Swagelok^® Variable Area Flowmeters

Achieve consistent accuracy with Swagelok variable area flowmeters for measuring gas and fluid flow. Select from glass or metal tube options to suit your specific application needs.

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Swagelok^® variable area flowmeters use a tapered tube and float to measure the flow rate of liquids and gases. As fluid flow increases, the float rises, and as flow decreases, gravity pulls it down. These flowmeters are easy to install, simple to read, and designed with no wearing parts, minimizing the need for maintenance. With a 10-to-1 turndown ratio—allowing the lowest measurement to be one-tenth of the full-scale reading—they provide accurate measurement. Available in both U.S. customary and metric scales, they suit a wide range of applications and locations.

Each Swagelok variable area flowmeter is factory-calibrated to the specified media, flow range, and accuracy class using clean, dry air for gas models and water for liquid models. They can also be calibrated for user-specific applications.

M Series Variable Area Flowmeters (M1, M2, M4, and M4H Models)

Swagelok^® M series flowmeters feature metal measuring tubes for challenging conditions involving high temperature or pressure. Since direct readings are not possible with metal tubes, these models come with mechanical or electronic displays to ensure clear and accurate monitoring.

M1, M2, M4, and M4H Model Specifications

Measured Flow Ranges	Air: 0.18 to 1.8 through 670 to 6700 std ft³/h; 5.0 to 50 through 18 000 to 180 000 std L/h Water: 0.08 to 0.8 through 270 to 2700 U.S. gal/h; 0.3 to 3.0 through 1000 to 10 000 L/h
Temperature Ranges	Process: M1, M2: –40 to 302°F (–40 to 150°C) M4, M4H: –40 to 572°F (–40 to 300°C) Ambient: M1, M2: –4 to 158°F (–20 to 70°C) M4, M4H: –40 to 248°F (–40 to 120°C)
Maximum Inlet Pressure	Up to 2888 psig (199 bar)
Process Connections	1/4 to 1 1/4 in. NPT fitting; 1/2 to 1 in. ASME flange adapter
Accuracy Class	1.6, 2.5, 4.0

G Series Variable Area Flowmeters (G1, G2, G3, G4, GM, and GP Models)

Swagelok^® G series models use glass measuring tubes for visibility of the process fluid and direct flow reading.

G1, G2, G3, G4, GM, and GP Model Specifications

Measured Flow Ranges	Air: 0.018 to 0.18 through 18 to 180 std ft³/h; 0.5 to 5.0 through 500 to 5000 std L/h Water: 0.065 to 0.65 through 4.2 to 42 U.S. gal/h; 0.04 to 0.4 through 16 to 160 L/h
Temperature Ranges	Process: 23 to 212°F (–5 to 100°C) Ambient: –4 to 212°F (–20 to 100°C)
Maximum Inlet Pressure	Up to 145 psig (10 bar)
Process Connections	1/4 in. NPT fitting; G 1/8 (ISO 228); G 1/4 (ISO 228)
Accuracy Class	1.0, 2.5, 4.0

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Variable Area Flowmeters Catalogs

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Variable Area Flowmeters, G Series and M Series

Features: Glass and metal (armored) tube models, including miniature armored model; Highly accurate measurement even at very low flow, with individually calibrated scales based on flow tests; Flexible and adaptable to specific system requirements; High quality, durability, and repeatability; 1/8 to 1 1/4 in. process end connections

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