Michell Instruments Easidew Online, Руководство пользователя

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Easidew Online User’s Manual
42 97094 Issue 18.5, March 2016
MAINTENANCE
• Complexity avoidance (tee pieces, in-line couplings, etc.)
Sample pipework should, ideally, be specially designed for each application rather than
adapted from that previously installed for another application. Dead space in sample
lines increases response time by holding water molecules which are more slowly released
to the passing gas sample.
• Sample Gas Selection
Generally, if the sample gas (in conjunction with water vapor) is not corrosive to base
metals, it will be suitable for measurement by the Easidew Online system. Gases
containing entrained solids should be fi ltered before application to the sample block.
Care should be taken with gas mixtures containing potentially condensable components
in addition to water vapor, e.g. oil, to ensure that only water vapor is present in the
sample.
4.2 Maintenance and Calibration
Routine maintenance of the Easidew Online Hygrometer is con fi ned to regular re-
calibration. For most applications, annual re-calibration ensures that the stated accuracy
of the Easidew Online Hygrometer is maintained.
Specialist calibration instrumentation is required to calibrate the transmitter and a true
calibration can only be performed by exposure of the dew-point sensor to a reference
gas of known dew point.
Calibration services are offered by Michell Instruments at their accredited calibration
laboratories. All calibrations are traceable to national standards either via the National
Physical Laboratory (UK) or the National Institute of Standards and Technology (USA).
The Easidew transmitter can be returned to Michell Instruments either directly or via
the authorized distributor, for calibration at 13 points across the range -100 to +20°Cdp
(-148 to +68°Fdp).
Alternatively, Michell Instruments can provide an exchange transmitter. Prior to re-
calibration, an exchange transmitter can be ordered from Michell Instruments or an
authorized distributor.
Once the replacement transmitter and calibration certi fi cate have been received, the
original transmitter can be disconnected from the sample line and the monitor and
the replacement transmitter fi tted in its place. Refer to Section 2.1.1. The original
transmitter should be packed in its original packing (see Figure 3) and returned to
Michell Instruments, either directly, or via their authorized agent.
Easidew transmitters are fully interchangeable and can be used with any Easidew Online
monitor. Transmitter interchangeability is not affected by cable length.
4.2.1 Clean Monitor
The front panel of the monitor should be cleaned with a moist lint free cloth. Mild
detergent may be used to remove any stubborn marks or stains but DO NOT use any
type of solvent, e.g. acetone, which could damage the instrument.