Water Transducer

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Alfa Laval Marine & Power

WT 200/MT 50

Water Transducer

P002172A

Product No.

Printed

Book No.

1764760-801764760-811764760-821764760-831764760-841764760-85

Nov 2000

1818051-02 V2


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Alfa Laval reserve the right to make changes at any time withoutprior notice.

Any comments regarding possible errors and omissions orsuggestions for improvement of this publication would begratefully appreciated.

Copies of this publication can be ordered from your local AlfaLaval company.

Published by: Alfa Laval Marine & Power ABSE - 147 80 TumbaSweden

Copyright Alfa Laval Separation AB 2000.


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1818051-02

Contents

1 Function Description 1

1.1 Application 1

1.2 Design 1

1.3 Working Principle 1

2 Fault Finding 3

3 Maintenance 53.1 Cleaning the

Water Transducer 5

3.2 Replacing the Oscillator Unit 5

3.3 Checking theTransducer Value 6

4 Technical Data 7

4.1 Specification 7

4.2 Dimensions 8

5 Installation 9

5.1 Specifications 9

5.1.1 Location 9

5.1.2 Connection 9

5.1.3 Oscillator Box 9

6 Spare Parts 11


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1818051-02


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1818051-02 1

1 Function Description

1.1 Application

The WT 200/MT 50 water transducer is used

to monitor the water content in the processed

oil leaving a separator. The signal from the

water transducer is processed in the EPC

program unit, and appropriate action is

initiated, depending on the status in the

separation system.

1.2 Design

The water transducer consists a housing (5), a

concentric electrode (4), and a electrical

conn.box fitted to the housing. The box

contains an oscillator unit (2), a test circuit

board (1) and connections. The electrode is

insulated (3) from the housing and form a

circular capacitor. The transducer is mounted

in the oil pipe by flanges on the outer pipe,

and the full oil flow passes through the

capacitor.

1.3 Working Principle

The EPC supplies direct current (DC) to the

transducer. The oscillator converts the DC to a

high frequency alternating current (AC) which

is fed to the capacitor. Changes of capacitance

are detected and continuously transmitted toand interpreted by the EPC.

G019892A

1 Test circuit board2 Oscillator unit3 Insulators4 Electrode5 Transducer housing


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1 Function Description WT 200/MT 50

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The capacitance varies with the dielectric

constant of the liquid flowing through it. As

the water content in the oil increases, so does

the dielectric constant, and consequently its

capacitance.

There is a large difference between the

dielectric constant of water and oil. Hence

fluctuations in dielectric constant is a very

sensitive measure of changes in water content.

Both free and emulsified water contamination

is measured.


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2 Fault Finding

The EPC monitor the signal from the

transducer and gives alarm if there is a fault.

The fault finding is described in the section

Alarms and Fault Finding.


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2 Fault Finding WT 200/MT 50

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1818051-02 5

3 Maintenance

3.1 Cleaning the Water

Transducer

Dirt that has klogged between the inner and

outer pipe of the transducer may cause high

transducer value. If this happens, the

transducer has to be opened and cleaned.

1. Remove the electrode and electrical

connection box carefully from the pipe

system, preferably whithout disconnecting

the signal cable.

2. Clean the electrode and housing with

suitable detergent. After cleaning, removeany detergent with a damp cloth.

3. Before remounting the transducer, check

that no solids or other matter that can

cause short-circuit is stuck between the

transducer electrode and housing.

3.2 Replacing the

Oscillator Unit

The oscillator unit must be replaced when the

EPC detects a transducer fault and the voltage

test indicates faulty oscillator unit (see Alarms

and Fault Finding).

The oscillator unit with test circuit board are

replaced together as a complete unit.

P002171A

P002161A


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3 Maintenance WT 200/MT 50

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1. Disconnect the cables from the oscillator

terminals.

2. Loosen the centre screw and lift out the

complete unit.3. Assemble the complete oscillator spare

part unit and connect the cables to the

terminals.

4. Fill in the report form and return it with

the faulty oscillator unit to Alfa Laval.

3.3 Checking theTransducer Value

If the transducer is connected to an EPC-400,

or an EPC-50, the EPC can display the

transducer value. The value should be 120

130 for the transducer in air.


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4 Technical Data

4.1 Specification

Body

Media Mineral oil

Media temperature Max. 110C

Max. working pressure 600 kPa (6 bar)

Max. testing pressure 1000 kPa (10 bar)

Material

Body Pressure vessel steel

Electrode Stainless steel

O-rings Viton

Insulators PTFE

Flanges according to DIN 2633 and JIS B2213

Ref. 1764185 Rev. 3

Connection box

Ambient temperature Max. 70C

Enclosure IP 65

Material Aluminium

Cable connection Pr 22.5/Pg 16 for cable 12.5 15.0

(WT 200)

Pr 18.6/Pg 11 for cable 6.0 9.0

(MT 50)

Weight 6 kg DN25

7 kg DN40

Ref. 1764185 Rev. 3


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4 Technical Data WT 200/MT 50

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4.2 Dimensions

Article No. DN A(mm) B(mm) C(mm) Oscillator

1764760-80 DN 40 / DIN 150 110 18 1 MHz

1764760-81 DN 40 / JIS 140 105 19 1 MHz

1764760-82 DN 25 / DIN 125 85 14 1 MHz

1764760-83 DN 25 / JIS 125 90 19 1 MHz

1764760-84 DN 25 / DIN 115 85 14 1 MHz

1764760-85 DN 40 / DIN 150 110 18 1 MHz

X006913A

Ref. 1764185 Rev. 3


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5 Installation

5.1 Specifications

5.1.1 Location

The transducer can be mounted in any

position.

5.1.2 Connection

The cable must be shielded.

Connections to the terminals must be in

accordance with the interconnection

diagram for the appropriate system.

5.1.3 Oscillator Box

Make sure the oscillator box is firmly

attached to the transducer bracket.

NOTE

If the specifications are not followed,

Alfa Laval can not be held

responsible for any malfunction

related to the installation.

MT

G019893A


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5 Installation WT 200/MT 50

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6 Spare Parts

Item Qty Article No. Description Remarks

1 223404-70 O-ring1, 2

1. Included in Spare parts kit 1765216-81

7.3x2.4

2 260104-19 O-ring1, 2 44.3x3.0

3 31830-6376-1 Oscillator unit, complete

Spare Parts Kit 1For 1764760-81 to

1764760-83

3 31830-6406-1 Oscillator unit, complete

Spare Parts Kit 2

2. Included in Spare parts kit 1765216-82

For 1764760-84 to1764760-85

X007181A


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6 Spare Parts WT 200/MT 50

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Documents

Water Transducer