CIRAS-3 Operation Manual V. 1.09  184  support@ppsystems.com 
 
External Air Inlet Filter Assembly (Part Number STD558) 
Beginning in May 2014, we started supplying an external air 
inlet filter assembly to improve the CIRAS-3 resistance to dirty, 
dusty environments.  As described above, the internal gas 
circuit and optics are protected with several filters but this 
external filter also provides added protection and can easily be 
changed.  It easily connects to the CIRAS-3 “AIR IN” port as 
shown below: 
This assembly is supplied with a filter element, 48 um, blue 
(Part Number STD556) as standard.  For severe dusty 
environments, we recommend the filter element, 10 um, Yellow 
(Part Number STD555). 
 
 
Filter Assembly (Air Supply) 
External Air Inlet Filter Assembly 
Filter Element, 10 um, Yellow (For severe dusty environments) 
Filter Element, 48 um, Blue 
 
Desiccants and Absorber Columns 
The CIRAS-3 has two well labeled absorber column assemblies (total of 4 absorber columns) for analyzer 
Zero and CO
2
 and H
2
O control.