Dwyer TFM-LP User Manual

Manual F-20-TF-L

June 2008

Revision 1

www.dwyer-inst.com

MODEL TFP-LI MODEL TFM-LI MODEL TFP-LP

MODEL TFM-LP

Flow Sensors and Flow Meters For Liquids

Installat

ion Manual & Operating Instructions

READ THIS MANUAL COMPLETELY BEFORE ATTEMPTING TO CONNECT

OR OPERATE YOU R FLOW SENSOR. FAILURE TO DO SO MAY RESULT

IN INJURY TO YOU OR D

AMAGE TO THE FLOW SENSOR.

T A B L E O F C O N T E N T S

A. Introduction ......................................................................................... 3

B. Installation ........................................................................................... 5

C. Operation .......................................................................................... 13

D. Maintenance And Product Care ............................................................ 19

E. Specifications ..................................................................................... 21

F. Dimensions ...................................................................................

..... 23

G. Connector Pin And Wire Color Cross Reference ..................................... 27

H. Tr

ouble Shooting Guide ...................................................................... 28

I. Warr

anty ........................................................................................... 30

. Contacting Dwyer ............................................................................... 30

1. Unpacking .................................................................................................. 3

2. Product Overview And Principle Of Operation .............................................. 3

1. General Considerations .............................................................................. 5

2. Mounting The Flow Sensor Or Flow Meter .................................................. 6

3. Tubing Connections .................................................................................... 7

4. Electrical Connections ................................................................................. 8

a) Overview ........................................................................................... 9

b) Connecting A Cable Assembly ................................................................. 9

c) Electrical Connections – Voltage Output Units (TFP-LI & TFM-LI Series) ..... 10

d) Electrical Connections – Units With Both Voltage & Pulse Outputs

(TFP-LP & TFM-LP Series) ......................................................................... 11

e) Using a 0-5VDC Output Power Adapter Package .................................... 12

1. Start-Up ................................................................................................... 13

2. Entrapped Air or Gas ................................................................................ 13

3. Flow Readings .......................................................................................... 13

a) 0-5VDC Analog Outputs ....................................................................... 14

b) Pulse Outputs ..................................................................................... 14

c) Units with an Integral Display ................................................................. 14

4. Operating at Flow Rates Outside the Calibrated Flow Range ....................... 15

a) Flows Above the Maximum Rated Flow ................................................... 15

b) Flows Below the Minimum Rated Flow .................................................... 16

5. Zero Adjustments ...................................................................................... 16

6. Recalibration ............................................................................................ 16

7. Calibrating Units for different Liquids ......................................................... 19

1. General .................................................................................................... 19

2. Cleaning and Flushing .............................................................................. 20

3. Returning Units For Repair Or Recalibration ............................................... 20

F-20-TF-L, pg. 2 of 30

A. Introduction

1. Unpacking

All sensors are suitably packaged to prevent damage during shipping. If external damage is noted upon receipt of the package, please contact

shipping company

to the device once it has left the manufacturing premises.

Open the package from the top, taking care not to cut too deeply into the package. Remove all the documentation and contents. Take care to remove all the items and check them against the packing slip. The products should also be checked for any concealed shipping damage. If any shortages or damage is noted, please contact the shipping company and/or Dwyer Instruments to resolve the problem.

Sensor, Calibration Certificate & Instruction Manual

the

immediately. Dwyer Instruments is not liable for damage

Typical Contents of Box

(Model TFP-LP shown, other models similar).

2. Product Overview and Principle of Operation

CAUTION: Take care not to

drop

your sensor or subject it to

sudden impact. Read the installation section of this manual before providing power or tubing connections to the unit. Any damage caused by improper installation or careless handling will not be repaired under warranty (see limited warranty on page 30 for

more details).

TF Series Flow Meters and Flow Sensors for liquids are capable of measuring flows as low as 13-100 ml/min or as high as 1.0-10.0 l/min. Highly repeatable results are achieved using a patented Pelton Turbine

F-20-TF-L, pg. 3 of 30

Wheel flow sensor design. This proven design minimizes zero drift while maintaining fast response and linear outputs with virtually no maintenance.

