Michell Instruments Easidew Portable HP User manual

Easidew Portable
High Pressure Version
User’s Manual
97120 Issue 2.3
October 2019

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© 2019 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 Portable HP
For Michell Instruments' contact information please go to
www.michell.com

Easidew Portable HP User’s Manual
iv 97120 Issue 2.3, October 2019
1 INTRODUCTION ................................................................................................1
2 INSTALLATION ..................................................................................................2
3 OPERATION ......................................................................................................4
3.1 General Operation .............................................................................................. 4
3.2 Measuring Dew Points Below -40°C (-40°F) .......................................................... 5
3.3 User Controls ..................................................................................................... 6
4 GOOD MEASUREMENT PRACTICE .......................................................................7
5 MAINTENANCE ................................................................................................10
5.1 Calibration ....................................................................................................... 10
5.2 Sensor / Battery Replacement ........................................................................... 10
5.3 Filter Cartridge Replacement ............................................................................. 12
5.4 Checking the Easidew Portable Electronics Calibration ......................................... 12
5.5 List of Spares ................................................................................................... 12
5.6 Troubleshooting ................................................................................................ 13
Contents
Safety ................................................................................................................................ v
Electrical Safety ........................................................................................................... v
Pressure Safety ............................................................................................................ v
Toxic Materials ............................................................................................................. v
Repair and Maintenance ............................................................................................... v
Calibration ................................................................................................................... v
Safety Conformity ........................................................................................................ v
Abbreviations ......................................................................................................................vi
Warnings ............................................................................................................................vi
Appendices
Appendix A Technical Specications ..............................................................................15
Appendix B Quality, Recycling & Warranty Information ...................................................17
Appendix C Decontamination Declaration ......................................................................19
Figures
Figure 1 Swagelok® Fitting Instructions .....................................................................3
Figure 2 User Controls .............................................................................................6
Figure 3 Material Permeability Comparison ................................................................7
Figure 4 2-Wire Connection - View Showing Rear of Connector Terminal Block ...........12

Easidew Portable HP User’s Manual
Michell Instruments v
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
qualied personnel and 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. The instrument is powered by an internally mounted
rechargeable battery. The input power supply voltage limits for the battery charger supplied with the
instrument are 90 to 264 V AC, 47/63 Hz.
NOTE: No battery charger unit other than that supplied with the instrument should be
used.
NOTE: Do not allow the battery to fully discharge.
Pressure Safety
DO NOT permit pressures greater than the safe working pressure to be applied to the instrument.
The specied safe working pressure is 300 barg (4350 psig). Refer to the Technical Specications 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 oces contact information.
Calibration
The recommended calibration interval for the Easidew Portable is one year, unless otherwise
specied by Michell Instruments Ltd. The instrument should be returned to the manufacturer, Michell
Instruments, or one of their accredited service agents for re-calibration (go to www.michell.com for
contact information).
Safety Conformity
This product meets the essential protection requirements of the relevant EU directives. Further
details of applied standards may be found in the product specication.

Easidew Portable HP User’s Manual
vi 97120 Issue 2.3, October 2019
Abbreviations
The following abbreviations are used in this manual:
AC alternating current
atm pressure unit (atmosphere)
barg pressure unit (=100 kP or 0.987 atm) gauge
°C degrees Celsius
°F degrees Fahrenheit
dp dew point
ft feet
kg kilogram
lb pound
mA milliampere
m meter
mm millimeter
MPa megapascal
Nl/min normal liters per minute
psig pound(s) per square inch (gauge)
scfh standard cubic feet per hour
μm micrometer
Ω ohm
V Volts
Warnings
The following general warnings listed below are applicable to this instrument. They are
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.

Easidew Portable HP User’s Manual
Michell Instruments 1
INTRODUCTION
1 INTRODUCTION
The Easidew Portable comprises an Easidew sensor tted into a sample block with an
integrated lter cartridge, and Swagelok® tube couplings on the gas inlet and outlet.
The measured dew point from the sensor is shown on the clear red LED display on the
front panel of the instrument.
The Easidew Portable can be supplied with either °C or °F dew-point measurement
units.
A 4-20 mA analog output is provided for connection to a chart recorder, data-logger or
computer system, so dew-point trends can be analyzed over time.
The electronics are housed in a rugged Peli case, providing NEMA 6 protection when the
lid is closed. The case is supplied with a lifetime guarantee.
The Easidew Portable is powered by a rechargeable NiMH battery pack, giving between
12 and 16 hours of measurement time from a full charge. The instrument is delivered
complete with a universal battery charger stored in the lid. It takes 16 hours to fully
charge the battery pack, during which time the instrument can be switched on or
o. The charger is suitable to connect power to the instrument indenitely, but it is
recommended to allow the battery pack to go through a full charge-discharge cycle at
least once per month.
All Michell Ceramic Moisture Sensors are subject to a 13-point calibration, where their
performance is characterized against a fundamental reference hygrometer. This process,
and subsequent quality testing, ensures that all sensors behave optimally before they
are used in the eld. A calibration certicate traceable to UK National Physical Laboratory
(NPL) and the US National Institute of Standards and Technology (NIST) is provided
from Michell Instruments' accredited laboratory. The certicate shows 7 points of the
13-point calibration.

