Thermal Dispersion Switch

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TDFS

Thermal Dispersion Flow Switch

TDFS Basics

Thermal DispersionSensing principle based on Convection across a heated sensor

Basics Cont’d

Operation:Integral impulse thermal dispersion measurement technique to measure the flow rate. The probe is heated. The flow rate is determined from the rate at which the probe cools. The measurement cycle time is approximately 7 seconds

TDFS ApplicationsCommon Applications:

Cooling tower flow proving to A/C UnitReverse OsmosisPump flow provingConcrete Truck ProcessingChillers

Direct Replacement of V6

For non-hazardous environments

SpecificationsWetted Materials: 316 SS and PolysulfonePressure Limits: 3400 KpaSet Point: Field Adjustable

Magnetic SetResponse Time: 7 seconds nominalPipe Size: 1.3 cm to 30.5 cmSwitch Type: 1 NO, 1 NC Switch Housing: IP 65

TDFS OperationWhen at desired flow rate:

Tap the set point pin 3 times with the supplied magnetLED indicator will blink slowlyCalibration completed when blinking stops

Local LED OperationDescription Color State

OffN/A Waiting for first measurement

or unit is off.Dimmed Pulses

Any Start of a measurement cycle (normal operation).

SteadyRed Flow is below the setpoint.

Green Flow is above the setpoint.

Variable Length

Red+Green Error Condition

Slow Blink(2/3

Second)

Any A setpoint adjustment was requested.

Green Flow is in the nominal range.

Red+Green Flow is below the nominal range.

Alternating Setpoint will be limited to the maximum allowable flow.

TDFS AdvantagesLow Cost

Approx. 30% less than CompetitorsConduit or Cable Gland Connection in one unitProgrammable set point

Magnet Calibration Local visual indicator

TDFS Advantages Cont’d

Compatibility316SS & Polysulfone body

Non-MechanicalLong Life versus paddle switches

Low Pressure DropNO BURNOUT

Does not overheat when liquid not present

Questions

To order a free catalog or for more information contact;Dwyer Instruments, Inc., P.O. Box 373,

Michigan City, IN., 46361Telephone: (800) 872-9141 or (219) 879-8000

Fax: (219) 872-9057Internet address: www.dwyer-inst.com

E-mail: info@dwyer-inst.com