1. When each fire extinguisher leaves the factory, the production date will be clearly marked on the tank, and a nameplate will be provided. The nameplate will generally indicate the production date, type, specification and validity period of the fire extinguisher. If you want to see if the fire extinguisher has expired, you only need to look at the expiration date on the fire extinguisher.
2. If it is a dry powder fire extinguisher, it needs to be inspected and maintained every two years after it leaves the factory for five years. The longest service life of dry powder fire extinguishers is 10 years from the factory date. Once this time is exceeded, the fire extinguisher will be regarded as expired and need to be sent to a special maintenance agency for scrapping.
The fire extinguisher will not only expire, but also fail. If you want to see whether the fire extinguisher is invalid, you can generally judge by looking at the pointer of the pressure gauge on the fire extinguisher. The pressure gauge of the fire extinguisher is generally divided into red, green and Huang San areas.
history
The first modern fire extinguisher was invented by George Manby of England in 18 16. The design at that time was to use a copper tank filled with compressed air and 3 gallons (about 7 liters) of potassium carbonate solution. Carbonic acid-sulfuric acid fire extinguishers have been used since the end of 19. The fire extinguishing agent contained in the container is mainly sodium bicarbonate (i.e. baking soda) solution, and sulfuric acid is contained in another small container.
When in use, the small container is broken, and the solution is pushed out by the pressure of carbon dioxide produced by mixing the two. By the middle of19th century, French doctor galil invented the portable chemical fire extinguisher. Mix sodium bicarbonate and water in a barrel, and put sulfuric acid in a glass bottle at the mouth of the barrel. When in use, the hammer breaks the bottle, so that the chemicals are mixed to produce carbon dioxide, which is discharged out of the barrel by water pressure.
1905, Professor Laurent of Russia invented a foam fire extinguishing agent in St. Petersburg. Aluminum sulfate is mixed with sodium bicarbonate solution, and stabilizer is added. Foam containing carbon dioxide produced after spraying floats on burning oil, paint or gasoline, which can effectively isolate oxygen and suffocate the flame.
1909, Davidson of new york obtained a patent. He used carbon dioxide to squeeze carbon tetrachloride out of a fire extinguisher, and this liquid immediately turned into a heavier nonflammable gas to extinguish the flame. Since then, small fire extinguishers such as dry powder fire extinguishers and liquid carbon dioxide fire extinguishers have appeared.