अग्निशामक - रसायन विज्ञान, सामान्य विज्ञान Video Lecture | सामान्य विज्ञानं (General Science) for UPSC CSE in Hindi

fire extinguishers a fire extinguisher
is an active fire protection device used
to extinguish a control small fires
often in emergency situations
typically a fire extinguisher consists
of a handheld cylindrical pressure
vessel containing an agent which can be
discharged to extinguish a fire the
modern fire extinguisher was invented by
British captain George William Mann by
in 1818 fire is the result of a chemical
combustion reaction typically a reaction
between oxygen in the atmosphere and
some sort of fuel there are three
essential elements involved introducing
fire heat oxygen and fuel to put a fire
out you need to effectively remove one
of these elements fire extinguishers are
designed to remove at least one of these
elements so that a fire will die out a
fire extinguisher is quite like a giant
a Crizal can often with two different
substances inside one of them is a solid
liquid or gas substance for fighting the
fire the other one is called a
propellant and is a pressurised chemical
that makes the firefighting substance
come out when you press the extinguisher
handle when you depress a lever at the
top of the cylinder the material is
expelled by high pressure inside an
extinguisher a plastic siphon tube leads
from the bottom of the fire suppressant
reservoir to the top of the extinguisher
a spring mounted valve blocks the
passageway from the siphon to the nozzle
at the top of the cylinder there is a
small cylinder filled with compressed
gas liquid carbon dioxide for example a
release valve keeps the compressed gas
from escaping to use the extinguisher
you pull out the safety pin and depress
the operating lever the lever pushes on
an actuating rod which presses the
spring-mounted valve down to open up the
passage to the nozzle the bottom of the
actuating rod has a sharp point which
pierces the gas cylinder release valve
the compressed gas escapes applying
downward pressure on the fire
suppressant material this drives the
material up the siphon and out the
nozzle with considerable force the
proper way to use the extinguish
is to aim it directly at the few well
rather than the flames themselves and
move the stream with a sweeping motion
there are three main types of
extinguisher and they work in slightly
different ways water extinguishes dry
chemical extinguisher and carbon dioxide
extinguishes it's important always to
use the right extinguisher for the fire
using the wrong extinguisher can put
your life in danger and make the fire
worse for example you must never use
water extinguishers on electrical fires
because you could electrocute yourself
and people nearby