Easidew Portable HP User’s Manual
297120 Issue 2.3, October 2019
INSTALLATION
2 INSTALLATION
On delivery, please check that all the following standard components are present in the
packing box:
• Easidew Portable
• Swagelok® 6mm metering valve
• Swagelok® 6mm tube port adaptor
• Battery charger
• Mains lead
• 3 pole ¼” jack plug (inside lid)
• Certicate of calibration
Before using the Easidew for the rst time it is recommended that the battery pack is
charged for a minimum of 12 hours.
The supplied Swagelok® port adaptor needs to be assembled before the metering valve
can be connected to the instrument. See below:
1. Slip the nut over the
machined ferrule end of
the port connector
2. Insert the port connector
into the end connection and
finger-tighten the nut
3. While holding the fitting
body steady, tighten the
nut one-quarter turn
Do not use the Swagelok gap inspection
gauge with machined ferrule ends.
!

Easidew Portable HP User’s Manual
Michell Instruments 3
INSTALLATION
NOTE: Connect the machined ferrule end before
connecting the tube adaptor end
4. Insert the tube adaptor until it rests firmly on
the shoulder of the Swagelok®tube fitting body.
Finger-tighten the nut.
5. Mark the nut at the 6 o’clock position. While holding
the fitting body steady, tighten the nut 1¼turns to the
9 o’clock position.
©2001-2010 Swagelok Company
September 2010, R4 MS-12-12
Figure 1 Swagelok® Fitting Instructions

Easidew Portable HP User’s Manual
497120 Issue 2.3, October 2019
OPERATION
3 OPERATION
!
Maximum operating pressure is 300 barg (4350 psig).
It is important that both the gas ttings and the Swagelok®
tube ttings are correctly tightened before use.
Failure to do so will aect the instrument's pressure rating.
3.1 General Operation
To operate the Easidew Portable, follow these instructions:
1. Ensure that both the gas ttings and the Swagelok® tube ttings are fully
tightened before use.
2. For measurement at line pressure, connect the supplied metering valve to
the outlet of the instrument. For measurement at atmospheric pressure,
connect the metering valve to the inlet.
3. Gas under test should be restricted to ow rates between 1 and 5 Nl/min
(2 and 10.6 scfh) and pressures from atmospheric to 30 MPa (300 barg
/ 4350 psig).
4. Connect the sample gas supply line to the instrument Gas In port.
5. Connect the sample gas vent line to the instrument Gas Out port.
6. Switch the instrument on. The display will begin to change as the sensor
responds to the applied dew point.
7. Allow the gas to ow until the display shows a stable reading. Typically
this would be around 15 to 30 minutes for spot checks at dew points of
-40°C (-40°F) and above.
8. Switch the unit o and disconnect the sample lines.
!Before disconnecting the Easidew Portable from the gas line
it is essential to vent the system to atmospheric pressure,
otherwise severe injury could result.
NOTE: Filters are essential for potentially dirty/contaminated gases – the
tted lter should be checked before and after use and replaced regularly, as
required.
NOTE: The High Pressure version features two gas ttings with 4mm orices
that give no restriction and are engraved with a number 1. Atmospheric or
line pressure measurement is achieved by changing the positioning of the
metering valve as per the General Operation instructions above.

Easidew Portable HP User’s Manual
Michell Instruments 5
OPERATION
3.2 Measuring Dew Points Below -40°C (-40°F)
Due to the signicantly lower levels of moisture present at dew points of this level, the
response times of the sensor will be signicantly increased. The table below oers an
approximate guide to the times taken for the instrument to stabilize at a given dew
point (from a starting point of 10°Cdp (50°Fdp) ambient):
Target Dew Point T100 Response Time
(mins)
°C °F
-30 -22 15
-40 -40 30
-50 -58 60
-60 -76 180
The Easidew sensor tted to the Easidew Portable is designed and calibrated to measure
dew points as low as -100°C (-148°F). However, due to the large internal volume of
the sample block, the hygroscopic nature of the built-in lter, and the potential of the
gas ttings to trap moisture at very low dew points, we recommend that the Easidew
Portable is not used to measure dew points below -60°C (-76°F). Suitable alternative
solutions in our range would be the Easidew Online, Pura xed installations, MDM300
Portable, or our cooled mirror range of instruments.

