MICHELL Instruments 97099 Easidew I.S Dew Point Transmitter User Manual Product Information Product Usage Instructions FAQ
- June 1, 2024
- MICHELL Instruments
Table of Contents
- 97099 Easidew I.S Dew Point Transmitter
- Product Information
- Specifications
- Features
- Product Usage Instructions
- 1. Introduction
- 2. Operation
- 3. Good Measurement Practice
- 4. Maintenance
- 5. O-Ring Replacement
- 6. Hazardous Area Certification
- FAQ
- Q: How often should I replace the O-Ring?
- Q: Where can I find Michell Instruments’ contact
97099 Easidew I.S Dew Point Transmitter
Product Information
Specifications
Product Name: Easidew I.S. Dew-Point
Transmitter
Order Code: 97099
Issue: 16.8, April 2024
Features
- Measurement of dew point
- Good measurement practice guidelines
- Maintenance instructions including O-Ring replacement
- Technical specifications for hazardous area certification
Product Usage Instructions
1. Introduction
The Easidew I.S. Dew-Point Transmitter is designed for accurate
measurement of dew point levels in various environments.
2. Operation
Follow the guidelines provided in the user manual to set up and
operate the transmitter effectively.
3. Good Measurement Practice
Ensure proper calibration and maintenance to achieve accurate
and reliable measurements.
4. Maintenance
Regular maintenance is essential for optimal performance. Refer
to the manual for detailed instructions on O-Ring replacement and
other maintenance tasks.
5. O-Ring Replacement
When replacing the O-Ring, make sure to use the specified
replacement part and follow the step-by-step instructions provided
in the manual.
6. Hazardous Area Certification
Refer to the technical specifications in Appendix C for
information on hazardous area certification and compliance with
safety standards.
FAQ
Q: How often should I replace the O-Ring?
A: It is recommended to replace the O-Ring during routine
maintenance or if signs of wear or damage are observed.
Q: Where can I find Michell Instruments’ contact
information?
A: For Michell Instruments’ contact information, visit
www.michell.com.
Easidew I.S. Dew-Point Transmitter
User Manual
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97099 Issue 16.8 April 2024
Please fill out the form(s) below for each instrument that has been purchased.
Use this information when contacting Michell Instruments for service purposes.
Product Name Order Code Serial Number Invoice Date Installation Location Tag
Number
Product Name Order Code Serial Number Invoice Date Installation Location Tag
Number
Product Name Order Code Serial Number Invoice Date Installation Location Tag
Number
Easidew I.S.
For Michell Instruments’ contact information please go to www.michell.com
© 2024 Michell Instruments This document is the property of Michell
Instruments Ltd and may not be copied or otherwise reproduced, communicated in
any way to third parties, nor stored in any Data Processing System without the
express written authorization of Michell Instruments Ltd.
Easidew I.S. User Manual
Contents
Safety ………………………………………………………………………………………………………………..vi Electrical Safety
……………………………………………………………………………………………..vi Pressure
Safety………………………………………………………………………………………………vi Toxic Materials
……………………………………………………………………………………………….vi Repair and Maintenance
…………………………………………………………………………………..vi Calibration
…………………………………………………………………………………………………….vi Safety Conformity
…………………………………………………………………………………………..vi
Abbreviations ………………………………………………………………………………………………………vii Warnings
……………………………………………………………………………………………………………vii
1 INTRODUCTION ………………………………………………………………………………..VIII 1.1 Features
……………………………………………………………………………………………. viii
2 INSTALLATION ……………………………………………………………………………………..1 2.1 Unpacking the
Instrument……………………………………………………………………….. 1 2.2 Preparation of the Sensor Cable
……………………………………………………………….. 2 2.3 Cable Connection
………………………………………………………………………………….. 4 2.4 Electrical Schematic
……………………………………………………………………………….. 4 2.4.1 Electrical Boundaries
…………………………………………………………………………. 5 2.5 Transmitter
Mounting……………………………………………………………………………… 5 2.5.1 Transmitter Mounting – Sample
Block (Optional) ………………………………………. 6 2.5.2 Transmitter Mounting – Direct
Pipeline Connection ……………………………………. 7 2.5.3 Transmitter Mounting – With
Additional Process Connection Adapter ……………. 8
3 OPERATION …………………………………………………………………………………………9
4 GOOD MEASUREMENT PRACTICE ……………………………………………………………10
5 MAINTENANCE ……………………………………………………………………………………13 5.1 O-Ring Replacement
…………………………………………………………………………….. 14
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Figures
Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure
9 Figure 10 Figure 11 Figure 12 Figure 13 Figure 14 Figure 15 Figure 16 Figure
17
DIN43650 Transmitter Unpacking Method …………………………………………….2 Connector Terminal Block Removal ……………………………………………………..3 Bare Wires …………………………………………………………………………………….3 Crimped Wires ……………………………………………………………………………….3 Cut to 5mm …………………………………………………………………………………..4 Connection to Connector Terminal Block……………………………………………….4 Wiring Connections………………………………………………………………………….4 Connector Installation………………………………………………………………………5 Electrical Connections ………………………………………………………………………5 Transmitter Mounting……………………………………………………………………….7 Transmitter Mounting – Pipe or Duct…………………………………………………….8 Transmitter Mounting with Adapter …………………………………………………….9 Installation Location ………………………………………………………………………10 Indication of Dead Space ………………………………………………………………..10 Material Permeability Comparison ……………………………………………………..11 Replacement of HDPE Guard ……………………………………………………………14 Dimensions …………………………………………………………………………………18
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Easidew I.S. User Manual
Appendices
Appendix A Appendix B Appendix C
Appendix D Appendix E
Technical Specifications ………………………………………………………………….. 17
A.1
Dimensions ……………………………………………………………………… 18
System Drawings…………………………………………………………………………… 20
B.1
Baseefa Approved System Drawing ……………………………………….. 20
B.2
QPS Approved System Drawing…………………………………………….. 21
Hazardous Area Certification ……………………………………………………………. 23
C.1
ATEX / UKCA ……………………………………………………………………. 23
C.2
IECEx …………………………………………………………………………….. 23
C.3
North American (cQPSus)……………………………………………………. 23
C.4
Terminal Parameters ………………………………………………………….. 24
C.5
Special Conditions of Use ……………………………………………………. 24
C.6
Maintenance and Installation ……………………………………………….. 24
Quality, Recycling & Warranty Information…………………………………………… 26
Return Document & Decontamination Declaration…………………………………. 28
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Safety
The manufacturer has designed this equipment to be safe when operated using
the procedures detailed in this manual. The user must not use this equipment
for any other purpose than that stated. Do not apply values greater than the
maximum value stated.
