1、Designation:F32708(Reapproved 2015)Standard Practice forSampling Gas Blow Down Systems and Components forParticulate Contamination by Automatic Particle MonitorMethod1This standard is issued under the fixed designation F327;the number immediately following the designation indicates the year of origi
2、naladoption or,in the case of revision,the year of last revision.Anumber in parentheses indicates the year of last reapproval.Asuperscriptepsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This practice describes how to connect,prepare,andsample pressurized gas s
3、ystems(having up to 19.1-mm(0.75-in.)diameter lines)for particulate contamination by using anautomatic monitor.1.2 The values stated in MKS units are to be regarded as thestandard.The values given in parentheses are for informationonly.1.3 This standard does not purport to address all of thesafety c
4、oncerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.For hazardstatements,see Section 5.2.Terminology2.1 Definitions:2.1.1 downstream t
5、erminal pointthe point in a gas systemfrom which gas is fed into a further system or component,usually the designated“sample port.”2.1.2 filtered gas systema gas system that is equipped withrequired filtration devices to furnish gas that is suitably cleanfor the intended application.2.1.3 purgeto fl
6、ush a gas supply system or componentwith a regulated flow of gas.2.1.4 sample portthe designated point in a gas system orcomponent from which a representative gas sample may betaken.3.Summary of Practice3.1 The pressurized gas system or component and theapparatus are prepared in accordance with the
7、requirements ofthe users sample analysis procedure.The sensing unit of theautomatic particle monitor is connected to the designatedsample port which is under purge condition.The systemflow-rate is adjusted to the sample flow rate requirement.Allthe gas passing through the sensing unit is monitored f
8、orparticulate contamination until the required sample volume hasbeen analyzed.4.Apparatus4.1 Automatic Monitor,with sensor that sizes and counts allentering fluid in accordance with the users requirements forpressure,flow,temperature,and accuracy.4.2 Filtered Gas SystemSee Fig.1.4.3 Stop Watch or Ti
9、mer,with a+1,0-s resolution.4.4 Miscellaneous Fittings,as needed for sampling pointadaption,cleaned and packaged within system contaminationrequirements.4.5 Connecting Lines,cleaned and packaged within systemcontamination requirements.4.6 Flowmeter,calibrated for the sample port fluid,flow,andtemper
10、ature requirements.5.Hazards5.1 Personnel must stand clear of exiting gas.5.2 Ear protection must be used when gas flow approachessonic velocity.5.3 All lines and associated system components must beconnected and operated within the requirements of recognizedsafety codes.6.Procedure6.1 Establish a m
11、inimum continuous purge pressure of 6.89kPa(1 psig)gage or 2.83 dm3/min(0.1 ft3/min),flow from thefiltered gas pressure supply.6.2 Connect one end of a suitable connecting line to thepurge outlet of 6.1,and then connect the other end to the inletof the component or system to be sampled.NOTE1If the s
12、ystem to be sampled is already connected to the filteredgas pressure supply,then establish the purge as noted in 6.1.1This practice is under the jurisdiction of ASTM Committee E21 on SpaceSimulation and Applications of Space Technology and is the direct responsibility ofSubcommittee E21.05 on Contam
13、ination.Current edition approved May 1,2015.Published June 2015.Originallyapproved in 1972.Last previous edition approved in 2008 as F327 08.DOI:10.1520/F0327-08R15.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 6.3 Connect a suitable co
14、nnecting line from the sample portto the inlet of the automatic monitor sensing device.(When nosample port is designated,use the down-stream terminal pointfrom which purge gas is flowing.)6.4 Increase the purge to one of the following:6.4.1 8.49-dm3/min(0.3-ft3/min)flow,6.4.2 34.5-kPa(5-psig)gage pr
15、essure,or6.4.3 5%of system operating pressure when this pressure isless than 34.5-kPa(5-psig)gage.6.5 Surge Pressure Cleaning:6.5.1 Quickly increase the continuous purge pressure for a5-s duration,three times at 1-min intervals in accordance withone of the following:6.5.1.1 To 689.5-kPa(100-psig)gag
16、e pressure,6.5.1.2 To 113.2-dm3/min(4.0-ft3/min)flow,6.5.1.3 70%of system operating pressure when this oper-ating pressure is below 689.5 kPa(100 psig)gage.6.5.1.4 Inaccordwithagivensystemoperationrequirement,but not to exceed the rated pressure of the sensingunit.6.5.2 Reduce the purge pressure to the level in 6.4 after eachsurge pressure application of 6.5.1(that is during 1-mininterval).6.6 Connect a flowmeter to the outlet of the automaticmonitor sensor and adjust the flow versus time to ach