Easidew Portable HP User’s Manual
697120 Issue 2.3, October 2019
OPERATION
3.3 User Controls
°Cdp
Power Fuse
4-20
mA
O/P
Battery
Charger
To measure
at
line
pressure
atmospheric
pressure
Gas Out Gas In
2 1
21




o
-
EASIDEW Portable Hygrometer
Gas Out Gas In
Filter Fitted
2
13 4
5
6
7

 





Figure 2 User Controls
1Digital Display
Indicates the measured dew point in °C from -100 to +20 (-148
to +68°F).
Under certain conditions the following error messages may be
displayed:
ErrL = Sensor under range
ErrH = Sensor over range
Err I = Sensor fault or sensor disconnected
2Power Switch Switches the Easidew Portable ON or OFF.
3 Fuse
This 1A quick blow fuse provides protection for the display
electronics in the event of a fault with the charger or battery
pack. Another protection fuse is located on the display PCB.
4NiMH Battery
Pack
Located in the top right hand corner of the instrument, it can be
accessed by removing two screws (5). The battery pack can be
recharged using the supplied charger, via the battery-charging
socket.
The battery pack will charge if the instrument is switched ON or
OFF.
6Analog Output
Socket
The Easidew portable features an analog output socket that
provides a linear 4-20 mA current loop, scaled to -100 to +20°C
(-148 to +68°F) dew point. This allowed the instrument to be
connected to a chart recorder, data logger or PC to enable dew-
point trends to be analyzed over time.
7Gas Fittings
The Easidew Portable can be used for measurements at line
pressure (up to 300 barg (4350 psig)) or atmospheric pressure.
Swagelok® tube ttings are supplied for use with 6mm OD
stainless steel tube. There is a 32mm particulate lter (99.5%
removal of 0.1 micron particles) tted as standard under the
Gas In port position.

Easidew Portable HP User’s Manual
Michell Instruments 7
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 Diusion
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 eect by showing the increase in dew point
temperature seen when passing very dry gas through tubing of dierent materials,
where the exterior of the tubing is in the ambient environment.
- 20
- 30
- 40
- 50
- 60
- 70
12345
Time (hours)
Dew point (ºC)
nylon
copper
polyethylene
PTFE
nickel
stainless steel
Figure 3 Material Permeability Comparison
What this demonstrates is the dramatic eect that dierent 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 eect is called diusion 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 nish 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 eects of diusion or moisture trapped in materials are
more signicant when measuring very dry gases than when measuring a sample with a
high level of humidity.

Easidew Portable HP User’s Manual
897120 Issue 2.3, October 2019
GOOD MEASUREMENT PRACTICE
Temperature and Pressure eects
As the temperature or pressure of the environment uctuates, water molecules are
adsorbed and desorbed from the internal surfaces of the sample tubing, causing small
uctuations 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 lm. 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 indenitely. 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 uctuation (i.e. through diurnal changes) continually
varying the rates of adsorption and desorption. This eect 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 aect 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 dierential will also allow water vapor to
contaminate the ow.
Theoretically ow rate has no direct eect on the measured moisture content, but
in practice it can have unanticipated eects on response speed and accuracy. An
inadequate ow rate may:

Easidew Portable HP User’s Manual
Michell Instruments 9
GOOD MEASUREMENT PRACTICE
• Accentuate adsorption and desorption eects 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 ow.
• Increase the chance of contamination from back diusion. Ambient air
that is wetter than the sample can ow 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 ow 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 eect 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 eects of
adsorption and desorption will become more apparent.
Dead volumes (areas which are not in a direct ow 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 lters, 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 lters 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 lter should be used. The
membrane provides protection from liquid droplets and can even stop ow to the
analyser completely when a large slug of liquid is encountered, saving the sensor from
potentially irreparable damage.

