Michell Instruments DryCheck Specifications

Dew-Point Transmitters

DryCheck

Self-Contained Dew-Point Instrument

A simple and effi cient, self-contained dew-point hygrometer, with fi ltration and fl ow control, for
measurement of dew point or moisture content.

Highlights

• Integrated instrument and sampling system

• Simple installation

• Wide measurement range

• Dew point or moisture content

• Analog output, display and dual alarms

• IP65 (NEMA 12) enclosure

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Applications

• Compressed air dryers

• Plastic moulding

• Ozone generators

• Medical gases

• Pneumatics

• Breathing air

• Welding gases

• ... and many more

Dew-Point Transmitters

DryCheck
Self-Contained Dew-Point Instrument

Background

The DryCheck system was designed by Michell Instruments
in response to demands from customers for an economic
instrument package with good accuracy and stability, inclusive
of a comprehensive sampling system, which could be easily
installed for use in a number of dew-point measurement
applications.

In air drying and many other applications a cost effective and
reliable hygrometer that is quick and simple to install is vital to
ensure that dew-point measurement can be made at the point
of use.

Fast Response and Accurate Measurement

The DryCheck utilises the Michell Instruments Easidew Online
to measure dew point in the range –100 to + 20°C (-148 to
+68°F) dew point, or moisture content in the range 0-3000
ppm. This well-proven instrument has Michell’s advanced
Ceramic Moisture Sensor at its heart, providing accurate and
stable measurement. The calibration data for each sensor
is stored within the transmitter’s fl ash memory. This allows
Michell Instruments to offer the unique sensor exchange
scheme, keeping calibration costs and downtime to an absolute
minimum.

Integral Sampling System

The DryCheck sampling system includes a 0.3 μm particulate
fi lter element, a monolithic sampling block to house the Easidew
Transmitter, and a valve and fl owmeter for setting the sample
fl ow. The fi lter element is easily replaceable to ensure that
the sensor is protected. All components are rated to 1 MPa
(10 barg/145 psig) and the DryCheck can be confi gured for
measurement of dew point at either system, or atmospheric
pressure.

Display and Outputs

The DryCheck features an extremely clear 20 mm (¾”) red LED
display, which can be programmed to display dew point, in °C or
°F and moisture content in ppmv. The instrument also provides
a 4-20 mA output and 2 off alarm relays. All these features are
easily confi gurable by the user via the front panel of the display,
making DryCheck one of the most versatile instruments on the
market.

Simple Installation

All components are housed in a rugged IP65 (NEMA 12) rated
polycarbonate case. This can easily be wall mounted at a
convenient point close to the gas sample.

A clear cover protects the display and the sample fl owmeter.
Gas connection (gas in and gas out) is provided using “quick
connect” push-fi ttings suitable for use with 6 mm (¼”) OD
Tefl on tubing. Mains power input, and connection to the
4-20 mA analogue output, and the two user programmable
voltage free relay contacts are all easily accessible behind the
lower panel.

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Dew-Point Transmitters

Technology

Ceramic Impedance Sensor

The DryCheck uses Impedance technology, based on Michell’s
advanced ceramic sensor. The operation of this sensor depends
on the dielectric property of water molecules absorbing onto an
active porous insulating layer sandwiched between two layers of
conductive material deposited on a ceramic substrate.

Water has a very high dielectric compared to the dielectric of
the active layer and the background of the carrier gas so it can
be detected easily.

The active layer is very thin – less than one micron and the
porous top conductor that allows water molecules to penetrate
into the active layer is less than 0.1 micron thick. This allows
the sensor to respond very rapidly to changes in the moisture
surrounding it both when moisture decreases (drying) and
increases in the sensor environment.

Permeable Gold film

g

g

Hygroscopic Mono-layer

Base Electrode

g

Ceramic Substrate

g

Moisture
Molecules

g

Michell ceramic sensor tile layers

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Dew-Point Transmitters

DimensionsTechnical Specifi cations

Measurement Range -100 to +20°C (-148 to +68°F) dew point

Accuracy ±2°C (±3.6°F) dew point
Operating Temperature -5 to +50°C (+23 to +122°F)
Storage Temperature -40 to +75°C (-40 to +167°F)
Output 4-20 mA maximum load resistance 500 Ω
Alarm 2 volt free contacts 3 A @ 240 V
User Interface Front panel confi guration of alarm

Display 20 mm (¾”) red LED
Power Supply 85 to 265 V AC, 50/60 Hz
Ingress Protection IP65 (NEMA 12)
Mains Cable 2 m cable supplied (6.5 ft)
Gas Pressure 1 MPa (10 barg/145 psig) max (high pressure

Sample Flow Rate 1-5 l/min (2.1 to 10.5 scfh)
Filtration 99.5 % removal of 0.3 μm
Gas Connection Quick Connect fi ttings for 6 mm OD Tefl on

3000 ppmv (ppmv output or non-standard
dew point range must be specifi ed at time
of order)

points

option available)

pipe

For full specifi cation, please see the Easidew Transmitter
and Easidew Online datasheets.

Michell Instruments Ltd, Rotronic Instruments Corp. 135 Engineers Road, Suite 150, Hauppauge NY 11788

Tel: [phone], Email: [e-mail], Web: www.michell.com/us

Michell Instruments adopts a continuous development programme which sometimes necessitates specifi cation changes without notice.
Issue no: DryCheck_97173_V2.1_US_0618

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