Series-TFM-LI

Supported Applications

The Dwyer Series TFM-LI Liquid Turbine Flow Meters are designed for industrial, commercial, and laboratory flow applications involving clean liquids compatible with the specified wetted materials. These meters utilize a patented Pelton Turbine Wheel design to measure liquid flow rates by converting them into linear electrical signals suitable for recording and data logging.

Operating Conditions & Performance

The series operates within a process temperature range of 41 to 131°F (5 to 55°C) with storage temperatures from 32 to 158°F (0 to 70°C). Units are rated for pressures up to 500 psig (34.5 bar). Performance specifications include an accuracy of ±1% of full-scale and repeatability of ±0.2% of full-scale. The meters feature a linear output with virtually no zero drift, as the micro-turbine assembly design eliminates wear on sapphire bearings.

Pressure drop varies by flow percentage; at 100% of rated flow, the pressure drop is 10 psid (0.7 Bar), while lower percentages show minimal to zero differential in the provided data table. The series requires a minimum load resistance of 2.5 kΩ for signal integrity.

Measurement Ranges

The Series TFM-LI covers seven distinct flow ranges, selectable by model number:

• .21 to 1.6 GPH (.013 to .1 LPM)
• .32 to 3.2 GPH (.02 to .2 LPM)
• .79 to 7.9 GPH (.05 to .5 LPM)
• 1.6 to 16 GPH (0.1 to 1 LPM)
• 3.2 to 32 GPH (.2 to 2 LPM)
• 7.9 to 79 GPH (.5 to 5 LPM)
• 16 to 160 GPH (1 to 10 LPM)

Media and Environmental Constraints

Liquids must be clean; if particles larger than 25 microns are present, a filter of 25 microns or less is required upstream. The unit should not be exposed to gas flow, strong magnetic fields, strong air flows, or excessive vibration.

Configuration Options

The series offers configurable process connections and output options tailored to specific installation needs.

Housing and Connections

The meter body is constructed of 316SS. Process connections are compression fittings sized according to the model range:

• Models TFM-LI03: 1/8" OD connection
• Models TFM-LI04 through TFM-LI07: 1/4" OD connection
• Models TFM-LI08 and TFM-LI09: 3/8" OD connection

The enclosure rating is IP10 (NEMA 1).

Electrical Outputs and Power

The series provides a linear analog output of 0 to 5 VDC. A 3-1/2 digit LCD display indicates the actual flow rate directly on the unit. Electrical connection is made via a four-pin power and signal connector, requiring an external power adapter or mating cable assembly for operation.

• Power Supply: 11.5 to 15 VDC
• Output Signal: 0 to 5 VDC (Minimum 2.5 kΩ load)

Wetted Materials

The internal components contacting the fluid include:

• 316 SS
• Acetal
• Sapphire
• Glass
• Epoxy
• Fluoroelastomer

Key Product Differences

The Series TFM-LI is distinguished by its specific model numbers (TFM-LI03 through TFM-LI09), which correspond to the flow range and tubing connection size. The series title identifies these units as having a 0 to 5 Vdc output, LCD display, and Turbo Wheel sensor technology.

Accessories are available for power and signal interfacing:

• A-454: 115 VAC Power Adapter and Signal Cable
• A-455: 230 VAC Power Adapter and Signal Cable
• A-456: 36" Mating Cable with Spliced Leads