Shaw SADP Operating Instructions Manual

SADP_Operating_ Instructions_0114

Model SADP

Automatic Dewpoint Meter

Operating Instructions

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SADP_Operating_ Instructions_0114

Unpacking your
Shaw Moisture Meters Model SADP

Please examine the SADP package for any damage or mishandling. If any
damage is evident please notify the carrier and the Shaw Moisture Meters
representative from where this unit was purchased.

You should have received (if ordered):

 1 Model SADP Instrument
 1 Carry Case
 1 Screwdriver & Allen Key
 1 Instruction Manual
 1 Pressure Dewpoint Circular Calculator
 1 2m length of PTFE tubing

If anything is missing please contact your distributor immediately.

SADP_Operating_ Instructions_0114

Index

Contents Page

1.0 General Description 1

1.1 Ranges 1

2.0 Safety Information 2

2.1 Hazardous Area Use – Safety Information 2

2.2 Pressure Exposure 2

3.0 Installing the Air / Gas Sampling System 3

3.1 Gases to Avoid 3

3.2 Piping Installation Schematic 4

3.3 Piping Schematic Component Index 4

4.0 Purging the Sample Connection 5

4.1 Sample Connections 5

5.0 Controls 5

6.0 Normal Operation 6

7.0 Calibration Checking 7

8.0 The Sensor 8

8.1 Gaining Access to the Sensor 8

9.0 Additional Information 9

9.1 Anti-Static Sample Case 9

9.2 Desiccant and Head Seal 9

9.3 Batteries and Battery Check 9

9.4 Temperature 10

9.5 Pressure 10

9.6 Response Time 10

9.7 Guarantee 10

10.0 Basic Definitions 11

11.0 Electrical Function Check 12

12.0 Problem Guide 13

13.0 Hygrometric Equivalents 15

14.0 SADP Specifications 16

SADP_Operating_ Instructions_0114

1.0 General Description

The SADP & SADP-TR are battery operated portable dewpoint meters designed for spot checks or

continuous use. The instrument provides direct indication in dewpoint temperature and parts per million
on a 12cm analogue scale. SADP-D versions perform the same function but display only Dewpoint on a
LCD display.

The instrument may be used to give a continuous reading as long as sample gas is flowing through the

test chamber [head] of the instrument, a reading will be given of the gas moisture content. Alternatively
results are obtained in a few minutes when making spot checks.

The SADP instrument is operated with its own internal batteries and requires no external power source.

The instrument comes supplied with 6 “c”-size cells. In normal operation these will last for over 12
months.

The unique measuring head is designed to keep the sensor dry when the instrument is not in use,

making spot checks a simple and speedy process with minimum air or gas usage.

The SADP is provided as standard with a padded carrying case with shoulder strap, a moisture

calculator, a screwdriver for the Automatic Calibration control, a special key for the security plate
covering the battery carriers, and a 2 meter length of flexible PTFE (Teflon) sample pipe.

The instrument is certified for use in hazardous areas (Ex ia IIC T6 Ga).

1.1 Ranges

SADP-(r): Range

Purple (P) -100 to 0 deg.C DP, 0-6000 PPM.
Silver (S) -100 to -20 deg.C DP, 0-1000 PPM.
Red (R) -80 to -20 deg.C DP, 0-1000 PPM, 0-10 on TR version.
Grey (G) -80 to 0 deg.C DP, 0 - 6000 PPM, and 0-10 on TR version.
Blue (B) -80 to +20 deg.C DP, 0 - 23,000 PPM, (manual-cal)

SADP_Operating_ Instructions_0114

2.1 Hazardous Area Use – Safety

All SADP Shaw Automatic Dewpoint meters are certified Intrinsically Safe as a standard feature.
They must be fully assembled to meet the certification requirements, i.e. they must not be switched on

in a hazardous location if any component is missing or removed. E.G. battery cover plate or sensor
head assembly etc. This instrument is only certified Intrinsically Safe to T6 with the use of Varta 3014
long life batteries as supplied.

Certification: ATEX Coding -

II 1G

Ex ia IIC T6 Ga (Ta = – 20ºC to +40ºC)

FM Coding - CLASS I, ZONE 0 AEx ia IIB+H2 T6

It is the responsibility of the user to ascertain the suitability of the SADP for use in hazardous areas.
Risk assessments should be performed prior to use, taking into account the SADP certifications, the
location and the gas being monitored etc.

The USA certification is to CLASS I, ZONE 0 AEx ia IIB+H2 T6, which effectively means that the

instruments may be used in any environment except a deep mine.

The ATEX certification is Ex II 1 G Ex ia IIC T6 Ga. This means:-

Ex-European certification mark for electrical equipment for use explosive atmospheres
II -Areas classified hazardous due to presence of flammable gases or vapour
1 -Areas classified as Category 1 Risk according to the ATEX Directive (equates to Zone 0)
G -Risk due to presence of flammable gases or vapours according to the ATEX Directive
Ex ia - Intrinsic Safe
IIC - suitable for use with all classes of gasses and vapours
T6 - the product has a maximum surface temperature of 85°C (in an ambient temperature range of -

20°C to + 40°C) and can be used with any gases or vapours which have an ignition temperature above
this.

Ga - EPL (Equipment Protection Level) marking

2.2 Pressure Exposure

The maximum pressure to which the telescopic measuring head is exposed

must not be more than

0.3barg, 4.35psig, 30kpag or 0.3kg/cm2g

Exposing the measuring head to higher pressures may damage the instrument

and result in injury to the operator or other personnel in the area

SADP_Operating_ Instructions_0114

3.0 Installing the Air/Gas Sampling System

The piping installation schematic diagram (see section 3.2) shows all components, which could be used

in a dry gas measurement application although not all the items shown will be required for every
installation.

Care should be taken to ensure that the sample presented to the SADP is not contaminated with any

component that will damage, contaminate or affect the SADP in a way that will impair the unit’s
accuracy.

It is strongly recommended that the sample should not contain particulate matter, oil, hydrocarbon or

any other condensate. If these components contaminate the sample system and/or the measuring
sensor, the SADP response time will be lengthened, although the sensor calibration will not be effected.

The flow rate, although not critical to the sensor measurement, should be low enough to avoid abrasion

to the sensor surface without being so low as to extend the SADP response time to an unacceptable
level. In general, a flow rate of between 5 and 8 litres/min at NTP will give the right balance.

The sensor used in the SADP is a variable capacitor, which is directly affected by changes in partial

pressure of water vapour, and these changes, that are proportional to the dew/frost point temperature,
are displayed on the instrument indicator.

3.1 Gases to Avoid

The moisture sensors are suitable for many different industrial and research applications. Most gases
can be checked for their moisture content with no need for the calibration to be altered when changing
between different gases, as the sensor operates only with reference to the water vapour content. There
are, however, some gases that must be avoided, as they are not compatible with the material of
construction of the sensor. Ammonia (NH

3

), Ozone(O3) and chlorine (Cl) must be avoided at all times,
even in small quantities. Hydrogen chloride (HCl) also attacks the sensors very quickly. Some, less
aggressive, acidic gases, such as sulphur dioxide (SO

2

), can be monitored, as long as the moisture

content is low, generally less than 100ppm(v). If in doubt, please ask your supplier.

Sulphur hexaflouride (SF

6

) has no effect on the sensor. If the gas has been exposed to arcing,
however, it is possible that various acidic species will have been formed that will corrode the sensor.
When testing SF

6

that may have been arced, therefore, an acidity test should be carried out first; if the

gas proves to be acidic then the moisture test should not be carried out.