Patented technology measures flow using a miniature turbine wheel similar in size to a U.S. dime (16 mm diameter, 0.75 mm thick). The micro-turbine wheel is supported on a very small sapphire shaft that is held in position by two sapphire bearings. The micro-turbine assembly is so light that it virtually floats in the liquid. This relieves force on the bearings and almost eliminates wear.

As flow passes through the flow sensor, a precision machined nozzle directs the fluid onto the very small teeth of the micro-turbine wheel. This causes the wheel to spin at a speed proportional to the flow rate.

The micro-turbine wheel has alternating white and black sections evenly spaced on one side of the wheel. An infrared light beam is directed onto the wheel. As the wheel rotates the infrared beam is reflected off each white section. The reflected beam is detected by a phototransistor that converts the reflections into electrical pulses. As the wheel spins faster the pulse rate increases. Processing circuitry provides analog and/or pulse output that are linearly proportional to the flow rate

When the wheel stops (under zero flow conditions), no pulses are generated. Consequently, zero drift is not possible and zero adjustments are never required.

Every unit is supplied with a calibration certificate detailing the results obtained during calibration. Units are calibrated using deionized water as the reference media. Flowing liquids with different specific gravities or viscosities may affect the calibration.

F-20-TF-L, pg. 4 of 30

B. Installation

CAUTION: Do not flow any gas through a liquid flow sensor.

This may damage the micro-turbine assembly and void the warranty. Do not exceed the pressure, temperature or power operating ranges detailed in the Specifications section of this manual. Dwyer Instruments shall not be liable for any damage or

injury caused by incorrect operation of their products.

1. General Considerations

It is recommended that a safety shut-off valve be installed upstream of (before) the sensor.

All wetted parts should be checked for compatibility with the liquid to be used. If there are any incompatibilities e.g. highly corrosive liquid, then the unit may be damaged or fail prematurely. Such damage will not be repaired under warranty.

Units should be installed in a clean, dry environment with an ambient temperature that is as stable as possible. Avoid areas with strong magnetic fields, strong air flows or excessive vibration.

If the liquid to be used may contain particles larger than 25 microns then a filter (25 microns or less) should be installed upstream of (before) the unit.

The required differential press (or pressure drop across the unit) decreases exponentially with decreases in flow rate.

Pressure Drop vs. Percentage of the Full Scale

Rated Flow (may vary ±10% of indicated psid)

0.8

Delta P psid

10 20 30 40 50 60 70 80 90 100

% o f rate d flow

100-1000 ml/min Units All Other Ranges

0.7

0.6

0.5

0.4

0.3

0.2

0.1

Delta P Bar

F-20-TF-L, pg. 5 of 30

To calculate the pressure drop at a certain flow rate use the formula

PD = (YourFlow / MaxFlow)2 x PDmax

PD = Pressure drop at YourFlow. YourFLow = flow rate (ml/min or l/min) MaxFlow = 100% rated flow for the sensor (in same units as YourFlow)

max = Pressure drop at 100% rated flow (see chart above)

If the pressure available for the flow sensor is BELOW the pressure drop at the required flow then flow through the unit will not be possible.

For example: You have a sensor with a 50-500ml/min flow range and want to know the pressure drop (or minimum differential pressure required) at 300ml/min. According to the chart above, the pressure drop at 100% of flow is approx 10psi. Using the formula above:

PD = (300 / 500)2 x 10 = 3.6 psid

Therefore, at 300ml/min the minimum required differential pressure for this unit is 3.6 psid. This means that if the available pressure is below 3.6psid then flow through the unit may not be possible.

Pressure drop through a system is cumulative. If the total pressure drop across all the components in a system exceeds the minimum pressure available then flow will not be possible.

