DFS-20 Series Teflon Flowmeters

The DigiFlow DFS-20 Series Teflon® flowmeters provide flow sensing capabilities in a wide variety of end-use and OEM applications, including corrosive aqueous liquids. Utilizing a rotor which, using a reflected infrared beam, generates a digital signal. The DFS-20 series offers an accurate, economical, and flexible design to meet many customer requirements. In either monitoring or flow controlled applications, the DFS-20 series can measure flow rates and totalize.
DFS-23, DFS-24
Design Features
  • Three ranges from 0.09 - 35 litres/minute (.025 – 9.2 GPM).
  • Wetted surfaces of PFA Teflon® with ruby glass bearing.
  • Outer housing of PFA or SS.
  • Accuracy within 1% or better (0.15% repeatability).
  • Low pressure drops.
  • Infrared signal pickup.
  • Mount in any position without flow straighteners.
  • Interchangeable/Disposable rotor assembly option.
  • CE mark approved.
  • Fiber optic signal transmission option.
Systems & Applications

The DFS turbine flow meter can monitor flow rates and/or total quantities when connected to a basic counter. In conjunction with a stand-alone controller or interfaced with process control or general purpose computers, the DFS is an integral part of flow controlled processes. In end-use, or in OEM applications, the DFS is a key part in a systems approach to a wide range of monitoring and controlling applications including:

  • Semiconductor and other high purity processes.
  • Dosing of chemicals into main stream flows for agricultural, water treatment, and other processes.
  • Additive injection in chemical processes.
  • Monitoring/Controlling fuel flows.
  • Medical/Pharmaceutical equipment.
Principle of Operation

The fluid flows though the meter, passing a fixed worm which imparts a spiral flow which, in turn, spins the rotor on a virtually friction free bearing. The rotor blades reflect an infrared beam which generates a high resolution digital output signal. The rotor is the only moving part and, due to its light weight and the helical pattern of the fluid flow, it has a minimal response time. DFS turbine flow meters can be mounted in any position and do not require flow straighteners or other specialized installations. Hose-barb, threaded, and other connectins are available.
SPECIFICATIONS DFS-22 / DFS-22W DFS-23 / DFS-23W DFS-24
(Data based on water) l
Media liquids liquids liquids
Flow Range 0.09 - 1.5 L/m (.025 - .4 GPM) 1.5 - 20 L/m (0.4 - 5.3 GPM) 2.5 - 35 L/m (0.66 - 9.2 GPM)
Turndown Ratio 17:1 13:1 14:1
Linearity Deviation +/- 1% (of actual flow reading) +/- 2% (of actual flow reading) +/- 3% (of actual flow reading)
Repeatablitiy <0.15% <0.15% <0.15%
Resolution Pulses 124,000 pulses/L (469,400 pulses/Gal.) 6,350/L (24,000 pulses/Gal.) 2,050/L (7,750 pulses/Gal.)
Temperature Range
All models: -20 to +80°C (-4 to +176°F)(Std. electronics)
For fiber optics units, -20 to +180°C (-4 to +350°F)
Static -20 to +100°C (-4 to +212°F) -20 to +100°C (-4 to +212°F) -20 to +100°C (-4 to +212°F)
Viscosity Range 0.8 - 10mm2/s (0.8 - 10 cSt) 0.8 - 15mm2/s (0.8 - 15 cSt) 0.8 - 15mm2/s (0.8 - 15 cSt)
Operational Pressure - Max (PFA)
Max (SS)		 20 bar (290 PSIG) @ 20°C (68°F)
200 bar (2900 PSIG)		 15 bar (217 PSIG) @ 20°C (68°F)
200 bar (2900 PSIG)		 10 bar (145 PSIG) @ 20°C (68°F)
150 bar (2175 PSIG)
Pressure Drop 0.2 bar @ .75 L/m (2.9 PSI @ .2 GPM) 0.2 bar @ 8 L/m (2.9 PSI @ 2.1 GPM) 0.2 bar @ 17 L/m (2.9 PSI @ 4.51 GPM)
Power Supply 4-9 VDC, 12 mAmp 4-9 VDC, 12 mAmp 4-9 VDC, 12 mAmp
Output Signal 5v Square Wave 5v Square Wave 5v Square Wave
Materials - Wetted Parts PFA-Teflon® - ruby glass bearing PFA-Teflon® - ruby glass bearing PFA-Teflon® - ruby glass bearing
Materials - Housing PVDF PVDF PVDF
Materials - O-rings Viton® Viton® Viton®
Electrical Lead 1 meter (39") in length, PVC shielded cable 1 meter (39") in length, PVC shielded cable 1 meter (39") in length, PVC shielded cable
Dimensions - Length 62 mm (2") 74 mm (2.91")
Dimensions - Max Diameter DFS-22: 17 mm (0.67"); DFS-22W: 32mm (1.26") 23 mm (0.9 ") 26 mm (1")

Connections - Hose barb
  - Threaded

7 mm (9/32")
1/8" MNPT
 12 mm (15/32")
1/4" MNPT
 N/A
1/2" MNPT or 1/2" MBSP
OPTIONS
Materials - Housing 316L SS 1/4" NPT 316L SS 3/8" NPT 316L SS 1/2" NPT
Materials - O-rings
EPDM (Ethylene Propylene Rubber)
Materials - Cable
Tefzel® shielded cable or fiber optical with amplifier 6700 (all models)
Output Signal
4 - 20 mA, 1 - 5V, 1 - 10V with external 6100 converter
Power Supply
12 - 24 VDC
Electrical Lead
Other lengths and insulations available
Connections
OEM custom design
Teflon®, Viton®, and Tefzel® are registered tradenames of E. I. DuPont, Inc.