Do you need a simple, economical, and maintenance-free way to measure or monitor fluid flow in your laboratory or process skid? When you need direct, local indication without the complexity of power or electronics, a variable area flowmeter is the ideal solution. The RAGN Rotameter from Yokogawa is a classic, precision-crafted variable area flowmeter designed for continuous flow measurement of liquids and gases. Featuring a durable borosilicate glass metering tube with an easy-to-read scale and robust 316L stainless steel fittings, the RAGN provides reliable, visual flow confirmation for a wide range of clean fluids.

Why Choose the RAGN Rotameter? Solving Complexity, Cost & Readability Challenges

Achieve simple, reliable flow indication with features that directly address common laboratory and process pain points.

• Eliminate Power and Wiring Hassles: Unlike electronic flow meters, this glass tube rotameter requires no external power supply. The flow rate is directly indicated by the position of a float in a tapered tube, making it inherently safe, simple to install, and perfect for remote locations or basic laboratory benches where wiring is impractical.

• Direct, Intuitive Flow Reading: Stop interpreting digital numbers; see your flow at a glance. The RAGN variable area flowmeter features a brightly colored float (stainless steel for liquids, PTFE for gases) that moves freely within the precision-bore borosilicate glass tube. The flow rate is read directly from the scale on the tube by observing the top of the float, providing immediate and unambiguous visual confirmation.

• Corrosion-Resistant Construction for Diverse Fluids: Worried about fluid compatibility? The standard model features 316L stainless steel fittings and wetted parts. For more aggressive chemicals, you can configure the RAGN with optional internals made from titanium, PTFE, or PVDF, ensuring long-term reliability with your specific process media.

• Wide Rangeability in a Compact Package: Achieve flexibility across different flow rates. With a standard measuring span of 10:1, a single RAGN rotameter can cover a broad range of flow conditions. Its compact design, with a standard 375 mm length (475 mm for flanged connections), fits easily into existing panels or piping.

Key Features for Demanding Applications

Engineered for simplicity, durability, and clarity:

• Easy-to-Read Scale: The brightly colored scale on the borosilicate glass (Duran 50) tube ensures excellent visibility, even in low-light conditions.

• Versatile Installation: Designed for vertical installation with flow from bottom to top. Choose from NPT thread or Flanged connections (1/2" to 2 1/2") to suit your piping.

• Robust & Safe Operation: Certified for operating pressures up to 16 bar (232 PSIG) and temperatures up to 100°C (212°F) , making it suitable for a wide variety of pilot plant and industrial applications.

• Configurable to Your Needs: Use the online FlowConfigurator tool to select the optimal materials, float type, and sizing for your specific liquid or gas application, ensuring accurate measurement right out of the box.

Technical Specifications at a Glance

General & Performance

• Product Name: RAGN Rotameter (Variable Area Flowmeter)

• Measurement Principle: Variable Area (Rotameter)

• Measurable Fluids: Liquids and Gases (clean, non-precipitating)

• Flow Indication: Direct reading via float position on glass tube scale

• Rangeability (Turndown): 10 : 1

• Measuring Accuracy: 1.6 % (acc. to VDI/VDE 3513 sheet 2, qG=50%)

Materials of Construction

• Metering Tube: Borosilicate Glass (Duran 50) – Length: 300 mm / 11.81 inches

• Standard Wetted Materials:

• Fittings/Nuts/Housing: AISI 316L Stainless Steel

• Float (Liquid): AISI 316 Stainless Steel

• Float (Gas): PTFE

• Gaskets: Buna (Standard)

• Optional Materials (Selectable):

• Internals/Float: Titanium, PVDF, PTFE, AISI 316L

• Gaskets: Viton, EPDM Synthetic

• Connections: PTFE lined available

Operating Conditions & Connections

• Maximum Operating Pressure: 16 bar (232 PSIG)

• Maximum Operating Temperature: 100 °C (212 °F)

• Installation Orientation: Vertical (flow from bottom to top)

• Process Connection Sizes: 1/2", 3/4", 1", 1 1/2", 2", 2 1/2"

• Connection Types: NPT Thread or Flanged (150#)

• Overall Length (L):

• Threaded Connections: 375 mm / 14.7 inches

• Flanged Connections: 475 mm / 18.7 inches

Ready to Simplify Your Flow Measurement with a Reliable, Direct-Reading Rotameter?

Whether you need to monitor cooling water, measure gas purge flows, or indicate chemical dosing rates, the RAGN offers a clear, maintenance-free solution.