STRATOS HSSD - Page 25

World Patents Pending ©AirSense Technology Ltd. 1999
ISSUE 2.4
Page 25
TECHNICAL. MANUAL
At the onset of pollution at the inlet the pollution at the outlet will not immediately rise
to the same level. For a pollution level of X% arriving at the inlet, the pollution level
at the outlet will rise with the inverse exponential of time towards X% and in theory
never actually reach it. This effect is illustrated in Figs. 3 & 4.
Plant Room
A
A
Filter
Air Inlet
0
Pollution at Inlet
(as seen by reference detector)
Transport
delay through
duct work
During this period aspirating smoke
detection system has low sensitivity
Reference
compensation
added here
Time
D
Smoke Density
Pump
Inlet
0
Pollution at Outlet
Time
D(1-E)
Smoke Density
0
CALCULATED POLLUTION ADDED
Time
Density required for alarm
D(1-E)
Smoke Density
Fig. 3. Smoke
levels at the onset of
an external source
of smoke.