INNOVATION AND FLEXIBILITY
If the outside air is appreciably colder than the m/d, the air’s RH will rapidly drop on entering the m/d. The problem seems to start when the delivered
air is much below 0°C, with the m/d still sitting at a nominal 10°C. If the ambient is -10°C the air gets over cold and over dry and static is likely to be
generated.
Bottled Air
Bottled air may be used if a compressor is unavailable or if cost is an issue but there are some limitations in its use. Bottled air at say 200 bar is very
dry (may have a dew point* of -50°C), since water has been driven off by the act of extreme compression. The use should be limited to around 30
minutes. During the 30-minute period the air will be getting drier by the minute, but should be OK. The extremely dry air will soak up any moisture
as it travels down the m/d and continuing for long periods will remove virtually all the moisture, resulting in less conductivity and increased static
charge generation.
* Dew Point = the temperature to which the air must be cooled for water vapour to condense.
9.8 Air Preparation Kit and Off-Shelf Compressors
Emtelle provide a basic compressor kit designed for FTTH applications. The kit contains a standard 10 bar unit, a generator for powering a blowing
unit and an air preparation kit.
The air preparation kit is needed to treat the hot and wet air coming from the compressor. A 10m hose is included with this system and its function
as well as connecting the compressor to the air preparation kit provides a basic after cooling function. An aftercooler is needed to bring the output
air from the compressor down to the ambient temperature. Without it or indeed using a much shorter hose will not allow ambient temperatures to
be reached by the time the air reaches the air preparation kit and this detrimental effect may lead to water being fed to the membrane dryer. As the
membrane drier is a vapour dryer damage may ensue.
CAUTION: If off the shelf compressors are used the compressor must be fitted with an aftercooler or alternatively it must be used with a long hose of
the order of 10m. Ensure that the hose is not heated externally, by local sources e.g. compressor exhaust, sunlight, etc
9 Fibre blowing
“This document is intended as a guide only. Whilst the information it contains is believed to be correct, Emtelle can take no responsibility for actions taken based on the information contained in this document. Emtelle reserves the
right to make changes to this document without notice. All sales of product are subject to Emtelle’s terms and conditions of sale only, which can be found on Emtelle’s website.”
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INNOVATION AND FLEXIBILITY
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