Dwyer Thermal Dispersion Flow Switch, Series TDFS
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Series TDFS Thermal Dispersion Flow Switch

Brand: Dwyer Instruments, LLC
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The Series TDFS Thermal Flow Switch uses impulse thermal dispersion measurement technique to indicate whether the flow rate is above or below a user set flow rate.

It provides NO and NC NPN outputs and two LED, one green and one red for high and low set point indication.
Features
  • Better long term reliability and life expectancy than mechanical flow switches with no paddles or vanes to wear or break, no jams in the paddle movement, and no seals on movement assembly to wear or leak
  • Not affected by empty pipe detection and avoids overheating by actively heating above the process temperature and then cooling down to process temperature
  • Set point is easily field set by taping the included magnet on the set point target three times at the desired flow rate
  • LED status indicators provide visual switch indication of set point
  • Low pressure drop, only needs to be 10% into the flow (e.g. 1/8˝ for 3/4˝ schedule 40 pipe)

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Specifications

Brand

Ambient Temperature Range

  • -15° to 75° C (5° to 167° F)

Applications

  • Boiler Flow Proving
  • Chillers
  • Hot Water Heaters
  • Liquid Transfer Systems

Approvals & Certifications

  • CE

Consumption

  • 300 mA - Peak
  • 93 mA - Average

Deadband

  • 0.1 ft/sec +15 % of Set Point

Electrical Connectors

  • 4-Conductor 22 AWG, 6' (1.83 m) Long with Cable Gland
  • 6 feet Cable

Electrical Protection

  • 0.5 A Fuse Reverse Polarity Protected

Enclosure, Body Material

  • 316 Stainless Steel
  • 416 Stainless Steel
  • Acrylated Urethane
  • Neoprene
  • Polycarbonate

Environmental Protection

  • IP65
  • NEMA 4X

Input Power

  • 400 mA, Derate mA/°C Above 23° C

Media

  • Compatible Water-based Fluids

NPT Connection

  • 1/2” NPT Male

Output Function

  • Complementary Outputs (One Normally Open, One Normally Closed)

Power Requirement

  • 9-24 Vdc

Pressure Range

  • psig: 300 to 500 (kPa: 2,068 to 3,447, bar: 20.68 to 34.47)

Process Temperature

  • -15° to 85° C (5° to 185° F)

Repeatability

  • 0.07 ft/sec +3 % of Set Point

Response Time

  • Approximately 8 seconds

Storage Temperature

  • -40° to 85° C (-40° to 185° F)

Switch Type

  • 1 Normally Open & Normally Closed NPN

Wetted Materials

  • 316 Stainless Steel
  • FKM
  • Polysulfone

  • Boiler Flow Proving
  • Chillers
  • Hot Water Heaters
  • Liquid Transfer Systems

Documentation

Approvals

Catalogs

Manuals

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