There are several types of gas cylinders: metal and composite (plastic). Each type has its advantages and disadvantages.
Metal gas cylinders. Still very widely used in use around the world. The Russian cylinders on the displacement are divided into 6, 12, 27 and 50 liters.
Advantages: low cost and wide distribution.
Disadvantages: severe, corrosive, inability to visually monitor the amount of gas, increased sparking during transportation
There are also aluminum cylinders from European manufacturers. They are significantly lighter, but three times more expensive than steel of similar size.
Composite (plastic cylinders). Distribution received not so long ago, but the popularity of this new type of cylinders every year becomes more and more.
Advantages: lightweight, non-corrosive, the ability to visually control the level of gas in the cylinder, a stylish and attractive appearance
Disadvantages: composite cylinder is 4-5 times more expensive than steel of the same size
At the moment there are several European manufacturers of composite cylinders, namely Ragasco LPG (Norway), Composite Scandinavia (cylinders of the Compolite CS and Passion series, Sweden) and Rugazko LLC (Russia). Ragasco Cylinders have 4 volume options (12.4, 18.2, 24.5 and 33.5 l.).
On October 13, 2014, LLC Rugazko decided to recall cylinders manufactured by Composites Scandinavia (Sweden) and Rugazko (Russia) produced between January 1, 2012 and October 13, 2014 and replaced by Ragasco cylinders. The reason for the recall was the incompatibility of the composition of the composite with the quality of Russian gas. The presence of methanol in the domestic gas detrimental to the walls of the cylinder, especially when used in conditions of high temperature. The above cylinders cannot be used with Russian gas, because It may harm your health.
Passion and Compolite CS to Ragasco safe cylinder replacement replacement scheme.
Why cylinders explode
The cylinders overwhelmingly explode due to the violation of storage and operation techniques, namely due to the critical increase in pressure inside the cylinder. When a cylinder enters the open flame, the liquid phase inside is boiled and the pressure in the cylinder increases. A threefold increase in pressure inside the cylinder relative to the norm leads to its rupture. At the same time, vapors from instantaneous ignition of the liquid are ignited, forming a "fireball". In open space, the fragments from the rupture of the balloon fly away in a radius of up to 250 m. The height of the fragments rise is up to 30 m.
Also, the cylinders explode when improper, uncontrolled refueling. It is necessary to fill a cylinder for 80% of its volume. Therefore, it is necessary to fill the cylinder not by its displacement, but by weight. For example, if you completely filled the cylinder in the winter in the cold, and then brought it into a warm room, the gas begins to heat up and expand. If the gas at this point has nowhere to go, it breaks the balloon.
How to protect yourself from the explosion of the cylinder
The Internet is replete with information that composite cylinders do not explode. This is true, but strained "behind the ears." They do not explode due not to their composite material, but to a valve with a special safety valve-insert. Such a safety valve relieves the overpressure of the gas in the cylinder with a gradual increase in temperature and, accordingly, pressure. The normal gas pressure in the cylinder should not exceed 1.6 MPa. The valve opening pressure is 2.6 MPa, while the critical pressure at which the cylinder may explode is 5.2-8.4 MPa. When finding a cylinder for more than 3-5 minutes at a temperature above 110 ° C, the fusible link is destroyed, gradually releasing the contents of the cylinder, excluding its explosion.
It should be noted that you can also put this valve with a fusible link on an ordinary metal container (European metal cylinders are equipped with such a valve).
The same there are valves with a float mechanism that prevents overfilling the cylinder. Here, the float-type protective mechanism cuts off the gas supply during the filling process when filling 80-85% of the cylinder volume.
Another important factor is the right mix of gases. In Europe, propane is used, the proportion of which in the mixture is 99% and its complete combustion is guaranteed to a temperature of -40 ° C. In Russia, to save money, they use a mixture of gases - propane and butane. The problem is that at 0 ° C, butane remains in a liquid form and does not evaporate. In the summer at gas stations, the gases are mixed in a ratio of 1: 1, while in winter it is 9: 1. If you fill the summer mixture in the winter, then propane will burn out, and the butane will remain in the tank in a liquid form. If after that you transfer the cylinder to heat, the butane will burn with a bright red flame with an unpleasant odor, unlike the blue flame, while burning propane.
Condensate. If you see or feel the presence in the cylinder of the liquid phase, but it does not burn - it is condensate. It is necessary to merge it and it is better to do it at specialized stations.
And of course you should not forget about the generally accepted safety rules when working with gas.