The Principle Of Life Jacket
Life jackets are broadly divided into two types: inflatable life jackets and foam life jackets.
1. Foam life jacket refers to a fabric made of nylon cloth or neoprene, filled with buoyant material such as foam board in the middle, and has sufficient buoyancy on the body to make the head of the water drop out of the water surface. Generally, we use all kinds of marine life jackets. The interior uses EVA foam material, which is compressed by 3D and has a thickness of about 4 cm (a domestically produced 5-6 thin hair material and a thickness of about 5-7 cm). Life jackets produced according to standard specifications have their buoyancy standards: generally 7.5 kg / 24 hours for adults and 5 kg / 24 hours for children, in order to ensure that the water surface above the chest.
2. Inflatable life jackets are divided into two types: automatic inflatable life jackets and manual inflatable life jackets. These life jackets are made of high-strength waterproof materials. The inflatable life jackets are mainly made of sealed inflatable vest airbags, miniature high-pressure gas cylinders and fast. It is composed of an inflation valve and the like, and is often used in work that has the possibility of falling into the water. Under normal circumstances (not inflated), the entire inflatable life jacket is worn like a belt on the shoulder of a person. Due to its small size, it does not hinder people's freedom of operation; once it falls into the water, it is dangerous to encounter buoyancy in the water. At any time, or according to the action of water, the air is automatically inflated (automatic inflatable life jacket), or the person pulls the cable (manual inflatable life jacket) on the inflation valve, which can be inflated into a buoyancy of 8-15 kg in 5 seconds. The life jacket; the life jacket lifts up the body and exposes the head and shoulders to the water surface, so that it can be safely protected in time. Because the surface of the life jacket is made of water-resistant and breathable materials, in addition to paying attention to its buoyancy, it should be noted that it is absolutely necessary to avoid sharp objects from piercing or damaging the waterproof layer, which may cause unimaginable serious consequences after leaking. Inflatable life jackets should be checked for leaks before use.
How to use life jackets:
1. Foam life jacket wearing method:
1) Put the life jacket on the neck, put the rectangular buoyancy bag in front of the body, and fasten the strap of the neckline;
2), the left and right two straps are respectively passed through the buckle loops on the left and right sides, and are wound around the back;
3), then pass the strap through the buckle loop on the chest and hit the knot.
1) Some life jackets are only equipped with a life jacket with a reflective film on one side. If the reflective film is worn inside, it will not work.
2), the belt should be tied to death, so as not to be shocked or float for a long time to loosen when diving.
2, manual inflatable life jacket wearing method:
1), put the head into the life jacket;
2), tie the left and right straps to the knot;
3) Pull the cables on the left and right sides, the inflation valve opens, and the life jacket is inflated in a few seconds.
The manual inflatable life jacket on the aircraft also comes with a variety of equipment: the power supply for the azimuth indicator is activated by sea water, and the power supply time can exceed 12 hours; some also have whistle, mirror and so on.