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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 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
2 1818051-02
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
4 1818051-02
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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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