Biomedical Engineering Reference
In-Depth Information
Fig. 4
Arrangement for the experiments using the first model of testing ring
To the N
2
O sensor
(testing ring outlet)
Separator
From the N
2
O sensor
(testing ring inlet)
y
Airflow in
the ring
90
8
135
8
45
8
0
8
180
8
x
225
8
315
8
270
8
Fig. 5
Front view of the testing ring and orientation used to locate the leak holes
and therefore difficult to maintain the same location for the leak hole for further
experiments. The other issue was the correct detection of the leakage spot in order
to acquire accurate results. For example, using the reference angles shown in Fig.
5
,
the values for the ppm curves for different angles should be different for the same
interval of time. This is because the further the leakage hole is from the sensor, it
will take longer to detect the gas, resulting in different response times.
When the results are compared for the angles of 0
ı
and 90
ı
, it can be seen from
Fig.
6
that the green curve (the different colours only represent different experiments
for a leakage positioned at the same angle) for the 0
ı
plot is similar to the blue
curve for the 90
ı
one. The red curves for both tests look similar, giving a final a
concentration close to 500 ppm. A possible reason for these results was that the
separator was not blocking the path in the groove properly. The gas was passing
through it and going straight to the sensor giving to the 0
ı
position higher readings
for the gas concentration.
The same outcome is seen for the comparison between the angles of 180
ı
and
270
ı
. The green and blue curves of ppm increase for the plot of 180
ı
gives a final
