Series-GFM

Gas Mass Flow Meter, LCD, Straight Tube, NIST Traceable, Accurate Flow

Straight-tube mass flow meter with NIST-traceable calibration for gas service
Accuracy ±1% FS and repeatability ±0.25% FS ensure reliable measurement
Outputs include selectable 0-5 VDC and 4-20 mA; easy integration into control systems
Minimal sensibility to temperature/pressure changes; leak integrity <1×10⁻⁹ cc He/s

See Product Overview

Series-GFM

From ^$ 2,201.41

Shop Models

16 Variations available

See all series options below

Data Sheet

Product Overview

Accuracy Detail ± 1% FS including linearity over 59 to 77°F (5 to 25°C) and 5 to 60 psia (0.34 to 4 bar); Series GFC X143, X144, X145, ± 1.5% FS
Display Note 90° tiltable, 3-1/2 digit
Display Type LCD
Leak Rate Under Vacuum less than 10^⁻9 cc He/s
Media Compatibility Clean dry air / inert gas, Fuel gases, HVAC / room air, Inert / non-reactive gases, Hydrogen, Nitrogen, Non-Corrosive Dry Gases, Oxygen
Operating Temperature, Max 122 °F
Operating Temperature, Min 32 °F
Output Detail Linear 0 to 5 VDC and 4 to 20 mA
Output Signal Current, Voltage
Particulate Size, Max 5 microns
Measurement Pressure Type Gauge
Process Connection Type Compression Fitting
Repeatability ± 0.25%
Response Time 2 s
Response Time Note 2 s to within ± 2% of actual flow
Series ID Series-GFM
Supply Power Type DC
Supply Voltage ± 12 Vdc
Volumetric Flow Rate, Min 0 ml/min

Supported Applications

The Dwyer Series GFM Gas Mass Flow Meters are designed for measuring the mass flow of clean gases compatible with wetted parts. The series combines a straight tube sensor with a restrictor flow element to provide high accuracy and repeatability, where flow rates remain virtually unaffected by temperature and pressure variations within specified limits.

Documented media compatibility includes air, nitrogen, oxygen, argon, helium, hydrogen, carbon dioxide, natural gas, propane, butane, ethylene, propylene, ammonia, chlorine, sulfur dioxide, nitrogen oxides, carbon monoxide, hydrogen sulfide, methane, and various hydrocarbons. The manual notes that K-factors are approximations and should not be used in applications requiring accuracy better than +/- 5 to 10%. Users must determine instrument appropriateness for oxygen applications and specify O2 cleaning service if required.

Operating Conditions & Performance

The Series GFM operates within a process temperature range of 32 to 122°F (0 to 50°C). Accuracy is specified as ±1% FS including linearity over 59 to 77°F (5 to 25°C) and 5 to 60 psia (0.34 to 4 bar); Series X143, X144, X145 models list an accuracy of ±1.5% FS. Repeatability is rated at ±0.25% of FS.

Pressure limits are defined as 1000 psig (68.9 bar) for standard series; Series GFM-X143, X144, and X145 list a limit of 500 psig (34.5 bar). The response time is documented as 2 s to within ±2% of actual flow. Leak integrity is specified at 1 x 10-9 sccs of He.

Measurement Ranges

The series supports a wide envelope of measurement ranges, including:

Low-flow models: 0 to 10 mL/m through 0 to 5 L/min
Mid-range models: 0 to 15 L/min through 0 to 200 L/min
High-flow models: 0 to 500 L/min and 0 to 1000 L/min

Note that specified flow ranges are for an equivalent flow of nitrogen at 70°F (21°C) @ 760 mm Hg.

Electrical & Environmental Specifications

Power Supply: ±12 VDC. Accessories include GFM-110P (110 V power supply) and GFM-220PE (220 V power supply).
Output Signal: Linear 0-5 VDC or 4-20 mA.
Display: 90° tiltable, 3-1/2 digit LCD readout showing actual gas flow in engineering units.

Configuration Options

The Series GFM is available with distinct wetted material configurations and process connection sizes tailored to specific flow rates. The series includes a NIST traceable certificate of calibration.

Housing & Wetted Materials

GFM-1XXX Models: Feature anodized aluminum, brass, 316 SS, and fluoroselastomer O-rings as wetted materials. The manual also lists ABS Plastic for the housing material.
GFM-2XXX Models: Utilize 316 SS and fluoroselastomer O-rings as wetted materials.

Process Connections

Compression fittings are sized according to the flow range:

≤50 L/m: 1/4" compression fitting
100 and 200 L/min: 3/8" compression fitting
500 L/min: 1/2" compression fitting
1000 L/min: 3/4" compression fitting

Options & Accessories

The series supports the following options and accessories as documented in the source bundle:

GFT Flow Totalizer for applications requiring totalization.
Cables: GFM-CBL4 (3' cable for 4-20 mA output) and GFM-CBL5 (3' cable for 0-5 VDC output).
Remote LCD Readouts and Panel Mounting Readouts are listed as options in the manual.

Key Product Differences

The primary distinction within the Series GFM is between the aluminum-based construction of the 1XXX series and the stainless steel wetted parts of the 2XXX series. Model numbers follow the pattern GFM-, with examples including GFM-1101, GFM-2101, GFM-1133, GFM-2133, and high-flow variants such as GFM-1145.

Dimensional variations exist across model groups:

GFM-1101 thru 1111 / 2101 thru 2111: Width 5-1/64 [127.51], Height 5-37/64 [141.86], Depth 4-1/2 [114.30].
GFM-1130 thru 1133 / 2130 thru 2133: Width 6-1/32 [153], Height 5-31/32 [151.64], Depth 4-7/8 [123.70].
GFM-1140 thru 1142 / 2140 thru 2142: Width 6-9/64 [156], Height 5-31/32 [151.64], Depth 4-7/8 [123.70].
GFM-1143 thru 1145 / 2143 thru 2145: Width and Height both 7-19/64 [185.42], Depth 4 [101.60].