Series-DFM

Supported Applications

The Dwyer Series DFM Digital Flow Meter is designed for the measurement of mass and volumetric flow rates of clean, non-corrosive gases. The instrument supports simultaneous display of process parameters including mass flow, volumetric flow, pressure, and temperature via an OLED interface with joystick navigation.

Operating Conditions & Performance

The Series DFM operates within a process temperature range of 14 to 140°F (-10 to 60°C). The device is rated for maximum pressures up to 120 psig (8.27 bar); exceeding this limit may cause permanent damage to the differential pressure sensor. Performance specifications include an accuracy of ±(0.5% of reading + 0.2% FS) and repeatability of ±0.15% FS, with a response time of 10 ms.

Media compatibility is limited to clean, non-corrosive gases compatible with the wetted materials. The maximum allowable particulate size is 20 microns. Leak integrity is rated at 1 x 10⁻⁹ sccs of helium. Wetted parts consist of 316 SS, 416 SS, high temperature polyamide, alumina ceramic, epoxy, silicone, glass, gold, and FKM O-rings.

Configuration Options

The series offers configurable options for process connections, output signals, and digital interfaces to accommodate specific installation requirements. The device is powered by a 9-26 VDC supply via a DIN connector or terminal block configuration depending on the model variant.

• Process Connections: Available as 1/8" compression fitting for flow rates ≤ 10 L/min, 1/4" for ≤ 50 L/min, and 3/8" for ≤ 100 L/min. Specific dimensional configurations include 10-32 UNF-2B or NPT ports depending on the range.
• Output Signals: Configurable analog outputs of 0-5 VDC, 0-10 VDC, and 4-20 mA are available. A programmable solid state relay is included with a maximum voltage rating of 48 AC peak/DC and a load current limit of 400 mA.
• Digital Communication: The unit features an RS-232 interface via a 9-pin D connector (included) or audio jack. An optional Modbus RTU digital communication interface is available, with RS-485 connectivity accessible through the factory-supplied A-DFM-CBL-A485DP cable.
• Display: Features a selectable 2 x 16 character OLED display for process information and configurable alarms.

Power Accessories

Optional power supply accessories include the GFM-110P (110 V) and GFM-220PE (220 V).

Key Product Differences

The Series DFM is available in multiple flow ranges, including 0.5 mL/min to 50 mL/min, 51 mL/min to 20 L/min, and up to 100 L/min configurations. Physical dimensions vary by range; for example, the 0.5 mL/min-50 mL/min model measures 4-13/32 [111.76] in dimension A and utilizes a 10-32 UNF-2B connection (C), while the 51 mL/min-20 L/min range uses a 1/8-27 NPT connection.

Weight varies by model size: DFM-01/50 models weigh 0.85 lb (0.4 kg) and DFM-51/56 models weigh 1.15 lb (0.52 kg). The series carries CE compliance certification. Note that the device is not designed for use with liquids or oxygen gas unless specifically cleaned and prepared, nor is it intended for life support applications.