Interview Questions on Smoke detection system
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Also Read: Instrumentation Questions with Answers
1.What
are the types of ‘smoke detectors’ in use in P.D.O.?
Two
types of smoke detectors are used in PDO. They are:
1. Optical
type, 2. Radioactive type, 3. Ionisation type.
2.Explain the operating principle of the
different types of smoke detectors.
Optical
type: when the smoke cuts the optical
detection path, and unbalance in the detector current loop raises a smoke
alarm. These type detectors are sensitive to larger particles of combustion 0.5
to 10 microns. It is suitable for applications where thermal turbulence can be
expected.
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| Interview Questions on Smoke detection system |
Radio
active type: when the
smoke is detected by the radio active substance, the unbalance in the detector
current loop raises a smoke alarm. This type of detectors are sensitive to air
movement greater than 5m/sec. It is normally installed with the photoelectric
(optical type) type smoke detectors.
3.Why is a smoke detector as important
as a ‘heat switch’ and ‘UV detector’?
Smoke
detectors are used in confined areas such as control rooms and electrical
switch rooms.
4.Where are smoke detectors generally
installed in P.D.O.?
Smoke
detectors are used in confined areas such as control rooms and electrical
switch rooms.
5.What happens when a smoke detector
detects smoke?
When
a smoke detector detects smoke, the detector loop current changes. The
unbalance in the loop current is detected as smoke.
Once
in every 10 secs the L.E.D on each smoke detector blinks as self loop check. On
detection of smoke, this L.E.D remains continuous on (bright).
6.name the manufacturers of smoke
detection systems.
Name
of the smoke detector manufactures are Firecheta, Cloride Gent…etc.
7.why are periodic checks and
maintenance required on smoke detection system?
Particularly
on the optical type smoke detectors, the collection of dust in the sensor path
may result in a false alarm. Also the periodic maintenance ensures the
reliability of the detection system.
8.What are the common problems faced
when maintaining a smoke detection system?
False
alarm due to accumulation of dust, floor cleaning, water vapour
Loose
connection results in the fluctuation of the detector loop current.
Improper base plug-in connection.Also Download: Instrumentation Android App