This manual contains operating and safety instructions, which must be followed
to ensure the safe operation and to maintain the equipment in a safe
condition. The safety instructions are either warnings or cautions issued to
protect the user and the equipment from injury or damage. Use competent
personnel using good engineering practice for all procedures in this manual.
Electrical Safety
The instrument is designed to be completely safe when used with options and
accessories supplied by the manufacturer for use with the instrument.
Pressure Safety
DO NOT permit pressures greater than the safe working pressure to be applied
to the instrument. The specified safe working pressure is 52.5 MPa (525
barg/7614 psig). Refer to the Technical Specifications in Appendix A.
Toxic Materials
The use of hazardous materials in the construction of this instrument has been
minimized. During normal operation it is not possible for the user to come
into contact with any hazardous substance which might be employed in the
construction of the instrument. Care should, however, be exercised during
maintenance and the disposal of certain parts.
Repair and Maintenance
The instrument must be maintained either by the manufacturer or an accredited
service agent. Refer to www.michell.com for details of Michell Instruments’
worldwide offices contact information.
Calibration
The recommended calibration interval for this instrument is 12 months unless
it is to be used in a mission-critical application or in a dirty or
contaminated environment in which case the calibration interval should be
reduced accordingly. The instrument should be returned to the manufacturer,
Michell Instruments Ltd., or one of their accredited service agents for re-
calibration.
Safety Conformity
This product meets the essential protection requirements of the relevant UK,
EU and US standards and directives. Further details of applied standards may
be found in the Technical Specifications in Appendix A.
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Easidew I.S. User Manual
Abbreviations
The following abbreviations are used in this manual:
barg °C °F DC dp fps ft-lbs g lbs/in µm m/sec mA max mm MPa Nl/min Nm oz ppmV psig RH scfh V ø ”
pressure unit (=100 kP or 0.987 atm) (bar gauge) degrees Celsius degrees Fahrenheit direct current dew point feet per second feet per pounds grams pounds per inch micrometer meters per second milliampere maximum millimetres megapascal normal liters per minute Newton meter ounces parts per million by volume pounds per square inch relative humidity standard cubic feet per hour Volts Ohms diameter inch(es)
Warnings
The following general warning listed below is applicable to this instrument.
It is repeated in the text in the appropriate locations.
Where this hazard warning symbol appears in the following sections it is used
to indicate areas where potentially hazardous
operations need to be carried out.
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INTRODUCTION
1
INTRODUCTION
The Easidew I.S. dew-point transmitter has been manufactured, tested and calibrated to the highest available standards and should be in perfect working order, ready for installation into a gas measurement application. If, after reading this manual, there are any questions about the instrument or how to install and operate it, please contact a Michell representative. Refer to www.michell.com for details of Michell Instruments’ worldwide offices contact information.
This manual covers the following Easidew I.S. (Intrinsically Safe) dew-point products:
Easidew I.S. with G 1/2″ BSP thread Easidew I.S. with 3/4″ UNF thread Easidew I.S. with 5/8″ UNF thread
1.1 Features
The Easidew I.S. dew-point transmitter is a continuous, on-line, 4…20 mA
transmitter for the measurement of dew-point temperature or moisture content
in air and other non-corrosive gases. It is designed specifically for use
within Zone 0, 1 and 2 hazardous areas.
The key features are:
· IECEx, QPS, ATEX, UKCA certified transmitter for use in hazardous areas ·
G1/2″ BSP, 3/4″ or 5/8″ UNF process connection · Dew-point or ppmV moisture
content · 2-wire loop powered connection · Rugged 316 stainless steel IP66
construction · Measurement ranges -100…+20°Cdp (-148…+68°Fdp)
-110…+20°Cdp (-166…+68°Fdp)
· Accuracy ±2°Cdp · Calibration Certificate (NPL, NIST)
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INSTALLATION
Easidew I.S. User Manual
2
INSTALLATION
Any leak/pressure test must be conducted using cylinder nitrogen (>=99.995%
purity) regulated to the required pressure (not exceeding the maximum
operating pressure of the sensor/system). Hydrostatic testing using water or
any
liquid is not permitted.
2.1 Unpacking the Transmitter
On removing the transmitter from the box, please check that all the following
standard components are included:
· Easidew Transmitter · Certificate of Calibration · Electrical Connector (DIN
43650 models only)
Easidew I.S.Dew-Point Range: – 100 / +20
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DIN43650 Transmitter Unpacking Method
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INSTALLATION
The Transmitter will also be supplied with a process seal, which will be
fitted to the unit. Depending on the version, this will either be a bonded
seal (5/8″ or G1/2″ thread versions) or an o-ring seal (3/4″ thread versions).
The transmitter sensing element is protected while in transit by a blue
plastic cover containing a small desiccant capsule. The cover should be
removed before operation but should be retained in case required for return
shipping.
Depending on the model, the transmitter may come with the electrical connector
fitted to protect the transmitter pins during transit. Keep the connector in a
safe place until ready to wire up the sensor.
