User manual

Accessories
MarathonSeriesFA/FR 35
8.2AirPurgeCollar
TheAir PurgeCollar accessory is used tokeep dust,moisture,airborne particles,andvapors away
fromtheopticalheadʹslens.Itcanbeinstalledbeforeorafterthebracket.Itmustbescrewedinfully.
Airflowsintothe1/8”NPTfittingandoutthefrontaperture.Airflow
shouldbeamaximumof0.5‐
1.5liters/sec(1‐3cfm). Clean(filtered)or“instrument”air is recommendedtoavoidcontaminants
fromsettlingonthelens.Donotusechilledairbelow10°C(50°F).Alsoprovidedisastainlesssteel
protectiontube,150mm(6inches)longby25mm
(1inch)diameterthatthreadsontothefrontofthe
airpurgecollar.

Figure31:AirPurgeCollarandProtectionTube(XXXFOHAPA)
8.3ProtectionTube
The protection tube is available as an accessory. It is305 mm (12 in.) long and 32 mm(1.26 in.) in
diameterandcomeswith¾”NPTexternalthreadatoneend.Theopticalheadisthreadedwiththe
protectiontube.Theuseoftheairpurgecollarinthesame
timeispossible.

Figure32:ProtectionTubeforOpticalHead