What is the fire extinguishing principle of a carbon dioxide extinguisher?
Fire extinguishing principle: the liquid carbon dioxide is compressed into the small steel cylinder when it is pressurized, and then it is sprayed out when it is extinguishing. It has the effect of cooling and isolating the air.
After introducing the fire extinguishing principle of the carbon dioxide extinguisher, let's talk about the classification of the fire extinguisher.
The carbon dioxide extinguisher can be divided into foam extinguisher, dry powder fire extinguisher and liquid extinguisher.
At last, we focus on one of them - foam extinguisher. The application range, principle and method of application are introduced in detail as follows.
1. Scope of application
The foam extinguisher is suitable for the general class B fire fighting, such as oil, grease and other fires. The foam extinguisher can also apply to the class A fire, but it cannot put out water soluble flammable and flammable liquids in class B fires, such as alcohols, esters, ethers, ketones and so on. And it also can't put out electrified equipment, class C and class D fires.
There are two containers in the foam extinguisher, which contain two kinds of liquids. They are aluminum sulfate and sodium bicarbonate solution. The two solutions are not touching each other, and no chemical reaction occurs. When using the foam extinguisher, the extinguisher is inverted, and the two solutions are mixed together to produce a large amount of carbon dioxide gas. Turn on the switch, the foam is ejected from the fire extinguisher and covered on the burning object, so that the burning matter is isolated from the air and the temperature is reduced, so as to achieve the purpose of extinguishing the fire.
When using, bring the extinguisher to the fire place, put down the fire extinguisher, pull out the safety pin, one hand hold the microphone root of the handle, and the other hand hold the valve opening and closing pressure. The nozzle of carbon dioxide extinguisher with no spray hose should be pulled up 70 - 90 degrees up. When using, we cannot directly use the hand to hold the outer surface of the cylinder or the metal connecting pipe, to prevent hand frostbite. When using carbon dioxide fire extinguisher, outdoor air should be selected for outdoor use. If used in indoor narrow space, after fire fighting, the operator should leave quickly to prevent suffocation.
There is a lifting ring on the upper part of the fire extinguisher and you can quickly pick up the fire. At this time, it should be noticed that the fire extinguisher should not be excessive tilt, and even cannot get sideways or upside down with, so as to avoid the mixing of the two agents in advance. When the ignition distance is about 10 meters, you can connect the cylinder upside down, and one hand grip ring, another hand hold the bottom of the barrel, let the jet is aimed at the burning object. In the fire of flammable liquid fire, if it's already flowing burning, spray the foam from far to the near, and let the foam completely covered the burning surface. If burning in a container, the inner wall of the container should be at the bubble, shoot the foam to the inner wall of the container, let the foam flow along the inner wall and gradually cover the surface of the fire. Avoid by all means direct injection to the liquid surface in order to avoid the impact due to the jet, but will break up or out of the burning liquid container, expand the scope of combustion. In the rescue of a solid material fire, the jet should be aimed at the most burning place. With the shortening of the effective spray distance, the user should gradually close to the combustion zone and eventually spray the foam on the burning object until it is extinguished. When using, the fire extinguisher should always remain in the inverted state, otherwise the injection will be interrupted.