2.2 Preparation of the Sensor Cable
The sensor cable is NOT supplied as standard. A cable can be obtained by
contacting your local distributor or Michell Instruments (see www.michell.com
for details).
The crimps supplied must be fitted onto any cable installed into the connector
in order to comply with Hazardous Area
Certification of the product.
If making a cable assembly it is important that the cable is correctly
terminated. See Figures 3 to 6.
Cable connection to the Easidew I.S. transmitter is made via the removable
connector. Removing the central screw enables the connector terminal block to
be removed from the outer housing by using a small screwdriver to prise it
clear.
O-ring and washer
Figure 2
Connector Terminal Block Removal
Caution: When removing the central screw ensure that the small sealing O-ring
and the washer are retained on the screw
and are present during re-installation.
NOTE: Figure 3 to Figure 6 shown below, should be followed in detail. The
crimps should be applied such that there is no possibility of a conductor
strand of a core becoming free (see Figure 4).
Michell Instruments
3
INSTALLATION
Easidew I.S. User Manual
Figure 3
Bare Wires
Figure 4
Crimped Wires
When the crimp is made it should have a minimum of 2 positions of crimping.
After the crimp is made it should be trimmed to a length of 5mm (see Figure
5). When the crimps
are installed into the connector terminal block ensure they are fully
inserted, as shown in Figure 6, before tightening the terminal clamping screw.
1
3
4
10
m m
2
Figure 5
Cut to 5mm
Figure 6
Connection to Connector Terminal Block
When all wire connections are made, ensure that there is a minimum clearance distance and a minimum creepage distance in air of 2mm (0.8″) between each terminal.
For the transmitter to work properly, and to achieve maximum performance, the sensor cable must be connected to the sensor connector as shown in the drawing below.
Note: The drawing below shows the identity of the connector terminals and wiring connections of the cable manufactured by Michell Instruments.
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INSTALLATION
GN
GREEN – 4-20 mA
RD
RED + POWER
BL
BLUE – SCREEN
SCALE 2:1
SHORT AS POSSIBLE
BRAID
GREEN
SIGNAL (SOURCE)
RED +POWER
1
3
BLUE
GND 24
VIEW ON REAR OF CONNECTOR
SCREEN
GREEN YELLOW
BLUE RED
BRAID
GREEN – 4-20 mA (SOURCE)
BLUE – SCREEN RED + POWER
Figure 7
Wiring Connections
Always connect the 4…20 mA return signal to a suitable load (see Figure 7)
before the power is applied. Without this
connection, the transmitter may be damaged if allowed to operate for prolonged
periods.
2.3 Cable Connection
When installing the connector, and to ensure that full ingress protection is
achieved, the securing screw (with the O-ring and washer) must be tightened to
a minimum torque setting of 3.4 Nm (2.5 ft-lbs). The sensor cable used must be
a minimum diameter of 4.6mm (0.2″).
O-ring and washer
Figure 8
Connector Installation
Michell Instruments
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INSTALLATION
Easidew I.S. User Manual
2.4 Electrical Schematic
NOTE: The screen/shield should be connected for maximum performance and to
avoid interference.
GALVANIC ISOLATION INTERFACE
HAZARDOUS AREA
DEW-POINT TRANSMITTER CERTIFICATION No’s: Baseefa06ATEX0330X IECEx BAS 06.0090X
TRANSMITTER VERSION TERMINAL NUMBER
EASIDEW I.S.
3
1
(+) (RETURN)
SAFE AREA
KFD2-STC4-Ex1 H
KFD0-CS-Ex2.50p
KFD2-CR-Ex1.20200
(+)
KFD2-CR-Ex1.30200
KFD0-CS-Ex1.50P
(-)
MTL5041
MTL5040
MTL5541
Figure 9
Electrical Connections
+ 4-20 mA
–
LOAD
+VS (20 – 35 V DC) VS –
2.5 Transmitter Mounting
Prior to installation of the transmitter, unscrew and remove the black, green or blue plastic cover and retain for future use. Take care to prevent any contamination of the sensor before installation (handle the transmitter by the main body only, avoiding contact with the sensor guard).
The Easidew I.S. can be mounted either into a flow-through sensor sampling block (optional) or directly into a pipe or duct. It can be operated at pressures of up to 52.5 MPa (525 barg/7614 psig) when fitted with the bonded seal or O-ring provided.
The recommended gas flow rate, when mounted in the optional sampling block, is 1 to 5 Nl/min (2.1 to 10.6 scfh). However, for direct insertion applications, gas flow can be from static to 10 m/sec (32.8 fps).
NOTE: Pass the seal over the mounting thread and assemble into the sampling
location, by hand, using the wrench flats only. DO NOT grip and twist the
sensor cover when installing the sensor.
When installed, fully tighten using a wrench until the seal is fully compressed and to the following torque settings:
· G 1/2″ BSP · 3/4″ – 16 UNF · 5/8″ – 18 UNF
56 Nm (41.3 ft-lbs) 40 Nm (29.5 ft-lbs) 30.5 Nm (22.5 ft-lbs)
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2.5.1 Transmitter Mounting – Sample Block (Optional)
INSTALLATION
The following procedure must be carried out by a qualified installation engineer.
To mount the transmitter into the sensor block (preferred method), proceed as
follows, refer to Figure 12.
1. Ensure that the green, blue or black protective cover (2), and its
desiccant capsule (2a), have been removed from the tip of the transmitter.
2. G 1/2″ and 5/8″ Versions – Ensure that the bonded seal (2) is over the
threaded part of the transmitter body.
3/4″ Version – Ensure the O-ring is fully seated in the recess.
Under no circumstances should the sensor guard be handled with the fingers.
3. Screw the transmitter (1) into the sample block (3) and tighten to the
appropriate torque setting (see Section 2.5). NOTE: Use the flats of the
hexagonal nut and not the sensor body.
