APPENDIX P. PQ167 High Altitude (miniPM Inlet)
IMPORTANT: FLOW RATE MUST BE SET FOR 5 lpm
1.0 Size selective inlet
The size selective inlet will be familiar to all who have had experience with the Standard EPA Louvered Inlet in its
original 16.7 lpm configuration. The only two differences are that it has been scaled down to 1/3 its original
dimensions and the acceleration jet in the impactor is changeable over five size ranges. An exploded diagram of
the inlet is shown in Figure 9 with all parts identified.
2.0 Jet Differential
If a Size Selective Jet (SSJ) other than PM10 was ordered/furnished with your instrument it was furnished as a
separate item. The individual jets are hand detachable and removed/installed by screwing in and out. A light
grease should be applied to the threads to prevent seizure. Jets manufactured prior to May,2005 were not
marked. As a guide to their functional size refer to the table of approximate internal dimensions below. Later jets
were color coded and their functional size can also be found in the following table.
3.0 Maintenance
Items which require cleaning and maintenance are common to all ambient air sampling devices fitted with size
selective inlets. The inlet and the sampler may be considered two separate items for cleaning and maintenance
purposes.
Cleaning should occur once every 90 days or sooner in highly polluted environments. Until such time as sufficient
experience has been gathered, the unit should be inspected once a month. In order to perform an inspection it is
only necessary, after removing the inlet from the top of the filter holder to unscrew the top from the bullet as
shown in Figure 10.
Normal cleaning of air sampling inlets is generally, best done with clean water and lint free wiping cloths. If an
ultrasonic cleaner is available it is the preferred device as it will remove dirt from deep corners and pockets,
avoiding the need for further disassembly. After ultrasonic, or any liquid cleaning, be certain to dry thoroughly
before reassembling and placing in service.
To Next Page
Loading...
Need help?
General