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ML576 | v2
Expo Technologies UK
T: +44 (0) 20 8398 8011
E: sales@expoworldwide.com
Expo Technologies US
T: +1 (440) 247 5314
E:sales.na@expoworldwide.com
Expo Technologies China
T: +86 532 8906 9858
E: qingdao@expoworldwide.com
4. Description and Principle of Operation
The Air isolation unit is designed to supply filtered air to a purge system from a remote location.
Filter elements can be changed without the need for switching off the air supply
To initially operate the system, all two-way valves must be closed prior to air being applied to the system.
Once the two-way valves are closed air can be supplied to the system.
To send airflow to the top filter, the red handle of the three-way L ported valve should be turned 90 degrees
anticlockwise and left in a horizontal position.
To send airflow to the bottom filter, the red handle of the three-way L ported valve should be turned 90
degrees clockwise and let in a vertical position.
Once the chosen filter (top or bottom) has been selected via the three-way L ported valve.
The two-way valve next to the chosen filter needs to be opened (rotate clockwise 90 degrees).
To change the filter that airflow is being directed to whilst the system in Operation, the following steps need to
be followed.
Check that the small two-way valves located at the bottom of each filter are normally closed.
To change the filter airflow is going to, the three-way valve needs to be rotated 90 degrees.
The filter that was previously in use needs to be drained and relieved of air via the small two-way valve located
at the bottom of the filter underneath the pressure gauge.
The two-way valve next to the filter that was previously in use needs to be closed and the two-way valve next
to the filter in use needs to be opened. Following this both small two-way valves located at the bottom of each
filter should be normally closed
5. Main Components
Air Supply Filter
The unit is provided with x2 40µ liquid / dust filter elements. The user of the Air isolation unit must ensure that
air supply is to the quality stated in Air Supply Quality paragraph found in the Installation of the System
section.
The system is designed so that air should only flow through one filter at any time.
6. Installation of the System
The Air isolation unit must be installed by a competent person in accordance with relevant standards, and local
codes of practice.
Copies of the Current Standard can be purchased from Expo Technologies or B.S.I or relevant local code /
Standard.
Air Supply Quality
The Air isolation unit system should be connected to a protective gas supply, which is suitable for purging and
pressurization.
The supply pipe connection to the air isolation unit must be appropriate for the maximum input flow rate for the
application.
The air supply must be regulated at a pressure less than the maximum stated inlet pressure.
The air supply must be: clean, non-flammable and from a non-hazardous location. The air should be of
Instrument Air Quality. Although the purge control system will operate with lower air quality, its operational life
will be adversely affected. The equipment that is being protected by the air isolation unit may also suffer
because of poor air quality.
With reference to BS ISO 8573-1: 2010, Instrument Air is typically specified as:
Particle Class 1
In each cubic metre of compressed air, the particulate count should not exceed 20,000 particles in the 0.1 to
0.5 micron size range, 400 particles in the 0.5 to 1 micron size range and 10 particles in the 1 to 5 micron size
range.
Humidity or pressure dew point
The dew point, at line pressure, shall be at least 10°C below the minimum local recorded ambient temperature
at the plant site. In no case, should the dew point at line pressure exceed +3°C.