4. Fit the transmitter cable/connector assembly to the plug located on the
base of the transmitter and tighten the fixing screw (see Section 2.3).
2 2a 4 1
3 4
Figure 10 Transmitter Mounting
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INSTALLATION
Easidew I.S. User Manual
2.5.2 Transmitter Mounting – Direct Pipeline Connection The transmitter may be directly mounted into a pipe or duct as shown in Figure 13.
Caution: Do not mount the transmitter too close to the bottom of a bend where
any condensate in the pipeline might collect
and saturate the probe.
The pipe or duct will require a thread to match the transmitter body thread.
Fixing dimensions are shown in Figure 13. For circular pipework, to ensure the
integrity of a gas tight seal, a mounting flange will be required on the
pipework in order to provide a
flat surface to seal against.
The following procedure must be carried out by competent personnel.
1. Ensure that the protective cover (and its desiccant capsule) has been
removed from the tip of the transmitter.
WARNING: Under no circumstances should the sensor guard be handled with the
fingers.
2. G 1/2″ and 5/8″ Versions – Ensure that the bonded seal (2) is over the
threaded part of the transmitter body.
3/4″ Version – Ensure the O-ring is fully seated in the recess.
3. Screw the transmitter (3) into the pipe (1). Tighten enough to obtain a
gas tight seal. NOTE: Do not overtighten or the thread on the pipework may be
stripped.
1 23
23 14 15
4 16
5 17
6 18
7 18
8 9 10 11 20 21 22 23
Optional display (available on request)
1
48mm 2 3 (1.9″) Figure 11
Optional cable
(available on request)
Transmitter Mounting – Pipe or Duct
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INSTALLATION
2.5.3 Transmitter Mounting – With Additional Process Connection Adapter Applicable to the Easidew I.S. 5/8″ Version ONLY
!
The following procedure must be carried out by a qualified
installation engineer.
To mount the adapter into the transmitter, proceed as follows (see Figure 14) |
---|
1. Ensure that the protective cover (2), and its desiccant capsule (2a), have |
been removed from the tip of the transmitter. |
2. Fit the bonded seal (3) over the threaded part of the transmitter body. |
3. Screw the adapter (4) onto the threaded part of the transmitter and |
tighten to 30.5 Nm (22.5 ft-lbs). NOTE: Use the flats of the hexagonal nut and |
not the sensor body. |
!
WARNING: Under no circumstances should the sensor guard be handled with the fingers.
4. Screw the transmitter (1) with its seal (3) and adapter (4) into the sample block (see Section 2.5.1) or pipeline (see Section 2.5.2) and fully tighten using a wrench until the seal is fully compressed and to the following torque settings:
G 1/2″ BSP
56 Nm (41.3 ft-lbs)
3/4″ – 16 UNF `
40 Nm (29.5 ft-lbs)
1/2″ NPT
Use a suitable sealant e.g. PTFE tape using correct taping procedures
NOTE: Use the flats of the hexagonal nut and not the sensor body.
2
2a 1
4 3
Figure 12 Transmitter Mounting with Adapter
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OPERATION
Easidew I.S. User Manual
3
OPERATION
Operation is very simple, assuming the following installation techniques are adhered to:
Sampling Hints
Be Sure the Sample is Representative of the Gas Under Test:
The sample point should be as close to the critical measurement point as possible. Also, never sample from the bottom of a pipe as entrained liquids may be drawn into the sensing element.
Figure 13 Installation Location
Minimize Dead Space in Sample Lines:
Dead space causes moisture entrapment points, increased system response times
and measurement errors, as a result of the trapped moisture being released
into the passing sample gas and causing an increase in partial vapor pressure.
Figure 14
Deadspace
Indication of Dead Space
Remove Any Particulate Matter or Oil from the Gas Sample:
Particulate matter at high velocity can damage the sensing element and similarly, at low velocity, they may `blind’ the sensing element and reduce its response speed. If particulate, such as degraded desiccant, pipe scale or rust is present in the sample gas, use an in-line filter, as a minimum level of protection. For more demanding applications Michell Instruments offers a range of sampling systems (for more information contact www.michell.com).
Use High Quality Sample Tube and Fittings:
Michell Instruments recommends that, wherever possible, stainless steel tubing and fittings should be used. This is particularly important at low dew points since other materials have hygroscopic characteristics and adsorb moisture on the tube walls, slowing down response and, in extreme circumstances, giving false readings. For temporary applications, or where stainless steel tubing is not practical, use high quality thick walled PTFE tubing.
Position Transmitter away from Heat Source:
It is recommended, as good instrumentation practice, that the transmitter is
placed away from any heat source to avoid adsorption/desorption.
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GOOD MEASUREMENT PRACTICE
4
GOOD MEASUREMENT PRACTICE
Ensuring reliable and accurate moisture measurements requires the correct
sampling techniques, and a basic understanding of how water vapor behaves.
This section aims to explain the common mistakes and how to avoid them.
Sampling Materials Permeation and Diffusion
All materials are permeable to water vapor since water molecules are extremely
small compared to the structure of solids, even including the crystalline
structure of metals. The graph above demonstrates this effect by showing the
increase in dew point temperature seen when passing very dry gas through
tubing of different materials, where the exterior of the tubing is in the
ambient environment.
– 20
– 30
– 40
nylon
Dew point (ºC)
– 50
– 60
copper
polyethylene
– 70
nickel
PTFE
stainless steel
1
2
3
4
5
Time (hours)
Figure 15 Material Permeability Comparison
What this demonstrates is the dramatic effect that different tubing materials have on the humidity levels of a gas passed through them. Many materials contain moisture as part of their structure and when these are used as tubing for a dry gas the gas will absorb some of the moisture. Always avoid using organic materials (e.g. rubber), materials containing salts and anything which has small pores which can easily trap moisture (e.g. nylon).
