), 19 mm (3/4″), and customized sizes
Wall Thickness: Available from approximately 1.5 mm to 12 mm depending on pressure requirements
Length: Standard lengths available from several inches up to approximately 1500 mm
End Finish: Square cut, ground, or fire polished ends
Customization: Diameter, length, thickness, red line position, and packaging can be supplied according to customer requirements
For high-pressure applications, heavy-wall gauge glass tubes are recommended to provide higher mechanical strength.
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KUNYO Industrial Components Co.,Ltd.
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No. 555 Longxing Road, High-tech Zone, Hengshui City, Hebei Province, China 053000
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