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variable area flowmeters

Swagelok® Variable Area Flowmeters

Achieve reliable results with Swagelok variable area flowmeters for the measurement of gas and fluid flow. Choose glass or metal tube options to meet your application requirements.

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Swagelok variable area flowmeters measure the flow rate of liquids and gases by means of a tapered tube and float. The float is pushed up by increasing fluid flow and pulled down by gravity as fluid flow decreases. They are simple to install and easy to read with no wearing parts, reducing maintenance needs. A 10-to-1 turndown ratio (the lowest measurement is one tenth of the full-scale reading) provides precision. Available measurement ranges in U.S. customary and metric scales allow for use in a range of applications and locations.

Every Swagelok variable area flowmeter is factory calibrated to the selected media, flow range, and accuracy class using clean, dry air for air flow range models and water for water range models and can be calibrated to user-specific applications.

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

Swagelok M series models feature metal measuring tubes for applications in which temperature or pressures contribute to difficult operating conditions. Because direct readings are not possible with metal tubes, these flowmeters are equipped with mechanical or electronic displays.


Measured Flow Ranges
Air 0.18 to 1.8 through 670 to 6,700 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 2,700 U.S. gal/h; 0.3 to 3.0 through 10,00 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;
1/2 to 1 in. ASME flange
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.


Measured Flow Ranges
Air 0.018 to 0.18 through 18 to 180 std ft³/h; 0.5 to 5.0 through 500 to 5,000 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; G 1/8 (ISO 228); G 1/4 (ISO 228)
Accuracy Class 1.0, 2.5, 4.0

Variable Area Flowmeters Catalogs

Locate detailed product information, including materials of construction, pressure and temperature ratings, options, and accessories.

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