5.5
Pressure Considerations
When sampling gases from sources above 50 psia the user needs to exercise some caution.
The model
PLMaEx
has a built-in orifice. This orifice can be used to regulate the flow from
various pressures.
PLMaEx Measuring near Atmospheric Pressure
PLMaEx Measuring at Pressure of Sample Gas
The inlet orifice eliminates the need for any pressure regulators while maintaining sufficient but
not excessive flows throughout the pressure rating of the analyzer. For example 0.004” to 0.016”
dia. orifices, produces flows described in the following table.
The grayed boxes are preferred operating points. Other orifices can be provided to accommodate
different pressures and flows. Consult PhyMetrix support for its proper sizing.
source pressure
psia - (Bar)
flow
SLPM
0.016” orifice
flow
SLPM
0.012” orifice)
flow
SLPM
0.008” orifice
flow
SLPM
0.006” orifice
flow
SLPM
0.004” orifice
15 - (1.03)
0.7 0.4 0.17 0.08 0.04
25 - (1.72)
2
1.3 0.6 0.3 0.1
35 - (2.4)
3
1.9 0.8 0.5 0.2
55 - (3.8)
4.8
3.0
1.4 0.7 0.3
75 - (5.2)
6.6
4.1
1.9
1.0 0.4
100 - (6.9)
8.9
5.5
2.6
1.4 0.6
150 - (10.3)
13.4
8.3
3.8
2.1 0.9
200 - (13.8)
17.9
11.0
5.1
2.7
1.1
300 - (20.7)
26.8
16.6
7.7
4.1
1.7
400 - (27.6)
35.7
22.1
10.3
5.5
2.3
500 - (34.5)
44.7
27.6
12.8
6.9
2.9
600 - (41.4)
53.6
33.1
15.4
8.2
3.4
700 - (48.3)
62.5
38.7
18.0
9.6
4.0
800 - (55.1)
71.5
44.2
20.5
11.0
4.6
900
-
(62)
80.4 49.7 23.1 12.4 5.1
1000
-
(68.9)
89.3 55.2 25.7 13.7 5.7
1500 - (103.4)
134.0
82.8
38.5
20.6
8.6
2000 - (137.9)
178.7
110.5
51.3
27.5
11.4
7