For example: A system has a pressure of 30-40psi. There are several components and the sum of their pressure drops at the required flow rate is 32psid. If the system is operating at 30psi flow would not be possible as the total of the pressure drops would be greater than the pressure available. The system will only operate if the system pressure is above 32psi.

If there is any possibility that there may be bubbles or entrapped gas in the system then the outlet tubing should be elevated above the inlet port. This will enable any gas that may become entrapped in the unit to escape (see section C2 for details of how to remove entrapped air or gas).

2. Mounting the Flow Sensor or Flow Meter.

The TF Series of Flow Sensors and Flow Meters have no particular installation requirements so may be mounted in any convenient position.

It is recommended that units be fixed to a suitable substrate with #4 screws using the two mounting holes provided.

F-20-TF-L, pg. 6 of 30

Mounting The Sensor

(Mounting hardware not included with sensor)

3. Tubing Connections

CAUTION: DO NOT FLOW ANY GAS THROUGH A LIQUID

FLOW SENSOR OR FLOW METER. THIS WILL DAMAGE THE MICRO-TURBINE ASSEMBLY AND VOID THE WARRANTY.

All tubing must be clean and without crimps, burrs or scratches.

Only use the fittings factory installed on the unit. If the fittings are removed the calibration of the unit may be effected and leaking may occur. If different fittings are required please contact Dwyer Customer Service for assistance.

When connecting the sensor to the tubing a wrench should be used to stop the fitting rotating in the sensor body. Take care not to over tighten the fittings or leaking may occur.

Connecting and tightening the Fittings

F-20-TF-L, pg. 7 of 30

CAUTION: DO NOT over tighten the fittings into the sensor body. Excessive force may damage the sensor body and will NOT be repaired under warranty.

The flow direction for the unit is clearly marked on the label. Do not reverse the flow direction or the unit will not function.

Close Up of Label Showing Flow Directions

(All models similar)

For the best results, precautions should be taken to minimize the amount of turbulence in the flow stream. Avoid valves, fittings, curves in the tube, and changes in the internal diameter or any other restrictions close to the inlet of the sensor. The tubing ID should be as large as possible and preferably not smaller than the ID of the fittings installed on the sensor.

For 0.2-2.0 L/min units a 10 cm straight length of tube before the sensor is recommended. For higher flow range units (0.5-5.0 L/min and 1.0-10.0 L/min), a 20 cm straight length of tubing before the sensor is recommended. If this is not possible it is recommended that straight lengths between all connections on the inlet side of the sensor are as long as possible and 90 degree fittings (with a large enough ID) are used instead of curves in the tubing.

4. Electrical Connections

CAUTION: Incorrect wiring may cause severe damage to the

unit. Applying an AC voltage (115VAC or 230VAC) directly to the unit will cause damage. Read the following instructions carefully before making any connections.

F-20-TF-L, pg. 8 of 30

a) Overview

The TFP-LP and TFM-LP series provide a 0-5VDC and pulse output proportional to the flow rate. This output may be connected to a display, data acquisition system or voltmeter.

The TFP-LI and TFM-LI feature an integral display that provides a local flow reading. These units also have a 0-5VDC analog output available. If required, this may be connected to another display, data acquisition system or voltmeter.

A stable D.C. power supply is required to operate the unit. The voltage and current requirements depend on the configuration of the unit. Full details may be found in the Specifications section of this manual.

Connecting wires should be as short as possible to avoid voltage drops. Twisted 2 pair conductor cable should be used if the length of the power wires is to be longer than 1 meter.

Units are supplied with an integral 4 pin connector. Connections to the unit are made using a mating cable assembly or power adapter package as detailed in the following sections (parts 4.b to 4.e of this manual). A connector pin and wire color cross reference may also be found in Appendix G (Page 27) of this manual.

b) Connecting the Cable Assembly

The connector on the end of the cable assembly should be pushed into the mating socket on the sensor taking care to ensure that it is the correct way up.

Connecting the Cable Assembly

(All models similar)

Electrical Connections are made to the cable assembly as detailed in the following sections.

F-20-TF-L, pg. 9 of 30

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