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VFS/VFS QT vortex flow sensor

The VFS is a combined flow and temperature sensor (two-in-one) from Direct Sensors. The sensor is based on the principle of vortex shedding behind a bluff body. The VFS sensor is fully compatible with wet, aggressive liquids. 

  • Description
  • Specification
  • DESCRIPTION

    The VFS is a combined flow and temperature sensor (two-in-one) from Direct Sensors. The sensor is based on the principle of vortex shedding behind a bluff body. The VFS sensor is fully compatible with wet, aggressive liquids. The sensor is based on MEMS sensing technology in combination with the corrosion-resistant Silicoat coating technology on the sensor chip. The sensor is supplied with a flow pipe.

     

    Applications

    • Pump control
    • HVAC systems
    • temperature control and chiller systems
    • renewable energies such as heat pumps, solar thermals, fresh water and micro-CHP systems
    • monitoring and control systems
    • water treatment plants
    • water utility and distribution systems
    • HPC (High-Performance Computing) and IT cooling systems.

     

    Features and benefits

    • Measurement principle with no movable parts, resulting in no wear and tear
    • flow and temperature measurement in one sensor (two-in-one solution) for easy and cost-efficient installation
    • MEMS technology
    • direct contact with the aqueous media resulting in a fast response time
    • plug and play for quick setup
    • smart system solution with Grundfos pump controls
    • compact and robust design
    • compatible with aqueous media
    • suitable for a wide temperature range
    • suitable for a wide range of applications.
    • For aqueous media below 2 μS/cm contact your local Grundfos sensor representative.

     

    Power supply requirements

    • 5 VDC ± 5 %, PELV
    • Ratiometric
    • Max. 10 mV ripple: 50 Hz
    • Min. output current: 25 mA
    • Separated from hazardous live circuitry by double or reinforced insulation.
    • Grounding of the sensor supply is required.

     

    Directives
    The Direct Sensors are in conformity with these council directives on the approximation of the laws of the EC member states:

    • Low Voltage Directive (2014/35/EU): Standards used: EN 61010-1:2010
    • EMC Directive (2014/30/EU): Standards used: EN 61326-1:2013 and EN 61326-2-3:2013

     

    The VFS flow sensor consists of a composite flow pipe and a sensor fitted with cable. The VFS flow sensor is available in 1-20, 2-40, 5-100,10-200, 20-400 l/min versions. The VFS QT flow sensor consists of a composite insert, a stainless steel flow pipe and a sensor fitted with cable. The VFS QT flow sensor is available in 1-18, 2-40, 5-100, 10-200 l/min versions.

  • SPECIFICATION

    Flow measuring range 1.3-20 l/min (0.34 to 5.3 gpm)
    2-40 l/min (0.5 - 10.6 gpm)
    5-100 l/min (1.3 to 26.4 gpm)
    10-200 l/min (2.6 to 52.8 gpm)
    20-400 l/min (5.3 to 105.7 gpm)
    1-18 l/min (0.2 to 4.8 gpm)
    2-40 l/min (0.5 - 10.6 gpm)
    5-100 l/min (1.3 to 26.4 gpm)
    10-200 l/min (2.6 to 52.8 gpm)
    Flow accuracy (± 1 σ) in water 0-120 °C (32-248 °F) ± 1 % FS
    Response time (63.2 %) Less than 1 s
    Resolution max flow/16384 l/min or gpm
    Temperature measuring range 0-120 °C (32-248 °F)
    Temperature accuracy (± 1 σ) 15-90 °C (59-194 °F) ± 0.5 K
    0-120 °C (32-248 °F) ± 1 K
    Response time (63.2 % at 50 % FS flow) 250 ms
    Resolution 0.006 K
    0.35 K
    Differential Temperature Accuracy 15-90 °C (59-194 °F) 0.3 K
    0-120 °C (32-248 °F) 0.5 K
    Liquid types Aqueous media compatible with wetted materials. Kinematic viscosity less than 2 mm2/s (cSt)
    Liquid temperature, operation Water 0-100 °C (32-212 °F)
    Liquid temperature, peak -25 °C (-13 °F), non-freezing 120 °C (248 °F) for 5 minutes, up to 3 weeks in sensor lifetime
    Ambient temperature, operation -25 to +60 °C (-13 to -140 °F)
    Ambient temperature, peak -55 to +90 °C (-67 to 194 °F)
    Humidity, relative 0-95 %, non-condensing
    Maximum System Pressure 24 bar (348 psig)
    Burst Pressure 30 bar (435 psig)
    Maximum system pressure examples Max 10 bar (145 psig) at 100 °C (212 °F)
    Power supply 5 VDC (± 5 %), PELV Grounding of sensor supply required
    Output signals Ratiometric
    Digital output signals Grundfos open data protocol
    Analog output signals 0.5 - 3.5 V for flow (zero at 0.35 V)
    0.5 - 4.1 V for temperature (zero at 0.5 V and 100 °C at 3.5 V)
    Power consumption Appr. 75 mW
    Load impedance > 47 kΩ
    Maximum cable length 3 m (9.10 ft)
    Sensing element Silicon-based MEMS
    Sealing EPDM O-rings, FKM O-rings or EPDM sealing cap with FKM O-rings
    Housing Composite (PPS, PA66)
    Flow pipe PPA 40-GF
    Wetted materials Corrosion-resistant coating, EPDM or FKM, PPS, PPA 40-GF
    Enclosure class IP44, cable connected
    Temperature cycling IEC 68-2-14
    Vibration, non-destructive 20-2000 Hz, 10G, 4 h
    Electromagnetic compatibility EN 61326-1
    Certificates CE - C, CSA, US - EAC

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