As well as trapping moisture, porous sampling materials will also allow moisture vapor to ingress into the sample line from outside. This effect is called diffusion and occurs when the partial water vapor pressure exerted on the outside of a sample tube is higher than on the inside. Remember that water molecules are very small so in this case the term `porous’ applies to materials that would be considered impermeable in an everyday sense such as polyethylene or PTFE. Stainless steel and other metals can be considered as practically impermeable and it is surface finish of pipework that becomes the dominant factor. Electropolished stainless steel gives the best results over the shortest time period.
Take into consideration the gas you are measuring, and then choose materials appropriate to the results you need. The effects of diffusion or moisture trapped in materials are more significant when measuring very dry gases than when measuring a sample with a high level of humidity.
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GOOD MEASUREMENT PRACTICE
Easidew I.S. User Manual
Temperature and Pressure effects
As the temperature or pressure of the environment fluctuates, water molecules
are adsorbed and desorbed from the internal surfaces of the sample tubing,
causing small fluctuations in the measured dew point.
Adsorption is the adhesion of atoms, ions, or molecules from a gas, liquid, or
dissolved solid to the surface of a material, creating a film. The rate of
adsorption is increased at higher pressures and lower temperatures.
Desorption is the release of a substance from or through the surface of a
material. In constant environmental conditions, an adsorbed substance will
remain on a surface almost indefinitely. However, as the temperature rises, so
does the likelihood of desorption occurring.
Ensuring the temperature of the sampling components is kept at consistent
levels is important to prevent temperature fluctuation (i.e. through diurnal
changes) continually varying the rates of adsorption and desorption. This
effect will manifest through a measured value which increases during the day
(as desorption peaks), then decreasing at night as more moisture is adsorbed
into the sampling equipment.
If temperatures drop below the sample dew point, water may condense in sample
tubing and affect the accuracy of measurements.
Maintaining the temperature of the sample system tubing above the dew point of
the sample is vital to prevent condensation. Any condensation invalidates the
sampling process as it reduces the water vapor content of the gas being
measured. Condensed liquid can also alter the humidity elsewhere by dripping
or running to other locations where it may re-evaporate.
Although ambient pressure does not change drastically in a single location,
the gas sample pressure does need to be kept constant to avoid inconsistencies
introduced by adsorption or desorption. The integrity of all connections is
also an important consideration, especially when sampling low dew points at an
elevated pressure. If a small leak occurs in a high-pressure line, gas will
leak out; however, vortices at the leak point and a negative vapor pressure
differential will also allow water vapor to contaminate the flow.
Theoretically flow rate has no direct effect on the measured moisture content,
but in practice it can have unanticipated effects on response speed and
accuracy. An inadequate flow rate may:
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GOOD MEASUREMENT PRACTICE
· Accentuate adsorption and desorption effects on the gas passing through the
sampling system.
· Allow pockets of wet gas to remain undisturbed in a complex sampling system,
which will then gradually be released into the sample flow.
· Increase the chance of contamination from back diffusion. Ambient air that
is wetter than the sample can flow from the exhaust back into the system. A
longer exhaust tube can help alleviate this problem.
· Slow the response of the sensor to changes in moisture content.
An excessively high flow rate can:
· Introduce back pressure, causing slower response times and unpredictable
changes in dew point
· Result in a reduction in depression capabilities in chilled mirror
instruments by having a cooling effect on the mirror. This is most apparent
with gases that have a high thermal conductivity such as hydrogen and helium.
System design for fastest response times
The more complicated the sample system, the more areas there are for trapped
moisture to hide. The key pitfalls to look out for here are the length of the
sample tubing and dead volumes.
The sample point should always be as close as possible to the critical
measurement point to obtain a truly representative measurement. The length of
the sample line to the sensor or instrument should be as short as possible.
Interconnection points and valves trap moisture, so using the simplest
sampling arrangement possible will reduce the time it takes for the sample
system to dry out when purged with dry gas.
Over a long tubing run, water will inevitably migrate into any line, and the
effects of adsorption and desorption will become more apparent.
Dead volumes (areas which are not in a direct flow path) in sample lines, hold
onto water molecules which are slowly released into the passing gas. This
results in increased purge and response times, and wetter than expected
readings. Hygroscopic materials in filters, valves (e.g. rubber from pressure
regulators) or any other parts of the system can also trap moisture.
Plan your sampling system to ensure that the sample tap point and the
measurement point are as close as possible to avoid long runs of tubing and
dead volumes.
Filtration
All trace moisture measurement instruments and sensors are by their nature
sensitive devices. Many processes contain dust, dirt or liquid droplets.
Particulate filters are used for removing dirt, rust, scale and any other
solids that may be in a sample stream. For protection against liquids, a
coalescing or membrane filter should be used. The membrane provides protection
from liquid droplets and can even stop flow to the analyser completely when a
large slug of liquid is encountered, saving the sensor from potentially
irreparable damage.
Michell Instruments
13
MAINTENANCE
Easidew I.S. User Manual
5
MAINTENANCE
Calibration
Routine maintenance of the Easidew I.S. is confined to regular re-calibration
by exposure of the transmitter to sample gases of known moisture content to
ensure that the stated accuracy is maintained. Calibration services traceable
to the UK National Physical Laboratory (NPL) and the US National Institute of
Standards and Technology (NIST) are provided by Michell Instruments.
Michell Instruments offers a variety of re-calibration and service exchange schemes to suit specific needs. A Michell representative can provide detailed, custom advice (refer to www.michell.com for details of Michell Instruments’ worldwide offices contact information).
The following procedure must be carried out by a qualified installation
engineer.
Sensor Guard Replacement
The sensor is supplied with either a white HDPE or a stainless steel guard.
The method of replacement is the same for both types.
