In complex industrial processing, the ability to visually verify fluid flow, color, clarity, and consistency in real time is paramount for quality control and operational safety. FlowBiz Exports Pvt. Ltd. delivers an uncompromised solution with our high-performance Double Window Sight Glass (Sight Flow Indicator) assemblies.
Operating from our premier manufacturing hubs in Mumbai, Maharashtra, we engineer cast construction and custom-fabricated sight glasses designed to withstand extreme fluid pressures and volatile thermal dynamics. Additionally, FlowBiz stands as a trusted market leader in manufacturing high-precision Spring-Loaded Safety Valves for critical overpressure protection.
The defining feature of a Double Window Sight Glass is its dual-lens configuration. Featuring two ultra-thick, toughened glasses mounted directly opposite one another, it allows light to pass completely through the pipeline. This grants operators true $360^\circ$ visual clarity to instantly identify blockages, pressure drops, or fluid discoloration.
To optimize inspection accuracy across different fluid types, FlowBiz offers specialized internal mechanics:
Rotating Blade / Impeller Design: Perfect for transparent liquids, where the rotation speed of the internal blade gives a clear visual gauge of flow velocity.
Flapper Type Design: Engineered specifically for gas or low-velocity clear liquid applications, where the deflection of the flapper indicates the presence and direction of flow.
Drip Tube Design (Optional): Ideal for vertical lines with low downward flow rates or condensation monitoring.
[ Light Source ]
Toughened Borosilicate Glass Window
INDUSTRIAL PROCESS FLUID [Internal Flapper or Rotor]
Toughened Borosilicate Glass Window
[ Operator Eye ]
Our sight flow indicators are built in compliance with international pipeline standards, guaranteeing zero visible leakage and complete pressure containment.
| Feature | Industrial Specification Profile |
| Size Spectrum | 15 mm to 600 mm Nominal Bore 15 NB to 600 NB ( to 24) |
| Pressure Limits | Standard up to 16 Bar; Heavy-Duty designs up to 100 Kg/cm |
| Thermal Ceiling | 20C to 200C (Higher temperatures possible with special alloys) |
| Body Metallurgy | Stainless Steel (SS304, SS316, SS316L), Carbon Steel (WCB), & Mild Steel |
| Glass Material | High-Premium Toughened Borosilicate or Tempered Glass (up to 25 mm thickness) |
| Sealing Gaskets | Pure PTFE, Viton, Graphite, or Neoprene for complete chemical inertness |
| End Connections | Flanged (ANSI, DIN, JIS), Screwed (NPT/BSPT), Socket Weld, or Butt Weld |
| Minimum Order Qty | 1 Piece |
For specialized chemical processes involving highly viscous fluids or media prone to solidification at room temperature, FlowBiz manufactures Jacketed Double Window Sight Glasses. The integrated thermal jacket allows hot water, oil, or steam to circulate around the sight glass body, maintaining uniform process temperatures.
Inline Inline Lens Replacement: Our inline maintenance blueprint allows field technicians to clean or replace a damaged glass window easily without dismantling the entire sight glass housing from the pipeline grid.
Zero Leakage Integrity: Precision-machined cushion seats combined with highly resilient gaskets eliminate structural stress on the glass windows while forming an absolute, leak-proof perimeter.
Highly Custom Add-Ons: For dark ambient spaces or opaque fluids, units can be custom-fitted with integrated industrial lighting attachments or mechanical wipers to wipe away internal scale or residue without stopping the process.
FlowBiz industrial flow indicators are heavily utilized across demanding commercial sectors:
Chemical & Petrochemical Processing: Visual monitoring of highly corrosive reagents, acids, and raw chemical streams.
Oil & Gas Refineries: Inspection of fuel oils, lubricants, and gas line separations.
Water & Wastewater Treatment: Monitoring filtration loops, backwash lines, and chemical dosing accuracy.
Pharmaceuticals, Biotech & Food/Beverage: Ensuring clean, continuous process fluid tracking in utility and clean-water systems.
A: A double window design allows external light to pass directly through the fluid column from the opposite side. This significantly improves clarity, allowing operators to accurately evaluate fluid color, cross-contamination, and turbulence, which is incredibly difficult with a single, dark window reflection.
A: Yes. FlowBiz sight flow indicators can be installed in both horizontal and vertical pipeline layouts. When monitoring vertical pipelines with downward flow, we recommend specifying our internal flapper or drip-tube models to achieve highly visible flow movement.
A: Selection depends entirely on your system's maximum pressure and chemical profile. For high-pressure networks (climbing toward our 100 Kg/cm rating), we use high-density toughened borosilicate glass up to 25 mm thick. This material offers superior structural strength and outstanding resistance to thermal shock and chemical etching.
A: A jacketed configuration is necessary if your process media (such as bitumen, heavy waxes, sulfur, or certain polymers) thickens, solidifies, or crystallizes when exposed to ambient room temperatures. The jacket keeps the media hot and flowing freely past the inspection window.
A: Maintenance is minimal. It consists of routine visual checks to ensure zero gasket weeping and checking lens clarity. If the glass becomes clouded by fluid deposits, our top-entry cover plates allow rapid removal for cleaning or replacement without disturbing the pipe connections.
A: Whether you need a single piece for a pilot loop or a bulk supply for an entire refinery infrastructure project, our Mumbai sales team provides rapid technical support. Contact us directly via our corporate portal to receive verified engineering datasheets, material test reports, and custom pricing configurations.

Price:
Price 5000 INR / Unit
Minimum Order Quantity : 1 Number
Temperature : 20C to 200C (Depending on glass type)
Disc : Toughened Borosilicate/Quartz Glass
Application : Industrial process observation, Chemical, Pharmaceuticals, Food processing industries
Media : Other, Liquids, Gases, Steam
Price 1000 INR / Unit
Minimum Order Quantity : 1 Number
Temperature : Up to 200C Celsius (oC)
Disc : SS 304
Application : Process Industries likeChemical, Power, Refinery, Petrochemicals, Nuclear, Water
Media : Water
Price 2700 INR / Unit
Minimum Order Quantity : 1 Number
Temperature : Up to 200C Celsius (oC)
Disc : SS 304
Application : Process Industries likeChemical, Power, Refinery, Petrochemicals, Nuclear, Water
Media : Water
Price 2500 INR / Unit
Minimum Order Quantity : 1 Number
Temperature : Up to 200C Celsius (oC)
Disc : SS 304
Application : Process Industries likeChemical, Power, Refinery, Petrochemicals, Nuclear, Sugar & Distilleries Plant
Media : Water