Easidew Portable HP User’s Manual
10 97120 Issue 2.3, October 2019
MAINTENANCE
5 MAINTENANCE
Routine maintenance of the Easidew Portable is conned to regular re-calibration of the
internal, removable Easidew sensor and replacement of the lter cartridge.
5.1 Calibration
The calibration of the internal sensor is traceable to national standards. For this reason
it should only be calibrated in an accredited, e.g. UK United Kingdom Accreditation
Service (UKAS) or US National Institute of Standards and Technology (NIST) standards
laboratory. If these facilities do not exist it is recommended that the sensor is returned
to the manufacturer, Michell Instruments, or an approved agent. A calibration certicate
bearing a seven-point calibration is issued with each sensor.
In most applications, annual re-calibration ensures that the stated accuracy of the
Easidew sensor is maintained.
5.2 Sensor / Battery Replacement
To remove the sensor, or battery pack:
1. Ensure instrument is switched o and that the battery charger, current
output and any sampling components are also disconnected.
2. Remove and retain the 10 cross-head screws from the top plate.
3. Lift the small battery pack cover in the top right corner of the instrument.
A small at bladed screwdriver may be required to gently pry the edges
of the cover if it has become stuck to the waterproof seal underneath.
Removing this cover rst will make it easier to lift the entire top panel out
of the instrument.
4. Lift the top plate of the instrument out of the case. Disconnect the battery
pack before removing the top plate completely to prevent it from straining
on the attached cable. If only replacing the battery pack, do not follow
the next two steps.
5. Undo the screw from the centre of the sensor connecting plug and pull
o the connector.
6. Unscrew the sensor from the block.
Fitting the replacement is simply a reversal of the above procedure. When tting a new
sensor it may be necessary to change the alignment of the GDSN connector (see next
page).

Easidew Portable HP User’s Manual
Michell Instruments 11
MAINTENANCE
If the front panel prevents the connector from tting onto the sensor, follow the
instructions below:
• Completely unscrew the cable gland on the GDSN connector to release
the cable tension.
• Remove the locking screw from the back of the connector (retaining the
metal O-ring).
• Remove the connector block using a small screwdriver.
• Rotate the connector block and push it back into the connector housing.
Take care not to trap any wires against the hole for the locking screw.


Easidew Portable HP User’s Manual
12 97120 Issue 2.3, October 2019
MAINTENANCE
• Replace the locking screw and cable gland.
5.3 Filter Cartridge Replacement
Unscrew the gas inlet tting to reveal the lter, which can then simply be removed for
checking or replacement.
5.4 Checking the Easidew Portable Electronics Calibration


Supply
4-20 mA
PIN 3
PIN 1
(GND) Screen/Shield
Optional
Figure 4 2-Wire Connection - View Showing Rear of Connector Terminal Block
To verify the display electronics are within calibration, a 4-20mA current source can be
connected in place of the sensor.
At 4 mA the display should show -100.0°Cdp ±0.5°C (-148°Fdp ±0.9°F)
At 20 mA the display should show +20.0°Cdp ±0.5°C ( +68°Fdp ±0.9°F)
If the displayed values are outside of this range, please contact Michell Instruments'
Service Department.
5.5 List of Spares
P/N Description
SSF-PF-10PK Pack of 10 particulate lter cartridges
EAP-BAT Replacement battery pack
EAP-CHR Replacement battery charger

Easidew Portable HP User’s Manual
Michell Instruments 13
MAINTENANCE
5.6 Troubleshooting
Symptom Cause Actions
Display shows “ErrI”Sensor disconnected
or sensor tile / sensor
thermistor fault.
NOTE: This error is
normally displayed
during the rst few
seconds while the
instrument is starting
up.
Check sensor cable is securely
connected inside instrument.
Check instrument electronics with
4-20mA source.
Exchange sensor.
Display shows “ErrL”Sensor reading under-
range.
Sensor current signal
< 4mA
Sensor tile open circuit.
Check instrument electronics with
4-20mA source.
Exchange sensor.
Display shows “ErrH”Sensor reading over-
range.
Sensor current signal >
20mA
Sensor tile short circuit.
Sensor may have been exposed
to saturation conditions or liquid
contamination. Check that lter and
sensor guard are clean and dry.
If liquid water has contacted sensor,
or sensor block, then disassemble
and dry thoroughly. After drying, it
is recommend to purge assembled
instrument with very dry (-75°Cdp
(-103°Fdp) / 1ppmV moisture) air for
12 to 24 hours.
Exposure to other contaminants can
cause lasting damage and may require
sensor to be exchanged.
Check instrument electronics with
4-20mA source.
Display ickers on
and o.
Battery voltage low. Connect charger.

Easidew Portable HP User’s Manual
14 97120 Issue 2.3, October 2019
APPENDIX A
Appendix A
Technical Specications