HDPE Guard
The HDPE guard provides <10m protection to the dew-point sensor. It is
designed to show any contamination and the guard should be changed if the
surface becomes discolored. When replacing the guard, care should be taken to
handle the guard by the bottom part only. Replacement guards (EA2-HDPE) a
pack of 10 can be obtained by contacting Michell Instruments
(www.michell.com) or your local distributor.
HANDLE,
USING
GLOVES, BY
BLACK PART
ONLY
M nstrIuCmeHnE
090 6 te r
I
Figure 16 Replacement of HDPE Guard
Stainless Steel Guard The stainless steel guard provides <80m protection to
the dew-point sensor. Please change the guard if contamination is apparent.
When replacing the guard, care should be taken to handle the guard by the
bottom part only. A replacement guard (SSG) can be obtained by contacting
Michell Instruments (www.michell.com) or your local distributor.
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97099 Issue 16.8, April 2024
Easidew I.S. User Manual
MAINTENANCE
Bonded Seal
If the installed bonded seal gets damaged or lost, a pack of 5 replacement
bonded seals (1/2-BS (for G 1/2 -BSP) or 5/8-BS (for 5/8″ -18 UNF)) can be
obtained by contacting Michell Instruments, or your local distributor.
5.1 O-Ring Replacement
If the installed O-ring gets damaged or lost, a pack of 5 replacement O-rings
(3/4OR (for 3/4″ – 16 UNF)) can be obtained by contacting Michell Instruments,
or your local distributor.
Do not touch the filter with bare hands
1. Identify the O-ring to be removed, as shown below.
BS116 (3/4″ x 3/32″) viton, 75 shore
2. Carefully slide tweezers, thin bladed screwdriver or a blunt needle under
the outer edge of the O-ring. NOTE: Take care not to scratch any of the
surfaces of the surrounding metal component.
3. Move the tool around the circumference to assist the extraction process.
Slide the O-ring clear of the thread and filter.
4. Make sure the groove has no scratches and is free from grease, dirt or debris. Slide the new O-ring over the filter and thread and into the groove. NOTE: Do not touch the filter with bare hands.
Michell Instruments
15
APPENDIX A
Easidew I.S. User Manual
Appendix A Technical Specifications
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97099 Issue 16.8, April 2024
Easidew I.S. User Manual
APPENDIX A
Appendix A Technical Specifications
Performance
Measurement Range (dew point) Accuracy (dew point) Repeatability Response Time Calibration
-100…+20°Cdp (-148…+68°Fdp) -110…+20°Cdp (-166…+68°Fdp) ±2°Cdp (±3.6°Fdp) 0.5°Cdp (0.9°Fdp) 5 mins to T95 (dry to wet) 13-point calibration with traceable 7-point calibration certificate
Electrical Specifications
Output Signal
Output
Analog Output Scaled Range
Supply Voltage Load Resistance Current Consumption Compliances
4…20 mA (2-wire connection current source) User-configurable over range
Dew point or moisture content for ppmV Dew point: -100…+20ºC (-148…+68ºF) OR
Moisture content in gas: 0 – 3000 ppmV Non-standard available upon request
12…28 V DC
Max 250 @ 12 V (500 @ 24 V)
20 mA max
CE & UKCA
Operating Specifications
Operating Temperature
Operating Pressure
Compensated Temperature Range: Storage Temperature: Flow Rate
-40…+60ºC (-40…+140ºF)
52.5 MPa (525 barg / 7614 psig) max Qualified over-pressure rating: (2 x
operating pressure) 90 MPa (900 barg / 13053 psig)
-20…+50°C (-4…+122ºF) NOTE: The transmitter accuracy statement is only valid for the temperature range: -20…+50°C (-4…+122ºF)
-40…+60ºC (-40…+140ºF)
1…5 Nl/min (2.1…10.6 scfh) mounted in standard sampling block 0…10 m/sec
(0…32.8 fps) direct insertion
Mechanical Specifications
Ingress Protection
Housing Material Dimensions
Sensor Guard
Process Connection & Material Weight Interchangeability Electrical Connection
Diagnostic Conditions (factory programmed)
IP66 in accordance with standard BS EN60529:1992 NEMA 4 in protection accordance with standard NEMA 250-2003
316 stainless steel
Transmitter plus connector: L=132mm x ø 45mm (5.19″ x ø 1.77″)
Standard: HDPE Guard < 10µm Optional: 316 stainless steel sintered guard < 80µm
G 1/2″ BSP; 3/4″ – 16 UNF; 5/8″ – 18 UNF Material – 316 stainless steel
150g (5.29oz)
Fully interchangeable transmitter
Hirschmann GDS series (DIN 4350-C)
Condition
Sensor fault Under-range dew point Over-range dew point
Output
23 mA 4 mA 20 mA
Michell Instruments
17
APPENDIX A
Easidew I.S. User Manual
Approved Galvanic Isolators
KFD0-CS-EX1.50P KFD0-CS-EX2.50P KFD2-STC4-EX1.H
Hazardous Area Certification
Certification Codes *
See Appendix C
- The end user has a responsibility to ensure that when installed in the Hazardous Area, the system is compliant with relevant local and international installation Standards for the use of equipment in explosive atmospheres.
