Description
Fluorine Lined Sight Glasses (also known as PTFE/PFA lined sight cups, butterfly sight indicators, or chemical flow sight glasses) are essential inline visual indicators designed for real-time monitoring of fluid flow, color, clarity, and phase changes in highly corrosive acid and alkali pipelines. Engineered with a heavy-duty metallic body, seamless virgin fluoroplastic lining, and high-strength tempered borosilicate glass windows, these sight cups prevent fluid leakage while ensuring full visual inspection of hazardous process media.
Ideal for hazardous process monitoring, these lined sight glasses integrate perfectly alongside our industrial butterfly valves and connect directly into fluoroplastic piping loops using precision-forged industrial flanges.
Technical Specifications
| Technical Parameter | Specification Details |
|---|---|
| Nominal Diameter Range | DN25 to DN300 (1" to 12") |
| Nominal Pressure | PN10 / PN16 / Class 150 |
| Outer Shell Material | Ductile Iron (QT450-10), WCB (Carbon Steel), Stainless Steel (CF8 / 304 SS) |
| Lining Material | PTFE (Polytetrafluoroethylene) / PFA (Perfluoroalkoxy) / FEP (F46) |
| Glass Material | High Borosilicate Tempered Glass / Quartz Glass Tube |
| Working Temperature | -20°C to 180°C (-4°F to 356°F) |
| Connection Standard | Flanged Ends (ASME B16.5 Class 150, HG/T 20592, EN 1092-1) |
| Testing & Inspection | 100% High-Voltage Spark Test (15kV-25kV) & Shell Hydrostatic Test |
Key Features & Visual Monitoring Mechanics
Safely observing aggressive chemicals during operation requires advanced fluoroplastic lining and thermal shock resistant glass:
- Complete Chemical Inertness: Virgin PTFE/PFA lining completely covers all internal metallic surfaces, resisting strong acids (hydrochloric, sulfuric, hydrofluoric acid) and aggressive organic solvents.
- Clear 360-Degree Flow Visibility: High-purity borosilicate tempered glass provides high light transmission and thermal shock resistance, allowing operators to safely check flow conditions and color changes.
- Leak-Tight Sealing & Vacuum Resistance: Precision-machined locking grooves secure the lining in place, ensuring reliable sealing and preventing lining displacement under vacuum or thermal cycling.
Target Applications & Industries
Our fluorine-lined sight glasses and sight cups are widely used in chemical plant safety and process monitoring:
- Chlor-Alkali & Fine Chemicals: Concentration tracking, acid recovery lines, and hazardous fluid transfer.
- Pharmaceutical & Fine Chemical Processing: Solvent distillation, crystallization monitoring, and reaction vessel outlets.
- Semiconductor & Metal Pickling: Ultra-pure chemical piping, waste acid treatment, and electroplating loops.
Frequently Asked Questions (FAQ)
Q1: How do I choose between PTFE and PFA lining for a sight glass?
PTFE offers exceptional cost-effective chemical resistance up to 180°C. PFA is melt-processable, offering higher purity, better vacuum resistance, and optical clarity for demanding applications.
Q2: What safety testing is conducted on lined sight glasses?
Every fluorine-lined sight glass undergoes a 15kV–25kV high-voltage spark test to ensure zero pinholes in the lining, followed by hydrostatic pressure testing to verify body and glass seal integrity.
Q3: Can replacement glass tubes or sight windows be supplied separately?
Yes. As a direct factory, Oucang Valve provides spare tempered borosilicate glass cylinders and fluoroplastic gaskets for fast site maintenance.
About the Manufacturer: Oucang Valve
Oucang Valve is an ISO-certified direct manufacturer specializing in fluoroplastic-lined valves, sight flow indicators, and forged industrial flanges. Operating our own casting workshop, PTFE/PFA molding facility, and spark testing laboratory, we deliver complete material traceability and custom engineering for global process projects.
- Core Capability: Precision PFA/PTFE lining injection, high-voltage spark testing, custom sight glass manufacturing, and fast direct export.
- Quality Compliance: ASME B16.5, HG/T 21562, EN, DIN, and ISO standards.
- Factory Inquiry: Contact our engineering sales team for direct factory prices, chemical resistance charts, and 2D/3D CAD drawings.
