Kawaki FS-II Sight Flow Indicator With Flapper – ANSI 150LB Raised Face

Overview

The Kawaki FS-II Sight Flow Indicator With Flapper is a premium industrial flow sight designed to provide visual confirmation of fluid flow within pipelines. As part of the FS series from KAWAKI, the FS-II model features a built-in flapper indicator that shifts with flow direction and magnitude, enabling operators to quickly verify fluid movement without relying solely on electronic instrumentation. This makes it especially useful in process inspection, diagnostics during maintenance, and systems where visual feedback enhances reliability and safety. 

Manufactured with corrosion-resistant materials (including SUS316 for key internal parts), the flow sight glass is transparent and built for durability under typical industrial conditions. The robust construction supports standard ANSI 150LB Raised Face (RF) flange connections and withstands typical process pressures up to 1.0 MPa with operating temperatures up to approximately 80 °C under normal working conditions. 

Each size variant—from 1/2B to 4B flange bore—ensures compatibility with standard piping systems, making the FS-II flow sight indicator adaptable to a wide range of fluid control environments including water supply lines, oil pipelines, HVAC systems, chemical processing loops, and industrial utility circuits.

In service, the transparent window and flapper mechanism allow not just confirmation of flow presence, but when equipped with an optional flow scale, also a visual representation of relative flow magnitude. This can be a vital tool in systems where rapid visual inspection is part of operational best practices. 

In addition to standard FS-II models, KAWAKI’s broader FS lineup includes other configurations such as FS-I (without flapper), FS-B (ball type), and FS-IV (bidirectional visualization), all with similar robust construction and transparent sight capabilities, enabling system designers to choose the most appropriate indicator type for their specific application. 

Key Features & Capabilities

• Transparent flow sight glass with integrated flapper indicator for real-time visual flow confirmation. 

• Constructed with corrosion-resistant materials including SUS316 components for enhanced service life. 

• ANSI 150LB Raised Face (RF) flange connection for standard industrial piping systems. 

• Multiple bore sizes (1/2B, 1B, 2B, 3B, 4B) for adaptable system integration. 

• Withstand pressure up to 1.0 MPa and standard working temperature up to ~80 °C. 

• Optional flow scale marking for enhanced visual flow magnitude feedback. 

• Suitable for water, oil, and compatible fluid systems where visual inspection assists operational workflows. 

Technical Specifications (General for FS-II Models)

Applications

The Kawaki FS-II Flow Sight Indicator delivers visual fluid insight across critical industrial and commercial systems:

• Visual confirmation of flow direction and presence in water pipelines

• Integrating into HVAC and utility systems for operating diagnostics

• Monitoring oil circulation loops and lubrication circuits

• Installation in chemical processing lines with compatible fluids

• Supporting visual inspection points in manufacturing and production piping

Visual flow indicators like the FS-II help operators and maintenance teams rapidly verify system status without requiring powered measurement devices.

FAQ 

Q1: What is the Kawaki FS-II Sight Flow Indicator?

A: A transparent flow sight glass with a built-in flapper indicator for direct visual confirmation of fluid movement in ANSI 150LB RF piping systems. 

Q2: What bore sizes are available for the FS-II model?

A: The FS-II flow sight is offered in multiple ANSI 150LB RF sizes from 1/2B to 4B to suit standard industrial pipe configurations. 

Q3: Can this flow sight be used for oil and chemical fluids?

A: Yes — FS-II models with appropriate material choices like SUS316 are suitable for water, oil, and many compatible fluid media. 

Q4: What is the maximum operating pressure?

A: Standard FS type flow sight indicators typically support pressures up to 1.0 MPa. 

Q5: Does the flapper show flow rate values?

A: With optional flow scale markings, the flapper’s movement can visually represent relative flow, aiding inspection. 

Call to Action

For pricing, availability, and technical consultation on Kawaki FS-II Sight Flow Indicators With Flapper (all ANSI 150LB sizes) including 1/2B, 1B, 2B, 3B, and 4B, contact Seven Star LLC. Our experts will assist with selection and system integration.