Fire is a disaster that brings great material losses, harm to he alth, and sometimes human casu alties. It often happens that a big fire starts with a small fire that could not be eliminated in time. In order to extinguish the source of fire in time, not allowing the elements to break out, fire extinguishers were invented.
What is a fire extinguisher
A fire extinguisher is a primary technical fire extinguishing tool designed to eliminate a source of fire in the first minutes of its occurrence. As you know, oxygen is needed for combustion, and if this factor is eliminated, the fire will stop. The fire extinguisher has an insulating effect, preventing the access of oxygen to the burning substance. Foam is especially good at insulating properties, hence foam extinguishers are very effective.
What are fire extinguishers
According to the type of insulating substance, fire extinguishers are divided into:
- foam (chemical, air-mechanical);
- powder;
- gas (carbon dioxide,freon);
- water;
- combined.
According to the active substance supply system:
- Pressure is created by mixing chemical components.
- Pressure comes from a separate cylinder in the fire extinguisher.
- Pressure was pumped into the cylinder from the outside.
- Pressure is created by the active component itself.
By launcher type:
- with valve;
- with a pistol grip;
- with lever;
- with start associated with a constant pressure source.
By balloon volume:
- manual portable with cylinder capacity up to 5 liters;
- portable industrial with cylinder capacity from 5 to 10 liters;
- mobile and stationary with a cylinder volume of more than 10 liters.
The number of varieties is constantly increasing, as there is a modification of designs, changes in order to increase efficiency, improvement and creation of new fire extinguishers. Fire extinguishing agents are labeled using letters indicating the type and numbers indicating the volume.
Fire extinguisher OHP-10
It is proposed to consider this device in detail, because it has a wide scope. This tool can extinguish the fire of solid and liquid combustible substances with chemical foam. It is used to eliminate the initial fire, no larger than 1 square meter. Exceptions are: alloy"electron", metallic potassium, magnesium, sodium (because they form hydrogen when interacting with water from a fire extinguisher, which will intensify combustion) and some liquids - alcohol, acetone, carbon disulfide (because they tend to absorb water contained in the chemical composition of the fire extinguisher, and the foam collapses from this). Important warning: It is strictly forbidden to use this fire extinguisher to extinguish live installations, as the foam is a conductor of electricity and you can get an electric shock.
Deciphering the name of the fire extinguisher OHP-10 - a chemical foam fire extinguisher 10 liters, therefore, it belongs to a portable industrial.
Chemical composition
In the OHP-10 fire extinguisher, foam is formed by mixing water-acid and water-alkaline solutions.
Composition of chemical foam:
- Carbon dioxide - 80%.
- Water - 19.7%.
- Foaming substance - 0.3%.
Hull structure
It is proposed to consider in more detail the structure of the fire extinguisher OHP-10.
- Steel body, welded, in which there is an alkaline charge of a fire extinguisher in a volume of 8.5 liters. The alkaline part consists of an aqueous solution of sodium bicarbonate NaHCO3 - soda, with a small amount of foaming agent - licorice extract.
- A glass of polyethylene, fixed with a screw cap on the neck of the body, in which there is an acid charge of a fire extinguisher in a volume of 0.45 liters. The acid part consists of an aqueous solution of sulfuric acid H2SO4 and sulfuric oxideiron.
- Side handle for holding fire extinguisher while in use.
- Eccentric handle.
- Stem - attached to the handle with a pin.
- Cap mounted on the body mouth.
- Sprinkle - a jet will come out through it.
- The valve that closes the acid part.
The alkaline solution is filled into the cylinder body, and the acid solution is filled into the inner polyethylene cup located in the neck of the cylinder body. When both components of the charge are mixed, a chemical foam appears, which is a lot of small bubbles filled with carbon dioxide. The carbon dioxide formed as a result of a chemical reaction vigorously mixes, foams the alkaline part and throws it out through the shower into the external environment.
The rod rests against the middle of the rubber valve that closes the acid glass with the help of a spring. On the other hand, the stem is attached to the eccentric handle, passing through the hole in the cover. Slightly above the valve in the acid tank there are holes located along the radius through which acid can pour out during the opening of the plug. A hole was made in the neck of the cylinder body - a spray, covered with a thin membrane that prevents alkali from leaking out of the fire extinguisher, which breaks through at a pressure of 0.08-0.14 MPa. Foam will fly out through the spray when using the can.
How to use
The use of the OHP-10 fire extinguisher begins with cleaning the spray hole with a metal rod, sinceit can be clogged by turning the eccentric handle 1800 until it stops, relative to the pin connecting it to the stem. The movement of the eccentric lifts the stem and valve, thus forming a circular gap around the circumference of the acid glass. Then the balloon is turned upside down and shaken a little. At this moment, acid mixtures through a circular slot and holes located along the radius enter the neck of the OHP-10 fire extinguisher, where they are mixed with an alkaline charge. A chemical reaction takes place between acid and alkali, producing large amounts of carbon dioxide, water, and s alt. The reaction products under high pressure, formed during the mixing process, break out of the spray in the form of foam in a jet of 6-8 meters.
When you need to extinguish solid combustible materials, you should direct the jet away from yourself, at a burning object under the flame, at the epicenter of the fire. When it comes to putting out burning liquids that have spread over a flat surface, you need to start at the edge. This will prevent splashing of combustible substance, gradually flooding the entire burning area.
If it is necessary to extinguish a flammable liquid in small open vessels, a stream of foam should be directed onto the side of the vessel so that the foam, flowing down the side, gradually covers the burning liquid.
Remembering that sulfuric acid is present in the charge, great care must be taken when using a fire extinguisher. If the spray is clogged during the operation of the fire extinguishing agent, you need to clean it with a metal rod and shake it several times with force. If it failsto clean the spray, you need to put the defective cylinder in a place inaccessible to people, as there is a possibility of an explosion of the body before the gas is completely out of it.
Flaws
The disadvantages of the OHP-10 fire extinguisher are: limited temperature range of use - from +5 °С to +45 °С; strong corrosive activity of the components, in connection with this, the possibility of damage to the extinguishing object; the need to recharge the extinguishing agent once a year.
Technical characteristics of the fire extinguisher OHP-10
- Foam output - 43 liters.
- Cylinder volume - 10 liters.
- The volume of charging liquids is 8 liters.
- The length of the foam jet is 6-8 meters.
- Working pressure - 0.1 MPa.
- Duration - 60 seconds.
- The weight of the cylinder with charging liquids is 14.5 kg.
- The weight of the cylinder without charging liquids is 4, 5-5, 0 kg.
- Recharge cycle - 1 year.
Thus, it is clear that the characteristic of the OHP-10 fire extinguisher allows the use of this fire extinguishing agent in enterprises and in ordinary domestic conditions.