A.1 Dimensions
SENSOR
132mm
G1/2″ BSP Bonded Seal
(5.19″) 46mm
(1.81″)
27mm
10mmø27mm
(0.39″) (1.06″)
(1.06″) A/F
G1/2″ BSP
10mm (0.39″)
ø28.65 x 2.61mm (ø1.12 x 0.10″)
G1/2″ Process Connection
45mm (1.77″)
SENSOR
132mm
3/4″ – 16 UNF O-Ring
(5.19″) 46mm
(1.81″)
27mm
10mmø27mm
(0.39″) (1.06″)
(1.06″) A/F
3/4″ UNF
10mm (0.39″)
ø18.72 x 2.62mm (ø0.75 x 0.09″)
3/4″ Process Connection
45mm (1.77″)
SENSOR
132mm
5/8″ – 18 UNF Bonded Seal
(5.19″) 46mm
(1.81″)
10mmø27mm
(0.39″) (1.06″)
27mm (1.06″)
A/F
5/8″ UNF
10mm
(0.39″)
ø25.4 x 2mm (ø1 x 0.07″)
5/8″ Process Connection
Figure 17 Dimensions
45mm (1.77″)
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97099 Issue 16.8, April 2024
Easidew I.S. User Manual
APPENDIX B
Appendix B System Drawings
Michell Instruments
19
APPENDIX B
Appendix B System Drawings B.1 Baseefa Approved System Drawing
Easidew I.S. User Manual
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97099 Issue 16.8, April 2024
Easidew I.S. User Manual
B.2 QPS Approved System Drawing
Michell Instruments
THE CAPACITANCE AND EITHER THE INDUCTANCE OR THE INDUCTANCE TO RESISTANCE RATIO (L/R) OF THE CABLE MUST NOT EXCEED THE FOLLOWING VALUES:
GROUP
AB C D
CAPACITANCE ( F)
46 nF 613 nF 2.11F
INDUCTANCE
OR
(mH)
4.2mH 12.6 mH
33mH
L/R RATIO ( H/ohm)
54 H/ 217 H/ 435 H/
THE ISOLATION OF THE SIGNAL WIRES WITH THE EASIDEW DISCONNECTED, MUST BE ABLE
TO WITHSTAND A 500V AC INSULATION TEST.
THE INSTALLATION MUST COMPLY WITH THE INSTALLATION PRACTICES OF THE COUNTRY OF
USE. i.e. ANSI/ISA RP12.6 (INSTALLATION OF INTRINSICALLY SAFE SYSTEMS FOR
HAZARDOUS [CLASSIFIED] LOCATIONS) AND THE NATIONAL ELECTRICAL CODE ANSI/NFPA
70.
THE CAPACITANCE AND THE INDUCTANCE OF THE HAZARDOUS AREA CABLES MUST NOT
EXCEED THE VALUES GIVEN IN TABLE 1
NON-HAZARDOUS LOCATION
LOAD
+VS (20 TO 35V DC) VS –
Approved 4/20mA + Barrier
(+)
(-)
HAZARDOUS LOCATION CLASS I, DIVISION 1, Gps A,B,C, & D CLASS I, ZONE 0 AEx ia IIC T4 Ga Ex ia IIC T4 Ga Tamb+70°C
TRANSMITTER VERSION
TERMINAL NUMBER
EASIDEW PRO I.S.
EASIDEW I.S. PURA I.S.
(+)
2
3
(RETURN)
4
1
EASIDEW DEWPOINT TRANSMITTER
Vmax = 28V Imax = 93mA Pmax = 820mW Ci = 37nf Li = 0
Intrinsically safe(entity), Class 1, Div1, Group A,B,C,D Hazardous Location Installations
- Control room equipment may not use or generate over 250Vrms. 2) Wire all
circuits for power supply per CEC Part 1. 3) Use only entity approved safety
barrier or other associated
equipment that satisfy the following conditions:
< < > > VCG V max, ISC IMAX, Ca Ci + CCABLE, La Li + LCABLE
Transmitter entity parameters are as follows:
V max < 2.8Vdc I max < 93mA Ci = 37nF Li = 0uH - WARNING: SUBSTITUTION OF COMPONENTS MAY IMPARE INTRINSIC SAFETY. 5) Ex ia is defined as Intrinsically Safe.
Type
Certificate Number
Interface
Connection to Easidew I.S.
Isolated Repeater
BAS98ATEX7343
UL Canada E106378CUL
KFD0-CS-Ex1.50P
Pin 1 (+) Pin 2 (-)
Dual Isolated Repeater
BAS98ATEX7343
UL Canada E106378CUL
KFD0-CS-Ex2.50P
Channel 1 – Pin 1 (+) Channel 1 – Pin 2 (-) Channel 2 – Pin 4 (+) Channel 2 – Pin 5 (-)
Transmitter Supply BAS00ATEX7164 KFD2-CR-Ex1.20200
Isolator
UL Canada E106378CUL
Pin 1 (+) Pin 3 (-)
Transmitter Supply Isolator
Smart Transmitter Power Supply
BAS00ATEX7164
UL Canada E106378CUL
BAS99ATEX7060
UL Canada E106378CUL
KFD2-CR-Ex1.30200 KFD2-STC4-Ex1.H
Pin 1 (+) Pin 3 (-)
Pin 1 (+) Pin 3 (-)
APPENDIX B
MICHELL INSTRUMENTS LTD. 01/11/05 DOF03
100mm 4 Inches
THIS DOCUMENT IS THE PROPERTY OF MICHELL INSTRUMENTS LTD. AND MUST NOT BE COPIED NOR DISCLOSED TO A THIRD PARTY WITHOUT THE CONSENT OF MICHELL INSTRUMENTS.
DRAWN
MSB
DATE 10/03/06
CHECKED DATE
APPROVED DATE
09
QPS
30/06/21 IMA
3rd ANGLE PROJECTION
MATERIAL
TOLERANCES: DIMENSIONS:
UNLESS OTHERWISE STATED
0 DEC. PLACE: ± 0.5 1 DEC. PLACE: ± 0.2
+0.1 HOLE Ø: -0.0
2 DEC. PLACE: ± 0.1 ANGLES: ±0.5°
FINISH
08 Pi increased 02/11/17 IMA
DRAWING
UNITS
SCALE
07
13395
16/12/13 IMA
mm NTS 06 11081
06/04/11 IMA
05 CERT ISS 15/06/09 IMA
04 CERT ISS 25/03/09 IMA
03 CERT ISS 16/06/08 IMA
ISSUE MOD. No.
DATE
SIGN
TITLE EASIDEW I.S. & EASIDEW PRO I.S.
