Theory Of Operation
Model 100E Instruction Manual
174
045150102 Rev XB1
flow rate of gas through the orifice is only related to the minimum 2:1 pressure
differential and not absolute pressure:
•
The flow rate of gas through the sample chamber will be the same regardless of
whether the analyzer is at the bottom of Death Valley or on top of Pikes Peak.
•
The flow rate of the gas is also unaffected by degradations in pump efficiency due
to age.
The critical flow orifice used in the Model 100E is designed to provide a flow rate of 650
cm
3
/min.
10.3.3.
Sample Particulate Filter
To remove particles in the sample gas, the analyzer is equipped with a Teflon membrane
filter of 47 mm diameter (also referred to as the sample filter) with a 1 µm pore size. The
filter is accessible through the front panel, which folds down, and should be changed
according to the suggested maintenance schedule in Table 9-1.
10.3.4.
Hydrocarbon Scrubber (Kicker)
It is very important to make sure the air supplied sample chamber is clear of
hydrocarbons. To accomplish this task the M100E uses a single tube permeation
scrubber. The scrubber consists of a single tube of a specialized plastic that absorbs
hydrocarbons very well. This tube is located within outer flexible plastic tube shell. As gas
flows through the inner tube, hydrocarbons are absorbed into the membrane walls. and
transported through the membrane wall and into the hydrocarbon free, purge gas flowing
through the outer tube. This process
is driven by the hydrocarbon concentration gradient
between the inner and outer of the tubes.
INNER
TUBE
(Ambient Air)
OUTER TUBE
(Clean Air)
SAMPLE AIR
FROM
PARTICULATE FILTER
CLEANED
SAMPLE AIR
TO
SAMPLE
CHAMBER
CLEAN
PURGE AIR
FROM
VACUUM MANIFOLD
USED PURGE AIR
TO
PUMP
AND
EXHAUST PORT
Figure 10-9: M100E Hydrocarbon Scrubber (Kicker)
In the M100E some of the cleaned air from the inner tube is returned to be used as the
purge gas in the outer tube (Figure 10-9). This means that when the analyzer is first
started, the concentration gradient between the inner and outer tubes is not very large
and the scrubber’s efficiency is relatively low. When the instrument is turned on after
Summary of Contents for 100E
Page 2: ...Model 100E Instruction Manual ...
Page 4: ...Model 100E Instruction Manual ii 045150102 Rev XB1 ...
Page 12: ...Model 100E Instruction Manual x 045150102 Rev XB1 ...
Page 20: ...M100E Documentation Model 100E Instruction Manual 18 045150102 Rev XB1 User Notes ...
Page 26: ...Specifications Approvals and Warranty Model 100E Instruction Manual 24 045150102 Rev XB1 ...
Page 46: ...Getting Started Model 100E Instruction Manual 44 045150102 Rev XB1 User Notes ...
Page 128: ...Operating Instructions Model 100E Instruction Manual 126 045150102 Rev XB1 User Notes ...
Page 156: ...EPA Protocol Calibration Model 100E Instruction Manual 154 045150102 Rev XB1 ...