DRAWING NUMBER
DEWPOINT TRANSMITTER
SYSTEM DRAWIN. QPS
USED ON
MICHELL INSTRUMENTS LTD. CAMBRIDGE ©
Ex90385QPS
SHEET 1 OF 1
A3
21
APPENDIX C
Easidew I.S. User Manual
Appendix C Hazardous Area Certification
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97099 Issue 16.8, April 2024
Easidew I.S. User Manual
APPENDIX C
Appendix C Hazardous Area Certification
The Easidew I.S is certified compliant to the ATEX Directive (2014/34/EU), the
IECEx scheme and SI 2016 No. 1107 UKCA product marking scheme for use within
Zone 0, 1 and 2 Hazardous Areas and has been assessed as being so by SGS FIMKO
Oy, Finland (Notified Body 0598) and SGS Baseefa UK (Approved Body 1180).
The Easidew I.S is certified compliant to the applicable North American
Standards (USA and Canada) for use within Class I, Division 1 and Class I,
Zone 0 Hazardous Locations and has been assessed as being so by QPS.
C.1 ATEX / UKCA
Certificate: Baseefa06ATEX0330X / BAS21UKEX0014X
Certification: II 1 G Ex ia IIC T4 Ga Tamb -20 °C…+70 °C
Standards: EN 60079-0:2012+A11:2013, EN 60079-11:2012
C.2 IECEx
Certificate: IECEx BAS 06.0009X
Certification: Ex ia IIC T4 Ga Tamb -20 °C…+70 °C
Standards: IEC 60079-0:2011, IEC 60079-11:2011
C.3 North American (cQPSus)
Certificate: LR1507-10
Certification: Class I, Division 1, Groups ABCD T4 Class I, Zone 0 AEx ia IIC
T4 Ga / Ex ia IIC T4 Ga Tamb +70 °C
Standards: UL 60079-0 7th ed., UL 60079-11 6th ed., FM 3600:2018, FM
3610:2018, UL 61010-1 3rd ed
CSA C22.2 No. 60079-0:19, CSA C22.2 No. 60079-11:14, CSA C22.2 No. 61010-1:12
These certificates can be viewed or downloaded from our website, at: www.ProcessSensing.com
Michell Instruments
23
APPENDIX C
Easidew I.S. User Manual
C.4 Terminal Parameters
Ui
= 28 V
li
= 93 mA
Pi
= 820 mW
Ci
= 37 nF
Li
= 0
C.5 Special Conditions of Use
1. The wiring connections to the free socket must be made via crimped
connectors in such a way that all the strands of the wire used are held
securely by the crimp.
2. The plastic plug and socket create a potential for electrostatic discharge
so must not be rubbed with a dry cloth or cleaned with solvents.
3. The Easidew I.S. Dew-Point Transmitter does not withstand the 500 V AC
insulation test to frame. This must be taken into account when installing the
equipment.
C.6 Maintenance and Installation
The Easidew I.S. must only be installed by suitably qualified personnel and in
accordance with the instructions provided and the terms of the applicable
product certificates.
Maintenance and servicing of the product must only be carried out by suitably
trained personnel or returned to an approved Michell Instruments Service
Center.
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97099 Issue 16.8, April 2024
Easidew I.S. User Manual
APPENDIX D
Appendix D
Quality, Recycling & Warranty Information
Michell Instruments
25
APPENDIX D
Easidew I.S. User Manual
Appendix D Quality, Recycling & Warranty Information
Michell Instruments is dedicated to complying to all relevant legislation and
directives. Full information can be found on our website at:
www.ProcessSensing.com/en-us/compliance
This page contains information on the following directives: · Anti-
Facilitation of Tax Evasion Policy · ATEX Directive · Calibration Facilities ·
Conflict Minerals · FCC Statement · Manufacturing Quality · Modern Slavery
Statement · Pressure Equipment Directive · REACH · RoHS · WEEE · Recycling
Policy · Warranty and Returns
This information is also available in PDF format.
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97099 Issue 16.8, April 2024
Easidew I.S. User Manual
APPENDIX E
Appendix E
Return Document & Decontamination Declaration
Michell Instruments
27
APPENDIX E
Easidew I.S. User Manual
Appendix E Return Document & Decontamination Declaration
Decontamination Certificate
IMPORTANT NOTE: Please complete this form prior to this instrument, or any
components, leaving your site and being returned to us, or, where applicable,
prior to any work being carried out by a Michell engineer at your site.
Instrument
Warranty Repair?
YES
Company Name Address
Serial Number
NO
Original PO #
Contact Name
Telephone # Reason for Return /Description of Fault:
E-mail address
Has this equipment been exposed (internally or externally) to any of the following? Please circle (YES/NO) as applicable and provide details below
Biohazards
YES
NO
Biological agents
YES
NO
Hazardous chemicals
YES
NO
Radioactive substances
YES
NO
Other hazards
YES
NO
Please provide details of any hazardous materials used with this equipment as indicated above (use continuation sheet if necessary)
Your method of cleaning/decontamination
Has the equipment been cleaned and decontaminated?
YES
NOT NECESSARY
Michell Instruments will not accept instruments that have been exposed to toxins, radio-activity or bio-hazardous materials. For most applications involving solvents, acidic, basic, flammable or toxic gases a simple purge with dry gas (dew point <-30°C) over 24 hours should be sufficient to decontaminate the unit prior to return. Work will not be carried out on any unit that does not have a completed decontamination declaration.
Decontamination Declaration
I declare that the information above is true and complete to the best of my knowledge, and it is safe for Michell personnel to service or repair the returned instrument.
Name (Print)
Position
Signature
Date
F0121, Issue 2, December 2011
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97099 Issue 16.8, April 2024
Easidew I.S. User Manual NOTES
Michell Instruments
29
www.ProcessSensing.com
References
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